I studied parasitology for a module at University and I've always been a fan of Leucochloridium paradoxum. It's the beastie that makes zombie snails. It's one of the few things that gets shown on normal TV that I find genuinely disturbing.

There's also a variation on the ant parasite that makes it climb to the top of the grass so it's eaten by the sheep in which stage 2 of the lifecycle takes place.

And when you find out just how much influence over your health and wellbeing your gut flora have, you wonder just how much of our lives are actually our own and how much are controlled by the bacteria, viruses, etc. that use us as hosts.

Typo fix: Dracunculiasis

You may like this: Man Dies After Tapeworm Inside Him Gets Cancer

Original article: Malignant Transformation of Hymenolepis nana in a Human Host.

The Emerald Cockroach Wasp is pretty weird, it stings cockroaches in very specific ganglia in order to suppress the cockroach escape response. Now completely docile the cockroach will sit there whilst the wasp chews off a bit of each antenna and uses what is remaining as a lead to guide the cockroach back to the wasp's burrow. There it will lay eggs in the cockroach and burry it in. Escape response destroyed the cockroach will sit there until larva eat their way out of it.

Hmm...for some reason imagining this in the Laundryverse conjure up weird S&M images. Would anyone realise that the dominatrix leading the vacant man on a lead at pride was actually an extradimensional parasite rather than the usual partygoers?

Vanzetti beat me by a minute.

But, WTH. Here's another tapeworm link.

http://www.geek.com/science/a-man-has-died-of-cancer-contracted-from-his-tapeworm-1638807/

Dude, CHECK THE FUCKING LINKS.

Hint; you post a link to a pop-sci site; I post the abstract of the original paper. Which you then re-post.

I should just ignore you for time-wasting, shouldn't I?

You too.

READ THE FRIGGING LINKS IN THE OP before you contribute unnecessary duplicates.

Cymothoa exigua, the tongue-eating louse. From wikipedia:

https://en.wikipedia.org/wiki/Cymothoa_exigua

"C. exigua extracts blood through the claws on its front, causing the tongue to atrophy from lack of blood. The parasite then replaces the fish's tongue by attaching its own body to the muscles of the tongue stub. The fish is able to use the parasite just like a normal tongue."

Not many other species out there stinging others in the self-preservation.

And why S&M? There's a lot more people being led around on leashes elsewhere...

A note, not as a direct line of conversation but as part of the book-writing research process, that the Ophiocordyceps fungus you mentioned was directly (and explicitly) used as the basis of the "zombies" in the popular video game The Last of Us (2013), where a variant of the fungus migrated to humans and thus zombie apocalypse.

Parasitism is the one topic of biology that is guaranteed to get weird, fast. The problem is this: hosts and parasites tend to co-evolve with each other and over time actually come to depend on each other. Human ailments like Crohne's Disease are autoimmune dysfunctions that may be better termed "missing parasite/symbiont syndrome". Treating people suffering from this condition by infecting them with the larvae of parasitic worms that are not quite the right species to thrive, but are close enough to survive, causes the immune over-reaction to reduce somewhat, and the person gets better through having a parasite.

On the other hand, parasites can go the other way. Wollbachia bacteria are egg parasites of insects, and because only female insects lay eggs, these bacteria try to kill off males. However, evolution comes into play here because one male insect can mate with many, many females and thus there is a huge genetic advantage to being one of the few males in an almost all-female population. Wollbachia also has a problem: if it is too good at culling males, it goes extinct with its host.

DNA can be parasitic. Most viruses are single strand RNA in a protein coating; they never get into the cell nucleus but spend all their time either as mostly-inert biological bombs in the cell matrix, or as madly subverting RNA in the cytoplasm. Retroviruses are different; they are DNA viruses and possess a modified transcriptase enzyme that can turn RNA back into DNA.

Retroviruses can, and do get incorporated into DNA in the cell nucleus, thus once infected by HIV a person may never be free of it. Other, older retroviral DNA is present in the genomes of all life forms, and some of it plays a vital role in placental mammals.

Placental mammals differ from marsupials in that their embryos have a placenta attached. A placenta looks a lot like a controlled cancerous growth, and the genes controlling it look like heavily-modified retroviruses. A great step forwards evolutionarily might be down to a viral parasite.

In a similar vein, there are quite a lot of intracellular parasites such as Rickettsia bacteria and the like. There always have been, and some in eukaryotes have survived and become first symbiotes, then actual parts of a new organism. Mitochondria are one example; they have their own incomplete genome that looks quite bacterial in form. Chloroplasts are a similar sort of thing; parasites that became indispensable.

The one thing to remember here is that most parasites are very, very, VERY specialised indeed. Most have extremely specific habitat and species needs, and tend to go badly wrong if placed in the wrong sort of situation. They also have strange, weird life cycles that often make very little sense indeed and most cycle between a sexual reproductive phase in one host, and an asexual one in a very different host. Parasites like the parasitoid in "Aliens" are rare to nonexistant; this thing appears to be an extraordinarily non-specific predator, and not really a parasite at all.

Oh, and my specialist topic is the sex pheromones of plant parasitic nematodes; make of this what you please.

Oh, reading farther into the wikipedia article I see that this particular parasite has not escaped Charlie's notice.

Sorry for being an idiot. It happens. :-(

I know Charlie already knows about this, since I learned of it byway of his tweeting it: Different Brain Regions are Infected with Fungi in Alzheimer’s Disease

Lots of potential nastiness there. And anything he comes up with might be cause for worry. Partcularly after Cymothoa Exigua started showing up in supermarket fish not long after he used them in a book.

A recent (not at all hard science) fictional example from Metal Gear Solid 5 with ties to real-life parasites. Skip a bit if you care about semi-spoilers.

The main threat in the game comes from vocal cord parasites that colonize and mimic membranes in the vocal cords near-perfectly. The parasites remain dormant until they hear a specific language, at which point they breed like crazy and devour the host's lung alveoli. The result is slimy tumors on the chest and death. The villain trains parasites to specific languages for genocidal purposes.

The real-life tie in is that the treatment for non-symptomatic victims is specialized Wollbachia bacteria, as Dan H. mentioned. "Specialized" meaning might as well be fictional - these Wollbachia actually gender-swap all the male parasites to female, rather than straight killing them, preventing the parasites from breeding and killing the host. For some reason this also renders male patients infertile by damaging their sperm - no mention if that applies to female patients.

There are other bizarre parasites in the game, including some that colonize the skin and allow the host to engage in photosynthesis, even breathing for one host with irreparable lung damage. And there are some that turn target humans into puppets under the control of the parasite's initial host.

It also goes into metal-eating archaea, which are interesting for a whole host of different reasons. Extremophile uranium enrichment, anyone?

Particularly after Cymothoa Exigua started showing up in supermarket fish not long after he used them in a book.

I mean really; "Halting State moments" are one thing, but "Laundry moments"?

I'll go get the popcorn and try not to hide behind the table as some of the nastier examples get trotted out.

May I suggest sacculina? Charlie, if it was in the links and I missed it, I'm sorry.

https://en.wikipedia.org/w/index.php?title=Sacculina&oldid=580448176

Now, what could parasitize that? A crab that consumes the barnacle? Or just the eggs? I mean, what could see in advantage in suborning the sacculina's abilities for its own?

Might be BORING & supposedly well-known but what about good old Malaria? Requires two or is it three hosts to go round a cycle completely? Any others that have multi-stage hostings? ( i.e >2 ?? )

Uranium enrichment can't be carried out biologically as U-235 and U-238 are chemically identical so biological processes treat both isotopes the same.

Cymothoa exigua, the tongue-eating louse.

YOU HAVEN'T BEEN READING MY BOOKS, HAVE YOU?

C'mon, people! This is a research Q! I'm looking for stuff I haven't heard of, or at least didn't put a link to in the OP! Not stuff I used in The Apocalypse Codex or Equoid!

May not necessarily be true in principle. Diffusion processes can be used for isotope separation.

I do agree it would probably be useless in practice.

@Greg:

I like malaria, as it implies some sort of moderately nasty parasite as a vector. Survive an initial attack, win something worse as a bonus prize.

This may not be what you're looking for (because it's mostly social parasitism, of which we find multiple variants in our own species), but parasitic ants are absolutely fascinating. Some of them steal larvae and pupae from other ant-species, then use the emerged adults as slave-workers in their own nests (some of these slaves even get to take part in subsequent raids on their own species). Others take this further by installing a queen of their own in the prey nest (the parasitic queens suck juices from the original ones to smell convincing). Yet others set up shop inside prey colonies and steal their host's food. And then there are the "guests with benefits" that usurp a colony, feast on its fungus fields and original inhabitants, but also produce lots of specialised armed workers which then defend the colony against attacks by a bigger and more aggressive warrior-species.
Also, I think you've met Peter Watts (Canadian author of "Blindsight" and the Rifters trilogy)? He writes and thinks about parasites quite a bit, so having a chat with him the next time you get a chance could be interesting for both of you.

"Laundry Moments" are a Real Thing. The Laundry seems determined to exist in a parallel universe, thankfully: that's the only reason I can think of why Osama bin Laden and Al Qaida managed to take down the Twin Towers between me submitting the original "The Atrocity Archive" for publication and the copy editor forcing me to find someone more obscure for a bad guy in Santa Cruz, or why ACPO was abolished right after the copy edit phase of "The Annihilation Score".

Yes, I brainstormed the equoid life cycle with him over a beer ...

Ribeiroia trematodes have 3; I'm pretty sure I've heard of a few more with 3, but can't off the top of my head remember any with 4.

Right, I'd forgotten about those bits. So long as it stays in its parallel universe.

Surely the leakage is going to become more serious as time goes on. Inconvenient news stories 15 years ago, supermarket fish today and Shoggoths kicking* your door in by christmas.

*dissolving.

I forgot to mention that the Dracunculiasis link goes to the previous Pinworm link.

Cut'n'paste error; now fixed. (When you said "typo" I thought you meant a spelling error.)

That's the sad thing, Charlie. I have read all the published Laundry novels. I even remember the relevant sub-plot -- now.

I also like viral pathogens that infect fungal pathogens. Like:

http://link.springer.com/article/10.1007/s00705-014-1992-8/fulltext.html

Phomopsis longicolla is fungal pathogen of soybeans. As such its transcriptome is sometimes sequenced. The case above revealed the fungus was infected with a novel hypovirus.

But maybe that is just one of the common tropes of biology: "parasites all the way down".

I like JamesP's reference to Alzheimer's and fungal parasites. I work in Elder Law and have a lot of experience dealing with people with dementia. I've always thought they could be fodder for horror writing. For example, what if a parasite sought out and occupied the bodies of people who's minds were vacated due to dementia?

I seem to remember a Larry Niven short story, whereby a society which used formalised war had a slight problem with a local plant form. This plant would, on encountering any deceased animal, infect it and jumpstart the neuromuscular system and get the formerly dead body moving about for a while, to try to infect more living animals with the same contagion.

This only happened during the night; as soon as day broke, each ambulatory body would simply collapse into a pile of convenient fertilizer for the now-sessile semi-parasitic plant, which would immediately flower (such being the stored energy of a dead body).

Diffusion works with UF6 at pressures of hundreds of bar with daisy-chained chambers separated by gas-permeable sintered ceramic plates. It's a big and energy-hungry process. The Oak Ridge diffusion line built for the Manhattan Project was the largest single building on the planet when it was completed and it was built in Tennessee because it had a lot of power generating capacity and cooling water thanks to the TVA. There's a reason everyone uses centrifuges today; even though they're also energy hogs they're a magnitude less effort to build and run than a diffusion line.

Good luck replicating a diffusion line (or a centrifuge) in a biological process.

Now a biological entity that can handle elemental fluorine would be something to see (preferably from a long distance away).

Sorry, I forgot to mention that I was allowing it to take several million years.

As for biological entities capable of handling fluorine, I think we may actually be approaching the topic of parasites again. I'm thinking Alien.

Good luck replicating a diffusion line (or a centrifuge) in a biological process.

Actually, that sort of trick happens a lot in biology. The trick lies in enzymatic catalysis. We tend to use high pressure and temperatures to drive reactions because we can engineer around the equilibrium gradients using lumps of metal and lots of energy; plants and animals get similar outputs using vastly less energy but some incredibly complex (not to say brain-mangling) chemistry running close to room temperature. Compare the efficiency of cracking cellulose to produce methanol or ethanol using heat vs. what yeast gets up to, by way of a trivial example.

Contrary to what everyone might think, it appears that the parasitic brain eating amoebas don't actually eat the brain. They merely pollute it enough to trigger an immune system overkill. (https://www.ncbi.nlm.nih.gov/pubmed/25930186?dopt=Abstract) They do come in a variety of fun shapes for the entire family to enjoy... (https://en.wikipedia.org/wiki/Naegleria_fowleri#/media/File:Naegleria_fowleri_lifecycle_stages.JPG)

Yeah, the origin of the placenta is a great "man bites dog" (man bites parasite?) story.

Another example of the host co-opting the machinery of one of its parasites, is the RAG1 protein that catalyzes V(D)J recombination--the basis of the adaptive immune system. This protein apparently derives from a DNA transposable element. See:

http://journals.plos.org/plosbiology/article?id=10.1371/journal.pbio.0030181

Here's a recent article: Meet the Parasites That Control Human Brains

Some already mentioned along with some others. Amoeba Naegleria fowleri sounds nasty.

When you said "typo" I thought you meant a spelling error.

Nah, I copied&pasted your spelling.

Re: N. fowleri And then I go and catch up on the comments...

Sorry, my bad, should have said "link error".

An interesting one is Polysphincta gutfreundi. This is a wasp whose larva feed off of its host, the orb-weaving spider Allocyclosa bifurca, and cause the spider to build a highly modified, physically stable orb web, to which the larva then attaches its pupal cocoon.

Night on Mispec Moor

Chemistry doesn't have any way of differentiating isotopes of the same chemical (except for heavy water which is a special case due the the exaggerated differential in mass and size of the isotopes of hydrogen).

Are there any biological systems that can handle a differential of a couple of hundred atmospheres? I think gaseous diffusion enrichment worked at high temperatures to improve performance and throughput, a thousand deg C or so which is another strike against the concept.

There are some interesting developments in laser/maser excitation that could result in a resurgence of diffusion as a viable enrichment technology but again as far as I know there are no laser emitters in the biological world. The fun part is that laser excitation should make extracting weapons-grade Pu239 from spent PWR fuel achievable even on a small scale. Something to look forward to, hey?

Hmmm. In ants, most of the social parasites are mimic ant larvae, and are treated by the ant species they parasitize as their offspring. This condition presumably evolved because the ants themselves selected the larva-mimics that most perfectly mimicked their own offspring, and killed the rest. The point is that parasitism is an evolving relationship, even though in horror books its portrayed as a sudden, alien affliction.

There's a parallel in humans: our pets. How often do you see pet owners referred to as "pet parents," or see bumper stickers that say "my (grand)child has paws?"

Now I'm not going to say that pets don't provide a lot of emotional support to humans, but in terms of nutrient transfer (one conventional means of measuring parasitism--whether there's a reciprocal mutualism where each party contributes somemething asurable to the other in a relationship), our pets tend to look just like the social parasites of ants, including the ants that parasitize other ants.

This is especially true when pets have kept humans from reproducing, taking the place of their offspring (fur-kids).

This is something we miss about social parasites: we tend to focus on the horror, but I've come to suspect that in most cases parasitism is anything but horrific. The best parasites are, instead, extremely charismatic and (in the hosts' opinion) fully deserving of their support and care. This, incidentally, includes vehement and sometimes violent attacks on those who call their pets parasites.

I can also to suspect that human hierarchies, especially where charismatic bosses are fully supported by their underlings, are parasitic relationships at least in the nutrient sense, but that's another story...

Dinocampus coccinellae. Strategy: lay an egg in a big bad predator (usually the female). When the egg hatches the larva eats the host's eggs, then goes after gonads and stored fat. When the larva's ready to pupate it paralyses the host, tunnels out of its body, then constructs its cocoon underneath its still-living body, whose warning markings (and occasional twitches) reduce predation. After metamorphosis fly off and repeat the cycle, leaving the victim about a 1 in 4 chance of recovering (and suffering lifelong PTSD, presumably).

Luckily for us they target ladybirds, not mammals.

Chemistry doesn't have any way of differentiating isotopes of the same chemical (except for heavy water which is a special case due the the exaggerated differential in mass and size of the isotopes of hydrogen).

Counterpoint: biochemical reactions discriminate between ¹³C and ¹²C.

Fluorine ecologies turn up in SF from time to time, but are generally shown as totally incompatible with Oxygen ecologies.

Offhand there is H. Beam Piper's Niflheim, in the prologue to Uller Uprising and the Inheritors in GURPS Traveller Alien Races 3.

Oh well, if you want boring old mushrooms parasitizing trees, there's the humongous fungus (pdf link). These fungi, things like Armillaria ostoyae/solidipes, are both far larger and far older than the trees they parasitize. The relationship works because Armillarias, in general, are more wood rotters than tree killers. Over time they'll kill a tree, but a sapling can grow to stunted maturity if it has the misfortune to sprout within reach of their mycelia.

Actually, the Nuytsia floribunda Christmas tree mentioned above does something similar, as it's a tree-sized Australian mistletoe that tends to parasitize the herbs and shrubs around it. Mistletoes use structures called haustoria (think hypodermic needle, sometimes accompanied by a clamp) to penetrate the bodies of their host plants, from which they suck nutrients. Nuytsia's haustoria are on its roots, and it can attack a number of other plants, including carrots. IIRC, an Australian telecom company had problems when Nuytsia trees clamped their haustoria around underground telephone lines and severed them. The company solved the problem by increasing the diameter of the cables to wider than Nuytsia could manage to wrap around. Sometimes there is a simple engineering solution to a complex parasitic problem. Digging outhouse holes at least six feet deep is another example of this, but as they say, that's another story.

Sorry, my bad, should have said "link error".

And I missed your earlier comment. I should just go back to bed.

Fromm Mark and Diana McMenamin's Hypersea, there's a purported example of at least a fifth level hyperparasite: The H5 hyperparasitic wasp parasitizes an H4 hyperparasitic wasp, which in turn parasitizes the H3 hyperparasitic wasp, which in turn parasitizes the H2 parasitoid wasp, which in turn parasitizes the host insect. Whether the host insect survives depends on which of the hyperparasites reaches maturity first. Unfortunately, they don't provide a direct link to the paper, so I don't know what the host is.

Actually, you could probably plot a novel around this kind of hyperparasitic cascade, not with the humans as the host for the parasites, but with an organization as the host to conspiracies within conspiracies, and the organization (perhaps a bank?) survives or not, depending on which conspiracy reaches fruition first.

There are at least two ways of separating isotopes (at least in theory) that aren't direct functions of isotopic mass: Nuclear spin, and electron excitation. For the first, you need two isotopes that differ in spin (like 12C and 13C); you need to couple the nuclear spin to an electron spin in, say, a diradical, and cause the latter to collapse to a chemically different state. For the second, you need an exquisitely tuned laser to excite an electronic transition in one isotope but not the other (this can actually be done).

I don't suppose biological organisms are likely to be able to take advantage of either.

Okay, very well-known as a human parasite but this bit is really interesting.

'The human body louse, its primary endosymbiont, and the bacterial pathogens that it vectors all possess genomes reduced in size compared with their free-living close relatives.'

IIRC, the mitochondria was initially a parasite. So the human body louse could be an example of typical on-going co-evolution that humans are simply too blind to see - literally. (Ever wondered why human vision stops at the scale larger than where most parasites can be seen?) Anyways, my imaginary progression of this evolution is: organisms diverge, develop new capabilities/evolve, then at some point re-merge first as parasites, then graduate into a symbiotic arrangement, until finally, they re-absorb each other.

http://www.pnas.org/content/107/27/12168.full?linkType=FULL&resid=107/27/12168&journalCode=pnas

Genome sequences of the human body louse and its primary endosymbiont provide insights into the permanent parasitic lifestyle

Abstract

As an obligatory parasite of humans, the body louse (Pediculus humanus humanus) is an important vector for human diseases, including epidemic typhus, relapsing fever, and trench fever. Here, we present genome sequences of the body louse and its primary bacterial endosymbiont Candidatus Riesia pediculicola. The body louse has the smallest known insect genome, spanning 108 Mb. Despite its status as an obligate parasite, it retains a remarkably complete basal insect repertoire of 10,773 protein-coding genes and 57 microRNAs. Representing hemimetabolous insects, the genome of the body louse thus provides a reference for studies of holometabolous insects. Compared with other insect genomes, the body louse genome contains significantly fewer genes associated with environmental sensing and response, including odorant and gustatory receptors and detoxifying enzymes. The unique architecture of the 18 minicircular mitochondrial chromosomes of the body louse may be linked to the loss of the gene encoding the mitochondrial single-stranded DNA binding protein. The genome of the obligatory louse endosymbiont Candidatus Riesia pediculicola encodes less than 600 genes on a short, linear chromosome and a circular plasmid. The plasmid harbors a unique arrangement of genes required for the synthesis of pantothenate, an essential vitamin deficient in the louse diet. The human body louse, its primary endosymbiont, and the bacterial pathogens that it vectors all possess genomes reduced in size compared with their free-living close relatives. Thus, the body louse genome project offers unique information and tools to use in advancing understanding of coevolution among vectors, symbionts, and pathogens.

Mistletoe, a parasitic plant, fits quite nicely with Laundryverse, as in Druids, Christmas and all that. (Used as probes into this universe?)

Chemistry doesn't have any way of differentiating isotopes of the same chemical (except for heavy water which is a special case due the the exaggerated differential in mass and size of the isotopes of hydrogen).

There is a lesser known mass-independent magnetic isotope effect in radical reactions in addition to the kinetic isotope effect you are talking about. The uranium 238/235 isotopes are among those that exhibit the effect.

Unusual Uranium Isotope Effect Induced by Photolysis of Uranyl Salts in Micelles

An unusual uranium isotope distribution between the products of uranyl photolysis, in contrast to that predicted by the classical isotope effect, has been observed and is attributed to the magnetic isotope effect.

Light-driven reactions in micelles are about the best you could hope for if you wanted to handwave a biological uranium-enricher.

First reading about this effect some years ago I was amazed. It seems a bit of chemical wonder that would attract more attention. Why is the literature still so sparse? My guesses:

1) Many early researchers are/were from Russia or the USSR, thereby tainting the field for Westerners who think "polywater, right?" when interesting discoveries come from that part of the world. 2) Unlike the kinetic isotope effect, nobody has industrialized and it's not needed (so far) to explain unusual isotope distributions found in nature. 3) If it were industrialized, it would be interesting mostly for its application to heavy nuclear elements. 4) For Western funders, a novel isotope enrichment process that has a completely different signature and is perhaps more efficient for heavy elements is thoroughly "do not want." The gas centrifuge is already vexing enough.

Another laser isotope separation method

You know, for being so young and primitive, artificial life already has some highly fascinating living going on. Lemme tell you a war story:

A friend of mine used to scan hosts that sent him spam since these tend to be part of botnets and found a webshell on one (for those unfamiliar with this: it's like a terminal, only that you use your webbrowser to enter commands). We played around with it[1], took a look at the source to see how it was controlled and how it spread[2]. It was controlled over IRC but the surprising part was: There was no trace of any code that would install the webshell we had used to enter, in fact it spread by googling for the webshell. How had that gotten there in the first place? Placed there by some other botnet that scanned for a specific jboss version and exploited it to install the shell. No trace of it being active though. So our little botnet was a parasite, and that made the two of us exploiting it second order parasites. And in what is another story, we later found the host botnet again in a totally different context.

[1]: The bot had somehow gotten cancer and filled up the directory with 35000 copies of itself in one instance. Deleting those was a fun exercise since the webshell didn't support globs. [2]: incidentally, it was a Perlbot, which seems to account for 80% of the skiddie botnets you usually find. Every version you see is slightly different and I can't even rule out whether its phylogenetic tree-err graph has loops...

Here's an episode of the show Radiolab on Parasites, maybe worth a listen if you can or have the time. I haven't re-listened to it, so I'm not sure if this has the story of the guy with a parasitic wasp he let grow in his forehead. And here's a little extra they put up: The Parasite Hit List

Oh and, remember the living computer viruses in Peter Watts' Starfish trilogy? Given the way artificial life in those novels evolves, those should be absolutely ridden with parasites but they aren't, as far as I can recall. Missed opportunity considering Watts wrote it.

And what about the many-angled ones having parasites? There could be metavampires serving as organs to vampires, possibly providing part of their powers.

And for a biological example, consider the fig wasp that started as a parasite and became, in essence, tree sperm: https://en.wikipedia.org/wiki/Fig_wasp#Life_cycle

A sickly, pale, mutant feeding off its relatives' lifeblood. I am, of course, talking about Redwood trees: https://en.wikipedia.org/wiki/Albino_redwood

Okay it wasn't a wasp larvae in his forehead, but a botfly larvae in his scalp. Still: Nope, no way. Glad Somebody likes Bugs

I was going to mention https://en.wikipedia.org/wiki/Toxoplasma_gondii but it's one of the parasites covered in that article you link to. A protozoan found in cat feces, and thus spread wherever particles of cat feces get in the air. Makes the rat victim reckless, so it takes chances and is easy for the cat to catch. Makes the human victim reckless also, so cat owners are statistically more likely to be involved in automobile accidents and have a generally less cautious approach to life. There was a rash of articles about it a few months ago in all the news sources like it had just been discovered.

In the spirit of tapeworm cancer:

Canine transmissible venereal tumor began life as a cancer afflicting some unfortunate canid millennia ago. Through some freakish mutation, it failed to die with its host and is now effectively an independent species, which looks and acts like cancer but can hop between hosts on contact, has its own DNA and is "believed to be the longest continually propagated cell lineage in the world".

And Toxo is the most widespread parasite worldwide ... clear evidence that cats (via their parasites*) are indeed planning to take over the world.

• Is there any reason why a sufficiently intelligent organism couldn't manufacture a 'parasite' to do its bidding/missionary work? Don't recall ever hearing/reading about parasites being beneficial, but there's no reason why they mightn't be.

Is there any reason why a sufficiently intelligent organism couldn't manufacture a 'parasite' to do its bidding/missionary work?

Sigh.

You just wait for THE DELIRIUM BRIEF (not next June's launch -- THE NIGHTMARE STACKS -- but the one after).

Morgellons is a delusion about skin infestation.

(There's a whole diagnostic category for "delusional infestation"; Mogrellons is a sub-category of it.)

In a Laundry context, with CASE NIGHTMARE GREEN progressing, I'd have to think Morgellons would turn real, inexplicable, and hideous very fast. (Morgellons sufferers have highly unfortunate expectations about what's really going on. Combine that with the stars coming right and ick.)

Not only are there actual infestations ("Nasopharyngeal Myiasis", ick) there are also really well-evolved parasites that likely don't cause problems. ("face mites" as a category.) Of course, having eight legs, face mites are technically face spiders....

That's a matter of definition. IIRC, an organism that derives benefit from a host which also derives benefit from the relationship is (by definition) not a parasite but a symbiont.

Of course, the relationship doesn't have to be symmetrical.

Charlie, you may be able to do something with this: It is thought by many in the field that some of the bizarre changes in female metabolism while pregnant are the result of an evolutionary arms race between the foetus and the mother. A foetus secretes all manner of chemicals whose function is to grab as much nutrition as possible from the mother's blood; and the mother's metabolism changes to correct the balance.

Naturally, a foetus that is too successful at sequestering maternal resources is probably going to die as a result.

Now; think of a tailored virus that makes the foetus much better at grabbing maternal resources - enough better that pregnancy kills both. Hmmm...

Some parasitic wasps have domesticated a virus (incorporated the virus genome in their own nuclear genome) and use that virus to know out the immune system of caterpillars. Which is really cool. I wanted to give you a link to read more about this, and found this recent story: http://www.theatlantic.com/science/archive/2015/09/parasitic-wasps-genetically-engineer-caterpillars-domesticated-viruses/405874/ It seems that the virus sometimes are incorporated into other hosts where it has changed so it protects the host against parasitism.

The comment on specific parasites makes me wonder how many of them are misplaced symbiotic life forms failing to adapt.

Like e-coli strains. Common enough in everyone's digestive system. Plays an important helper role in digesting.

Occasionally the strain mutates, or one from another life form gets introduced and proceeds interact badly with the environment.

Heck can a cognitive parasite originate from a symbiotic parasite? Or is there another dimension where the V-parasites are from where they're more adapted for long term mutual benefit in humans.

Myiasis ... that's not too far from what I have planned for THE DELIRIUM BRIEF. (I believe you are privy to the closed discussion where plans are aired ...)

That sounds kind of like Tasmanian Devil facial tumor disease, described as a parasitic cancer, which hopefully won't lead to extinction of the species.

Note to self: follow links before commenting.

Yea! ... But ... but ... that's almost two years (sigh).

"Or is there another dimension where the V-parasites are from where they're more adapted for long term mutual benefit in humans." What if that's how humans became conscious in the first place? An extradimensional infestation by those "souls" as they call them? No wonder Blindsight's aliens were grossed out by us.

Case nightmare green is just a bucket of disinfectant.

Charlie, I'm sure you know Thomas Ray's Tierra program, but for anyone who doesn't, I'll summarise. It ran a virtual world which was a simulated computer memory in which lived creatures that were strings of machine code and that reproduced by copying themselves. What's relevant to the current topic is that the creatures lived in a time-sharing system and faced selection pressure to make as many copies as possible in the time available. Tierra subjected them to frequent mutation by randomly flipping bits in their machine code. Ray found that evolution was rapid and that:

From a single ancestral “creature” there have evolved tens of thousands of self-replicating genotypes of hundreds of genome size classes. Parasites evolved, then creatures that were immune to parasites, and then parasites that could circumvent the immunity. Hyper-parasites evolved which subvert parasites to their own reproduction and drive them to extinction. The resulting genetically uniform communities evolve sociality in the sense of creatures that can only reproduce in cooperative aggregations, and these aggregations are then invaded by cheating hyper-hyper-parasites.

That's from the abstract of Thomas S. Ray, "Evolution, Ecology and Optimization of Digital Organisms", Report # 92-08-942 of the Santa Fe Institute, 1992.

The machine code was specially designed to be evolvable, so that mutations (which happened often) would have a chance of running. Unlike real machine codes. Ray achieved this partly by making the number of instructions small (about the same size as the genetic code), and partly by a unique addressing mechanism used for jumps and for accessing data. He called this "address by template" and based it on the lock-and-key binding of one molecule's active region to a complementary region on another molecule. In a jump, for example, rather than specify an address, you specify a sequence of bits. The jump searches for the nearest complementary pattern of bits, jumps to it if found, and does nothing otherwise. I've always felt that this idea has been much under-explored.

Another thing that fascinated me about the program was that creatures evolved to optimise themselves. Computer scientists know that you can make loops faster by "unrolling" them, replacing "do A three times" by "do A, do A, do A". The latter is faster because the instructions that test the number of cycles no longer have to be run. Well, Ray's original creatures copied themselves by executing a loop that copied every instruction in their body into a new location. And some Tierrans actually did evolve unrolled versions of this loop! I'll declare an interest here: I once wrote a Guardian article which the editor titled "Unrolling the Loop in the Primordial Soup".

Ray's home page and bio are at http://life.ou.edu. Amongst other things on it is A Proposal to Create a Network-Wide Biodiversity Reserve for Digital Organisms. Plenty of scope for weird parasite phenomena there.

Another transmissible tumor afflicts a type of clam. See:

http://www.twiv.tv/2015/05/17/twiv-337/

Note the retrovirus mentioned here is not the method by which the tumor spreads to other clams.

I am trying to remember who it was who wrote the SF story where there are no male human beings, only female human beings, some of whom are afflicted with a large partially external parasite that uses them to transport it around so it can inject its offspring into other human beings . . . I think maybe John Varley? You have probably read it, but if not it may be of passing interest as an example of what another SF writer did with the topic. Then there was Octavia Butler's Blood Child, about aliens who use humans as carriers for their offspring. You know, there seems to be something of a theme here about parasitism as an image of human sexuality and reproduction.

Hmm, well I think the body horror parasite trope has been done to death over the years - though comparatively more rarely on the positive symbiote end of things. You can conceive of a parasite/symbiote that makes the infected more intelligent, more ruthless, more good looking, etc. as a way to make them more successfully and likely to breed, passing on the symbiote. Psychopathy as a parasite infection? You obviously have religion in that role too (quiverful).

You've also had the "life itself is a parasite of planets" trope repeated quite often - though not the similar one of stars having parasites. That would seem to make more sense.

And finally you have the memetic/virus concept of ideas and data already mentioned - although no one has referenced biology adapting to leach power from circuits directly (literal bugs in the machine).

Are there other, weirder, ideas? Well how about concrete parasites to go with concrete cancer - catalysing and feeding off the biochemical reactions between rebars and calcium to bring down buildings and spreading spores in the clouds of dust from the collapse? How much concrete is there around?

Cell line infections are really weird. Here's a good article about them:

https://westhunt.wordpress.com/2015/04/09/cell-line-infections-or-my-dog-has-no-bones/

Your tapeworm encysting in the brains example reminds me of brain-eating amoeba (Naegleria Fowleri). Naegleria Floweri can be found worldwide in warm lakes, ponds, puddles, slow-flowing low streams, untreated swimming pools, etc.

While clearing my nose in the morning shower I sometimes wonder about brain-eating amoeba.

Probably "Manikins" by John Varley. One of the scariest stories I read, up there with "The Screwfly Solution".

Another possibly good parasite SF story is "The Giving Plague" by David Brin, about a disease that makes giving blood feel good. Which often causes people to be more altruistic in general.

"Dark Benediction" Walter M Miller Jr featured a an alien parasite that improved fitness by giving peoples senses an upgrade.

It also caused worldwide panic because it was highly visible, spread by touch and tweaked peoples brains so it felt good to infect people.

The best parasites are, instead, extremely charismatic and (in the hosts' opinion) fully deserving of their support and care. This, incidentally, includes vehement and sometimes violent attacks on those who call their pets parasites.

John Wyndham did it in Midwich...

Cut out the middleman, and run with the selfish gene; no-one's mentioned "children as parasites on their adult hosts", particularly from the perspective of the non-breeder.

Babies are charismatic (to their parents), who singularly fail to note how unpretty they are. They trigger the most extreme sacrificial urges in the host; and demand high levels of attentional focus.

Of course, as a parent, I am guilty of all of the above, love my children to bits, and apologise to the uninfected on behalf of all of us. We are shortly to enter the chrysalid phase with our oldest, as puberty beckons - feel for us :(

Since this is a topic that's in my new book, let me straighten it out.

Symbiosis is the overarching category. Per Paracer and Ahmadjian (2000) Symbiosis: An Introduction to Biological Associations, 2nd Edition), a symbiosis is a relationship between two organisms. A symbiosis doesn't have to be permanent, the organisms do not have to be inseparable, the relationship does not have to be positive or negative for any partner, and it can vary over time and space and among partnerships.

Under symbiosis, there are categories. I'll use the conventional idea of a relationship between two organisms, but it can be expanded ad nauseum: --Mutualism: Both partners benefit --Predators, Parasites, Pathogens, and Parasitoids (aka exploiters). One partner benefits at the other's expense. In predation, one partner kills and eats the other. In parasitism, one partner benefits at the other's expense without directly killing it and/or eating it. If one partner in a parasitic relationship is a bacterium or virus, that partner is a pathogen on the other (multicellular parasites get labeled as parasites). If the host being exploited is an insect, the other partner (a wasp or fly) lays and egg (or eggs) in it, and the larva(e) eats the host alive and bursts out of it, Alien-style, that's a parasitoid (halfway between parasite and predator. Hyperparasites are parasites that parasitize other parasites. There's no overarching term for these relationships, but I like to call them exploitative relationships. --Commensal: One partner benefits, but the other partner is neither helped nor hurt. Dust mites in human houses are an example of this, but there are many others. Scavenging on others' kills is the classic example, and there's a whole decomposing ecosystem based on these relationships. --Amensal: One partner is harmed, and the other is neither helped nor hurt. Many instances of resource competition are amensal relationships. If a tree overshadows another tree and kills it, the first tree may not notice that it is killing its neighbor. If a human runs over a squirrel, the human isn't hurt. If humans overfish an area and cause all the non-human predators on the fish to starve, that's an amensal relationship. --Synnecrosis: both partners are harmed by the relationship. Many exotic diseases fall into this category, and do human-on-human wars of attrition. The term synnecrosis isn't widely used, but it really should be.

One thing you'll find is that every single idiot symbiosis researcher (and I used to be one, so I'm allowed to say this) has their own definition, and they'll write whole books saying why their definition is right and everyone else is wrong, wrong, wrong. There's also more than a little Cold War politics in this mess too, but that's another story. The definitions I've provided above are probably the most useful, because they can be used as a framework to understand any relationship between organisms.

Note, please, that relationships do vary over time and space. There are well-documented cases where two species (such as a flower and the moth species that pollinates it) are mutualists in some areas, while the moth parasitizes the plant in others. This is part of the geographic mosaic theory of coevolution (by John N. Thompson), which is a really powerful theory. It's also worth realizing that relationships are complex, so you can study relationships in terms of nutrients, safety, evolutionary fitness, and so forth.

Here endeth the sermon.

I was coincidently watching QI today and they mentioned brood parasites. It reminded me of changeling stories.

One of my favorites from a while-back parasitology class was the Pomphorhynchus laevis worm. The whole genus uses arthropods as intermediate hosts and lives out its reproductive life in the guts of vertebrates. P. laevis spends its youth inside the body cavity of freshwater amphipods, and its terminal hosts are generally perch. The infected amphipods have an inverted photophobic response- whereas the healthy crustaceans will hide in the darkest nooks of a tank, their hotwired siblings will bask in the light- and will move in the brightest direction if startled. This naturally makes them more visible prey for the fish whose guts they will, in turn, wreck- visibility further enhanced by the parasite increasing the production of haemocyanin, the oxygen carrier in most arthropods, which makes them bright red.

And to top it off, it seems that it does another reflex inversion. Plenty of creatures seem to exhibit a flight response to the stink of their own dead- sharks and lampreys spring to mind. Infected amphipods are instead drawn to the stink of their slain cousins emanating from the intestines of the aforementioned perch.

Dammit, you beat me to bringing up vampire trees. Well, here's two more links:

http://blogs.discovermagazine.com/discoblog/2010/12/08/a-creepy-monster-of-the-forest-the-albino-vampiric-redwood-tree/

http://news.nationalgeographic.com/news/2014/03/140319-redwood-albino-chimera-california-tree-tallest/

The latter is about a chimeric redwood that is only half albino. It's also a hermaphrodite.

Olaf Stapledon had stars infested with parasites in Star Maker, back around 1930, I think. Of course Stapledon was one of early SF's greatest idea sources.

Good to know. Is it possible for them to oxidize metal enough to cause rapid rusting?

Microchimerism: https://en.wikipedia.org/wiki/Microchimerism#Human

Cells can pass in both directions across the placenta, from child to mother, and mother to child, and then persist for decades.

When your mother says "I will always be with you" it's literally true - you probably have a few of her cells tucked away in out of the way pockets of your circulatory system.

And she's got some of your cells too, along with those of your siblings.

Who knows what Eeeeevil artificially-installed RNA-bits could be lurking within the DNA of every living thing that has evolved since the last time The Stars Were Right? And how those bits may have strayed, on a species-by-species basis, since The Stars Went Wrong, and those bits were...no longer relevant to current conditions.

Or, for that matter, what non-evil bits that arose in response to the Things From Beyond, have similarly drifted off-message.

</sinister music>

Hmm, well I think the body horror parasite trope has been done to death over the years - though comparatively more rarely on the positive symbiote end of things.

See Algis Budrys's "Silent Brother" and Hal Clement's Needle.

Kingsley Amis wrote about "Silent Brother" in his 1960 survey of science fiction New Maps of Hell:

[...] 'Silent Brother', which inverts a common theme of horrific science fiction. The hero finds an alien intelligence living symbiotically in his own body and mind. The alien benefits by locomotion and the power to manipulate; the human being has his missing teeth grown back for him — the physical aspect is again indispensable — and experiences the sense of a 'gentle, intelligent being within him' giving him 'sanity and rest, tranquillity and peace', seeing to it that 'age is calm, and death is always a falling asleep'. The hero would not be a science-fiction hero if he did not see to it that silent brothers were made available to anybody who felt the need of one. This is perhaps no more than hankering after a kind of super-confidence pill, but I am not one who can allot priorities among rods and staffs and comforters.

I was going to ask whether the word "saprophyte" was still in use, meaning a plant that lives on the decaying remains of other plants and animals. Living on the Chilterns, I've probably seen at least one so-called saprophytic orchid, the bird's nest orchid.

A quick Google found plenty of wild-flower pages that do use the word, but also this:

Further research has proved that, in reality, there are no saprophytic plants. The word 'saprophyte' is a misnomer - and is no longer a recommended term in botany. In it's stead is the term 'myco-heterotrophs'. Plants once considered saprophytic, such as Monotropes (such as "Yellow Bird's-nest") or non-photosynthetic orchids (such as "Bird's-nest Orchid" or "Ghost Orchid") are now known to be parasitic on fungi.

So that's good, I've learnt something today. I once saw a graffito in one of the Oxford chemistry labs which read "Undergraduates are parasites; graduates are saprophytes". I suspect the author considered saprophytes to be morally superior.

Comment 87 already mentioned brood parasites (like cuckoo birds). I was thinking about whether an animal stealing food from another (seagulls, anybody?) would be a form of parasitism, and discovered it was called kleptoparasitism. Turns out Wikipedia has an interesting page on them.

The funny thing is that most plants are saprophytes, in that they get their nutrients from decaying material, aka manure, soil, etc. They don't get their energy from this substrate, as fungi do.

Mycoheterotrophs are plants that do not have functional chlorophyll, and get both energy and nutrients by parasitizing ectomycorrhizal fungi (generally) that grow on trees. Energy and carbon pass from tree to mycorrhizal fungus to mycoheterotrophic plant.

Orchids do this one better. They start off as 18-cell undifferentiated embryos (actually, most mycoheterotrophs have tiny embryos), but orchids only develop when they are attacked by a fungus, occasionally an ectomycorrhizal species. The orchid then starts parasitizing the fungus, sucking all the nutrients it needs out of the fungus. The orchid generally then turns into a green plant, and it may at that point dump the fungus it's parasitizing. Or not. Ghost pipes and other non-photosynthetic orchids simply keep their juvenile parasitic condition into adulthood.

Orchids are really the ultimate grifters in the plant world. They grow only by parasitizing a fungus, and often, they get pollinated only by duping their pollinators. The reason this works is that they transfer huge numbers of pollen grains during each pollination event, so even if they're scamming their pollinators, it only has to work once, and they can produce thousands of those tiny, parasitic seeds. And so it goes.

A very common mistake is to confuse Parasitism with Symbiosis. ( Didn't we have a discussion recently on how symbiosis was a verboten subject for discussion in the USA? I expect someone else, probably heteromeles, to tell us more on this subject, since, IIRC, he mentioned it a while back?

OTOH, there's a wonderful book called: "The Life that lives on Man" ( which I guarantee will have you scratching after a couple of chapters ) where, at one point a visiting parasitologist observes CRAB LICE in the eyebrows of the local British ambassador, ahem ....

Myiasis ... hmm "screwflies" ... hmm ... James Tiptree Junr ( Alice Sheldon ) Ah yes, knew why that rang a bell: "The Screwfly Solution" Yuck.

Yes, I thought you'd be along on this one! Obviously I have NOT "read down the list as I comment, but - one niggle. Commensals - some of us remember the "commensals of Orgoreyn" who were anything but beneficial, though that's just lying "human" political labelling like Deutsche Demokratische Republik etc ....

And thank-you for the "sermon" too!

The Dramaturges of Yan John Brunner

Thank you for that. Explains why they are such utter bastards to grow from seed - you have to have the correct (mycorrhizal?) fungi in place before you can get a germination, right?

This "orchid" is completely implausible. Nothing like that would ever be viable. It's a Rube Goldberg/Heath Robinson affair. Nope, not buying it. Come up with something better.

Or to put it another way: orchidding!

Who knows what Eeeeevil artificially-installed RNA-bits could be lurking within the DNA of every living thing that has evolved since the last time The Stars Were Right?

Nice idea, but the problem with genetic time-bombs is that they tend to get jettisoned over time (borked by random transcription errors) unless there's some selection pressure forcing their retention. Extra codons are metabolic dead weight, after all.

(We're seeing this with antibiotic resistance genes: we stopped using Chloroquine as an anti-malarial in the mid-1980s because of widespread, almost total, resistance; 30 years later, the malaria parasites are showing signs of renewed susceptibility because there's no pressure on them to retain the resistance trait. ((Malaria oocytes take 8-15 days to mature, sporozoites live for 5-16 days, aside from the cyclic asexual phase the generational time of the parasite approximates to a month, so resistance has taken at least 400-500 generations to begin to subside.)

Why have no human diseases evolved that are fun to have and to spread?

http://www.nature.com/news/sex-redefined-1.16943

There was another article too, but I can't locate it right now. Bookmarked on a different computer.

Why have no human diseases evolved that are fun to have and to spread?

Good question. Muse: Possibly STIs might qualify. Are there studies on the well being & internal psychological states of victims in the early stages? Do STI sufferers have more sexual encounters than average? Though one might imagine an STI that modifies attitude & behaviour, such that one is more likely to pass the infection on, kind of a low level glamour, and be reluctant to seek a cure.

But such a disease would presumably make it tricky for people to remain together, since the disease "wishes" to spread. Presumably there's no such disease for the same reason no disease confers immortality.

Which reminds me: the Audible production of Carmilla was rather good, I thought.

"Kronk" by Edmund Cooper (pub. 1970) was a novel featuring just such a parasite: an STD that spreads peace and love (at least at first). (Warning: oddball British SF writer circa 1950-1975. Ahead of the game when he was on form, but much of Cooper's later work has been visited by the Suck Fairy since his death in 1982 -- he got bitten by the misogyny vampire in the 1970s and his writing didn't recover.(Diagnosing an author's mental condition through their work is always prone to wild inaccuracy, but I suspect a bad marriage in the days before divorce law reform may have had something to do with it -- that, or grumpy old man syndrome: he was only 56 when he died, stopped selling new novels 4 years before then. Might well be indicative of hypertension and early antihypertensive-induced impotence, or of a series of heart attacks. But I'm just guessing here.))

Related to the Braconidae are the Ichneumonidae, which apparently were a component in Darwin losing his faith in intelligent design:

But I own that I cannot see, as plainly as others do, & as I sh^d wish to do, evidence of design & beneficence on all sides of us. There seems to me too much misery in the world. I cannot persuade myself that a beneficent & omnipotent God would have designedly created the Ichneumonidæ with the express intention of their feeding within the living bodies of caterpillars, or that a cat should play with mice.

(Also check out that Wikipedia section title: Worst band name, or best?)

He didn't even know about most of the horrors in this comment section! But now I wonder, if he had known about some of the more bafflingly intricate parasite relationships, might he have reconsidered? :-P

I note with interest that Toxoplasma gondii oocytes infect their intermediate hosts through the duodenal lining. It's a bit of a reach, but if a strain emerged that preferentially formed tissue cysts in the testes and/or vaginal epithelium that'd be a dead-ringer for what you're asking for -- behaviour modification and sexually transmissible in one package. As long as it didn't fully encyst, but remained in the bradyzooite stage -- the genital regions are kind of short on the proteolytic digestive enzymes we use to crack open the shell of the little nugget of goodness that is the oocyte, and which is a precondition for infection.

Hi Tim

One of my fave Darwin quotations. And presumably why the RCC, and proponents of ID, IIRC, maintain that the fact of the Universe/Creation establishes God, but special revelation (in the technical theological sense) is necessary to know His nature. Because if you attempt to deduce the nature of God from His creation, He's not going to be very nice, being both profligate and supremely disinterested in the problem of pain and the individual, a bit like my my CEO...

maintain that the fact of the Universe/Creation establishes God Except, of course, it doesn't. Followed-up by the usual question: "I fF BSF exists, why is he/she/it/they undetectable?" Followed next by unbelievable amounts of wriggling & lying.

Speaking of which my cat just bit me again... So no doubt we shall see. Though this behaviour did modify my behaviour to the point of buying a laser pointer, which it "likes" (is a slave to). Now I need to mount the pointer on a pendulum in the corridor!

But if there was a disease / parasite that increased sexual desire / ability / attractiveness, no doubt spam would increase on the back of pharmaceutical developments aka the next big thing (as it were).

Well, such an organism might exist, but I doubt we'd class it as a disease, especially given the historical conflation of virtue with physical health.

On the other hand, if the reports that Toxoplasma causes behaviour modification in humans towards greater risk-taking are correct, you might look at the kinds of fun investment bankers were having during the run up to the 2008 crash and conclude that they were infected and enjoying the result.

Brian Stableford's "Hooded Swan" series had an alien, cognitive symbiont in the protagonist's head - The Wind...

Big Engine republished all six stories in a single volume, it was fun to read them again :)

But do investment bankers generally own cats or just indulge in pussy?

Except, of course, it doesn't.

I refer you to the decree "Lamentabili" (3 July, 1907)!

While I don't think this is the place to argue the ins and outs of RCC theology, it's my feeling they never formally contradict themselves. While they are wrong, it is tricky to prove it. In a strict sense, given the nature of proof... IMO.

Look forward to Bob Vs. the Pope!

Any chance of the Fuller Memorandum on Audible? The other recents explain a few things!!

Any chance of the Fuller Memorandum on Audible? The other recents explain a few things!!

Not in the UK. (I believe it's available in audio format in the USA.)

Sales of the first two Laundry audiobooks in the UK didn't justify the expense of recording and releasing the next two as back-list titles. However, I believe Orbit are considering releasing audio editions of "The Rhesus Chart", "The Annihilation Score", and future titles on the basis of growing sales. (I have expressed my unease at seeing a two book gap in the audio bookshelf, but the decision isn't down to the author or editor; it's strictly about accounting.)

Not in the UK. (I believe it's available in audio format in the USA.)

Sure. But obtaining a USA credit card is tricky, in lots of ways. Not difficult, but it does raise your profile, for a given value of Profile. Rights, eh?

While looking at this I had quite a good chat with the H.P Lovecraft Historical Society about a theatrical production. But the powers that be wouldn't even name a sum for rights! Presumably because I was looking at a kickstarter to raise the funds for a UK edition, and am an unknown git... with "views". Such is life. And the release of the UK stuff.

However given [redacted] was extremely cordial, if not forthcoming, fair enough, so far! Accountants rule everything, and suggesting otherwise apparently labels one as "entitled".

Oh, nice MR James on Radio 4 extra playback: The House at world's End.

They're not particularly dramatic, but I've always been a fan of Schistosoma sp. (mansion, japonicum, etc.), as they represent one of nature's great love stories. Their life cycle is not very weird by the standards of parasitic helminths, but unlike many invertebrates, they mate for life! The female actually lives inside of a groove on the male's ventral surface (the gynaecophoric canal) for most of their adult life. Awww!

Of course, the disease that they cause in humans, Schistosomiasis (or Bilharzia), is pretty gnarly, and even though these days it's relatively easy to treat with praziquantil it is still a major public health problem in much of the world. For bonus points, look up the story of Claude Barlow, a pioneer of parasitology, who was responsible for getting the first viable Schistosoma eggs to the US for study in the 1940s. After several failed attempts, he finally accomplished this by infecting himself with cercaria in Egypt and then getting on a boat back home. He managed to survive long enough to get back to Johns Hopkins and start shedding eggs, though it was apparently a pretty close call.

This was not actually the first time that Dr. Barlow had produced important parasitological results via self-experimentation. See:

Barlow, Claude H.. 1921. “Experimental Ingestion of the Ova of Fasciolopsis Buski; Also the Ingestion of Adult Fasciolopsis Buski for the Purpose of Artificial Infestation”. The Journal of Parasitology 8 (1). The American Society of Parasitologists: 40–44. doi:10.2307/3270940.

So what you're (not) saying is, you want your fans to put together an amateur reading of the manuscript, complete with arguments over accent and pronunciation, and then to release the beast onto the net for our listening enjoyment?

Could we take over a pub for the recording session?

No, what I want is a fat TV or movie deal and piggy-back sales to convince my EU publisher that the back list is now moving fast enough to justify a professional job (that doesn't cannibalize my sales). Or for Audible US to get over themselves and offer to license the rights to the US recording to the UK publisher for an affordable price based on demand.

Bravo Lima Poppa 3 @ 17, and later comments about human sexually-transmitted behaviour-modifying parasites: Sacculina has explicitly inspired a story about such things. It is a very long time since I read it and I have no idea of the title or author - I can't even remember whether I did properly read it or just flicked through it having come across the book lying about - but I do remember that it concerned a parasite which infected humans and caused them to have "awful fishy breath"; when two infected humans caught a whiff of each other's breath they would instantly develop an uncontrollable desire to shag, which act resulted in the exchange not of their own gametes but those of their respective parasites. Someone investigating the disease compared it to a parasite which infects crabs and converts their own mating process into a mating of parasites; I was inspired to find out if such a thing actually existed and this is why I know about Sacculina.

Therion667 @ 109: Oliver Sacks describes a real-life example of something which somewhat resembles your postulate in "The Man who Mistook His Wife for a Hat". A patient was just beginning to develop the symptoms of tertiary-stage syphilis some 70 years after the original infection. She wanted not to eliminate the disease, but simply to halt its progress so the symptoms would remain at their current level, because they counterbalanced some of the effects of old age and made her feel young again. Not quite what you meant, but there is a resemblance.

Martin @ 85: Wyndham seemed to like parasites. I suppose you might describe Chocky as a benevolent mind parasite. There was also his short story about an attempt to weaponise a parasitic puffball fungus.

And yeah, the whole mammalian reproductive process is horribly parasitesque and yuck.

David Earle @ 15: "Extremophile uranium enrichment, anyone?" Oh yes. This is a real phenomenon. Pretty sure I even mentioned it on here recently.

There are isotopic differences in redox potentials of uranium species. They are very small, but they are significant and usable. The French have researched a chemical method of uranium isotope separation based on isotopic effects in redox reactions involving U(III) and U(IV). The Japanese have researched a method based on similar differences between U(IV) and U(VI).

The latter couple is one that occurs frequently in geological conditions, especially where bacteria that derive energy from any handy redox reaction get involved. The solubility difference between U(IV) and U(VI) plus the isotope effect on the redox potential result in the mobility of one isotope in groundwater being a tiny bit higher than the other, so fractionation occurs.

There are quite a lot of papers on this, mostly from Japan it seems. Their overt concern is with the mobility in groundwater of uranium from nuclear waste, but this does not explain the interest in isotope effects - the amount of fractionation is far too small to cause any risk of unintentional criticality. But given that it is also Japan which is interested in the conventional-chemistry equivalent for purposes of uranium enrichment - which is still pretty unwieldy and uses a fair bit of energy - it seems highly likely to me that an unspoken motive is to investigate the possibility of recruiting a low-energy biological process to do the same thing in a more elegant manner.

Well, I might have a monkey's paw that I could sell you, although you've got to pay the shipping and insurance on it...

Yeah, multi-stage hostings aren't uncommon. Look into flukes. But that's not being a hyperparasites.

The story was "Night on Mispec Moor", IIRC

It's not clear how effective molecular scale chemistry can get in handling separation of isotopes. That it can do it SOME is testified to by carbon isotope preferences. But carbon is a low weight isotope (12-14) where as uranium is a high weight isotope (233-238) so the degree of difference is a lot less. And getting enzymes to make that kind of distinction isn't going to be easy, and likely not possible. Even the carbon isotope preference isn't a drastic concentration. You could improve that some with multiple stages, but it's not clear how much.

When the thread is this long I'm sure anything I can come up with has already been posted (eg the multiple mentions of Night on Mispec Moor), and the subject matter means that trying to read it all will likely freak me out.

So all I' can suggest is starting a Yourtube ramble on David Attenborough's cordyceps video, and keep going until your brain explodes.

Little wasps have littler wasps, Inside their guts to eat 'em, And littler wasps have still littler wasps --- Hyperparasitism repeating!

I've wondered for a while if Swift's epigram about fleas was making a sarcastic point about the hangers-on of the rich and powerful. The original Greek meaning of "parasitos" was a man who ate at a richer man's table. . . .

Parasites that make you go yuck are one thing, but what about parasites that have a charismatic, beautiful imago? The Large Blue caterpillar is a brood parasite on red ants. It was extinct in the UK for about 5 years, and on re-introduction its sole breeding site in the UK was kept secret by ecologists for ages.

Getting itself re-introduced at all, with ongoing work to increase the UK population, is entirely due to its charisma. That arguably makes it a parasite on a second social species, us. No-one is trying to re-introduce malaria!

It needs to eat a specific food as a caterpillar, wild thyme or wild marjoram, as well as get itself into a specific red ant nest. Otherwise, not a particularly complicated lifestyle as far as I can tell. (Apart from the bit where they shed their external skeleton... several times... and then remodel their entire body out of a kind of thick organic soup. But a lot of insects do that so we think it's normal. A billion years of evolution can do some very weird things.)

The situations are a bit different. Carbon is a component of organic molecules and enzymes act to break some of its covalent bonds and form others. The organisms involved in fractionating uranium in groundwater movement are not incorporating it into any of their molecules. It remains in solution in ionic form, and they are doing one of two things: either they are simply causing minor localised changes in pH (or some other concentration) which shifts the position of the equilibrium between U(IV) and U(VI) in their immediate neighbourhood, or they are deriving energy from inducing it to interchange electrons with other ions. Either way they are not fussy, and fractionate other elements as well to an extent related to their susceptibility to such fractionation.

In all cases the fractionation is in biological terms an irrelevant side-effect, but it is the last case which is interesting, because it implies that they could possibly be mediating the reaction using a mechanism reminiscent of the Japanese chemical separation process, which operates by adsorbing or desorbing uranium ions depending on their oxidation state. If this is the case, then it is easy to imagine the possibility of tweaking the substrate to improve its selectivity for uranium ions much as the Japanese tweak their zeolites.

Maybe it would go something like this: make up several cultures of microorganisms in conditions providing U plus Fe or something close to it, give them all a mild dose of UV to induce a few mutations, leave them to sit and breed for a bit, test each culture to see which have happened to achieve the most fractionation, throw the rest away and use the best ones to seed the next round.

Parasites that make you go yuck are one thing, but what about parasites that have a charismatic, beautiful imago?

Jinx! (see #46)

remodel their entire body out of a kind of thick organic soup

Which is almost like something a parasite might do... Could butterflies have started out as parasites on caterpillars?

That's not the standard theory, of course; I don't know to what extent the origin of metamorphosis is known well enough to rule it out. In any case, it's plausible enough for fictional creatures.

I guess it's on a scale with the already-mentioned figs, just with closer integration of both body and reproductive cycle (and therefore destiny).

Sounds like something Lynn Margulis came up with (or at least wrote about). I think the book was "Acquiring Genomes", but it went back to the library so I can't check.

There was also a chap named Williamson (or Williams) who published a paper that butterflies got their genomes crossed with velvet worms — fertilized the wrong egg or something like that. Not parasites, but strange.

I don't remember seeing any hypotheses about land animals in the book of his I read. It was mostly about marine animals, especially those with radical metamorphoses. I seem recall his having echinoderm eggs fertilized by sperm from animals of entirely different phyla.

Sexual parasitism and anglerfish, https://en.wikipedia.org/wiki/Anglerfish The male becomes a parasite on the female and all functions except the gonads wither away.

Paper, not book. Think this is the one I saw:

http://www.pnas.org/content/106/47/19901.abstract

Looks like it's refuted:

http://blogs.scientificamerican.com/observations/controversial-caterpillar-evolution-study-formally-rebutted/

But for fiction, still a usable idea :-)

Didn't Orson Scott Card go there with the Descolada in Speaker for the Dead?

Looks like it's refuted:

Refuted with knobs on—by the standards of academic writing, the paper referred to in that blog (link may be behind a paywall: I'm on a university computer that has subscriptions to academic journals) is pretty scathing about Williamson's "astonishing and unfounded claim".

Metamorphosis itself, especially as practised by more advanced insects such as flies, is still a fascinating process though: the cells that will become the adult form are there, doing nothing, throughout the larval stages (as "imaginal discs"), before being kicked into action by a hormone surge in the last larval moult. Got to be something there for the inventive alien designer...

My mind shut down after the first post by Detective Clayton ..ick!

I appreciate that this is Not a scientific response but my excuse is that I'm in the midst of an allergic reaction to minor Building Works involving repairs to the installation damage occasioned by the latest updates in my 7 year cycle of Household Technology - SHINNY ! - this time Ultra High Definition 75" TV wall panel - that needed holes to be cut into the walls - and various other Necessary Stuff to feed the same. Anyway Dust, Dust, and yet more Dust ..that doubtless contains many a fragment of skin and all sorts of IKY creatures that feed upon the same and trigger Allergic reactions.

Normally I only have trouble in the Summertime - Light Triggered Dermatitis, Not Vampirism!But nature is capricious and is making a Wintertime Exception just for me.

I shall get round to reading the posts that came after ..

"And when you find out just how much influence over your health and wellbeing your gut flora have, you wonder just how much of our lives are actually our own and how much are controlled by the bacteria, viruses, etc. that use us as hosts." and only dare to mention Allergic Reactions to Iky Things as being worthy of note.

Oh, and just in case it hasn't been mentioned with sufficient enthusiasm? Hal Clements " NEEDLE " and its Sequel " Through the Eye of a Needle " deserves attention as a genuinely original detective/police procedural novel that caused me to wonder - way back in the days of my youth - where parasites begin and symbiosis ends ..or vice versa.

"Needle is a 1950 novel written by Hal Clement, originally published the previous year in Astounding Science Fiction magazine. The book was notable in that it broke new ground in the science fiction field by postulating an alien lifeform, not hostile, which could live within the human body.[1] Also published as From Outer Space, the book would, in 1978, spark the sequel Through the Eye of a Needle."

https://en.wikipedia.org/wiki/Needle_%28novel%29

Where did you think I got "Equoid" from?

yes, but enzymes use molecules shapes and electric load patterns, I don't see how an enzyme could differ different U-isotopes.

okay, reading on I see that there's much I have to learn about isotope separation.

I have a story in which brain-eating amoeba meet cold war politics meet environmental regulations.

Mid 1980s, one of Reagan's pet projects for ramping the cold war back up again was to increase plutonium production even though the US had a tidy surplus of the stuff. At the Savannah River site, this entailed a project to re-activate the L-reactor (which had been dormant since the 60's).

Because environmental regulation had been invented in the interim, they could not follow the old school practice of simply dumping boiling hot cooling water into the stream and to hell with the ecological consequences downriver, so a lake (L Lake) was built to cool the water enough that it would not sterilize the river.

While the layout of the previously built cooling pond for P and R reactors (Par Pond) included some long narrow arms in which the waste water could initially cool from scalding before entering the main body of the pond, the layout for L lake was more simple, with scalding water directly entering the main body of the lake. So, while the reactor was operating, the entire lake became hot enough to become a breeding ground for Naegleria fowleri.

But those environmental regulations also required that the shoreline of the lake not be allowed to remain a barren moonscape. It had to be planted with an ecologically appropriate community of wetland plants. My father's firm was hired to do the job, and being an impoverished college student I helped him get the project up and running during spring break.

It turns out that not getting infected with brain-eating amoebas comes down to "don't let water containing the amoeba get up your nose" and "just in case, don't let anything that has been in the water recently near your nose." Protective clothing for planting marsh plants in the shallows of a lake teeming with Naegleria fowleri consisted of 1) wearing a disposable surgical mask while standing in the lake to protect against splashes, and 2) wearing rubber gloves to help remind you not to touch your face with your hands. I can speak from experience when I say that being able to pull the damned mask off once you'd gotten clear of the water was an extremely pleasurable sensation.

And then, only a few months after my dad finished planting the lake, they shut the reactor down for good, only 3 years after starting it up again.

I know the question was about actually existing parasites, not about coming up with weird parasites for the Laundryverse. But looking at the weird lifecycles I can't help but think about a parasite whose lifecycle hops over habitats and hosts that exist in different multiverses, part of its lifecycle it exists only as a meme or ide fixe in a host (or maybe the memes are like pollen). Because the complicated lifecycle would be terribly easy to break, the different hosts and stages form a closed timelike loop over several multiverses.

The fig wasp has been mentioned, but I want to point out the phenomenon of forming a Gall: The parasite/smbiont gets the host to build them a house.

https://en.wikipedia.org/wiki/Parasitic_cone

...I'll show myself out.

Rural communities warned to chlorinate after waterborne brain-eating parasite kills three children

Regional communities are being advised to chlorinate their house water after a third child death from a "brain-eating parasite".

The amoeba, Naegleria fowleri, thrives in warm fresh water across large parts of inland Australia.

While authorities say infection is very rare, medics warn survival is even rarer.

"It causes catastrophic meningitis encephalitis, and by the time these kids are diagnosed the treatments are usually ineffective," public health physician Dr Steven Donohue said.

"We think that probably 98 per cent of cases die even in the best of hands, even in the most modern intensive care units."

...

Naegleria fowleri was first identified in South Australia in the 1960s and has since caused 300 known deaths worldwide, mostly youth and children.

It is not only communities from north-west Queensland at risk.

The amoeba thrives in water temperatures above 25 degrees Celsius and has been discovered in lakes, creeks, dams, bores and rain water tanks across the country.

Authorities stress infection from Naegleria fowleri cannot occur from drinking, cooking or washing clothes in the water.

The danger arises when contaminated water enters the nose.

"It gets into the brain through the nose and it's usually a form of pressured water, from jumping into water or having water sprayed into your nose," paediatric intensivist Dr Greg Wiseman said.

Clinical microbiologist Dr Robert Norton said: "On the inside there is a very thin slither of bone that separates the outside brain from the surface, and in children this bone is underdeveloped.

"And for some reason the Naegleria tends to pass through this."

Only skimming the thread due the high squick-factor, but... Here's a brood parasite that evolved from its host into a separate species: http://smithsonianscience.si.edu/2014/08/new-species-ant-offers-compelling-evidence-controversial-theory-species-formation/

I cannot even imagine what sorts of brood parasites could evolve in the Other Dimensions, but the Mycocepurus castrator story left me thinking about business parasitology.

While it could be argued that many corporate executives operate like brood parasites, employing their marketing, business, political and social skills mainly toward getting paid* instead of earning their keep, some things (e.g. arranging for stock buybacks) actually stray into the realm of making the company act against its own or its stockholders' interest, and purely for the benefit of the (option-holding) executives.

Of course, there's still a lot to be studied with regard to the epidemiology and population dynamics of corporate parasites. (By which I mean, the parasites that prey on corporations, not the corporations that prey on humans.) The golf-course and ivy-league transmission vectors, the role of immunocompromised corporate boards, or environmental factors such as the propagation of the "professional executive" myth (see: John Sculley) could all be profitable areas to explore.

• I've got nothing against getting paid, mind...

Of course, you could always have a genetic engineered parasite. Say one that infected the host, pieced together a small amount of high explosives from the organic chemistry floating by in their blood stream, and then blew the host's spinal cord/neck to hell.

Now where have I heard of an idea like that before ...

And on a political axis, a designed virus that dumped a parasite in the host's brain that altered the brain chemistry to make them more authoritarian, more religious, less sharing, etc. would be the end point of democracy and political campaigning, and right up Karl Rove's street. It might also explain Trump's and Carson's current poll numbers.

What's the difference between and infection and parasites ... apart from saying it's the immune system that fights/protects against infections*? Or are we splitting hairs, arguing scale?

• Recall hearing/reading that syphilis and thalassemia provide some 'immunity' from malaria.

Virus that dumps a parasite? That seems a bit overcomplicated. Surely you could just dump in the parasite itself? Anyway, you might not even need to use a special parasite to do it. There is evidence that high prevalence of parasites and diseases causes authoritarianism without the need for specifically tailored parasites. http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0062275 Of course, it might make sense to tailor the parasites, simply to make it harder for the medical system to find and get rid of them. But there's no need to go to all the trouble of tailoring a virus to tailor a parasite to alter the target's political views.

He's written two books, Larvae and Evolution and The Origins of Larvae. My local university library has both, and I've read both. They're right up there with Julian Jaynes's bicameral mind theory for wild speculation, though unlike it they haven't inspired any science fiction (both John Barnes and Harry Turtledove have written stories based on Jaynes).

that would be sickle cell and thalassemia, not syphilis. They're both heterozygous advantage-type mutations.

IIRC, Gary Naban posited that there's a weird interaction between beta thalassemia in the Mediterranean, fava beans, and malaria.

The Tirtledove one I've got (and like). What's the Barnes one?

Found a couple things that might be interesting (and possibly more useful than parasitic volcanic cones) regarding paleoparasitology.

First off, mammal-specific parasites that go back to mammalian ancestors (Couldn't find the peer review article on this one, sorry): http://newsroom.unl.edu/releases/2014/12/01/Scientists+find+240+million-year-old+parasite+that+infected+mammals'+ancestor

Evidence of parasitic isopods (which still exist today ( https://en.wikipedia.org/wiki/Bopyridae )) infesting other crustaceans way back in the Jurassic: http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0092551

I found another article, "The earliest evidence of host–parasite interactions in vertebrates" purporting to display signs of parasites going back to the Devonian- unfortunately, I couldn't find an open posting of it online. (I do have access to a PDF, if there's any interest.)

Tapeworm eggs in a 270 million year old shark coprolite: http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0055007

Finally, an article about heterotrophic heteronomy, where the sexes infest entirely different species- it occurs (rarely) today, and there appears to be fossil evidence of it. I couldn't find a public version of the article, but I do have access to the PDF. (Cryptic diversity and female host specificity in a parasitoid where the sexes utilize hosts from separate orders.)

Sorry for the giant pile of links- hopefully one of them proves useful.

It's possible to make an argument that human hierarchies and possibly even civilization are based on intraspecies parasitism.

(Note that I don't think that all parasitism is bad. Most species on Earth are parasites, and they add an enormous amount of diversity to natural ecosystems).

Here's the idea: --All humans have to care for their children and sometimes our elders for an extended periods. In simple societies, all adults have to forage, farm, or herd, and people normally share food in a relatively small network, to balance out the inevitable shortages and surpluses.

--Specialists organizers (big men, chiefs, etc.) initially work by facilitating sharing and redistribution across a bigger group, in return for a share of the trade. In some circumstances, this makes sense, and allows the group to grow beyond Dunbar's Number. In nutrient terms, these organizers are permanent children, so there has to be a modicum of charisma and a general reason why productive individuals need to support these "parasites." People have to have a reason to support them.

--If there are consistent surpluses, the hierarchy of non-productive individuals can grow and elaborate, taking up specialized functions that don't directly produce food and resources. Effectively, it's a parasitic ecosystem (remember, we're talking about food and supplies, not money). Perhaps counterintuitively, this parasitic system can cause a society to balloon enormously into a civilization.

--At this point, we get into Piketty's r>g inequality. The producers fall behind, while those who control the means of production get progressively richer. This is an unstable situation, and it's the classic problem of parasitism: the conflict between the hosts and the parasites they support. In human societies, this gets resolved in one of three ways: redistribution (including a jubilee), revolution, or the society falls to invasion.

Note, again, that I don't think parasites or parasitic ecosystems are necessarily bad, but it certainly is easy to see it this way. If we see all human parasitism as bad, then we're in classic anarcho-primitivist land, where there is this notion that people need to live in an egalitarian tribe without rulers of any sort. This sounds appealing, but realize that it limits redistribution of resources to people who know each other, so groups formed this way are going to be around Dunbar's Number ~150-200 people maximum.

Everyone else can argue that both specialization and redistribution are normal and necessary in civilization, and I wouldn't disagree. However, it's a fundamentally unstable system, because it's based on exploitation of the producers. Unlike Marx, I don't think it's possible to get rid of this exploitation.

Moreover, as in the natural world, parasitism promotes diversity. After all, in this model, most or all of us get our food and resources from others, and give something called "money" in exchange. All of it is crowned by a system that focuses on power, which is always closely related both to charisma and the power to redistribute resources to others, rather than produce them directly.

Probably need to unpack "charisma", and of course "power to redistribute resources" here is just a euphemism for violence. But given both the 19th century potato famine and the Soviet collectivisation of agriculture were outcomes of this sort of power, this is a great way to undercut ideology as a form of explanation.

I think though that exploitation is about power imbalance more than about any intrinsic property of the human condition. We can fix that, sort of.

Okay, that's a really neat way of looking at things and it explains so much about the shape of the world today that I think I'm going to have to run with it some more.

But not right now.

a designed virus that dumped a parasite in the host's brain that altered the brain chemistry to make them more authoritarian,

Or anhedonic. More rage, more depression, more hate -- less happiness. Perfect for a leader who wants to get those marching boots on.

I can also see some misguided fundies wanting to build an STD that selectively attacks the neural pathways that lead to orgasm, on the assumption that all non-procreative sexual activity is bad but decent god-fearing people will continue to manufacture babies to order anyway. (Such an STD would be "god's punishment on the deviants", preferentially targeting folks who sleep around. Or, presumably, luck into some other transmission vector, because there's rarely just the one, as Isaac Asimov discovered the hard way.)

* Recall hearing/reading that syphilis and thalassemia provide some 'immunity' from malaria.

Other way round, I thought, at least wrt. syphilis/malaria? Treponema pallidum isn't very heat-tolerant, and Julius Wagner-Jauregg demonstrated that inducing a high fever (over 41 celsius) by infecting a terminal syphilis patient with malaria cured the syphilis infection.

Another particularly pernicious military parasite also suggests its self, and at this point I would like to issue the following warning:

Possible Troll Ahead

Humans default to being female, unless a relatively small subset of genes found on the Y chromosome are present. A parasite engineered to inject those genes into any and every zygote it finds would make all such zygotes male, or reasonable facsimile thereof.

Any culture that strongly prefers male children over female children and which isn't sophisticated enough to spot a poisoned chalice when one is offered to it would be susceptible; were uptake of the poisoned offering to be widespread, a near genocide would result.

End Possible Troll

This could also be engineered for the better. Inserting genes for new photoreceptive eye pigments onto autosomes instead of just the X chromosome would almost eliminate red-green colour blindness; inserting the genes lost in primates that synthesise vitamins C, the B-complex and niacin would also confer great advantages on the recipient.

Whether redistribution of resources depends on violence is an issue of scale. Feasting and redistribution of stuff to family and friends are pretty ubiquitous, and at smaller scales, they depend more on issues of fairness than on violence.

A more durable parasitic hierarchy provides uses a wide spectrum of means, including providing (through redistribution) food, shelter, medicine, laws, education, land tenure, and family organization, as well as coercive violence. Any bandit group can specialize in violence, and these tend not to last. In practice, the groups that are the hardest to dislodge (see governments, or groups like Hamas, the Taliban, or ISIL) use most or all of them.

Mention of Malaria as a possible treatment for something reminds me that Sickle cell trait can give resistance to Malaria.

So now thinking about a story idea where a mutation that protects from a parasite causes problems when the parasite isn't present, making it necessary to be infected with it. Too early here to be thinking about this stuff.

Yes - you/Heteromeles are right... I should have rechecked Wikipedia ... had that backward.

Wkipedia:

'Julius Wagner-Jauregg (7 March 1857 – 27 September 1940) was an Austrian physician, who won the Nobel Prize in Physiology or Medicine in 1927.[1] His Nobel award was "for his discovery of the therapeutic value of malaria inoculation in the treatment of dementia paralytica".[2]'

Suppose this would provide a credible historical basis for using parasites. And such researchers could, like Bob, end up with more on their hands than they'd bargained for.

BTW ... blood brain barrier breached using ultrasound thus providing yet another way of uploading your parasite, virus, etc.

http://www.techtimes.com/articles/104505/20151109/canadian-doctors-perform-breakthrough-blood-brain-barrier-surgery-using-focused-ultrasound.htm

When I took genetics, the way it was explained was that being heterozygous for sickle cell conferred resistance to malaria, at the expense of some reduction in general fitness; but being homozygous was lethal. So it's not quite "causes problems when the parasite isn't present." The severe problems of homozygosity come about when the parasite IS present, too. In fact they really mostly occur in environments where the parasite is common; outside those regions, even heterozygosity lowers net fitness enough to be selected against, and rare, so getting the gene for it from both parents is almost unheard of, but if the majority of adults are heterozygotes, a lot of the children will be homozygotes.

So now thinking about a story idea where a mutation that protects from a parasite causes problems when the parasite isn't present, making it necessary to be infected with it.

Not that it's an issue with the principle as a story idea, but that's not how sickle-cell works: the problems associated with it occur whether malaria is present or not. It's just that where malaria is endemic, the advantage of increased resistance to malaria for heterozygotes outweighs the disadvantage of the early death of homozygotes, thereby making it advantageous for the population to maintain a mix of sickle-cell and normal genes.

However, there definitely are cases in which parasitic infection is beneficial: "The jury is no longer out: there is overwhelming data, especially from animal models, that infection with helminth parasites can ameliorate the severity of concomitant inflammatory diseases. ... Representatives of major classes of helminth parasites have consistently been shown to alleviate disease in rodent (typically mouse) models of airway inflammation/hyper-reactivity, diabetes, inflammatory bowel disease (IBD) and multiple sclerosis (MS)" (Derek M McKay, Parasite Immunology, 2015, 37, 324–332).

Worms can be good for you.

So the question is: Which rare and unpleasant but survivable genetic conditions are most likely confer resistance to Cthulhu?

A form of redistribution of resources that can occur not only without overt violence, but without legal compulsion, is true classical model insurance. You are worried, let us say, about your house burning down; so you join a pool, put in your money, and the one whose house burns down gets the money and can build a new house. That's redistribution from a general population to a person in need.

Of course there are failure modes for it: Paying off too well can make people voluntarily expose themselves to damage (there's an old joke is one businessman asking the other, "So how do you start a flood?"). Charging more than the protection is worth can result in people deciding to take their chances. The concept of actuarially fair rates emerged to maximize the number of people who could be brought into an insurance scheme—that is, who would sign up to have some of their income redistributed voluntarily because they felt that participation made them better off. That is, classical insurance is a scheme of purely voluntary "socialism" (in the sense of income and wealth redistribution, not in that of state ownership or control).

The restrictions needed to make this work, though, inevitably deny coverage to some people, and make it cost more than other people can afford. So you have the alternative, which is to impose a scheme that protects everyone. And since that scheme can't be actuarially fair, you also need either compulsory participation or direct government funding out of taxes, to deal with the people who will no longer sign up voluntarily because it no longer makes them personally better off. These systems are also often called "insurance," but having the same word for two rather different things makes it hard to discuss them.

"Restricted to the Necessary," published in Apostrophes and Apocalypses.

That depends on what you think Cthulhu actually does. Most versions of Cthulhu have him go around stomping and eating people, which makes him just a huge predator, like the critters in Pacific Rim, and defenses against predators run to hiding, running away ("I don't have to run faster than Cthulhu, I just have to run faster than you!"), or making yourself taste horrible. But Lovecraft's own account has him infecting humanity with what looks like radical egoism, in the Stirnerite amoralist variant. For that, I think you'd want either resistance to telepathic influence, or an advanced case of some moral belief system.

Here's a theory for you: Cthulhu's telepathic influence has been with us for a long time; but people who succumb to it become dangerous to other people, in a predatory fashion akin to vampirism. So we developed moral convictions, and beliefs to support them. Most people have a mild case and are resistant enough to Cthulhu to continue to function as human beings. But some people get a doubly reinforced case and become moral or religious fanatics, which tends to shorten their own lives and has other costs. This accounts for the bizarre empirically unfounded beliefs of many religions and ideologies, I think.

Another approach would be to look at the Big Five personality traits (Openness to experience, Conscientiousness, Extraversion, Agreeableness, and Neuroticism) and ask which ones might make people less susceptible to Cthulhu.

Any culture that strongly prefers male children over female children and which isn't sophisticated enough to spot a poisoned chalice when one is offered to it would be susceptible; were uptake of the poisoned offering to be widespread, a near genocide would result.

TOO LATE! This has already happened in India & "Pakistan". ( Selective abortions & infanticide, actually, but the end-result is the same. ) It's not going to end well ...

The same phenomenon was seen in China but apparently went into reverse between about 2009 and 2013, with the sex ratio of neonates returning towards normal. (It's not there yet but it's moving in the right direction fast enough that it'll be there by 2025-30 at the latest.) Scarcity and smaller familities makes girl children more socially desirable. (Hopefully India and Pakistan will go the same way.)

Blast! The one Barnes book I don't have… :-(

China's going to be interesting to watch. The One Child Policy has been repealed, but in places like Shanghai and Beijing the average family size was less than one child — a significant number of couples were opting to not have a child, even if they were allowed one.

(I suspect an educated female workforce and 1960s-level maternity benefits have something to do with that, but I have no evidence for that, just a suspicion.)

Re: 'A form of redistribution of resources that can occur not only without overt violence, but without legal compulsion, is true classical model insurance.'

Tying this back to the topic - parasites - how about inoculating humans with parasites to manage their food preferences. Humans are omnivores which is fine when scavenging for nutrients. It's a problem though when the desire and ability to eat almost anything turns into eating too much and/or the wrong mix of foods. would definitely impact industry, socialization, etc.

By managing food preferences I mean someone with food preference parasite A (FPP-A) would get ill if presented with non FPP-A foods. This might reduce food waste because if I can only eat apples and can no longer tolerate oranges, then this reduces the demand/price for oranges. This may also translate into more mixed-food/crop farming (?) ... that is, growing more that one food crop in the area.

Of course someone is going to complain that this will actually drive up food prices as in 'higher volume always equals lower unit price' law.

Decided to look at animal studies ... here's an excerpt from an Abstract... url follows.

Excerpt:

'Gastrointestinal nematodes reduce voluntary feed intake and efficiency of feed utilisation, a key feature being an increased endogenous loss of protein into the gastrointestinal tract. Overall there is movement of protein from productive processes into repair of the gastrointestinal tract, synthesis of plasma proteins and mucoprotein production. ... Supplementation of the diet with additional protein does not appear to affect initial establishment of nematode infections but the pathophysiological consequences are generally more severe on lower planes of protein nutrition. The main effect of protein supplementation is to increase the rate of acquisition of immunity and increase resistance to reinfection and this has been associated with an enhanced cellular immune response in the gastrointestinal mucosa.'

http://vetscan.co.in/v4n2/exploiting_nutrition_parasite_interaction_for_sustainable_control_of_gastrointestinal_nematodosis_in_sheep.htm

I have not read the study in full (but may do so) but the whole thesis seems sketchy.

Almost every assertion they make can be turned on its head, saying that authoritarian systems are worse at protecting their people from disease (They say parasites but state at the start that they mean any infectious disease), so disease would not cause authoritarianism but the other way round: Conformity ensures that best practices protecting from disease are kept? How about traditional burial practices in many parts of the world, or European doctors resisting such newfangled ideas like washing their hands now and then? People more afraid of disease are more ethnocentric and xenophobic? Or is t the other way round, xenophobes (or rather racists)rationalize by stressing their fear of disease? and so on.

This also shades into Vinge's "A Deepness in the Sky" and 'focus'.

Once any authoritarian, or even 'not particularly freedom loving' government gets control of brain chemistry and mood, they are going to want to use it to 'control' the populous - in other words turn them into mindless automatons who do what they are told.

In fact any parasite is better off if it can exert control over the host, make it do what benefits the parasite rather than the host - it's something of an axiom.

Arguably you could say that our society is already designed to turn the vast majority of the populous into mindless machines - following along a narrow track that does work and consumes goods; and that reproduces new copies to carry that along. Very few spend much of their time being 'better humans' or doing things that obvious portray the best of what it means to be human.

The obvious vector is drugs. Make it pleasurable and addictive and you can easily spread it through certain strata of society - with the mood adjustment ready built in. If the long term effects are a bias towards doing what you are told, well 'we made it illegal, didn't we'.

So society shifts from a coat to protect you from the elements into a straight jacket to control your behaviour and eventually converts you to a mindless host for the parasite of someone else's aims and ambitions.

Why am I shivering?

I find myself imagining what a Charlie Stross - Peter Watts collaboration might make of this subject.

Be very afraid.

E.g.: http://www.rifters.com/crawl/?p=6315

That's a good formula for a state that lasts at most three generations. You've got three problems here: one is who gets to do the thinking, the other is keeping the parasite/drugs/whatever under control, so that the people who are supposed to be doing the thinking aren't affected or even tempted by it. The third problem is that the leaders actually have to know what they're doing, because their underlings have no agency.

I think Charles Mann said it fairly well in 1491. The quote was something like there are four basic modes of government: bottom up, top down, great monster, and enormous scam (I'm rewording this from memory), and that governments tend to use some mix of all four modes.

If you're drugging the population, it's entirely a top-down system, and that's not safe. To pick one example at random, the leader wants to be able to tell his rocket scientists to build rockets for him, and for them to do it. If the rocket scientists are zombified, then the leader has to tell them how to build the rocket. Now, one of the inherent problems in hierarchical leadership is that the leader can't know everything that's going on at the levels below him, any more than you monitor and regulate your liver enzyme activity on a continuous basis. A zombified, happy population might sound good in theory, but in practice, I think you'll find they need more agency to actually do their jobs.

The simpler solution is social parasitism, wherein the leaders make themselves out to be the best, most potent, capable, even sexy of people, well worthy of our support and adoration. That's the essence of charisma. They don't necessarily always get their way, but they do get a lot of support for whatever they want to do. This is a simpler trick when you can pull it off.

The scenario portrayed would be better overall if the yogurt were served at Board meetings. To really change things, change the decision-makers. And, instead of feeding rage, consider feeding altruism by resetting the satiety level for money/success/fame.

So here's a question: in the competition for resources between management and employees (or between corporations and the public, I think it works out the same) which is the parasite, and which is the host?

It's easy to say the larger population is the host. But symbionic relationship arent about numbers, they are about resource exchange. The employees make the stuff (the consumers buy it) but it's the shareholders capital that created the employment in the first place, and their capital largely funds new product development and growth into new markets. Investors dole out access to their pool of capital, an odd role for a parasite.

To me is seems more similar to aphid herding ants. The aphids take the food that the ants provide them, and they convert it into a different kind of food the ants can use. Of course, the ants dont generally kick the aphids out into the cold when they arent feeling especially hungry.

pretty close to the plot of "Battlefield Earth" and Scientology in general...

The problem is in the disproportionality. There should be a fair exchange. Plus, most of the wealth derived from shares these days is not from holding onto them but in trading them and ratcheting up their prices. Seriously ... how can one justify a stock trading at over 100x its earnings. Same with CEO/C-Suite compensation - up to over 1,700x more in pay than the lowest paid worker gets. And unlike workers, CEOs always get paid. See below for the highest ratios. Personally, I think that corporations should show their 'mini-GINI profile' along with what proportion of their employees earn a living wage based on a 40-hour week. Consider that people who work those hours but cannot afford the basics only end up having to be supported by government programs. Then, because the 0.1%ers have lower tax rates, what really happens is that it's largely tax-paying middle and lower socio-economic schleps who end up having to dole out even more. Really quite sickening.

http://go.bloomberg.com/multimedia/ceo-pay-ratio/

It is just a guess, but the zombie snails and their multiple-host-species lifecycle may have inspired some of Upstream Color, where the parasite migrates from human to pig to orchid and back.

There are two things to realize:

One is that symbiotic relationships can be complex and they can change over time. For instance, part of a population may be parasitic, part may be mutualist. In a workplace example, think of it in cost-benefit terms. Two divisions employ the workers earning the same wages and with the same skills, yet one is in a market where demand is 50% what the other division gets. The first division is clearly making money, so there's likely a mutualism: workers are happy, owner's happy, customers are happy. In the second case, they're bringing in half as much money. If they can't make payroll, the workers are parasitizing the company, taking more than they're making. If, in a third division, the owner's holding down wages while pocketing increased profits, the owner's the parasite. Conditions are always a central part of the relationship.

The second thing to realize is that whether a relationship is mutualistic or parasitic isn't just about whether resources are exchanged, it's about whether both sides have the ability to punish cheating. If one partner can't punish the other for cheating, then that first partner is in danger of becoming a host and the second partner can fexploit their relationship. Being able to punish cheating is a central part of a mutualistic relationship, odd though that may sound at first.

In a corporation, a mutualistic relationship between owners and workers would be where the owners could fire unproductive workers, but the workers could shut down the plant and deprive the owners of income. In such a case, the partners can work out a relationship that benefits both sides. If the workers can't strike, or, alternatively, can't be fired, that's when trouble starts.

Or imagine an engineered parasite that makes one want to climb up to a high point and lose consiousness. A bird eats a morsel. It shits over some plants. Plant gets eaten by cow, sheep or other critter that is eaten by people.

Another version could be attraction to trains instead of heights. Trains do a good job of scattering bodyparts over a good sized area. I once saw a kneejoint when I looked out the window when a train that I was in had stopped because of a suicide. Other parts were several hundred meters back. A few pieces are bound to be left behind for the rats.

Parasitic plants can be especially creepy.

One of the most extreme of these is Rafflesia. This once-photosynthetic plant now spends most of its existence as mycelial-like threads of cells inside a host vine. It's the botanical equivalent of the Sacculina crab parasite, occasionally erupting into the monstrous flower it is best known for.

Mycoheterotrophs, also mentioned above, are plants that parasitize mycorrhizal fungi--the fungi involved in symbioses with green plants--for part or all of their life. As such they are indirect or 'epiparasites' of green plants.

Most mycoheterotrophs live by attracting fungal hyphae into underground organs, where they digest them... Some mycoheterotrophs are completely non-photosynthetic, like the non-green ghost orchids, and the corpse plants (indian pipe or false beech-drops, Monotropa, which is related to heathers) often found around beech trees in the UK.

There are about 50 known evolutionarily independent origins of full-scale mycoheterotrophs. Only half of these origins are found in the orchids.

A few mycoheterotrophs parasitize saprophytic fungi (instead of mycorrhizal fungi) -- they are parasites of organisms that live on dead and decaying matter... How creepy is that?

Older field guides refer to mycoheterotrophs as 'saprophytes', but this was a misreading of their basic biology.

In the US, the federal minimum wage (if actually paid) is sufficient, most places, for a full time worker to live on, provided she or he has a room mate to split rent with, has perfect health, and doesn't indulge in any luxuries like a car or any kind of entertainment or luxuries. Low wages lead to the public subsidizing the cheap employer is when a family tries to live off the earnings of a single minimum wage worker. This is not possible. Also, there are many ploys used to evade minimum wage laws, such as calling workers "contractors", hiring illegal aliens who are unlikely to complain about illegal treatment (the employment of illegal aliens is not illegal, which creates a power differential like if providing sex work were illegal but hiring it were not). But the companies that do this are not really parasitic. They are in fact symbiotic, because the low prices made possible by their tactics benefit the poorest people, which is paid for mostly by those who are more well off (though not by the most prosperous, who hide it all in tax havens). I propose that a symbiote is simply a parasite that has been tolerated for so long that it has been turned to good use. A more parasitic type relationship has been created by the college loan program. This has made it possible for students to go into lifelong peonage by paying exorbitant tuitions. Another example is in medicine, where insurance or subsidy isolates the customer from actual costs, thus eliminating the functioning of market controls while maintaining the justifications of the market system. What happens is that prices are jacked way up, which the customer doesn't notice because the customer isn't really paying (directly, or now). The universities and hospitals that do this are non profit corporations, so the money just goes into exorbitant administrator salaries and investments in very expensive buildings, equipment, and contracted services. An investigator could probably find connections between the administrators and those contracted. Like the very expensive grounds maintenance contractors being somebodies cousin. But some millionaire hospital or university administrator will justify the obscene wealth as being fairly earned in a free market. This situation was created by conservative (aka criminal and plotting) design and liberal (aka gullible and short sighted) cooperation, and on top various forms of religious ideology ice the cake. The preachers to the crooks tell them they deserve what has "come their way" and the preachers to the victims tell them they also deserve what they have "gotten themselves into".

Hopefully India and Pakistan will go the same way. Nah Neither islam nor hinduism value women - at all. Makes even 17th-19thC christianity look enlightened. I would love to be wrong, but I'm not holding my breath ....

Now, one of the inherent problems in hierarchical leadership is that the leader can't know everything that's going on at the levels below him, ...... Which is what shafted both the Nazis & the Soviets, in different ways, of course. ANY completely totalitarian system will (eventually) collapse because of this. When, eventually, N Korea goes, it ain't going to be pretty. ( The J Brunner short "Who Steals my Purse" might be a good way to crash DPRK, incidenntally )

A start has been made on this, very recently by our guvmint. I can't remember if it was a "Coalition" move or this lot, but it's going through anyway. As of very soon, all companies employing over 250 people will have to report the number of women employed & their proportions & what they are paid, compared to the men. One of the "big "accountancy" practices (Deloitte) have already jumped the gun & all the others are now shitting themselves, including one I know of, where up to about £75k a year it's 52% female & then, above that level, it suddenly becomes one or two token women.

This, the "glass ceiling" is still the biggest bar to equitable treatment in our society - what about the USA & others? [ Let's not even think about "Asia" for now, shall we? ]

Dodder ( Cuscuta sp. ) Very fortunately, not frost-hardy, but it can be a real nuisance, even here.

NOT easily possible here, in spite of siren-voices calling for "more efficient private providers" supplying (ripping off) parts of the NHS. Similar in the other developed European countries, too. Our minimum-wage laws just got stricter & I don't think the "contractor" get-out is allowed, either.

Any "law" we devise, such as "hierarchical/totalitarian systems are doomed because the leader can't know and control everything", is really contingent on non universal conditions. Technology may change this, as it does so much. AI and genetic engineering may enhance the "leader's" abilities and, at the other end, various technological forms of dependency may make it possible to provide the "led" with more autonomy without fear of loss of control. The question becomes philosophical. What do you give the man who has everything? If you can create subservient intelligences devoted to your service, what do you do with it? Why do you want that? What can we make the meaning of life? And how long do we have until the cops arrive and take away the slaves?

Heteromeles, if you haven't read "A Deepness in the Sky" it's worth doing so. Vinge is never short of a novel idea or two, and 'focus' is a good/chilling example which deals with many of your objections.

In short, it is like the name implies - a monomania on one fixated subject or task, 'focus', enhancing the cognition if anything, but turning the person into the 'cog in a machine' that current mechanised society tries to do by monetary means.

The ruling class, of course, remain unaffected.

Our minimum-wage laws just got stricter & I don't think the "contractor" get-out is allowed, either.

IR35 basically closed the "contractor" loophole (by punishing the contractors, not the employers), but the employers are getting around it via the whole zero-hours contract thing.

Note also the explosion of self-employment in the UK since 2010 -- and the really low income most of the newly self-employed make.

So, under perfect conditions, it's possible for someone earning minimum wage to 'survive'.

Survive with no kids and no illness.

In other words, survive without reproducing until they aren't needed, at which point they are free to die. Like worker bees or ants.

A question for Heteromeles (and others who know more about the math of this than I do):

Could you model ideologies (and other beliefs) as parasites? They need a host to reproduce (although you could argue written tracts are spores), they don't necessarily 'care' about the host as long as they get transmitted before the host dies, etc.

I'm certain someone has use the idea of memetic parasites in fiction before (sounds like something Brin might do in the Uplift universe) but I'm wondering if the idea stands up mathematically. (At least well enough to argue about at the pub — not looking for peer-reviewed levels of detail here.)

We're off in the land of the selfish meme, so the first and probably best answer is no.

However...

If you want to make the questionable and dubious assumptions that a meme can be treated as something akin to viral DNA AND that the minds that contain memes are sufficiently analogous to genomes that we can talk about selection, then you could in theory use the math of epidemiology to study the spread.

If you want to dive into the math, the only reference I've even looked at is Roy Anderson and Robert May's Infectious Diseases in Humans, and as usual, I'm far from an expert on this.

The basic equation is mostly in Greek and with subscripts, so if you'll accept some letter substitutions, it looks like:

R0=BN/(a+b+c), where

R0 is the basic reproductive rate of infection, aka a measure of its evolutionary success (R0=0 means it's dead) B is the transmission rate N is the population size a is a lethality rate b is rate of recovery from infection c i the normal death rate from other causes.

If a meme is non-lethal, then a and c go away, and the rate of spread is proportional to the transmission rate and the number of people infected, and inversely proportional to the recovery rate. This actually looks a bit like how trends move, but it's also highly abstract. If a meme is lethal (YOLO!), then you've got to add in the lethality rate and the normal death rate as well, as both slow down transmission of the meme.

The next level up is to look at the world as a mosaic of populations and add a term for transmission between populations, rather than assuming everyone is bundled together in one huge population. That's when the interesting dynamics and the existence of super-spreaders (aka taste-makers) becomes critical.

Hope this helps.

Yes However - two sorts of zero-hours contracts exist & there is not sufficient public discrimination between the two. One: Partial or optional, where the employee is not tied to one employer exclusively. These are OK & can be fair, as a useful part-time income, especially for nominally "retired" people who need a bit of extra cash - guess how I know?

Two: The sort getting all the bad publicity & justifiably so, are where so-called "employees" are tied exclusively to one employer, with no prospect of a reasonable number of hours etc ... These latter need stamping on, yesterday, but nothing's happening at the moment.

So ideology as virus not parasite, assuming one is trying to use a biological analogy?

OK. I feel no desire to dive into Greek equations about this. (I might if I was thinking of using it as an idea for a book, but I'm not.)

Thanks for the explanation.

A bit of a tendency towards scrupulosity might be helpful. Obviously clinical levels of scrupulosity are not good under any circumstances, but when Cthulhu is telling you that you don't have to care about anyone else, a tendency to worry about being a bad person might provide a good counter. Anecdotally, people I've seen who struggle with scrupulosity tend to find egoist ideas helpful, so it's plausible that a mild dose of Cthulhu would deal with the bad parts of scrupulosity, while the scrupulosity could prevent Cthulhu from taking over entirely.

I think what you may be looking for is the concept of an "Information Cascade": https://en.wikipedia.org/wiki/Information_cascade

The article contains examples of the math used to model the cascades. I hope you find it helpful.

You have arachnids living in your eyelashes.

Í'm not kidding.

Statistically likely that you do anyway: most humans do, but it's not universal. Infestation rates increase with age of the host, those of us over 40 are very likely to be infected, in children infection rates run as low as 30%.

They are demodex mites.

Since you're asking for cool parasite facts:

The fact that lice are species-specific means that they tend to co-evolve with their host species.

(Um, except for the exceptions. As is usual of simple rules about species and evolution.)

The evolutionary split between (most) birds' lice and (most) mammals' lice is as old as the dinosaurs. Which suggests that dinosaurs had lice, though I'm not aware of any direct fossil evidence of that.

http://www.scp-wiki.net/ had a look at any of these ,?

Same with fleas. The "human flea" is different from the "cat flea" is different from the "dog flea." While your pet's fleas can get on you and bite, they tend to actually breed only on the target animal, or something like it. The fact that the human flea also lives on rodents has been historically important. But lice, fleas and bedbugs (not mentioned yet, but there's a big epidemic of them in the USA) are common.

bedbugs (not mentioned yet, but there's a big epidemic of them in the USA)

If they were naming them nowadays, they could be called "Library Bugs" -- and bug-sniffing dogs are being used more regularly.

Re: 'The next level up is to look at the world as a mosaic of populations and add a term for transmission between populations, rather than assuming everyone is bundled together in one huge population.'

Yes, start conditions would have to include varying distributions/incidences by types.

Because sooner or later biological models tend to get applied to humans as a way of explaining human behavior/traits (esp. between gender/race/culture), how would you handle the fact that humans intermarry therefore can potentially create novel groups? (Or, is this where mutualism steps in?)

Would be interesting to see an analysis of 'how we got here' for various scenarios, with numbers/weightings attached.

Which sounds particularly awful when you think of demodectic mange, but then there we have the difference between a parasitic infestation which is out of control and one which is not. Humans play host to all sorts of hideous yucky creatures but their numbers remain small enough that you never notice until you happen across some "10 Horrible Things That Are Living On You Right Now" clickbait.

All pigeons are host to a trichomonad parasite which lives in the upper digestive tract and is passed from parent to chick during feeding. Normally it causes no problems, but if the mucosa is damaged (for instance by swallowing a large and scratchy piece of food) it can get more of a hold and proliferate out of control, causing lesions which look like scrambled egg but have the consistency of foam rubber. The lesions are vascularised, firmly attached, cause significant damage to the underlying tissue, cannot be removed without causing worse damage, and rapidly block the gullet so the bird cannot feed but causes itself more damage in trying. Fortunately metronidazole works like magic. (And the parasite is highly bird-specific and does not attack humans, so it is perfectly safe to mouth-to-beak feed a bird hospitalised with it.)

Did you hear about the website that had no server? No, what was that? Oh, this site that operated by pinching resources off other sites. It would exploit wordpress vulnerabilities to install itself on servers it found, constantly finding new ones to move on to as the old ones clued on to it and cleaned it off. At any given time it would be hosted on about a hundred different servers using DNS-based load balancing to try and keep its resource use on any one server below a noticeable level. Oh, right. Clever stuff... What was the site about? Parrots.

Drugs that attack parasites can be easily identified by their tendency to attach themselves to aromatic rings at the 3 position.

Parasites – to facilitate/maximize success (spread) need ‘multiple’…

• Modes of transmission • Carriers/hosts • Rewards/benefits for hosts/carriers • Environments/living conditions • Nourishment/food sources

Therefore the most successful parasites would be the most flexible organisms. Extending this, such organisms’ DNA would also have to be especially ‘flexible’ – adaptive, allow themselves to be changed/edited. At the same time however, such organisms would need to have DNA regions that have been proven to prolong success made tamper-resistant. (Not tamper-proof because such a strategy could backfire in a completely novel situation.) Therefore the ultimate parasite would be a 'chameleon parasite'.

Because two people from different populations can interact and share resources with each other, it's as if hosts can share parasites with each other- perhaps closer to a flea infection than most of the other kinds of relationships we are discussing here.

My favorite parasite is the lowly hookworm which I'm sure Charles Stross finds boring, but I like the peculiar life-cycle: (1) skin (2) blood stream to lungs (3) coughed up and swallowed (4) excreted in feces ready for the next foot to come along.

It exhibits most of the features Dan H. talks about in "11" very well: they're tuned up for particular species to the point where if a a dog hookworm finds itself in human skin, it just kind of wanders around lost, and eventually gives up. There's also some ambiguity about whether they're parasites or symbiotes. Get too many of them and they cause anemia (hence, they're working on a vaccine), but there's also a plausible theory that they assist the host by suppressing allergies.

Almost ten years ago, this guy Jasper Lawrence was making the internews with a tale of having decided to try hookworms-as-allergy-meds himself without waiting for any more scientific trials by just travelling to Cameroon and tromping around barefoot in latrines.

Since then, he decided to go into business selling hookworms, and after being hassled by the FDA decided to leave the United States, where he now continues doing business from an undisclosed location (or so they say at the rawpaleodietforum which I'm sure is a reliable source of information).

Most recently Jasper Lawrence has been writing about how Cameroon is a scary scary place, and you really shouldn't think about going there and doing what he did, it's totally worth it to buy his own special line of hookworms instead.

One obvious question: is Jasper Lawrence a parasite or a symbiote?

And I find myself wondering if the hookworms he sells are bred from his own feces, ala the proceedure he originally described: How I reinfest myself: "Simply, I have created a temperature and humidity controlled growing environment in which I mix my hookworm embryo containing feces with a moisture-bearing medium."

(In a world with Japer Lawrences running around, one feels sorry for fiction-writers.)

Re: Jocelyn Ireson-Paine, at 107:"Why have no human diseases evolved that are fun to have and to spread?"

In the early stages of catching a cold, I often feel an odd burst of energy that keeps me up late at night working until dawn. I'm pretty sure this is a viral "strategy": it gets me to wear myself down to make infection easier.

Because then it wouldn't be called a "Dis-Ease", it would be a "Pro-Ease" or something like that ("Uni-Ease" if you want to stick to latin prefixes).

It sounds like you just said that for those people, Cthulhu would be a benign parasite. Perhaps they might even coevolve. (Maybe we need a word like "megaparasite"?)

Yes, but only while Cthulhu's influence was still relatively mild. I expect that, if Cthulhu ever woke up all the way, nobody would be immune.

I was thinking about how to campaign, (here in the USA), on some economic issues regarding the last 40 to 60 years of change.

I came up with the idea of a parasite, where a few of the organisms of a large population turn against the rest of the population and begin stealthily stealing everything. They slowly rearrange things so that the new societal habits not only conceal the thefts, but, in conforming to the new societal standards, the rest of the population actively cooperates in delivering the stolen goods/materials/economic resources.

The societal pressures to conform are so well tied into the status and then the perceptions of what they need that most of the population is focused so narrowly on this work that they don't see that there actually killing themselves.

That's a blunt heavy-handed description, but it's not an in accurate summation of the current economic-political manipulation going on here in the United States where the tax structures and fee structures that run our society have been rearranged in a fashion that now requires the people who make the least money to pay for most of the infrastructure and operation of government.

In the universe of the atrocity archives an analog to this might be something like a magical relationship that causes consumerist activities to generate or deposit energy/life force into the of whatever your parasitic co-op creature is.

Everything we do would feed into it. Clubbing, extreme sports?, Every form of couch surfing, TV, Internet, twitter,...especially ironic would be when one part of our society is cruel to another part would also feed the parasites.

That's all I got.

Combination of parasitism and addiction, so 'paraddict' as the new meme?

Did a search for whether parasites produce novel compounds in their hosts ... not much of a yield.

1) Malaria Parasites Produce Volatile Mosquito Attractants

ABSTRACT

'The malaria parasite Plasmodium falciparum contains a nonphotosynthetic plastid organelle that possesses plant-like metabolic pathways. Plants use the plastidial isoprenoid biosynthesis pathway to produce volatile odorants, known as terpenes. In this work, we describe the volatile chemical profile of cultured malaria parasites. Among the identified compounds are several plant-like terpenes and terpene derivatives, including known mosquito attractants. We establish the molecular identity of the odorant receptors of the malaria mosquito vector Anopheles gambiae, which responds to these compounds. The malaria parasite produces volatile signals that are recognized by mosquitoes and may thereby mediate host attraction and facilitate transmission.'

http://mbio.asm.org/content/6/2/e00235-15.full

2) Could only see one chapter (pgs 378-380) of this text book, but the info may be useful. What caught my layman's eye: a) Actinobacteria are inimical to several parasites. b) Some compounds are also well-known cancer drugs, so (IMO) suggest an interesting relationship between parasites and cancer.

Marine Pharmacognosy: Trends and Applications edited by Se-Kwon Kim

3) Global warming may result in where parasites call home (geographically). There is a possibility that they may become more widespread as their hosts/they head north to more populous climes. (Apologies, but I've not yet read the sample chapters that Heteromeles posted -- in the middle of another book at the moment -- so don't know whether his book already covers this.)

Metabolic approaches to understanding climate change impacts on seasonal host-macroparasite dynamics.

Abstract

'Climate change is expected to alter the dynamics of infectious diseases around the globe. Predictive models remain elusive due to the complexity of host-parasite systems and insufficient data describing how environmental conditions affect various system components. Here, we link host-macroparasite models with the Metabolic Theory of Ecology, providing a mechanistic framework that allows integrating multiple nonlinear environmental effects to estimate parasite fitness under novel conditions. The models allow determining the fundamental thermal niche of a parasite, and thus, whether climate change leads to range contraction or may permit a range expansion. Applying the models to seasonal environments, and using an arctic nematode with an endotherm host for illustration, we show that climate warming can split a continuous spring-to-fall transmission season into two separate transmission seasons with altered timings. Although the models are strategic and most suitable to evaluate broad-scale patterns of climate change impacts, close correspondence between model predictions and empirical data indicates model applicability also at the species level. As the application of Metabolic Theory considerably aids the a priori estimation of model parameters, even in data-sparse systems, we suggest that the presented approach could provide a framework for understanding and predicting climatic impacts for many host-parasite systems worldwide.'

Not directly related to parasites but may be useful ...

Poster title: Cell-reprogramming technology and neuroscience

http://www.nature.com/nrn/posters/ipsc/nrn_ipsc_poster.pdf

Glad that we got to memes; John Barnes' meme war series is some of my very favourite SF.

Those who like the TED talk format will enjoy Ed Yong's relevant parasite talk; Ed is a good writer and this is one of his favourite topics. [https://www.ted.com/talks/ed_yong_suicidal_wasps_zombie_roaches_and_other_tales_of_parasites/citations]

Note that in neuroscience, we parasitise parasites, quite often: use their machinery as vectors for delivery of a payload that we design (protein up- or down-regulation, gene expression, insertion of control tools like channelrhodopsins, etc). Viruses are the most common such tool, but only because they're easiest to manipulate and often very effective. I've been teaching this stuff the past couple of weeks, and in combination with discussion about what it would take to cause a zombie apocalypse (answer: one competent and pissed-off neuroscientist, basically), we've had some fun speculation about what parasites might be doing inside us currently and in the near future :).

Is it OK if I lower the tone of the conversation?

Like, all the way down into filth and depravity?

YES?

...Thank you.

. . . . . .

Orgasm fungus.

More precisely, a stinkhorn mushroom, Phallus Indusiatus (or possibly P.Merulitus) found in Hawaii:

https://en.m.wikipedia.org/wiki/Phallus_indusiatus

Twenty male researchers found the smell disgusting, but 6 out of 16 women reported immediate spontaneous orgasms, with the remainder showing physiological signs consistent with excitement.

Is this fungus a parasite? Nothing in the published research supports such a conclusion.

However I would speculate that it is, or could be, parasitic. I have grave suspicions about the male researchers' failure to notice anything out of the ordinary - indeed, they were repelled by the smell of a fungus well-named 'stinkhorn', which may be an evolutionarily-advantageous protective reflex.

I fear the worst: the fungus is a sex-selective parasite of men, whose lungs are colonised by the mycelium; women are entirely unaffected, except for a behavioural response that makes them willing vectors, eager to approach potential carriers - and with an unimaginably powerful incentive to infect as many men as possible.

The parasite promotes its propagation, and the reproduction of its host.

Could this speculation form the basis of a novel?

Of course. But I suspect that authors in a very different genre to Science Fiction are already hard at work.

...And they need to work fast - the press picked up on this a month ago:

Http://www.independent.co.uk/news/science/there-is-a-type-of-fungus-that-can-instantly-induce-orgasms-in-women-with-its-smell-a6687611.html

And you can be certain that the pharmaceutical industry is pouring billions of dollars into this most interesting area of human 'lifestyle' pharmacology.

I give it five years, max, before any publication casting doubts on wonder drugs from Orgasm Fungus will be buried under heaving piles of libel lawyers.

Enough speculation:

The academic article which brought this to the world's attention (or rather, its surprising inattention) in 2001 is:

Holliday JC, Soule N. (2001). "Spontaneous female orgasms triggered by smell of a newly found tropical Dictyphora species". International Journal of Medicinal Mushrooms 3 (2–3): 162–7. doi:10.1615/intjmedmushr.v3.i2-3.790. ISSN 1521-9437

A riveting read.

If the split between bird and mammal lice is pinned to the Mesozoic, that would either mean

a) if you assume shared parasites always means shared ancestry, the molecular clock in question is seriously out of order, since the original diapsid(lizards, crocodiles, dinos and birds)-synapsid(those more or less hairy critters) goes back much further

b) birds and mammals exchanged their parasites at some point long after the diapsid-synapsid split. It's been known to happen, the lice of Australian marsupials switched from birds, while the lice of South-American marsupials belong to a different group:

http://www.ncbi.nlm.nih.gov/pubmed/7729981 http://www.researchgate.net/profile/Stephen_Barker5/publication/14510804_Lice_cospeciation_and_parasitism/links/546acda40cf2397f78301e98.pdf

Also, it seems the insect group containing parasitic lice and some non-parasitic relatives only appeared in the Cretaceous

http://www.ncbi.nlm.nih.gov/pubmed/16537135

so that would indicate it might have been somewhat generalist at first and later on gave rise to specialised forms:

http://www.ncbi.nlm.nih.gov/pubmed/20860811

Sadly, no pterosaur lice to date for another likely source.

Also note parasitic lice themselves are likely polyphyletic,

http://www.ncbi.nlm.nih.gov/pubmed/15315891 http://www.ncbi.nlm.nih.gov/pubmed/16007465

e.g. extant parasitic lice are descendants of different non-parasitic insects that switched to an ectoparasitic lifestyle at different points, so that doesn't mean the LCA of avian and mammal lice was itself parasitic.

(but see http://www.ncbi.nlm.nih.gov/pubmed/20211746)

For a somewhat more recent review of lice phylogeny, see

http://www.ncbi.nlm.nih.gov/pubmed/22429457

As for human lice in particular, we are host to two to three different species of lice, first of the head louse, where we might count the closely related body louse as a different species

https://en.wikipedia.org/wiki/Head_louse https://en.wikipedia.org/wiki/Body_louse

Time of divergence is sometime around 100.000 years ago and has been linked to the advent of clothing. Our general alopecia might be another explanation, but that would rise some questions about the other louse, the crab louse, but more on this later. Also note that head and body louse are quite closely to chimp lice.

As for the crab louse,

https://en.wikipedia.org/wiki/Crab_louse

it's a much more distant relative of the other human and chimp lice, actually it's most closely related to gorilla lice:

http://www.ncbi.nlm.nih.gov/pubmed/17343749

And the point of divergence is much later that the split between Gorilla and Pan/Homo.

Current opinion is we gained it at some point after our two main hairy areas got seperated, though we might argue about the way this happened. I've heard stories about early hominids using gorilla nests for sleep, but than, as we know crab lice are an STD. And I have always suspected the final split between Homo and the other apes was "whoever was to slow to climb the trees when Homo was horny".

Two final points, related to my last holiday in Italy and visit to Milan:

https://en.wikipedia.org/wiki/Museo_Civico_di_Storia_Naturale_di_Milano

First of, there was a display of sexual dimorphism in slugs that made me think of Equoid, I'll have to look it up.

Second of, the look on my brother's face when I explained possible Neanderthal admixture

https://en.wikipedia.org/wiki/Archaic_human_admixture_with_modern_humans#Neanderthals

was quite priceless. ;)

Awesome comment! Always a pleasure to encounter someone who really knows what they're talking about.

I enjoyed looking at the linked articles, particularly "Taxonomy of lice and their endosymbiotic bacteria in the post-genomic era."

Though the fact that "Molecular clocks show that the major families of lice arose in the late Mesozoic and radiated in the early Cenozoic, following the radiation of mammals and birds." is a bit vague on my dinosaur-lice theory.

Given that the raptor side of the dinosaurs appear to have been feathered, and also given that lice really appreciate having something to hang on to, I strongly suspect that at least some dinosaurs were lousy.

I also suspect that if lice hadn't turned up earlier, they'd have arrived not long after the arrival of fur and/or feathers. That's an ecological niche, and ecological niches don't usually stay empty for long if there's anything around that can make use of them.

An interesting point about evolution. If most of the food your species eats has vitamin C it, and you have a mutation that blocks your internal production of vitamin C, it doesn't affect your fitness.

There was an interesting Radiolab episode title Shrink about giant viruses positing that many viruses my have started as bacterial parasites that got simpler and simpler, as they evolved to rely more and more of their lifecycle to their hosts, until they were no-longer bacteria at all.

I have vague memories of a story about a time-travelling dinosaur hunting safari where the successful hunter brought down his (unfeathered) Tyrannosaurus trophy only to be jumped by giant crab-lice abandoning their original host.

J Tiptree story ???

Possibly Brian Aldiss's short story Poor Little Warrior. Though that one was a "Brontosaurus".

Ovine Pulmonary Adenocarcinoma spreads by sheep coughing up phelgm on the grass and other sheep eating it. I mention this mostly because the diagnostic test involves a researcher grasping a sheep roughly by its hind legs, lifting it sharply, and seeing what comes out of the front of the sheep. Picture that if you will, ahh - the glamour.

Also see -

http://www.moredun.org.uk/research/practical-animal-health-information/disease-summaries/ovine-pulmonary-adenocarcinoma-opa-or

I think you could come up with a nasty enough scenario to make people Quiver with this one:

http://www.bbc.co.uk/news/health-34857022

This might be of interest. A bunch of mostly-fish parasites just got reclassified as Cnidaria — the same phylum as jellyfish & sea anemones. Partially because folk spotted structures very like the stinging structures in jellyfish.

http://www.pnas.org/content/early/2015/11/13/1511468112

Fun!