The book manages to be gross and fascinating and occasionally beautiful.
Given the age, I'm sure some of the science is outdated, perhaps even by people who grew up reading the book. But it remains one of my favorites, and it's an accessible read. If not always a comfortable one!
> it inspired quite a few researchers to go into the study of parasites
That was me!
First I read Peeps by Scott Westerfeld when I was ~13, where ever odd numbered chapter is the story, and every even numbered chapter describes a different parasite.
At the end of the book was a blurb that said "if you enjoyed the parasite chapters, go read Parasite Rex, which I did. I loved it.
That book inspired me to take AP Bio, then get degrees in molecular biology and bioinformatics. In college I did research on a few different species of parasitic wasp for a couple years. I've written the wikipedia page for two different parasitic wasps and given numerous presentations on my favorite wasps.
The wasps are more of a spare time passion these days, though. It's much easier to make a living with bioinformatics and robotics.
I still keep my (well-worn) copy of Parasite Rex on the nightstand.
I remember listening to the radio (I believe on cbc canada), and one issue of studying any living thing is, whether your animal/creature of choice is in vogue currently or not. People below have mentioned funding which ties into that, but, if you're studying birds it's a lot easier to publish, there's more of an ecosystem and conferences, etc... than if you were to study some insect that nobody has heard of. Even within existing conferences you might not get "top-billing", even if you're presenting.
Pity as the things nobody has ever heard of are probably the most interesting.
I wish I remembered more details so could link something.
It's a pretty widely known thing that studying charismatic megafauna gets you lots of money. However, they're also generally WAY more of a pain to study. Fewer individuals, larger home ranges, expensive permits, etc. A good friend studies basking sharks and the shark research world is insanely competitive, full of crazy type A folks. Compared to the insect ecology world (where I come from), which is full of pretty chill stoners and weirdos.
> studying charismatic megafauna gets you lots of money
May I ask how so? Is it from producing popular documentaries or something? Or is there the research grant money from conservationist institutions or societies? (I can see how that wouldn't be there for parasites).
Well, researchers mostly use the subjects which are available which tends to be broke college students, studying corporate executives is more difficult.
> Parasitism is far from easy living; hundreds of millions of years of evolution have prodded parasites to find and manipulate other animals, just as those animals have evolved their own unique methods of survival.
Parasites manipulating their hosts is something that really fascinates me from an evolutionary point of view. An example given in the article is T. gondii [0]:
> [...] a parasitic protozoan that boasts “Mind Control,” because it attracts its rodent host to the smell of cat urine, where the rat spreads the parasite to felines.
Infected mice also have a reduced fear from predators, likely for the same reason.
A parasitoid lays multiple eggs in a caterpillar host. The larvae eventually hatch out of the host's body, but do NOT kill it. They then need to pupate outside the host, which leaves them vulnerable to predation. Their former host, the caterpillar whose body they just violently erupted from, will then act as a BODYGUARD. It will body slam any insects that approach, knocking them away from the pupae. Truly the stuff of science fiction.
There's a nematomorph parasite that infects crickets, and part of its life cycle is aquatic. It will induce crickets to jump into water and drown themselves (there are some crazy videos of this on YouTube). This study found that the allochthonous input (land to water) coming from the crickets jumping into a Japenese stream was a large part of an endangered trout species' diet. In short, his trout was kept alive because of a parasite driving crickets to drown themselves.
What's weird is that it then... basically acts like a tongue? It doesn't seem to be massively detrimental to its host, but it's absolutely insane to see a fish's mouth open and then there's just like, a little guy hanging out in there.
Tangentially: assuming I had the drive + health to make the change, do you feel it would be a particularly challenging move for a software engineer to abandon their career to go back to school and study insects or other arthropods? I'm not a competitive person at all, and I saw your other comment above about the field, but I still imagine the money available for studying bugs is a tiny fraction of that for writing them.
Don't you think you're underplaying your hand here a little? The mechanism of this behavioral modification is in itself both beautiful and extremely spooky: https://en.m.wikipedia.org/wiki/Bracovirus
Ancestral humans shared territory with leopards, and children were vulnerable (1). Big cats are still dangerous.
Having a leopard stare at you, even through a fence, does raise the heart rate. But I don't know why we regard big cats so relatively favourably, when an evolved innate repulsion, such as to spiders or snakes, would make as much sense.
Some people lost fear from other predators: aggressive dogs. They even force family members to live in dangerous situation, where they get attacked and injured regularly.
Mental illness or brain parasite is the only possible explanation for dog owners behavior.
"Attacks in India are still relatively common, and in some regions of the country leopards kill more humans than all other large carnivores combined.[9][10] "
A fascinating video of a leopard attacking baboons[1]. The big cat achieves a scratch on one baboon and then runs away from the troop. Enough to infect and then later pick off an errant victim? To my eye, the baboons are sad at the expectation that they will soon lose a friend.
Toxo comes into the picture by way of an old wives' tale forbidding mothers from having cats around during pregnancy. Basically the only spot that toxo can reproduce itself is within a cat's stomach. The toxo then goes out with the feces (which is where the caution comes from) and rodents eat the feces. Toxo's mission is to get that rodent back into the stomach of a cat.
Rodents themselves are genetically wired to fear cats. A rat that smells cat urine will go the other way. However, get that same rodent infected with toxo and it will suddenly be attracted to the scent. Thus it checks out cat urine and becomes more likely to find itself in the stomach of a cat.
So you'd think toxo is wreaking havoc with all sorts of elements within the rat, turning it into a deranged rat. Nope. Everything else remains and functions normally - olfaction, social behavior, learning and memory, and even fear behaviors all stay the same.
It takes about 6 weeks for toxo to migrate from the gut to the brain. In the brain it forms cysts in multiple locations, but mainly in the amygdala region. The amygdala is the brain's center for fear and anxiety. It is also the brain center for forming predator aversion pathways. Once in the amygdala toxo is able to take dendritic nerve cell endings and cause them to shrivel up.
Shrivel up the dendritic spine, shrivel up the fear pathway.
Taking the creepiness up several notches, recall that other fear/anxiety based behaviors remain constant. The parasite is actually locating and unwiring the very pathway it needs to destroy.
Amazingly, it does not stop there. Toxo wants to make cat urine attractive and it is able to do so by hijacking another well known pathway; sexual attraction. Part of the neural connection for sexual activity passes through the amygdala. This gets rewired and a rodent infected with toxo will no longer have a fear response to the urine but it will have activation of this sexual response pathway, resulting in attraction to the scent.
Eau de merde. C'est fantastique!
They are mapping out the toxo genome. One curious element discovered is that this protozoan parasite has two genes for tyrosine hydroxylase. This is responsible in part for the production of dopamine, which is all about rewards and the anticipation of rewards (really it's the thing that gets you to do the thing needed for the reward). It acts as a catalyst in the conversion of L-tyrosine into L-DOPA, which is in turn a precursor for dopamine.
So at the right moment, the parasite secretes the enzyme, thus driving the neurons to create dopamine at the time the toxo wants them to, thus associating dopamine with the neural pathway that toxo wants used!
Do other parasites that are closely related to toxo share this gene? No. Strangely it does not have genes for other common hormones - just this one that allows it to plug into the key for mammalian reward systems. And it starts generating it after it has penetrated into the brain and formed cysts, especially cysts in the amygdala.
For humans the current clinical dogma is that it's a disaster for a fetus but otherwise runs its course and goes latent. However, a small literature exists suggesting that males in particular become more impulsive after a toxo infection and that people who are toxo infected are 3-4 times more likely to be killed in car accidents that involve reckless speeding.
He quips that this is a protozoan parasite that knows more about the neurobiology of fear and motivation than 25,000 neuroscientists standing on each others' shoulders.
And it's not alone. The rabies virus knows how to control the neurobiology of aggression. It makes the animal more likely to bite and pass on the rabies infection.
>In the fall of 1985, Scott L. Gardner found himself standing over his toilet bowl, fishing around in the squishy output of his empty bowels with a chopstick.
fsckboy's law of headlines: If the headline asks a question, check if the first sentence has your answer
>...Gardner was prescribed an antiparasitic pill, and the next morning, he pooped out his intestines’ inhabitant—all 12 inches of it.
irl, my brother got a parasite once, a tapeworm. This was all without leaving an upscale suburb of Boston. Only "noticed" it when he, a well-built vigorous athlete, lost a lot of weight out of the blue. It was eating his lunch, so to speak.
How does that work. A tapeworm is pretty small relative to your brother (eg by mass), one would think it's caloric needs are similarly small and it would just use a small fraction of his food. Can a tapeworm really consume a significant fraction of an adult's food?
At the Meguro Parasitological Museum [1], they have an 8 meter long tapeworm [2] extracted from a human. Yes, that is an extreme example and still less mass than a person, but they can get large.
there are different types of tapeworms that infect different hosts. cattle tapeworms can grow to 12 feet and much more. It doesn't take much googling to find claims of 100 feet.
google "tapeworm symptom loss of weight" and you will get the recommendation "time to see a doctor"
Okay but: when he stepped on the scale, he was weighing himself and the tapeworm. A tapeworm can't just magically eat your lunch and send the calories into another dimension.
There's got to be something else to it, like that your belly feels strange and you lose your appetite.
Suddenly losing a lot of weight points toward dehydration, for one thing.
Maybe if the guy was well muscled he needed a constant influx of protein, also. Breakdown of muscle which is mostly water doesn't translate to a lot of calories.
I recommend the funny and gross book, "New Guinea Tapeworms and Jewish Grandmothers: Tales of Parasites and People" by Robert S. Desowitz. Basically a bunch of horrible parasite diseases, some with a bit of detective story to figure out.
Readit News
The book manages to be gross and fascinating and occasionally beautiful.
Given the age, I'm sure some of the science is outdated, perhaps even by people who grew up reading the book. But it remains one of my favorites, and it's an accessible read. If not always a comfortable one!
That was me!
First I read Peeps by Scott Westerfeld when I was ~13, where ever odd numbered chapter is the story, and every even numbered chapter describes a different parasite.
At the end of the book was a blurb that said "if you enjoyed the parasite chapters, go read Parasite Rex, which I did. I loved it.
That book inspired me to take AP Bio, then get degrees in molecular biology and bioinformatics. In college I did research on a few different species of parasitic wasp for a couple years. I've written the wikipedia page for two different parasitic wasps and given numerous presentations on my favorite wasps.
The wasps are more of a spare time passion these days, though. It's much easier to make a living with bioinformatics and robotics.
I still keep my (well-worn) copy of Parasite Rex on the nightstand.
Pity as the things nobody has ever heard of are probably the most interesting.
I wish I remembered more details so could link something.
May I ask how so? Is it from producing popular documentaries or something? Or is there the research grant money from conservationist institutions or societies? (I can see how that wouldn't be there for parasites).
Parasites manipulating their hosts is something that really fascinates me from an evolutionary point of view. An example given in the article is T. gondii [0]:
> [...] a parasitic protozoan that boasts “Mind Control,” because it attracts its rodent host to the smell of cat urine, where the rat spreads the parasite to felines.
Infected mice also have a reduced fear from predators, likely for the same reason.
[0] https://en.wikipedia.org/wiki/Toxoplasma_gondii
This is my absolute favorite example: https://journals.plos.org/plosone/article?id=10.1371/journal...
A parasitoid lays multiple eggs in a caterpillar host. The larvae eventually hatch out of the host's body, but do NOT kill it. They then need to pupate outside the host, which leaves them vulnerable to predation. Their former host, the caterpillar whose body they just violently erupted from, will then act as a BODYGUARD. It will body slam any insects that approach, knocking them away from the pupae. Truly the stuff of science fiction.
There's a nematomorph parasite that infects crickets, and part of its life cycle is aquatic. It will induce crickets to jump into water and drown themselves (there are some crazy videos of this on YouTube). This study found that the allochthonous input (land to water) coming from the crickets jumping into a Japenese stream was a large part of an endangered trout species' diet. In short, his trout was kept alive because of a parasite driving crickets to drown themselves.
This one isn't really a manipulative parasite, but there is an isopod that will eat a fish's tongue: https://oceanconservancy.org/blog/2022/04/28/tongue-eating-l...
What's weird is that it then... basically acts like a tongue? It doesn't seem to be massively detrimental to its host, but it's absolutely insane to see a fish's mouth open and then there's just like, a little guy hanging out in there.
Tangentially: assuming I had the drive + health to make the change, do you feel it would be a particularly challenging move for a software engineer to abandon their career to go back to school and study insects or other arthropods? I'm not a competitive person at all, and I saw your other comment above about the field, but I still imagine the money available for studying bugs is a tiny fraction of that for writing them.
In primates, there's some non-fear of cats too. For humans and domestic felines, this isn't much of an issue. For chimpanzees who share territory with leopards, this is more of an issue. https://www.nytimes.com/2016/02/16/science/a-parasite-leopar... (and the paper - Morbid attraction to leopard urine in Toxoplasma-infected chimpanzees https://www.sciencedirect.com/science/article/pii/S096098221... )
Having a leopard stare at you, even through a fence, does raise the heart rate. But I don't know why we regard big cats so relatively favourably, when an evolved innate repulsion, such as to spiders or snakes, would make as much sense.
1) https://en.wikipedia.org/wiki/Leopard_attack#Leopard_predati...
Mental illness or brain parasite is the only possible explanation for dog owners behavior.
"Attacks in India are still relatively common, and in some regions of the country leopards kill more humans than all other large carnivores combined.[9][10] "
[1] https://www.youtube.com/watch?v=p5wnKEXs6YM
More often busted for breaking the speed limit.
More often founding a company.
Rodents themselves are genetically wired to fear cats. A rat that smells cat urine will go the other way. However, get that same rodent infected with toxo and it will suddenly be attracted to the scent. Thus it checks out cat urine and becomes more likely to find itself in the stomach of a cat.
So you'd think toxo is wreaking havoc with all sorts of elements within the rat, turning it into a deranged rat. Nope. Everything else remains and functions normally - olfaction, social behavior, learning and memory, and even fear behaviors all stay the same.
It takes about 6 weeks for toxo to migrate from the gut to the brain. In the brain it forms cysts in multiple locations, but mainly in the amygdala region. The amygdala is the brain's center for fear and anxiety. It is also the brain center for forming predator aversion pathways. Once in the amygdala toxo is able to take dendritic nerve cell endings and cause them to shrivel up.
Shrivel up the dendritic spine, shrivel up the fear pathway.
Taking the creepiness up several notches, recall that other fear/anxiety based behaviors remain constant. The parasite is actually locating and unwiring the very pathway it needs to destroy.
Amazingly, it does not stop there. Toxo wants to make cat urine attractive and it is able to do so by hijacking another well known pathway; sexual attraction. Part of the neural connection for sexual activity passes through the amygdala. This gets rewired and a rodent infected with toxo will no longer have a fear response to the urine but it will have activation of this sexual response pathway, resulting in attraction to the scent.
Eau de merde. C'est fantastique! They are mapping out the toxo genome. One curious element discovered is that this protozoan parasite has two genes for tyrosine hydroxylase. This is responsible in part for the production of dopamine, which is all about rewards and the anticipation of rewards (really it's the thing that gets you to do the thing needed for the reward). It acts as a catalyst in the conversion of L-tyrosine into L-DOPA, which is in turn a precursor for dopamine.
So at the right moment, the parasite secretes the enzyme, thus driving the neurons to create dopamine at the time the toxo wants them to, thus associating dopamine with the neural pathway that toxo wants used!
Do other parasites that are closely related to toxo share this gene? No. Strangely it does not have genes for other common hormones - just this one that allows it to plug into the key for mammalian reward systems. And it starts generating it after it has penetrated into the brain and formed cysts, especially cysts in the amygdala.
For humans the current clinical dogma is that it's a disaster for a fetus but otherwise runs its course and goes latent. However, a small literature exists suggesting that males in particular become more impulsive after a toxo infection and that people who are toxo infected are 3-4 times more likely to be killed in car accidents that involve reckless speeding.
He quips that this is a protozoan parasite that knows more about the neurobiology of fear and motivation than 25,000 neuroscientists standing on each others' shoulders.
And it's not alone. The rabies virus knows how to control the neurobiology of aggression. It makes the animal more likely to bite and pass on the rabies infection.
from: http://www.robertsapolskyrocks.com/toxoplasmosis.html
https://pubmed.ncbi.nlm.nih.gov/29906469/https://www.ncbi.nlm.nih.gov/pmc/articles/PMC117239/https://www.mdpi.com/2077-0383/13/2/593
Martin Shkreli is still getting raked of the coals over his deraprim pricing shenanigans
https://www.ftc.gov/news-events/news/press-releases/2023/01/...
>Why do so few researchers study them?
>In the fall of 1985, Scott L. Gardner found himself standing over his toilet bowl, fishing around in the squishy output of his empty bowels with a chopstick.
fsckboy's law of headlines: If the headline asks a question, check if the first sentence has your answer
>...Gardner was prescribed an antiparasitic pill, and the next morning, he pooped out his intestines’ inhabitant—all 12 inches of it.
irl, my brother got a parasite once, a tapeworm. This was all without leaving an upscale suburb of Boston. Only "noticed" it when he, a well-built vigorous athlete, lost a lot of weight out of the blue. It was eating his lunch, so to speak.
How does that work. A tapeworm is pretty small relative to your brother (eg by mass), one would think it's caloric needs are similarly small and it would just use a small fraction of his food. Can a tapeworm really consume a significant fraction of an adult's food?
[1] https://www.kiseichu.org/e-top
[2] Visible in the tall blue case here: https://static.wixstatic.com/media/079dcd_843c7597ef244423aa...
google "tapeworm symptom loss of weight" and you will get the recommendation "time to see a doctor"
There's got to be something else to it, like that your belly feels strange and you lose your appetite.
Suddenly losing a lot of weight points toward dehydration, for one thing.
Maybe if the guy was well muscled he needed a constant influx of protein, also. Breakdown of muscle which is mostly water doesn't translate to a lot of calories.
https://www.microbe.tv/twip