twilyth
Aug 2, 2011, 12:44 AM
Well, toxoplasma gondii. Toxoplasmosis is the disease it causes. It infects and estimated third of the world's population but is generally considered harmless. I suppose that would be "harmless" in the same sense as asbestos was once regarded as harmless.
This is an incredibly devious protozoan if I might be permitted to anthropomorphize for a moment. It can only reproduce in cats so it's primary objective is to infect an animal that will be eaten by cats. The preferred vector seems to be mice. Once it infects a mouse, it dulls the animal's sense of fear and actually causes it to have an affinity for cat urine - thus making it even more likely that it will be caught and eaten.
However there is some evidence that it also has similar effects in people.
article (http://blogs.discovermagazine.com/notrocketscience/2011/07/26/is-the-parasite-toxoplasma-gondii-linked-to-brain-cancer/)
Humans can become infected with T.gondii, either through contact with soil contaminated by cat faeces, or by eating infected meat. These infections are extremely common, and up a third of the world may carry the parasite. However, rates of infection vary greatly from country to country, from just 7 percent in the UK and 11 percent in the USA, to around 67 percent in Brazil.
In the first few weeks of an infection, the parasite causes mild flu-like symptoms, if any. Afterwards, it creates cysts within the blood cells and neurons of its host, and it can persist that way for an entire lifetime without any obvious ill effects. It only causes serious problems for people with weakened immune systems, who can become seriously ill.
But T.gondii can have subtler effects on its hosts. The parasite clearly changes the behaviour of mice and rats, fatally drawing them to the scent of cats. This increases the odds that the parasite will end up in a cat, the only animal in which they can mature and reproduce. There’s some evidence that it does similar mind-bending tricks in humans. All of these associations are disputed, but previous studies have linked the parasite to: subtle personality changes; mental illnesses like schizophrenia, anxiety and bipolar disorder; a higher risk of traffic accidents; and even global differences in human culture. Now, brain cancer joins this controversial list.
edit: the article mainly focuses on it's link to brain cancer, but since there was a great article in SciAm Mind that focused on the behavioral aspects (potentially) and since I can't post links to that article, I decided to quote this one for that purpose. :toast:
This is an incredibly devious protozoan if I might be permitted to anthropomorphize for a moment. It can only reproduce in cats so it's primary objective is to infect an animal that will be eaten by cats. The preferred vector seems to be mice. Once it infects a mouse, it dulls the animal's sense of fear and actually causes it to have an affinity for cat urine - thus making it even more likely that it will be caught and eaten.
However there is some evidence that it also has similar effects in people.
article (http://blogs.discovermagazine.com/notrocketscience/2011/07/26/is-the-parasite-toxoplasma-gondii-linked-to-brain-cancer/)
Humans can become infected with T.gondii, either through contact with soil contaminated by cat faeces, or by eating infected meat. These infections are extremely common, and up a third of the world may carry the parasite. However, rates of infection vary greatly from country to country, from just 7 percent in the UK and 11 percent in the USA, to around 67 percent in Brazil.
In the first few weeks of an infection, the parasite causes mild flu-like symptoms, if any. Afterwards, it creates cysts within the blood cells and neurons of its host, and it can persist that way for an entire lifetime without any obvious ill effects. It only causes serious problems for people with weakened immune systems, who can become seriously ill.
But T.gondii can have subtler effects on its hosts. The parasite clearly changes the behaviour of mice and rats, fatally drawing them to the scent of cats. This increases the odds that the parasite will end up in a cat, the only animal in which they can mature and reproduce. There’s some evidence that it does similar mind-bending tricks in humans. All of these associations are disputed, but previous studies have linked the parasite to: subtle personality changes; mental illnesses like schizophrenia, anxiety and bipolar disorder; a higher risk of traffic accidents; and even global differences in human culture. Now, brain cancer joins this controversial list.
edit: the article mainly focuses on it's link to brain cancer, but since there was a great article in SciAm Mind that focused on the behavioral aspects (potentially) and since I can't post links to that article, I decided to quote this one for that purpose. :toast: