Thursday, February 09, 2006

Parasites on the Brain

Parasites on the Brain (article)

Like cats?


Toxoplasma gondii may be the most prevalent human parasite. As many as 50% of humans worldwide, and up to 80% in urban areas, have been infected with it at some time in their lives.

There are some interesting studies showing striking behavior differences between rats that have been infected with Toxoplasma and those that haven't. Normal rats are very reactive to the smell of cat urine - an unsurprising survival instinct. If they encounter cat urine in their environment they have an extreme fear reaction, and they will avoid that spot thereafter. Rats infected with Toxoplasma don't do this. They have no fear reaction to the smell of cat pee; they don't avoid the areas where they smell it. In fact some of the studied rats preferentially returned to the sites where they had smelled the urine. It's hard to see how this could benefit the rat, but easy to see how it could benefit Toxoplasma, which could return to its preferred host to complete its life cycle if the rat gets eaten.


Oh yeah, it gets better.

E. Fuller Torrey of the Stanley Medical Research Institute has found evidence of some that may be more drastic. Toxoplasma is associated with damage to the brain's astrocytes - glial cells that function as an interface between neuronal and non-neuronal tissues. Astrocyte damage has also been associated with schizophrenia. Now add in that pregnant women with high levels of Toxoplasma antibodies are more likely to have children who later develop schizophrenia, and you have something to give most people pause.


Why do people like cats again?
But this does shed some light on why 'cat people' are the way they are.
Crazy.

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