There’s a new paper out that extends the record of host manipulation by toxoplasma. We already knew that toxoplasma infections cause mice to lose fear of cat urine – turns out that toxoplasma infections also cause chimpanzees to develop a morbid attraction to leopard urine, a marker of their main predator. Uninfected chimps avoid it. Interestingly, infected chips don’t seem attracted to lion or tiger urine, which suggests a specific strain of toxo.
The background is that toxoplasmosis infects many warmblooded creatures as the intermediate host, but can only sexually reproduce in cats, their definitive host. These protozoans (apicomplexans, like malaria) need to have their intermediate host eaten by a cat, and they’ve apparently evolved methods of manipulating host behavior to help bring that about, probably through their colonization of the brain.
There is some evidence that toxoplasma in the brain has effects on human behavior, such as slowed reaction…
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