My favorite example of animal parasitism
I’ve already written about two amazing parasite stories today, but I’ve saved the best for last. Toxoplasmosis gondii is a parasitic protozoan that can live inside any warm-blooded animal. However, in order to reproduce, they need to be digested by cats. They can then be passed onto other mammalian hosts, including humans, through cat feces.
What, you might ask, happens to a protzoan that finds itself in a non-feline host - say, inside of a rat? This is the amazing part. The parasite secretes the neurotransmitter dopamine inside of the rat, causing it to lose its fear of cats. Not only that, the infected rats become sexually attracted to cats. As you might expect, this is a particularly effective strategy for parasites that want to find their way back to cats.
I’m done editorializing. Mind blown.