LETTERS

摘要

The protozoan Toxoplasma gondii makes infected mammals more likely to take risks and also gives them a preference for the smell of cat urine, so infected rats and mice are easy prey for cats (30 May, p 42). Colin Barras didn't, however, suggest any benefit to the protozoan in altering human behaviour. What could that benefit be, since we aren't usually cat prey? But this is to look at the problem from the protozoans' viewpoint, when surely the whole system is for the benefit of cats. Cats spread the bug to infect rodents, which are then more easily caught thus benefiting the cats. The cats also spread the bug to humans who inexplicably take a liking to cats, despite the disdain they show for us. Why else would humans feed cats and look after them, unless their brains were deranged by toxoplasmosis?