Rome has a cat problem.
The Ufficio dei diritti degli animali (Office of Animal Rights) estimates that there's about 300,000 stray, feral cats living around Rome. I live near Largo di Torre Argentia, a massively interesting set of ruins that contains one of the many places in Rome where Julius Caesar (him of the salad fame) was allegedly killed. Except you wouldn't know it to look at it, because with so many ancient ruins dotted around the place and so many cats running wild in the streets, the council - understandably - threw up their hands and said "balls to this malarky, let the cats have it." Now the square is probably more famous as a cat sanctuary than as an actual historical monument in its own right.
The point is, Rome has a lot of cats. With me so far?
One of the many parasites carried by cats is toxoplasmosis. It's a parasite that thrives in cats. It can live in other organisms, but it can only reproduce in the intestines of cats. So, in rats and mice, the parasite effects the brain by making cat piss smell amazing. This draws them to the cat and makes them more likely to be eaten, so the parasite will make its way back to cat intestines. There's also a theory that it does much the same for people. This is the parasite that causes people to turn into crazy cat ladies - without knowing it, they surround themselves with cats to increase their chances of being eaten. (And for the record, if you die and there's no-one around to feed it, your dog will usually wait a week or so before eating your body. Your cat, on the other hand, might wait a day, if you're lucky. More proof that cats are mean-spirited little fucks.)
Listening to this week's Radio Lab, I discovered another potential side effect of toxoplasmosis in humans: it makes them worse drivers. Someone infected by toxoplasmosis is two and a half times more likely to die in a car accident than someone who is not infected.
So to sum up: Rome has an abundance of cats, and cat parasites make you a reckless driver.
Just sayin'. It's not like I'm suggesting these two points are linked.