Is There a Disease That Makes us Love Cats?

Today, about a third of the world's population is infected with a strange disease called toxoplasmosis — and most of them never even know it. And while the parasite can multiply in practically any host, it can only reproduce sexually in the intestines of cats. Could this disease be the reason so many people love cats and keep them as pets? TED ED shares what we know about toxoplasmosis.