When I was taking large doses of methotrexate weekly, I shopped for wedding shoes with socks on. I was so embarrassed by my chronic foot fungal infections, which I simply couldn't seem to get rid of, that I was willing to risk buying shoes that didn't fit. Reading Casadevall's wonderfully titled tome, I began to understand why. Casadevall is a medical specialist in fungi, and he was inspired to write this by all his friends asking him how much science the Last of Us was actually based on, and the answer it turns out, is more than you would like.

To be clear, the bit about turning into zombies is not super realistic . Fungal infections can drive ant behaviour, but our brains are very different to ants. Fungal infections can and do affect human brains, but not so much in a controlled way. But the part that Casedevall argues is plausible is the climate-change induced evolution of fungal species that may lead to an explosion of fungi able to survive in human body temperature - currently just a small fraction. Casadevall posits a theory that it was the warm blooded protection against fungi that assured the rise of mammals in the wake of the asteroid hit that killed off the dinosaurs.