Nils Stenseth

That's the one that most people think are the right one. They are wrong.

I usually say to my students that if you want to have enemies within science, study plague. Because there are so many strong personalities and there are so many different opinions and they hate each other.

It became very clear that the rat could not have played a major role in the spread of plague in Europe.

In humans, it can be spread partly by ectoparasites or by droplets. So coughing, when you're having a cold, then that's a way of transmission.

And for the last 25 years or so, I've been studying plague, Yersinia pestis, the bacterium that caused the Black Death.

The Black Death killed half of the European population in a year or two. The plague expresses itself in the human being in three different forms. The most common one is bubonic, where it's swellings on the body. That may evolve into a pneumonic one that goes into the lung, and both might develop into a form that goes into the blood.

If you're infected by eosinopestis, if you don't come to a doctor within four or five days, you can consider yourself being dead.