And normally if we get hold of these people we can cure them. But now let's focus on why did this happen? How did the little bacteria, the little flea, the little rat get all the way to London? So how did the Black Death start, the great plague, the great mortality? We do know that there were some type of natural disasters that occurred in the 1330s in the Central Asia Mongolia area. It could have been an earthquake, but there was drought, there was famine, there was a change in the environment. That probably caused some of those varmints, some of those rodents, some of those rats to go scurrying about.