It's that bacteria that is the cause of plague. And that bacteria has existed for a long, long time. And the actual plague we're going to talk about is going to really be centralized in Mongolia and it's going to spread outward from there. But basically this is a bacteria that exists in various rodent populations, some cute, some not so cute like the black rat. And it attacks fleas and it blocks up the mid-gut section of the flea. The flea then tries to eat, it can't, it keeps trying to suck blood. It throws up that bacteria into the rodent it's living on and then that rodent's going to die.