The bubonic plague, that flea-borne bacterial disease that wiped out a good portion of Europe in the Middle Ages, is back.

Actually, it never left. Outbreaks still happen, though they are rare and usually treatable (thanks, antibiotics!). There have even been some cases of the plague in America, both in our squirrels and our humans.

The majority of plague outbreaks are in Africa these days. With an average of 500 cases every year, the country of Madagascar is the worst. In October, the Red Cross began working with Madagascar's prisons to control the rat population and make conditions more hygienic to try to stop the spread, but now comes word of an outbreak in the village of Mandritsara. At least 20 have died so far, and two cases of the pneumonic plague (the most deadly form of the disease) have been confirmed.

The fact that this is one of the worst outbreaks the world has seen in quite some time and that it happened outside of "plague season," is cause for additional concern.

In 2012, Madagascar recorded 60 plague deaths, the highest number in the world.