Bubonic plague kills at least 20 in Madagascar

Bacteria that causes the plague.</p>

Bacteria that causes the plague.

At least 20 people in a remote village in Madagascar have died from bubonic plague in one of the worst outbreaks in recent years.

The deaths last week come after a warning in October from the International Committee of the Red Cross that the country was at risk of an epidemic of the disease.

More from GlobalPost: What's up with the bubonic plague?

They are especially troubling because the outbreak occurred outside the island's normal plague season, which runs from July to October, and at a far lower elevation than usual — suggesting it might be spreading.

Known as the Black Death in the Middle Ages, bubonic plague is spread by unsanitary conditions, transmitted to humans via fleas, usually from rats.

Living conditions in the island nation have deteriorated since a coup in 2009 and the ensuing political crisis, the BBC reported.

More from GlobalPost: Risk of bubonic plague epidemic in Madagascar has experts worried

The bubonic plague killed an estimated 25 million people in the Middle Ages, and while it's now much more rare, it's still alive and well.

The World Health Organization reports around 2,000 cases of the plague each year, more than 90 percent of which are in Africa, especially Madagascar and the Democratic Republic of Congo. 

Sixty people died from the disease in Madagascar last year — the highest number globally.

Health officials are now headed to the area to investigate.