A form of the plague has killed some 40 people and infected more than 100, the World Health Organization said Friday.

TRNS reported that 119 total cases have surfaced in Madagascar in the past few months, and one person has died in the capital city of Antananarivo.

"There is now a risk of a rapid spread of the disease due to the city's high population density and the weakness of the healthcare system," WHO said.

Cases have been reported in 16 districts.

The bacterial illness sickening people is caused by Yersinia pestis and is primarily spread as rodents carrying infected fleas bite humans. WHO said that people bitten by a flea carrying the disease develop a form of bubonic plague. Early diagnosis yields a higher cure rate.

CBC News noted that only two percent of the cases become pneumonic plague, which kills much faster than the bubonic form and can be spread from person to person by coughing.

Word of any outbreak is that last thing anyone wants to hear amid the Ebola crisis. That virus has claimed the lives of more than 5,000 people mostly in West Africa.