Rochester, Minnesota - A large outbreak of plague, including the rare form known as pneumonic plague, has health officials in Madagascar working to prevent the bacterial infection from spreading to neighboring countries. The World Health Organization (WHO) says there have been more than 1,800 confirmed, probable or suspected cases of plague since August 1, including 127 deaths.

Dr. Pritish Tosh, an infectious diseases specialist at Mayo Clinic says, "Public officials are concerned about this going on in Madagascar and potentially moving to neighboring areas. At this point, I think it’s unlikely that this is going to go much farther beyond that just because by the time people are able to transmit, they are pretty sick."

"Right now, there are cases of pneumonic plague coming from human-to-human transmission occurring in Madagascar. Plague, thankfully, is treatable with antibiotics. We can treat people who have been exposed with antibiotics to prevent that from developing into infection."

Plague is divided into three main types - bubonic, septicemic and pneumonic - depending on which part of your body is involved. Signs and symptoms vary, depending on the type of plague. Pneumonic, which is being seen in Madagascar, is the least common, most dangerous and the only form of plague that can be spread from person to person.

The plague, says Dr. Tosh, is  "unlike Ebola where any bodily fluid would be infectious."  He says with pneumonic plague, the infection is transmitted through respiratory droplets. The infection progresses rapidly, and may cause respiratory failure and shock within two days of inhaling plague bacteria.

Dr. Tosh says the plague is caused by the bacteria Yersinia pestis, which is often found in rodents and their fleas.

The WHO says it expects more cases of the infection to be reported until the typical plague season ends in Madagascar in April 2018.