Yersinia pestis, bacteria that causes the plague. An outbreak of pneumonic plague has killed 33 people in Madagascar. Image by royaltystockphoto.com/Shutterstock

Oct. 7 (UPI) -- The World Health Organization issued a warning about a worrisome outbreak of plague on the African island of Madagascar that has caused 200 infections and 33 deaths since September.

The outbreak of plague is an annual occurrence in Madagascar, which normally reports about 400 cases per year, usually in the remote island highlands. What makes this outbreak different, according to the WHO, is that many of the infected live in more densely populated towns and the capital Antananarivo. Also, the infections reported are pneumonic plague, which is transmitted by air, making it more difficult to control.


Pneumonic plague is different from bubonic plague, which is the more common form on Madagascar. Bubonic plague is transmitted when an infected individual is bitten by fleas carried by rats. On Madagascar, the outbreaks are more common in rural rice farming areas and are not as easily transmitted.

Both versions of the plague were the cause of the Black Death epidemic in the mid-14th century, which wiped out a third of Europe's population.

In response to the threat, Madagascar's government has closed schools, businesses and outlawed large public gatherings including concerts and sporting events where the disease could be spread to dozens or even hundreds of people at a time.

The disease is confirmed to have left the island after several participants in an international basketball tournament displayed symptoms after arriving home. One coach from the Indian Ocean island nation Seychelles died and another from South Africa was diagnosed but survived. Other tournament participants were being monitored for symptoms.

Pneumonic plague often appears to present as influenza or a common cold that advances to pneumonia. It is more deadly than bubonic plague.

The WHO said it sent 1.2 million doses of antibiotics to the island to help treat the sick and contain the outbreak. The organization said there are enough antibiotics to treat 5,000 infected patients and 100,000 people who have been exposed.

"Plague is curable if detected in time. Our teams are working to ensure that everyone at risk has access to protection and treatment. The faster we move, the more lives we save," said Dr. Charlotte Ndiaye, WHO's representative in Madagascar.

The New York Times reported the outbreak is believed to have started when a man infected with the disease traveled via bush taxi from a remote part of the island through Antananarivo on his way to his home in the coastal city of Toamasina. The man was exhibiting symptoms and died en route to his destination. A large cluster of second-generation infections were discovered in people with whom he interacted while making the trip.

The first documented case was confirmed when a 47-year-old woman died on Sept. 11 and her blood tested positive for pneumonic plague. The WHO was notified two days later and further testing of individuals exhibiting plague symptoms began yielding increased diagnoses in cities and towns dotting the island.

The outbreak is similar in some respects to the deadly Ebola outbreak that ravaged parts of west Africa in 2014. Similar to Madagascar's outbreak, a single individual infected in an isolated area traveled to a population center, sparking a deadly outbreak.