An epidemic of the deadliest form of plague, pneumonic, has hit major cities and towns in Madagascar and is spreading fast. As of 7 October, the Madagascar Health Ministry reported that 343 people had been infected and 42 died, and numbers are rising rapidly.
A massive response is underway, and the World Health Organization (WHO) is on high alert. This poor island nation is regularly hit by plague outbreaks, but they are typically the relatively less dangerous bubonic form, transmitted from rats to humans by fleas, and occur largely in remote areas. Bubonic plague killed an estimated 60% of Europe’s population during the Black Death in the 14th century.
What’s particularly alarming now is that pneumonic plague is easily transmitted person to person by coughing, and the outbreak has reached relatively densely populated urban areas, including the capital, Antananarivo, commonly known as Tana. Left untreated with antibiotics, pneumonic plague is 100% fatal. (Both forms are caused by the bacterium Yersinia pestis; pneumonic plague develops when a person with bubonic plague is not treated, and the infection spreads to the lungs.)
The so-called index case—the first case to be described by health workers—was a 31-year-old man with malarialike symptoms who traveled by bush taxi from a remote area through the capital. He died in transit on 27 August. Large clusters of cases then began to appear along his route. The disease took off when it reached Tana, where schools have been closed and public events cancelled. The outbreak has now hit 20 districts in 10 regions.
WHO learned of the outbreak on 23 September, following the 11 September death of a 47-year-old woman in a hospital in the capital. Health officials are carefully monitoring the contacts of a basketball coach from the Seychelles, who was in Madagascar for a regional tournament, contracted the disease, and died. Reports are conflicting on whether he died in Tana or at home.
WHO has assessed the risk of national spread high, regional spread moderate, and international spread low, but those rankings are being reassessed. Plague can be cured if antibiotics are administered immediately; on 6 October WHO delivered 1.2 million doses of antibiotics and released $1.5 million to fight the outbreak. More drugs should be on the way soon.
Plague is endemic in many countries—the United States had 16 cases of bubonic plague in 2015—but Madagascar, the Democratic Republic of Congo, and Peru are the countries that frequently have serious outbreaks.