A widespread outbreak of the plague has gripped Madagascar. The disease has killed at least 30 people, and 194 have been infected since August, according to the latest figures from the World Health Organization (WHO).
Plague is endemic to the African island nation, with at least 400 reported cases annually during high season, September through April. But this year, that number has risen faster and sooner than normal.
Of the reported cases, nine people have died from the more common bubonic strain of plague. But about two-thirds of cases have been attributed to the more severe pneumonic plague, which has killed 21 people.
Here’s what to know about the disease.
What is plague?
Plague is an infectious disease caused by the Yersinia pestis bacteria. There are two main forms: bubonic and pneumonic. Bubonic plague is spread by infected rats via flea bites. Sufferers can experience painful swelling of lymph nodes, called bubos, as well as flu-like symptoms.
Pneumonic plague is transmitted person-to-person by the inhalation of infected respiratory droplets. It’s more uncommon but deadlier because it causes a severe lung infection and is especially contagious. Plague, especially pneumonic, has fatality rates of 30-100% if left untreated.
Isn’t plague from the Middle Ages?
Many people associate plague with medieval times, as the Yersinia pestis bacteria is believed to have caused the Black Death, which killed an estimated 50 million people in Europe in the 14th Century. But the disease continues to affect communities to this day.
According to WHO data from 2010-2015, there were 3,248 reported cases of plague in humans worldwide, resulting in 584 deaths. The disease is found in all continents, except Oceania, but it’s most endemic to Madagascar, Democratic Republic of the Congo and Peru.
In the U.S. there are an average of seven cases of the plague reported each year.
Plague remains a risk wherever infected animals live in close proximity to humans. For those living in poverty in unsanitary conditions, the risk of human transmission is greater.
While the disease hasn’t been totally eradicated, medicine has advanced in leaps and bounds. Treatment exists, and plague can be cured with antibiotics if diagnosed early.
“This is a treatable and preventable disease,” Christian Lindmeier, a spokesperson for the WHO, told TIME. “It’s not like the Middle Ages when we had no idea what we were doing.”
What’s happening in Madagascar?
The plague outbreak in Madagascar is particularly concerning because it has spread to urban areas, including the capital and port towns, raising the risk of transmission.
So far, 74 cases have been reported in the capital, Antananarivo, and 40 from the eastern port city Toamasina. According to Lindmeier, rumors have generated some panic, causing people to stockpile medicine.
Those on the ground say they aren’t yet sure why the disease has spread so early so fast. “We’re figuring that out now,” says Lindmeier, adding that the WHO’s main priority for the moment is halting the plague’s transmission.
The Madagascar government has sent teams to spray schools and public spaces to ward off fleas and rodents, and t he WHO has deployed staff and released $300,000 in emergency funds to combat the outbreak. It has also appealed for an additional $1.5 million in funds from the U.S. government. Public institutions in Madagascar have temporarily closed, including two universities and schools across the country, and music festivals and sports tournaments have been called off.
“We have have 13 regions which are affected now,” Dr. Charlotte Ndiaye, WHO Representative in Madagascar, told TIME. “The main problem is the contact tracing. Because is [pneumonic plague] is a human transmission, we need to have a very strong method of contact tracing.”
The risk of the disease spreading around the region is “moderate,” WHO have said. But the risk of plague spreading further internationally was “low.”