Plague: Four Things You Need to Know

As the African island nation of Madagascar struggles to control an unprecedented outbreak of pneumonic plague in the capital city of Antananarivo, the World Health Organization is setting up procedures in surrounding countries to prepare for spread of the highly contagious bacteria.

The epidemic could “explode” if containment efforts fall short, says the Red Cross. More than 1,400 people have been infected in the congested capital of more than two million people, and more than 100 have died despite the susceptibility of plague to antibiotics like doxycycline. A 2014 outbreak was considered particularly bad; that year only 40 people died.

According to the WHO, there is a moderate risk the disease could spread to neighboring countries in east and southern Africa and a very high risk of spread locally. “The situation will continue to deteriorate,” said the United Nations.

Plague, caused by the bacteria Yersinia pestis, is endemic to the southwestern United States; there were 16 cases last year, according to the U.S. Centers for Disease Control and Prevention, with a case-fatality rate of 25%. It’s believed the bacteria first arrived in the 19th century on ships originating in Asia that were infested with rats, but it can be traced back thousands of years and famously killed 50 million people in the 1300s when it swept through Europe and earned the nickname “the Black Death” for its skin-blackening blisters, known as buboes.

Plague has also been identified as a potential bioterrorism weapon. The Department of Health and Human Services lists it as a Tier 1 organism, making it one of the most likely biologic organisms to be used as a weapon, along with anthrax, Ebola, and smallpox. The U.S. and Soviet Union considered using aerosolized plague as a weapon in the Cold War, and it’s suspected Japan used plague-infected fleas in parts of China during World War II.

With plague being endemic to the U.S., epidemic in Africa, and at the top of the list for bioterrorism, we’ve compiled a list of the top four things you need to know about it.

Why is this Madagascar outbreak particularly worrisome?

“This year we are seeing urban spread of the pneumonic type,” said Tonje Tingberg, the Red Cross field team leader in the country, who notes seven out of 10 cases this year have been pneumonic rather than the more typical bubonic type. Bubonic plague is endemic in rural Madagascar and can only be transmitted by fleas living on rats, animals infected with the bacteria, or when a lymph node is punctured. But this year the pneumonic variant is prominent; highly contagious, it infects the lungs and can be spread between people by droplets in the air.

What are the signs and symptoms of plague?

Bubonic plague causes fever, chills, and tender, swollen lymph nodes in the groin, neck, and armpits. Usually a bite or scratch mark from an infected flea or animal is near the affected nodes. Pneumonic plague also causes fever and chills in addition to respiratory symptoms like cough and dyspnea, as well as hemoptysis. Rarely plague can cause sepsis, which causes abdominal symptoms that can include pain, diarrhea, and vomiting. Coagulopathies can present as bleeding and bruising.

How is plague treated?

The bacteria the causes plague is susceptible to many inexpensive antibiotics, such as doxycycline and ciprofloxacin. Typically, a 10–14-day course of intravenous antibiotics is prescribed. In severe cases IV fluids and ventilator support may be required. If plague is treated in the first 24 hours, the cure rate is 100%. There are no known vaccines for plague, and if exposed, first responders are placed on postexposure prophylactic antibiotics for seven days.

How is the international community responding to the outbreak?

Humanitarian agencies like the WHO and Red Cross are on the ground in Madagascar applying lessons learned from the 2014 Ebola epidemic of West Africa. “We are adopting a no-regrets approach to this response,” international Red Cross president Elhadj Sy said. “Our experience in responding to disease outbreaks is that quick, decisive action can save lives.”

Plague treatment centers are assessing and treating patients, and local teams are tracking the disease and offering people who may have been exposed prophylaxis. Surveillance of passengers exiting the country is being enhanced at airports, and vector-control specialists are striving to reduce rat and flea populations. Ensuring safe and dignified burials is also important; during Ebola many transmissions occurred during burial rituals and by workers who handled dead bodies. Most important, the Red Cross aims to educate the public to prevent fear and stigma.

After a decade working as a helicopter paramedic, Blair Bigham, MD, MSc, EMT-P, completed medical school in Ontario, Canada, where he is now a resident physician in the emergency department. E-mail him at blair.bigham@medportal.ca; follow on Twitter @BlairBigham.