When most people hear "the plague," they immediately think of the "Black Death" that killed more than 50 million Europeans in the 14th century.

However, despite modern medicine, the plague continues to be endemic to many areas of the Democratic Republic of Congo, Madagascar and Peru. Currently, Madagascar is experiencing an unusually early plague that has affected 684 people with at least 54 deaths.

The plague is caused by the bacteria Yersinai pestis, which is usually found on small mammals, such as rats and mice, and their fleas. It is transmitted between humans and animals by the bite of an infected flea, direct contact with infected tissues and inhalation of infected respiratory droplets.

According to the World Health Organization (WHO), there are three forms of plague infection:


The most common form of plague, which is caused by the bite of an infected flea. The bacteria enter at the bite and travels to the lymph nodes where it replicates. The affected lymph nodes become inflamed, tense and painful and are called a "bubo." If left untreated, the lymph nodes can turn into open sores filled with pus.


If the bubonic form remains untreated, the infection spreads in the blood stream, often causing the first symptoms. It can eventually cause bleeding, tissue necrosis (which is where it gets the name "Black Plague," from the skin turning black), shock and eventual death.


The lung-based plague is the most virulent form, yet is often rare. It is transmitted easily from an infected person via droplets. With a short incubation period of 24 hours, it can spread quickly before symptoms are seen. If no diagnosed and treated early, can be fatal.

Prior to the advent and use of antibiotics, the plague was fatal in 60-99 percent of those affected, which the cause of the widespread devastation in Europe. However, with the use of antibiotics, the fatality rate is now about 16 percent.

The typical outbreak season occurs during the rainy season, between November and March. It is during this time the rains drive out the rodents. However, this year the cases started three months early, in August, catching health authorities off guard.

With such a short incubation period, tracking down individuals who had contact with the first victims has been challenging. Health authorities expect there to be an increase in reported cases, but should further peak, as resources are not in place to help manage the early outbreak on the island of 25 million people.

Of great concern with the present outbreak is the high incident of pneumonic plague, which as accounts for 474 (69.3 percent) of the cases. The contagious and fatal form is likely to continue to contribute to the rapid spread through the population via coughing and sneezing. Although all forms of the disease can be treated with antibiotics, early detection is a priority. The incubation time is short and the infected person could die within 12 to 24 hours if not promptly treated.

Due to the rapid spread and high mortality, the international community has mobilized resources to support the Madagascar Ministry of Public Health. WHO announced on October 6, 2017 that it had delivered nearly 1.2 million doses of antibiotics and $1.5 million in emergency funds.

Despite the increase of the highly contagious pneumonic form during this current outbreak, health officials feel the risk of international spread is low. Considering the short incubation period, those affected are often too sick to travel, but WHO is still working closely with airport authorities to ensure measures are in place to prevent spread outside the country. But more importantly, unlike the Ebola outbreak of a few years ago, plague is easily treated with antibiotics.