Black Death, the same Medieval disease that wiped out ONE-THIRD of Europe’s population in the 13th and 14th centuries, has killed more than 100 people in Madagascar and infected another 1,200 since August.
The World Health Organization today issued a travel warning to NINE countries surrounding Madagascar, amid fears the disease could spread via sea trade and flight routes. The deadly outbreak is especially serious and a more significant threat to the region than past outbreaks because this time a majority of the cases were the pneumonic form of the disease, which can quickly spread from person to person.
With almost 70% of the cases consisting of the pneumonic variant of the Black Plague, experts are warning that the deadly plague could easily move further outside the region given the regular flights going in and out of the area.
Plague Fact Sheet from the World Health Organization
Plague, famously known as the “Black Death” that killed 50 million Europeans in the 14th century, is a disease caused by the bacterium yersenia pestis, a zoonotic bacteria, usually found in small mammals and their fleas. It is commonly transmitted between animals by their fleas. Humans can be contaminated by the bite of infected fleas, through direct contact with infected materials or by inhalation.
There are three forms of plague infection, depending on the route of infection: bubonic, septicaemic and pneumonic.
- Bubonic plague (known in mediaeval Europe as the ‘Black Death’) is the most common form of plague and is caused by the bite of an infected flea. Plague bacillus, Yersinia pestis, enters at the bite and travels through the lymphatic system to the nearest lymph node where it replicates itself. The lymph node then becomes inflamed, tense and painful, and is called a “bubo”. At advanced stages of the infection the inflamed lymph nodes can turn into open sores filled with puss.
- Pneumonic plague-or lung-based plague- is the most virulent form of plague. Incubation period can be as short as 24 hours. Typically, the pneumonic form is caused by spread to the lungs from advanced bubonic plague. However, a person with secondary pneumonic plague may form aerosolized infective droplets and transmit plague via droplets to other humans. Untreated pneumonic plague is always fatal.
- Septicaemic plague occurs when infection spreads through the bloodstream, following a bubonic or a pneumonic plague.
Plague can be a very severe disease in people, particularly in its septicaemic and pneumonic forms, with a case-fatality ratio of 30–100% if left untreated. The pneumonic form is invariably fatal unless treated early, is especially contagious and can trigger severe epidemics through person-to-person contact via droplets in the air.
Plague is an endemic disease in Madagascar; cases of bubonic plague are reported nearly every year, during the epidemic season (between September and April). However, the ongoing pneumonic plague event has been reported in a non-endemic area and in densely populated coastal cities for the first time.
Pneumonic plague is a form of plague that is transmissible from person-to-person, with a potential to trigger severe epidemics if inadequately controlled. Detection of this outbreak occurred more than two weeks after the first case died during which cases traveled to different parts of the country, including the capital Antananarivo. Therefore, the overall risk at the national level is high. The overall regional risk is moderate due to frequent flights to neighboring Indian Ocean islands. The global risk is low.
Untreated plague can be rapidly fatal, so early diagnosis and treatment are essential for survival and reduction of complications. Antibiotics and supportive therapy are effective against plague if patients are diagnosed in time.