The Black Plague (Black Death) killed 20 million Europeans between 1347 and 1352. The same plague struck Africa with a deadly blow in late August of this year.
Cases of the plague aren't unheard of in modern times (even in the United States), but the death toll of the current African epidemic has reached over 100 people, with almost 1,300 cases. Madagascar has been hit the worst, with reports of infection in 18 out of 22 regions.
The plague is caused by bacteria usually transmitted from rodents or fleas to humans. The disease occurs more often in areas of the world with poor sanitation and high levels of poverty, though the Madagascar strain is reportedly unusually urban.
Symptoms can be very flu-like and include a fever, chills, weakness and vomiting, amongst even more serious symptoms depending on the type of plague.
When the infection reaches the bloodstream, it causes skin to turn black and die, hence its menacing name.
According to the World Health Organization, the type of plague one is infected with is dependent on where the infection attacks the body. WHO says there are three forms of the plague:
"Bubonic plague is the most common form of plague and is caused by the bite of an infected flea. Plague bacillus, Y. 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 suppurating open sores. There is no inter human transmission of bubonic plague."
"Septicaemic plague occurs when infection spreads through the bloodstream Septicaemic plague may result from flea bites and from direct contact with infective materials through cracks in the skin. Advanced stages of the bubonic form of plague will also lead to direct spread of Y. pestis in the blood."
"Pneumonic plague-or lung-based plague- is the most virulent and least common form of plague. 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 has a case-fatality ratio close to 100%."
Madagascar reportedly sees about 400 cases of the plague every year, mostly of the bubonic strain. Currently, pneumonic plague is the most popular and the most dangerous. Pneumonic plague has a 100 percent mortality rate if left untreated.
Is it treatable?
Yes. All forms of the plague are treatable with antibiotics if diagnosed early enough. If left untreated, the plague can kill within one to three days.
Could this be a worldwide threat?
WHO says the global risk is low. That said, "the risk of regional spread is moderate," and the risk that plague will spread throughout Madagascar is "considered very high."
Madagascar has a 'plague season' every year, but this plague outbreak is happening earlier than previous years. Health officials suspect the outbreak began with a 31-year-old man who developed symptoms similar to malaria in late August. The man used public transportation to travel from Ankazobe District to Tamatave (about a nine hour nonstop drive), while symptomatic, though populated areas (the capital of Madagascar, Antananarivo) before passing away.
Several people who came in contact with the man then became infected.