Plague disease is caused by the bacteria Yersinia pestis. The plague is primarily a disease of rodents and carried by their fleas, which can infect humans. It is a severe disease in people with case fatality rates of 50-60% if left untreated. Plague disease has been responsible for widespread pandemics with high mortality in the pre-antibiotic era. It was known mainly as the "Black Death" during the fourteenth century, causing an estimated 50 million deaths.
The most famous outbreak of plague is known as the “Black Death”, occurring in fourteenth century Medieval Europe. Plague spread by rodents and fleas infesting them spread the disease rapidly among the population of Europe starting in the 1340’s. The epidemic reached its height between the years 1348 and 1350 before beginning to subside. All told, it is estimated this outbreak took the lives of 50 million people.
Outbreaks off the plague disease have occurred both before and after the Black Death, as far back as the Byzantine era. The Plague of Justinian occurred in the years 541 and 542 killing an estimated 25 million people, with a further 25 million dying to recurrent outbreaks over the next two centuries.
Multiple notable outbreaks of the plague have since occurred in Asia, South America, Africa, and even Hawaii. Greater understanding of the disease as well as the advent of antibiotics in the era of modern medicine have limited the spread and virulence of plague outbreaks, and since the 1990’s they have been confined mostly to Africa.
The most recent data from the WHO indicates in 2013 there were 783 reported cases of the plague and 126 deaths. Countries with the highest endemicity of plague are Madagascar, the Democratic Republic of Congo, and Peru.
There are three main forms of plague in human.
Empirical treatment should begin when clinically suspected of pneumonic plague as the disease is almost always fatal if treatment is not initiated within 24 hours of the onset of symptoms.
Total duration of treatment is 10-14 days
Face to face contact (within 2 meters) of patients with pneumonic plague or persons possibly exposed to a plague aerosol should be given antibiotic prophylaxis.
Suspected pneumonic plague cases require strict isolation with droplet precautions for at least 48 hours of antibiotic therapy or until sputum cultures are negative in confirmed cases.