Plague

Plague is an infectious disease caused by the bacteria Yersinia pestis, usually found in small mammals and their fleas. It is transmitted between animals through fleas. Humans can be infected through: the bite of infected vector fleas unprotected contact with infectious bodily fluids or contaminated materials the inhalation of respiratory particles from a patient with pneumonic plague. Plague is a very severe disease in people, particularly when the bacteria spreads through the bloodstream (septicaemic plague) or infects the lungs (pneumonic plague). It has a case-fatality ratio of 30% to 100% if left untreated. The pneumonic and septicaemic forms are invariably fatal unless treated early. Pneumonic plague is especially contagious and can trigger severe epidemics through person-to-person transmission via respiratory particles. Historically, plague was responsible for widespread pandemics with high mortality. It was known as the "Black Death" during the fourteenth century, causing more than 50 million deaths in Europe. Nowadays, plague is easily treated with antibiotics and the use of standard precautions to prevent acquiring infection.