Plague is caused by the bacteria Yersinia pestis, a zoonotic bacteria usually found in small mammals and their fleas. People infected with Y. pestis often develop symptoms after an incubation period of one to seven days. There are two main clinical forms of plague infection: bubonic and pneumonic. Bubonic plague is the most common form and is characterized by painful swollen lymph nodes or 'buboes'. Plague is transmitted between animals and humans by the bite of infected fleas, direct contact with infected tissues, and inhalation of infected respiratory droplets. Plague can be a very severe disease in people, with a case-fatality ratio of 30% to 60% for the bubonic type, and is always fatal for the pneumonic kind when left untreated. Antibiotic treatment is effective against plague bacteria, so early diagnosis and early treatment can save lives. From 2010 to 2015 there were 3248 cases reported worldwide, including 584 deaths. Currently, the three most endemic countries are the Democratic Republic of th