Bubonic plague research. Medical researchers cutting open rats suspected of carrying bubonic plague. This is New Orleans,USA,in 1914,when one of the last major outbreaks of bubonic plague in the USA took place. A few dozen people caught the disease and ten died,but the outbreak was contained by rat-catching and rat-proofing measures. Bubonic plague,caused by the Yersinia pestis bacteria,is primarily carried by fleas on rats. Transfer to humans occurs when the fleas feed on human blood. Infection is rapid,causing swollen lymph nodes,and leading to septicaemia,pulmonary infection and often death |