Yersinia bacteria infection

Plague is caused by Yersinia pestis, bacteria that are carried through infected flea bites, direct contact, and by inhalation of infective materials. Bubonic plague is the most common form of plague and is derived from the bite of a flea that fed previously on infected animals. Pneumonic plague causes the greatest amount of mortality and is transmitted by aerosol. It... 

Plague has been one of the worst human pandemics throughout history. Its use as a biological warfare agent, however, is not known. The disease is attributed to the bacteria Yersinia pestis, and caused mostly from bites of rat flea. The animals that transmit this disease are mostly black rats and the rock and ground squirrels. When the flea bites an infected animal the bacteria enter into the body of the flea and multiply inside. When the infected flea attempts to bite again it vomits clotted blood and bacteria into the bloodstream of the victim, either human or a small mammal, usually rat. Thus the disease is mostly transmitted from rodents from the bites of infected fleas. 

A. By fleas that become infected with bacteria Yersinia pestis that cause plague. 

Beijing, then to Mukden (Manchuria) where he obtained Yersinia pestis (plague) bacteria. Two condemned North Korean prisoners were infected with the plague. One of them was put to death and his body used as evidence of biological warfare, which was presented to the visiting International Scientific Commission team mentioned above. 

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