Pestis (Yersinia pestis) - As Biological Weapons

Yersinia pestis (formerly Pasteurella pestis) is a type of bacterium. It is believed to have been responsible for plagues of the early 1300s. More accurately, it is a Gram-negative rod-shaped coccobacillus. It is a facultative anaerobe that can infect humans and other animals. Human Y. pestis infection takes three main forms: pneumonic, septicemic, and bubonic plagues. All three forms are widely believed to have been responsible for a number of high-mortality epidemics throughout human history, including the Justinianic Plague of the sixth century and the Black Death that accounted for the death of at least one-third of the European population between 1347 and 1353. It has now been shown conclusively that these plagues originated in rodent populations in China. More recently, Y. pestis has gained attention as a possible biological warfare agent and the CDC has classified it as a category A pathogen requiring preparation for a possible terrorist attack. Every year, thousands of cases of plague are still reported to the World Health Organization, although, with proper treatment, the prognosis for victims is now much better. A five- to six-fold increase in cases occurred in Asia during the time of the Vietnam war, possibly due to the disruption of ecosystems and closer proximity between people and animals. Plague also has a detrimental effect on non-human mammals. In the United States of America, animals such as the black-tailed prairie dog and the endangered black-footed ferret are under threat from the disease.