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Plague is an infectious disease of humans and wildlife caused by the bacterium Yersinia pestis. It is generally contracted through the bite of a flea carrying the bacterium or by handling or ingesting meat from an animal infected with the disease. Almost 250 species of mammals, mostly rodents, carnivores and rabbits can become infected. Some species are more likely to become sick and die. Species with high mortality rates include cats (wild and domestic), marmots, prairie dogs, rabbits, ground squirrels, tree squirrels, and wood rats. Dogs (wild and domestic), most mustelids (skunks, weasels, etc.), deer mice (Peromyscus maniculatus), and kangaroo rats (Dipodomys ordii) have high resistance to the disease. Birds are not susceptible to plague. Y. pestis is not native to North America. In the early 1900’s rats on trade ships from Asia likely brought the disease to this continent.

From 1994-2012, plague-positive animal or flea samples have been taken from Bennett, Custer, Dewey, Fall River, Jackson, Lyman, Mellette, Pennington, Shannon and Stanley counties. Plague likely occurs in most counties west of the Missouri River. Presence of plague does not indicate an outbreak is occurring.

Plague can cause severe illness or death in humans. Antibiotic treatment is effective against plague if the infected person is treated promptly. In the United States, an average of seven human cases is reported annually. Most are from New Mexico, Arizona and Colorado as well as California, Oregon and Nevada. There have been NO cases of plague in humans reported in South Dakota. Human patients generally have a history of exposure in rural areas

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