Plague
Plague is a reportable disease in Oklahoma. Plague is an infectious disease caused by the bacterium Yersinia pestis. Plague is known as the infamous Black Death of medieval Europe, which is believed to have killed approximately one-third of the world’s population in the 14th century. Currently in the United States, plague occurs mostly in the western United States from the Great Plains to the Pacific Coast. Most reported cases occur in New Mexico, Arizona, and Colorado.
Symptoms of plague include a painful, swollen lymph node (called a bubo), fever, chills, tiredness, muscle aches, nausea, sore throat, and headache. Symptoms appear between one and seven days after being infected, but a person usually becomes ill with plague within two to six days. The bacteria in some cases can spread to the lungs causing a severe respiratory illness called pneumonic plague. Another rare form is called plague septicemia, in which the bacteria enter the bloodstream. When a bubo occurs, the form is called bubonic plague.
In nature, plague is a disease of wild rodents, but can also infect humans and other mammals. Fleas become carriers of the bacteria by feeding on chipmunks, prairie dogs, ground squirrels, and other rodents that are infected with the bacteria. Less often, other mammals may become accidentally infected with plague, but they play no significant role in the disease cycle. Rarely, humans are bitten by plague-carrying fleas from rodents and become infected. In addition, humans may become infected after handling tissue or body fluids of sick or dead animals infected with plague, for example, while hunting. The species of fleas that infest dogs and cats do not transmit plague; however, rodent fleas may attach themselves to domestic pets that are allowed to enter the habitat of wild rodents. When brought into the home, these fleas may then bite humans and cause disease.
A rare form of the disease, pneumonic plague, is spread from person-to-person. Pneumonic plague can spread from person to person by sneezing or coughing. People must have face-to-face contact with the ill person. Pneumonic plague can also be spread to people by cats with pneumonic plague. Bubonic plague does not usually spread from person to person unless the person with bubonic plague also develops pneumonic plague.
