Plague is a disease caused by a bacterium, Yersinia pestis, which affects humans and other mammals. Humans usually get the disease after being bitten by a rodent flea that is carrying the plague bacterium or by handling an animal infected with plague. People can also be exposed by breathing in infectious droplets. Plague can have different symptoms depending on how the patient was exposed, but the three most common forms are bubonic, septicemic and pneumonic. Antibiotics can be used to treat patients with plague; however, it is important that they are started promptly after illness onset.
Plague can be found in many parts of the world. In the United States, most human cases occur in rural and semi-rural areas of the southwest states. While plague bacteria are not naturally found in Indiana, plague cases may occur in people or animals who have traveled to higher risk areas.
NOTICE: Plague is an immediately reportable disease in Indiana and is required to be reported upon identification by a healthcare provider, hospital, or laboratory. Specific reporting requirements for plague can be found here.
Page last reviewed/updated: April 2025