Infectious Disease Epidemiology Program
Vaccine-preventable Diseases - Plague
Plague is a disease caused by Yersinia pestis (Y. pestis), a bacterium found in rodents and their fleas in many areas around the world. People usually get plague from being bitten by a rodent flea that is carrying the plague bacterium or by handling an infected animal or Yersinia pestis used in an aerosol bioterrorist attack could cause cases of the pneumonic form of plague. In North America, plague is found in certain animals and their fleas from the Pacific Coast to the Great Plains, and from southwestern Canada to Mexico. Most human cases in the United States occur in two regions: 1) northern New Mexico, northern Arizona, and southern Colorado; and 2) California, southern Oregon, and far western Nevada. Plague also exists in Africa, Asia, and South America. To prevent a high risk of death, antibiotics (such as doxycycline) or a fluoroquinolone (such as ciprofloxacin) should be given within 24 hours of the first symptoms. Currently, no plague vaccine is available in the United States.