Plague (Bubonic, Pneumonic, Septicemic)

Infectious Agent

The gram-negative bacterium Yersinia pestis .


Usually through the bite of infected rodent fleas. Less common exposures include handling infected animal tissues (hunters, wildlife personnel), inhalation of infectious droplets from cats or dogs with plague, and, rarely, contact with a pneumonic plague patient.


Endemic to rural areas in central and southern Africa (especially eastern Democratic Republic of Congo, northwestern Uganda, and Madagascar), central Asia and the Indian subcontinent, the northeastern part of South America, and parts of the southwestern United States. Overall risk to travelers is low.

Clinical Presentation

Incubation period is typically 1–6 days. Symptoms and signs of the 3 clinical presentations of plague illness are as follows:

  • Bubonic (most common)—rapid onset of fever; painful, swollen, and tender lymph nodes, usually inguinal, axillary, or cervical
  • Pneumonic—high fever, overwhelming pneumonia, cough, bloody sputum, chills
  • Septicemic—fever, prostration, hemorrhagic or thrombotic phenomena, progressing to acral gangrene


Y. pestis can be isolated from bubo aspirates, blood cultures, or sputum culture if pneumonic. Diagnosis can be confirmed in public health laboratories by culture or serologic tests for the Y. pestis F1 antigen. Plague is a nationally notifiable disease.


There are a number of antibiotics used in the treatment of plague including gentamicin, doxycycline, ciprofloxacin, and levofloxacin. The parenteral antibiotic, moxifloxacin, may also be used. Parenteral streptomycin and chloramphenicol are alternatives.


Reduce contact with fleas and potentially infected rodents and other wildlife. No plague vaccine is available for commercial use in the United States. Antibiotics are used for postexposure prophylaxis.

CDC website:


  1. Bertherat E. Plague around the world, 2010–2015. WHO Wkly Epidemiol Rec. 2016;91:89–104.
  2. Butler T. Plague gives surprises in the first decade of the 21st century in the United States and worldwide. Am J Trop Med Hyg. 2013;89:788–93.  [PMID:24043686]
  3. Perry RD, Fetherston JD. Yersinia pestis—etiologic agent of plague. Clin Microbiol Rev. 1997 Jan;10(1):35–66.  [PMID:8993858]


Paul S. Mead