Content Information
Disease Information
Plague is caused by the bacterium Yersinia pestis. It is a zoonotic disease of rodents and their fleas, which can be spread to humans.
Overview
Report Immediately by Phone
Potential Bioterrorism Agent Category A
Also known as: Petis, Bubonic Plague, BlackPlague, Black Death
Responsibilities
- Hospital/Infection Preventionist: Report by phone immediately
- Lab: Report by phone immediately
- Physician: Report by phone immediately
- Local Public Health Agency (LPHA): Follow-up required. Iowa Department of Public Health will lead the follow-up investigation.
Iowa Department of Public Health
Disease Reporting Hotline: (800) 362-2736
Secure Fax: (515) 282-5698
A. Etiologic Agent
Plague is caused by the bacterium Yersinia pestis. It is a zoonotic disease of rodents and their fleas, which can be spread to humans.
B. Clinical Description
The initial signs and symptoms of plague in humans are usually non-specific, and include fever, chills, malaise, sore muscles (myalgia), nausea, sore throat, headaches, and weakness. Bubonic plague, the most common form, is a syndrome that includes painful swelling of lymph nodes. Pneumonic plague refers to a form affecting the lungs; septicemic plague is a form caused by disseminated infection of the blood stream. Meningeal plague, or plague affecting the membranes lining the brain and spinal cord, is rare. Both pneumonic and septicemic plague can be primary or secondary to another form of plague. Untreated bubonic plague is fatal in 50% - 60% of cases, while untreated primary septicemic and pneumonic plague are fatal in 100% of cases.
C. Reservoirs
Certain wild rodents and their fleas carry Y. pestis. In the United States, ground squirrels and prairie dogs in the western U.S. are the primary reservoirs of Y. pestis. Lagomorphs (rabbits and hares), wild carnivores (meat-eating mammals) and domestic cats may also be a source of infection to people. There is probably no wild reservoir in Iowa.
D. Modes of Transmission
Plague is acquired primarily through the bite of an infected flea or through inhalation of airborne Yersinia pestis, either through proximity to a human or animal case of pneumonic plague or by accidental exposure in a laboratory. Plague can also be acquired by handling tissues of infected animals or by being bitten or scratched by an infected animal.
E. Incubation Period
From 1 - 7 days.
F. Period of Communicability or Infectious Period
Patients with pneumonic plague are considered infectious throughout their symptomatic illness and for 72 hours following initiation of antibiotic treatment. Discharge from lesions in patients with bubonic plague is considered infectious.
G. Epidemiology
Wild rodent plague exists in large areas of South America, Africa, Eastern Europe and Asia. Since the early 1990s, there has been an increase in the annual incidence of human cases of plague, and the disease has reappeared in countries where it has not been reported in decades. In the United States, wild rodent plague occurs primarily in ground squirrels and prairie dogs in the western part of the country. Human cases there occur sporadically, usually following exposure to wild rodents or their fleas. Approximately 5 to 15 people are diagnosed with plague each year in the United States. Five instances of primary plague pneumonia through cat-to-human transmission have been recorded. No person-to-person transmission has been documented in the United States since 1925.
H. Bioterrorism Potential
Category A Agent Y. pestis is considered a potential bioterrorism agent. If effectively disseminated, Y. pestis could cause a serious public health challenge in limiting casualties and controlling other repercussions. All cases of plague need to be reported immediately by phone. (See Reporting & Investigation for reporting requirements).
I. Additional Information
The Council of State and Territorial Epidemiologists (CSTE) surveillance case definitions should not affect the investigation or reporting of a case that fulfills the criteria in this chapter. (CSTE case definitions are used by the state health department and the CDC to maintain uniform standards for national reporting.)
Fact Sheets and Forms
References
American Academy of Pediatrics. 2009 Red Book: Report of the Committee on Infectious Diseases. 28th ed. Elk Grove Village, IL: American Academy of Pediatrics; 2009
CDC. Plague website. www.cdc.gov/plague/
Heymann, David L., ed., Control of Communicable Diseases Manual, 20h Edition. Washington, DC, American Public Health Association, 2015.