Plague Factsheet

Clinical Features?

Bubonic plague: enlarged, tender lymph nodes, fever, chills and prostration.
Septicemic plague: fever, chills, prostration, abdominal pain, shock and bleeding into skin and other organs.
Pneumonic plague: fever, chills, cough and difficulty breathing; rapid shock and death if not treated early.

Etiologic Agent

Yersinia pestis - bacillus.

Incidence

In the U.S., 1 to 40 cases reported annually (avg = 13 cases) by western states, 1971-1995. Worldwide, 2861 cases reported by 10 countries to WHO in 1995.

Sequelae

Rare, consequences of disseminated intravascular coagulation, lung damage. Mortality 50-90% if untreated; 15% when diagnosed and treated.

Costs

Not known.

Transmission

Flea-borne, from infected rodents to humans.
Direct contact with infected tissues or fluids from handling sick or dead animals.
Respiratory droplets from cats and humans with pneumonic plague.

>Reservoirs

Primarily wild rodents in U.S. (especially rock squirrels, ground squirrels, prairie dogs, other burrowing rodents) Commensal rats may be important elsewhere.

Risk Groups

In the U.S., persons exposed to rodent fleas, wild rodents, or other susceptible animals in enzootic areas of western states. Most cases occur in southwestern states of NM, AZ, CO, and in CA. Highest rates in Native Americans, especially Navajos; other risk groups: hunters; veterinarians and pet owners handling infected cats; campers or hikers entering areas with outbreaks of animal plague.

Surveillance

National Notifiable Disease Surveillance System (NNDSS) for animal plague surveillance, for reports of human cases, and laboratory testing of fleas, animal tissues and serum specimens, and serosurveys of carnivores CDC, Fort Collins, is a WHO Collaborating Center for Reference and Research on Plague Control, and reports all human plague cases in the U.S. to WHO.

Opportunities

Increased self-sufficiency of state and county public health labs.
Expanded active surveillance through carnivore serosurveys and application of geographic information systems (GIS) to surveillance programs.
Increased education of public and health professionals.
Collaborative applied research on plague prevention and control with other federal, state, and local health agencies, including application of GIS to surveillance.

Research

Ecology-based prevention and control strategies.
Improved diagnostic reagents and methods.
Development of potential vaccine candidates.
Risk factor identification using landscape ecology and epidemiology.