Biological Warfare

Plague

Plague is an infectious disease of animals and humans caused by the bacterium Yersinia pestis. Y. pestis is found in rodents and their fleas in many areas around the world. There are five kinds of plague syndromes:

• Bubonic plague is the most common in humans and presents with painful swollen lymph nodes (called bubos, hence bubonic) and fever. It can occur 2 to 8 days after an infected flea bite. Other organs effected may include skin, liver, and spleen.



• Septicemic plague occurs after infection, when fever predominates and there is an absence of swollen lymph nodes. Patients can die from sepsis from high concentrations of bacteria in the blood.



• Pneumonic plague occurs during bubonic or septicemic plague when the Y. pestis bacteria infects the lungs from the bloodstream. The first signs of illness in pneumonic plague are fever, headache, weakness, and cough productive of bloody or watery sputum. The pneumonia progresses over 2 to 4 days and may cause septic shock and, without early treatment, death. Person-to-person transmission of pneumonic plague occurs through respiratory droplets, which can only infect those who have contact with the ill patient.



• Cutaneous plague can accompany bubonic or septicemic plague when the skin becomes infected. Infections can appear as areas of inflammation with puss or scabbing. Bruising with swelling can occur that can evolve into gangrene.



• Meningitic plague is a rare complication of bubonic or septicemic plague when the meninges, the tissue that surrounds the central nervous system becomes involved. Headache and stiff neck are clinical signs.

Early treatment of plague is essential. Several antibiotics are effective, including streptomycin, gentamicin, tetracycline, and chloramphenicol.

There is no vaccine against plague.

Prophylactic antibiotic treatment for 7 days will protect persons who have had face-to-face contact with infected patients.