Plague is a bacterial disease caused by Yersinia pestis. Wild rodents, especially ground squirrels and prairie dogs, are the natural reservoir for plague. Rats, wild rodents, cats, and dogs can become infected with plague and the disease is occasionally transmitted to people by fleas. Bubonic plague: enlarged, tender lymph nodes, fever, chills and prostration Septicemic plague: fever, chills, prostration, abdominal pain, shock and bleeding into skin and other organsPneumonic plague: fever, chills, cough and difficulty breathing; rapid shock and death if not treated early
Symptoms
A person usually becomes ill with bubonic plague 2 to 6 days after being infected. When bubonic plague is left untreated, plague bacteria invade the bloodstream. The pathognomic sign of plague is a very painful, usually swollen, and often hot-to-the touch lymph node, called a bubo. This finding, accompanied with fever, extreme exhaustion, and a history of possible exposure to rodents, rodent fleas, wild rabbits, or sick or dead carnivores should lead to suspicion of plague. Onset of bubonic plague is usually 2 to 6 days after a person is exposed. Initial manifestations include fever, headache, and general illness, followed by the development of painful, swollen regional lymph nodes. Occasionally, buboes cannot be detected for a day or so after the onset of other symptoms. The disease progresses rapidly and the bacteria can invade the bloodstream, producing severe illness, called plague septicemia. Once a human is infected, a progressive and potentially fatal illness generally results unless specific antibiotic therapy is given. Progression leads to blood infection and, finally, to lung infection. The infection of the lung is termed plague pneumonia, and it can be transmitted to others through the expulsion of infective respiratory droplets by coughing. The incubation period of primary pneumonic plague is 1 to 3 days and is characterized by development of an overwhelming pneumonia with high fever, cough, bloody sputum, and chills. For plague pneumonia patients, the death rate is over 50%. Bubonic plague: enlarged, tender lymph nodes, fever, chills and prostration Septicemic plague: fever, chills, prostration, abdominal pain, shock and bleeding into skin and other organsPneumonic plague: fever, chills, cough and difficulty breathing; rapid shock and death if not treated early Complications: Rare, consequences of disseminated intravascular coagulation, lung damage Mortality 50-90% if untreated; 15% when diagnosed and treated.
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 Pneumonic plague is far more contagious because it is spread through the air by sneezing or coughing. RESERVOIRS Primarily wild rodents in U.S. (especially rock squirrels, ground squirrels, prairie dogs, other burrowing rodents) Commensal rats may be important elsewhere
Diagnosis
Plague is diagnosed by isolating the bacteria from sputum, blood, spinal fluid, or infected glands.
Treatment
As soon as a diagnosis of suspected plague is made, the patient should be isolated, and local and state health departments should be notified. Confirmatory laboratory work should be initiated, including blood cultures and examination of lymph node specimens if possible. Drug therapy should begin as soon as possible after the laboratory specimens are taken. The drugs of choice are streptomycin or gentamycin, but a number of other antibiotics are also effective. Those individuals closely associated with the patient, particularly in cases with pneumonia, should be traced, identified, and evaluated. Contacts of pneumonic plague patients should be placed under observation or given preventive antibiotic therapy, depending on the degree and timing of contact. It is a U.S. Public Health Service requirement that all suspected plague cases be reported to local and state health departments and the diagnosis confirmed by the CDC. As required by the International Health Regulations, CDC reports all U.S. plague cases to the World Health Organization.
Prevention
When traveling in areas where plague is common, it is important to avoid being bitten by infected fleas, or having contact with plague-infected animals, or persons infected with pneumonic plague. Patients with pneumonic plague should be quarantined until 3 full days of antibiotic treatment have been administered. Buildings should be rat-proofed, with appropriate storage and disposal of food, garbage, and refuse. Dogs and cats in such areas should be treated with insecticides to prevent flea infestation.
Links
Protection from Chemical Hazards
Wildpony ..... The Druidess Casts Her Spell
Biological Agents:
Anthrax/Botulism/Brucellosis/Campylobacteriosis/Cholera/Dengue Fever/Ebola Fever/E. Coli/Hanta Fever/Lassa Hemorrhagic Fever/Legionellosis/Marburg Hemorrhagic Fever/ Plague/Rift Valley Fever/Smallpox/Streptococcus/Tularemia/West Nile Fever
