Quick Facts about Plague

  • Plague is caused by Yersinia pestis, a gram-negative bacillus
  • Plague is a zoonosis that affects primarily rodents
    • Endemic to Arizona, Colorado, New Mexico, and California
    • Humans are "accidental hosts"
  • Transmission occurs in one of five ways
    • Bites of infected fleas
    • Human to human transmission of pneumonic plague by respiratory droplets
    • Handling of infected animal carcasses
    • Cat bites or scratches
    • Deliberate aerosolization of bacteria
  • Three plague syndromes are recognized
    • Bubonic
      • The most common naturally occurring form of the disease
      • 2 to 8 days following inoculation symptoms include the abrupt onset of fevers chills, headache, and weakness
      • Painful proximal lymphadenopathy develops, most commonly in the inguinal, axillary, or cervical areas. Lymph nodes become enlarged, matted, and associated with extensive, overlying edema (buboes)
      • Gastrointestinal symptoms such as nausea, vomiting, and abdominal pain may occur
      • Bacteremia may follow, resulting in sepsis and death
    • Pneumonic
      • The most likely presentation of a bioterrorist attack
      • Infection results from deliberate aerosolization of bacteria or contact with respiratory droplets from an infected person
      • Symptoms develop 1 to 6 days following exposure
      • Rapidly developing bronchopneumonia characterized by fever, cough, dyspnea, and serosanguineous sputum
      • The time from respiratory exposure to death ranges from 2 to 6 days
      • Suspicion of a deliberate attack should be raised by the rapid progression of a lethal pneumonia in a group of previously healthy people
    • Septicemic
      • May arise secondary to bubonic plague or following a fleabite without the development of buboes
      • Septicemia is associated with disseminated intravascular coagulation, necrosis of small blood vessels, purpuric skin lesions, and acral gangrene
      • Death is the result of shock and multiple organ failure
  • Diagnosis
    • Gram stain of the sputum or blood may reveal gram-negative bacilli or coccobacilli
    • Under the best of circumstances, cultures of sputum or blood are positive in 24to 48 hours. Depending on method used, results typically may take from 72 hours to 6 days
    • Rapid diagnostic tests, such as antigen detection, IgM enzyme immunoassay, immunostaining, and polymerase chain reaction are available only at selected state health departments, the CDC, and the military
    • Survival depends upon presumptive treatment prior to microbiological confirmation of the diagnosis
  • Treatment (based upon the interim recommendations of the Working Group on Civilian Biodefense, Johns Hopkins University Schools of Medicine)
    • Adults: Preferred choices
      • Streptomycin, 1 g IM BID
      • Gentamicin, 5 mg/kg IM or IV once daily or 2 mg/kg loading dose followed by 1.7 mg/kg IM or IV TID
    • Adults: Alternative choices
      • Doxycycline, 100 mg IV BID or 200 mg IV once daily
      • Ciprofloxacin, 400 mg IV BID
      • Chloramphenicol, 25 mg/kg IV QID
    • Children: Preferred choices
      • Streptomycin, 15 mg/kg IM BID, maximum dose 2 g
      • Gentamicin, 2.5 mg/kg IM or IV TID
    • Children: Alternative choices
      • Doxycycline: If > 45 kg, give adult dose. If < 45 kg, give 2.2 mg/kg IV BID (maximum dose 200 mg/day)
      • Ciprofloxacin, 15 mg/kg IV BID
      • Chloramphenicol, 25 mg/kg IV QID
    • Pregnant women: Preferred choice
      • Gentamicin, 5 mg/kg IM or IV once daily or 2 mg/kg loading dose followed by 1.7 mg/kg IM or IV TID
    • Pregnant women: Alternative choice
      • Doxycycline, 100 mg IV BID or 200 mg IV once daily
      • Ciprofloxacin, 400 mg IV BID
    • Therapy should be continued for 10 days. Oral therapy should be substituted when patient's condition improves
  • Post-exposure prophylaxis
    • Asymptomatic persons with household, hospital or other close contact (within 2 meters) with persons with untreated pneumonic plague
      • Adults: oral doxycycline, 100 mg BID x 7 days
      • Children: if > 45 kg give adult oral doxycycline dosage. If < 45 kg, give oral doxycycline, 2.2 mg/kg BID x 7 days
      • Pregnant women: oral doxycycline, 100 mg BID x 7 days
    • Persons receiving post-exposure prophylaxis who develop fever or cough
      • Antibiotic treatment as described above for pneumonic plague
    • Persons in a community experiencing a pneumonic plague outbreak who develop a fever > 38.5° C, or new cough, or infants with tachypnea
      • Antibiotic treatment as described above for pneumonic plague
  • Infection Control
    • Isolate patients for the first 48 hours of antibiotic therapy and until clinical improvement occurs
    • Transported patients should wear surgical masks
    • Observe standard respiratory droplet precautions including gowns, gloves, and eye protection for close contacts
    • Disinfect contaminated clothing and linens according to hospital protocol

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