Yersinia pestis

Aka: Yersinia pestis, Pneumonic Plague, Bubonic Plague, Plague

1. See Also
   1. Bioterrorism
2. Epidemiology
   1. Madagascar (fall 2017)
      1. Cases: 1800 as of November 2017
      2. Deaths: 127 as of November 2017
      3. http://www.who.int/csr/disease/plague/en
3. Cause: Plague
   1. Yersinia pestis
4. Pathophysiology
   1. Gram Negative Rod
      1. Bipolar staining
      2. Facultative anaerobic bacterium
   2. Incubation
      1. Pneumonic Plague: 2-3 days
      2. Bubonic Plague: 2-10 days
   3. Organism survival
      1. Viability
         1. Water, moist meal, grain for weeks
         2. Near freezing Temperatures from months to years
         3. Dry Sputum, flea feces, buried bodies
      2. Killed by
         1. Heated for 15 minutes at 72 C
         2. Several hours in direct sunlight
   4. Transmission
      1. Reservoir: Rodents (rats, mice, ground squirrels)
      2. Flea Bites transmit bubonic form
      3. Aerosolized organisms transmit pneumonic form (Bioterrorism)
5. Types: Plague
   1. Bubonic Plague (80-95% of cases)
      1. Non-fluctuant inguinal Lymphadenitis
   2. Primary septicemic Plague (10-20% of cases)
      1. May occur in combination with Bubonic Plague
      2. Gastrointestinal symptoms predominate early
      3. Multiorgan failure, DIC, Sepsis occur later
   3. Pneumonic Plague (rare)
      1. Hematogenous seeding or droplet inhalation
      2. Mortality >60%
6. Findings: Symptoms and signs
   1. Pneumonic Plague
      1. High fever
      2. Chills
      3. Headache
      4. Hemoptysis
      5. Toxic appearance
      6. Rapidly fulminant Pneumonia within 2-3 days of exposure
      7. Disseminated Intravascular Coagulation (DIC) or Shock may ensue
   2. Bubonic Plague
      1. Malaise
      2. High fever
      3. Tender lymph nodes (buboes)
         1. Primarily inguinal (legs most commonly flea bitten)
7. Labs
   1. Fluid Gram Stain (from Sputum or buboe)
      1. Gram Negative Bacilli with "safety pin" appearance
8. Imaging: Pneumonic Plague
   1. Chest XRay with consolidative Pneumonia, bilateral and multilobar
9. Management
   1. Treat for 10-14 days
   2. Isolate plague Pneumonia patients for first 48 hours
   3. Doxycycline (over age 8 years)
      1. Convert to oral dosing when clinically improved
      2. Adult: 200 mg IV, then 100 mg IV every 12 hours
      3. Child: 2.2 mg/kg IV (max: 100 mg) every 12 hours
         1. Dose as adult for children over 45 kg
   4. Ciprofloxacin
      1. Adult: 400 mg IV every 12 hours
         1. When improved convert to 750 mg oral twice daily
      2. Child: 15 mg/kg (max: 400 mg) IV every 12 hours
   5. Gentamicin
      1. Adult: 5 mg/kg IM or IV every 24 hours
      2. Child: 2.5 mg/kg IM or IV every 8 hours
   6. Chloramphenicol
      1. Adult: 1 g IV every 6 hours
      2. Child: 25 mg/kg (max: 1 g) IV every 6 hours
   7. Streptomycin
      1. Adult: 30 mg/kg/day divided q12 hours IM
      2. Child: 15 mg/kg (up to 2 g) IM q12 hours
10. Prevention
    1. Licensed, killed Vaccine (no longer available)
       1. Doses at 0, 1-3 months, and 5-6 months
       2. Booster at 6 month intervals x3, then every 1-2 years
       3. Effective against bubonic, but not pulmonic Plague
    2. Post-exposure Prophylaxis (adult dosing below)
       1. Continue for 7 days or length of exposure
       2. Doxycycline 100 mg PO bid
       3. Ciprofloxacin 500 mg PO bid
       4. Tetracycline 500 mg PO qid
11. Prognosis
    1. Mortality 100% if untreated (or treatment delayed >48 hours)
12. References
    1. Gilbert (2016) Sanford Guide, accessed 12/24/2016 on IOS version
    2. Seeyave (2015) Crit Dec Emerg Med 29(5): 13-21
    3. Inglesby (2000) JAMA 283:2281-90 [PubMed]