Plague

Epidemiology

  • Bubonic plague (“black death”) pandemics have occurred several times throughout the centuries
  • Less than 20 cases annually in US
  • Most common in SW states

Etiology

  • Yersinia pestis infection
  • Gram-negative cocco-bacillus
  • Reservoir: rodents

Physiology

  • Transmission: bite from infected flea
  • Incubation: 1-6 days (may be as short as 2-4 days)
  • Bubo formation (regional necrotizing lymphadenitis)

Diagnosis

  • Sputum GS/Cult+Sens: may reveal gram negative cocco-bacillus
    • Bipolar (“safety pin”) staining with Wright, Giemsa, or Wayson stains
    • Confirmatory
  • CXR/Chest CT patterns:
  • PCR, antigen detection, immunoassays: available from state ref labs and CDC

Clinical

  • Pneumonic plague: any case of pneumonic plague should be considered a possible bioterrorism event
    1) Productive cough:
    2) Chest pain:
    3) Dyspnea:
    4) Hemoptysis:
    5) GI symptoms: abdominal pain
    6) Acral gangrene:

Treatment

-Streptomycin + gent:
-Alternative: tetracycline
-Alternative: fluoroquinolones

Infection control: human-to-human transmission by respiratory droplets from pulmonary involvement
-Highly contagious
-Respiratory isolation for at least the first 48 hrs of therapy

Post-Exposure Prophylaxis: dooxy x 7 days

Vaccine: none available


Prognosis

  • Case-fatality rate without treatment: near 100%
  • Case-fatality rate with streptomycin: 5-14%

References

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