Monday, July 28, 2014
     

Tularemia

Epidemiology:

  • Highly infectious after aerosolization
  • Infectious dose can be as low as 20-15 organisms
  • Person-to-person transmission does not occur

Clinical:

  • Incubation period is 3-6 days (ranges 1-21 days)
  • Aerosolization would most likely result in typhoidal tularemia, with pneumonic involvement
  • Typhoidal tularemia is a nonspecific illness, with fever, headache, malaise and non-productive cough (mortality rates can be as high as 30-60%)
  • Diagnosis requirea high index of suspicion given nonspecific presentation

Laboratory Diagnosis:

  • Bacterial cultures should be handled in a bio-safety level 3 facility; isolation of organism can otherwise put laboratory workers at risk
  • Organism is difficult to culture and grows poorly on standard media; cysteine-enriched media is required
  • Serology is most commonly used for diagnosis

Patient Isolation:

  • Standard precautions. Droplet isolation not required

Treatment:

  • Streptomycin (7.5 mg/kg im q 12 hours x 10-14 days) or gentamicin (3-5 mg/kg/day iv or im qd in 3 divided doses x 2--14 days) are the preferred antibiotics
  • Tetracyclines are alternative choices, although they are bacteriostatic and associated with higher relapse rates and must be continued for at least 14 days

Prophylaxis:

  • Antibiotic prophylaxis is most effective if begun within 24 hours after exposure to aerosol
  • Tetracyclines are recommended for 14 days