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