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Colorado Tick Fever

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Colorado Tick Fever

  • See Also
  1. Tick-Borne Disease
  2. Vector Borne Disease
  3. Prevention of Tick-borne Infection
  4. Tick Removal
  • Epidemiology
  1. Incidence: 200 to 300 cases per year
  2. Region: Most common in Rocky Mountains
  • Pathophysiology
  1. Cause: RNA orbivirus
  2. Transmission
    1. Dermacentor andersoni (wood Tick Bite)
    2. Infected Blood Transfusion
  • Risk Factors for severe infection
  1. Asplenic patients
  2. Immunocompromised patients
  1. Timing
    1. Onset 3-5 days after inoculation (Tick Bite)
    2. Symptom duration 7-10 days
  2. Pharyngitis
  3. Biphasic high fever (saddle-back fever)
  4. Meningitis
  5. Rash
  6. Conjunctivitis
  7. Photophobia
  8. Retro-orbital Headache
  • Diagnosis
  1. Serology
    1. Confirms diagnosis at 2-4 weeks
  2. PCR
    1. Reverse-transcriptase PCR can make the diagnosis within days of onset
  • Differential Diagnosis
  1. Tick-Borne Disease
  • Labs
  1. Blood smear with immunofluorescent stain for virus
  2. Complete Blood Count
    1. Leukopenia
    2. Thrombocytopenia
  • Management
  1. Symptomatic (self-limited, no specific treatment exists)
  • Complications
  • Uncommon
  1. Encephalitis
  2. Myocarditis
  3. Pneumonitis
  4. Hepatitis
  5. Disseminated Intravascular Coagulation
  • References
  1. Pace (2020) Am Fam Physician 101(9): 530-40 [PubMed]