II. Epidemiology

  1. Incidence: 200 to 300 cases per year
  2. Region: Most common in Rocky Mountains

III. Pathophysiology

  1. Cause: RNA orbivirus
  2. Transmission
    1. Dermacentor andersoni (wood Tick Bite)
    2. Infected Blood Transfusion

IV. Risk Factors for severe infection

  1. Asplenic patients
  2. Immunocompromised patients

V. Symptoms: Influenza-like illness

  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

VI. Diagnosis

  1. Serology
    1. Confirms diagnosis at 2-4 weeks
  2. PCR
    1. Reverse-transcriptase PCR can make the diagnosis within days of onset

VII. Differential Diagnosis

VIII. Labs

  1. Blood smear with immunofluorescent stain for virus
  2. Complete Blood Count
    1. Leukopenia
    2. Thrombocytopenia

IX. Management

  1. Symptomatic (self-limited, no specific treatment exists)

X. Complications: Uncommon

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Ontology: Colorado Tick Fever (C0009400)

Definition (MSH) A febrile illness characterized by chills, aches, vomiting, leukopenia, and sometimes encephalitis. It is caused by the COLORADO TICK FEVER VIRUS, a reovirus transmitted by the tick Dermacentor andersoni.
Concepts Disease or Syndrome (T047)
MSH D003121
ICD10 A93.2
SnomedCT 186607005, 6452009
LNC LA10445-7
English Colorado Tick Fever, Tick Fever, Colorado, COLORADO TICK FEVER, Fever, Colorado Tick, American mountain tick fever (diagnosis), Colorado tick fever (diagnosis), Colorado Tick Fever [Disease/Finding], colorado fever tick, mountain fever, colorado tick fever, mountain tick fever, American mountain tick fever, Colorado tick fever, CTF - Colorado tick fever, Colorado tick fever (disorder), American; mountain tick fever, fever; American mountain tick, fever; Colorado tick, fever; mountain, American mountain tick (virus), fever; mountain, fever; tick-borne, American mountain tick, fever; tick-borne, Colorado, mountain tick fever; American, mountain; fever, American mountain tick (virus), mountain; fever, Colorado tick; fever, tick-borne; fever, American mountain tick, tick-borne; fever, Colorado, Tick fever, American mountain, Tick fever, Colorado
Japanese コロラドダニ熱, コロラドダニネツ
Swedish Coloradofästingfeber
Czech koloradská klíšťová horečka, Coloradská klíšťová horečka
Spanish Fiebre por Garrapatas del Colorado, fiebre por garrapatas de Colorado (trastorno), fiebre por garrapatas de Colorado, fiebre transportada por garrapatas de las montañas americanas, Fiebre por garrapata de Colorado
Finnish Coloradon puutiaiskuume
Korean 콜로라도 진드기 열
Polish Gorączka kleszczowa Kolorado, Gorączka górska
Hungarian Colorado kullancs láz
Norwegian Colorado tick fever
Dutch Amerikaans; bergtekenkoorts, Colorado-teek; koorts, bergtekenkoorts; Amerikaans, fever; mountain, Amerikaanse bergteek (virus), fever; mountain, koorts; Amerikaanse bergteek, koorts; Colorado-teek, koorts; door teken overgebracht, Amerikaanse bergteek, koorts; door teken overgebracht, Colorado, mountain; fever, Amerikaanse bergteek (virus), mountain; fever, teken overgebracht; koorts, Amerikaanse bergteek, teken overgebracht; koorts, Colorado, Colorado-tekenkoorts, Koorts, Colorado-teken-, Tekenkoorts, Colorado-
Portuguese Febre do Colorado transmitida por carraças, Febre do Carrapato do Colorado
German Colorado-Zeckenfieber, Coloradozeckenfieber
French Fièvre à tique du Colorado, Fièvre à tiques du Colorado
Italian Febbre da zecche del Colorado