Colorado tick fever
Colorado tick fever: Excerpt from Professional Guide to Diseases (Eighth Edition)
Colorado tick fever is a benign infection caused by the Colorado tick fever arbo-virus and transmitted to humans by a tick. It occurs in the Rocky Mountain region of the United States, mostly in April and May at lower altitudes and in June and July at higher altitudes. Because of occupational or recreational exposure, it's more common in men than in women. Colorado tick fever apparently confers long-lasting immunity against reinfection.
Causes and incidence
Colorado tick fever is transmitted to humans by a hard-shelled wood tick called Dermacentor andersoni. The adult tick acquires the virus when it bites infected rodents and remains permanently infective.
Incidence is high in Colorado, where up to 15% of people who regularly camp show past exposure. It's much less common in the rest of the United States.
Signs and symptoms
After a 3- to 6-day incubation period, Colorado tick fever begins abruptly with chills; temperature of 104° F (40° C); severe aching of back, arms, and legs; lethargy; and headache with eye movement such as extraocular movement. Photophobia, abdominal pain, nausea, and vomiting may occur. Rare effects include petechial or maculopapular rashes and central nervous system involvement. Symptoms subside after several days but return within 2 to 3 days and continue for 3 more days before slowly disappearing. Complete recovery usually follows.
Diagnosis
CONFIRMING DIAGNOSIS A history of recent exposure to ticks along with moderate to severe leukopenia, complement fixation tests, or virus isolation confirm the diagnosis.
Treatment
After correct removal of the tick, supportive treatment focuses on relieving symptoms, combating secondary infection, and maintaining fluid balance. Colorado tick fever needs to be differentiated from Rocky Mountain spotted fever and tularemia.
Special considerations
❑Carefully remove the tick by grasping it with forceps or gloved fingers and pulling gently. Be careful not to crush the tick's body. Keep it for identification. Thoroughly wash the wound with soap and water. If the tick’s head remains embedded, surgical removal is necessary. Give a tetanus-diphtheria booster as ordered.
❑Be alert for secondary infection.
❑Monitor the patient's fluid and electrolyte balance, and provide replacement therapy, as indicated.
❑Reduce fever with antipyretics and tepid sponge baths.
❑To prevent tickborne infection, tell the patient to avoid tick bites by wearing long-sleeved clothing, tucking pant bottoms into the top of his boots, and carefully checking his body and scalp for ticks several times a day whenever in tick-infested areas. He should also use insect repellant.
Book Source Details
- Book Title: Professional Guide to Diseases (Eighth Edition)
- Author(s): Springhouse
- Year of Publication: 2005
- Copyright Details: Professional Guide to Diseases (Eighth Edition), Copyright © 2005 Lippincott Williams & Wilkins.
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Copyright notice for book excerpts: Copyright © 2008 Lippincott Williams & Wilkins. All rights reserved.
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Insect bites and stings (Professional Guide to Diseases (Eighth Edition))
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