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Cause:
Spiral-shaped bacteria (spirochetes). Borrelia
hermsii for tick-borne relapsing fever and B.
recurrentis for louse-borne relapsing fever.
Illness and treatment:
Symptoms include
a fever lasting 2 to 7 days cycling with afebrile periods of
4 to 14 days, with 1 to 10 cycles if untreated. Along with
fever there may be shaking chills, sweats, headache, muscle
or joint pain, or sometimes a rash. Treatment is with
antibiotics.
Sources:
The most common reservoirs in Washington for tick-borne
relapsing fever appear to be wild rodents and
Ornithodorus hermsii, a soft tick typically found in
eastern parts of the state at higher altitudes (1500 – 8000
feet). The ticks live in rodent nests and inflict painless
bites at night that are often unnoticed. Louse-borne
disease is not endemic to the United States but may
occur in travelers if an infective body louse contaminates a
wound or mucous membranes.
Prevention:
Avoid sleeping in rodent
infested buildings in regions with endemic tick-borne
disease. Rodent-proof structures to prevent future
colonization by rodents and their soft ticks.
Recent Washington trends:
Each year there are 1 to 12 reports. Almost all tick-borne
cases are associated with overnight stays in rural cabins.
Louse-borne disease is rare even in travelers.
2008:
Four tick-borne cases were reported, including 2 with
exposures in central or eastern Washington counties, one
with exposure in Idaho, and one with exposure in Belize.
Purpose of Reporting and
Surveillance
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To educate potentially exposed persons about
signs and symptoms of disease to facilitate early diagnosis
and treatment.
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To inform owners of potentially
tick-infested property (e.g., a vacation cabin) how to
reduce their risk of exposure.
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To identify endemic geographic areas within
Washington state.
Reporting Requirements
- Health care providers: immediately notifiable to
Local Health Jurisdiction
- Hospitals: immediately notifiable to Local Health
Jurisdiction
- Laboratories: no requirements for notification
- Local health jurisdictions: notifiable to DOH
Communicable Disease Epidemiology within 7 days of case
investigation completion or summary information required
within 21 days
Last
update
November 2009 |
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