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Cause:
Various viruses transmitted by arthropods.
Arthropod-borne
viral (arboviral) diseases include
West Nile virus disease
and yellow fever
(both discussed separately below),
Chikungunya virus disease,
Colorado tick fever, dengue fever, eastern and western equine
encephalitis, St. Louis encephalitis,
and
Japanese encephalitis.
Illness and treatment:
There are 4 main clinical forms: central nervous system (CNS) illnesses;
fevers of short duration with or without rash; hemorrhagic
fevers; and polyarthritis and rash with or without fevers.
Treatment is supportive.
Sources:
Transmission is most commonly by the bite of arthropods (e.g., mosquitoes,
sandflies, ticks). Rare transmission occurs through blood transfusions.
Prevention:
Avoid arthropod bites by wearing appropriate clothing and using insect repellents. If
traveling to risk areas, consult with a travel clinic or the
CDC Travelers’ Health website regarding additional measures,
including vaccination for Japanese encephalitis or yellow fever.
Recent Washington trends:
In recent years, 10-20 cases of travel-associated dengue fever and a few
travel-associated Chikungunya cases have been reported annually. Rare reports of
other travel-associated arboviral diseases including Colorado tick fever and
Japanese encephalitis in 2008, and St. Louis encephalitis and Toscana virus in 2009.
Other than West Nile virus, the last reported human arboviral infection acquired
in the state was western equine encephalitis in 1988. St. Louis encephalitis infections
occurred in the past, primarily east of the Cascade Mountains.
2010:
Nineteen (19) cases of dengue fever were reported following travel to India, Vietnam,
Haiti, Philippines, Puerto Rico, Indonesia, Laos, Mexico, Tanzania, East Timor, and
Venezuela. Three cases of Chikungunya virus disease were reported after travel to
India and Indonesia.
For current information on WNV in Washington State, please see the
DOH West Nile Virus hompage .
Purpose of Reporting and Surveillance
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To distinguish arboviral infections acquired locally from those related to travel
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To better understand the epidemiology of these infections in Washington State in order to target
education and control measures
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To identify emerging arboviral infections in Washington
Legal Reporting Requirements
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Health care providers:
notifiable to local health jurisdiction within 3 business days
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Health care facilities:
notifiable to local health jurisdiction within 3 business days
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Laboratories:
Arboviruses (eastern and western equine encephalitis, dengue, St. Louis encephalitis,
La Crosse encephalitis, Japanese encephalitis, Powassan, California serogroup,
Chikungunya) acute infection by IgM positivity, PCR positivity, and viral isolation, within 2 business days.
Specimen submission is on request only.
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Veterinarians:
Suspected human cases notifiable within 24 hours to the local
health jurisdiction; animal cases notifiable to
Washington State Department of Agriculture (see:
http://apps.leg.wa.gov/WAC/default.aspx?cite=16-70)
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Local health jurisdictions:
notifiable to Washington State Department of Health (DOH) Communicable Disease Epidemiology
(CDE) within 7 days of case investigation completion or summary information required within 21 days.
Last update
December 2011 |
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