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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), Colorado tick fever, dengue
fever, eastern and western equine encephalitis, St. Louis
encephalitis, Japanese encephalitis, and Chikungunya virus
disease.
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:
Each year, 0 to 10 cases of travel-associated dengue fever
are reported with rare reports of other travel-associated
arboviral diseases including Chikungunya fever in 2006.
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.
2008:
14 cases of dengue fever
were reported following travel to El Salvador, Guatemala,
Honduras, India, Mexico, and the Philippines. Seven of these
14 were traveling in a group together. One case of Japanese
encephalitis occurred in a patient after travel to Cambodia
and Vietnam. In addition, one case of Colorado tick fever
was reported after travel to Montana.
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 work
days
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Hospitals: notifiable to local
health jurisdiction within 3 work days
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Laboratories: isolation of an
arbovirus, or detection of viral antigen, antibody or
nucleic acid notifiable to local health jurisdiction of
the patient» s residence within 2 work days
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Local health jurisdictions:
notifiable to Washington State Department of Health (DOH)
Communicable Disease Epidemiology Section (CDES) within
7 days of case investigation completion or summary
information required within 21 days
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Veterinarians: notifiable to the
local health jurisdiction or to Washington State
Department of Agriculture
Last
update
November 2009 |
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