August 14, 2008 (Yakima, WA)— The Yakima Health District (YHD) received word late Wednesday afternoon
that mosquitoes trapped within the greater Yakima area have tested positive for West Nile Virus. The pool of
Culex pipiens mosquitoes was collected north of the gap (Ahtanum Ridge) on August 6, 2008 by the Yakima
Health District, in partnership with Mosquito Control District No.1. Three new mosquito pools trapped by the
Benton County Mosquito Control District have also tested positive. This brings the year-to-date total for Yakima
County to 8 positive mosquito pools and 3 positive horses.
“We’re seeing a greater number of environmental positives earlier in the mosquito season this year,” says Laura
Charters, Environmental Health Specialist with the Yakima Health District. “We’re also seeing an increase in the
number of complaints regarding mosquitoes from many parts of the county.”
The first line of defense against West Nile virus is to eliminate standing water that mosquitoes breed in.
Anything that can hold water can become a mosquito breeding ground in less than a week, so people should
check their property regularly, as well as change water in pet bowls, animal troughs and bird baths at least once
weekly. The second step is to avoid being bitten by mosquitoes. Screen windows and doors that remain open
for ventilation. When possible, avoid being outside at dusk and dawn when mosquitoes are most active.
People should also cover their skin by wearing long pants, long-sleeved shirts, socks, and shoes. Mosquito
repellants containing DEET, Picaridin, oil of lemon eucalyptus, or IR3535 are safe and effective against
mosquitoes when used according to label instructions.
“We haven’t had any human cases yet, but 11 positive mosquito pools and horses in the span of one month
definitely emphasizes the importance of continued prevention efforts across the Yakima Valley and region,”
Charters adds.
Symptoms of mild West Nile Virus illness include fever, headache, body aches, rash, and swollen lymph
glands. A more serious form of WNV disease produces symptoms such as neck stiffness, disorientation,
coma, tremors, convulsions, muscle weakness, and paralysis. Anyone experiencing any of these symptoms
should consult their medical provider, especially if there is a recent history of mosquito bites. The very young
and the elderly are most susceptible to the more serious form of WNV illness.
As a reminder, owners are urged to vaccinate their horses against WNV. Previously-vaccinated animals also
need yearly boosters. Even horses a few months old can be vaccinated against WNV. Please talk to your
veterinarian about available equine WNV vaccines.
