The first West Nile virus-positive mosquitoes found in the state this year were trapped Wednesday near Mesa in Franklin County, according to the state Department of Health.
The virus is not uncommon in the region. Last year, Franklin, Grant and Yakima counties had West Nile-carrying mosquitoes, but no illnesses were reported in people.
West Nile virus spreads when mosquitoes bite an infected bird then bite another bird, animal or person. No human vaccine or cure exists for the virus, so health officials urge protecting against mosquito bites.
Benton and Franklin counties each have a mosquito control district that takes measures to reduce mosquito populations.
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Planes from the Benton County district took to the sky Thursday in a recent mosquito control effort.
By day, the planes dropped ground-up corncobs with larvae-killing bacteria into stagnant pools of water around the Yakima River delta, West Richland Golf Course, Finley and between Prosser and Mabton. By night, they released fog from 300 feet in the same areas to kill adult mosquitoes.
The district sends out its planes about three times a year and trucks more often, District Manager Angela Beehler said Thursday. The Franklin County district uses similar methods, she said.
But warming temperatures during the next week could cause a spike in potentially disease-carrying mosquito populations, like the West Nile virus detected in Mesa, Beehler said.
The state monitors West Nile through traps set strategically by mosquito control districts. Monitoring and testing mosquitoes and dead birds around the state began in June.
The Benton County district sets 40 mosquito traps every week, Beehler said.
Most people who contract the West Nile virus experience few to no symptoms, according to the Department of Health.
But one in 150 can become severely ill or die.
Paul Champoux, owner of Champoux Vineyards in the Horse Heaven Hills south of Prosser, was bitten by a mosquito three years ago this week and was paralyzed with West Nile virus July 17, 2009.
Three years later, he still cannot walk without aid. He comes to therapy twice a week in Richland and recently was able to walk 600 feet with a walker.
"I'm feeling fantastic. My left leg still won't support me, but everything I do is getting easier," he told the Herald on Friday.
The virus poses the greatest threat to those with weak immune systems and the elderly.
The state Department of Health recommends avoiding mosquitoes by wearing bug repellent and protective clothing when mosquitoes are active. Getting rid of standing water around the home can limit mosquito breeding grounds.
Because birds can carry the virus, people also are encouraged to report dead birds. Benton and Franklin County residents can report dead birds to the Benton Franklin Health District by calling 460-HAWK (460-4295).
Updated West Nile virus information is online at www.doh.wa.gov.