Local West Nile Virus confirmed

Two mosquito pools taken from a water reservoir in west Porterville have tested positive for the West Nile Virus — a potentially deadly virus that can be transmitted to humans and animals through a mosquito bite.

Mosquitoes become infected when they feed on infected birds.

“We submitted a sample of 38 mosquitoes from the same spot and two separate mosquito pools tested positive,” said Yolanda Lourenco, assistant manager of Delta Vector Control District.

The mosquitoes were collected a week ago in a sample pool between Westfield Avenue, Pioneer Avenue, Lombardi Street and Westwood Street.

Testing areas are determined by historical data, Lourenco said, either from prior findings of positive mosquitoes or based on reports of concentrations of dead birds.

“That area is out of our district but we set traps there because we had found the virus there in a previous season,” Lourenco said. “We have two kinds of traps — one that targets the female mosquitoes looking for a meal and one that targets females looking for a place to lay their eggs.”

With that in mind, the vector control district placed two separate traps at the one location.

“We’ll be setting subsequent traps in the surrounding neighborhoods. There are not a lot of residences in that area,” Lourenco said. “There is no mosquito abatement district in the city of Porterville. All we are doing is conducting surveillance and providing the information to the county to see if there could be a spread to the population.”

According to the state’s West Nile virus Web site, the virus has been reported in 28 counties, including Fresno, Kern and Tulare counties. Seven counties have reported positive human cases in 2008, with the latest human case reported earlier in the week in San Diego County. Tulare County’s first human case was reported in Visalia on June 20, Lourenco said.

Last week, 292 mosquitoes in 19 counties have tested positive — 137 of them identified as new WNV positive samples reported, including 48 in Orange County, five in Fresno County and three in Tulare County.

“While there is currently no vaccine or treatment for humans, Tulare County Health Department officials urge residents to reduce their risk of mosquito-borne diseases by taking precautions,” said Allison Lambert, media specialist for TC Health and Human Services Agency. “Residents are also encouraged to report dead birds or squirrels that are thought to possibly be infected with West Nile Virus.”

Visit www.westnile.ca.gov to submit an online report or call (877) WNV-BIRD, (877)-968-2473.

Contact Esther Avila at 784-5000, Ext. 1047 or eavila@portervillerecorder.com.