Squirrel Tests Positive for West Nile Virus in San Mateo County

A squirrel found in Menlo Park has tested positive for West Nile virus, becoming the first squirrel in San Mateo County to test positive for the virus this year, the San Mateo County Mosquito and Vector Control announced Monday.

The Western gray squirrel, collected July 3, had a low level of West Nile virus, referred to as a “chronic”  infection, according to county officials.

The low level indicates the squirrel was not likely infected recently, and possibly acquired the virus last year.

Tree squirrels don’t travel long distances, meaning the infection was likely acquired in or near Menlo Park, county officials said.

Along with birds including ravens, crows and jays, tree squirrels are highly susceptible to West Nile virus. West Nile virus is transmitted through the bite of an infected mosquito.

“We are taking special precautions to determine whether this West Nile virus-positive squirrel is an indication of elevated disease risk,” Angie Nakano, Acting Laboratory Director for the San Mateo County Mosquito and Vector Control District, said in a statement.

Vector control technicians have been setting extra mosquito traps in the neighborhood where the positive squirrel was found to detect any potentially disease-carrying mosquitoes in the area, county officials said.

All mosquitoes trapped are being sent to state health labs to be tested for West Nile virus. If virus is detected, additional technicians will be deployed to the community to seek out and destroy mosquito breeding sources.

“Residents who are getting bitten by mosquitoes around their homes or workplaces should contact the district,” said Nakano.

Measures that can help people protect themselves from mosquito bites include:

• Eliminate standing water, which can breed mosquitoes.
• Wear repellent in areas with a lot of mosquitoes.
• Stay covered or inside during dawn and dusk.
• Contact the district for assistance with a mosquito problem at (650) 344-8592. REPORT DEAD BIRDS AND SQUIRRELS.

Reports of dead birds are an early indication that the virus is circulating in the environment. Residents are encouraged to help by reporting fresh carcasses of birds or tree squirrels to the West Nile virus hotline, online at www.westnile.ca.gov  or by phone at 877-WNV-BIRD (877-968-2473).

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