An American Goldfinch from Redwood City and a red-shouldered hawk from Emerald Hills tested positive for West Nile virus, according to officials from the San Mateo County Mosquito and Vector Control District.
The Redwood City bird was reported June 12 and the Emerald Hills bird was reported June 17. Both had chronic positive results which means the birds had a low level of virus and indicated they probably contracted the disease a while ago, possibly last season.
In June, district officials announced two dead birds were found in San Mateo that had tested positive for West Nile virus. A Scrub Jay was reported in the Hillsdale area east of Alameda de las Pulgas and an American Crow was reported in the Hayward Park area. They were the county’s first cases of West Nile virus this year, according to the district.
The district reported five positive cases of West Nile virus found in birds last year. Birds are the primary hosts of the virus, which are transmitted by an infected mosquito’s bite.
To prevent mosquito breeding, people are advised to drain standing water in flower pots, rain gutters, pet bowls and other places where mosquitoes lay their eggs.
Anyone who finds bird or tree squirrel carcasses are advised to report them to the West Nile virus hotline at (877) 968-2473 or online at www.westnile.ca.gov.