Two more dead birds found in Sonoma County have tested positive for West Nile virus, according to the Marin/Sonoma Mosquito & Vector Control District.

An American crow found in Geyserville and a Steller’s jay discovered in Healdsburg bring to eight the number of birds collected in Sonoma County this year that are confirmed to be infected with the virus.

West Nile is spread through the bite of an infected mosquito, although fewer than 1 percent of people infected develop serious illness. Mild symptoms include fever, headache, body aches, nausea, rashes, swollen lymph nodes and vomiting.

Residents can help prevent the spread of the virus by taking steps to keep mosquitoes from breeding near their homes, especially by draining temporary sources of standing water and stocking backyard ponds with mosquitofish, which can be obtained free from the district.

District officials encouraged residents to report dead birds so they can be collected and tested. The toll-free number for the mosquito district is (877) 968-2473.

You can reach Staff Writer Elizabeth M. Cosin at 521-5276 or