Two more mosquitoes and five dead birds have tested positive for West Nile virus, the Marin/Sonoma Mosquito & Vector Control District said Friday.

One mosquito was collected from the vicinity of Citrus Fair Drive and Asti Road in Cloverdale and the other from the vicinity of Millbrae Avenue and Langner Avenue in Santa Rosa, the district said.

Three of the dead birds were from Sebastopol and one each from Healdsburg and Forestville.

In addition, two Marin County residents — from Tiburon and Fairfax — have been diagnosed with the virus, said Nizza Sequeira, spokeswoman for the mosquito control district.

Both residents had traveled to areas with high West Nile virus activity, making it likely they may have contracted the virus elsewhere, Sequeira said.

The district has "increased our surveillance measures in all areas where the virus has been detected, including near the Marin County residents' homes," she said.

Residents are asked to report mosquito problems online at or by calling (800) 231-3236.

They are also advised remove standing water from their property and to protect against mosquito bites by wearing long-sleeved shirts, long pants and applying an effective repellent to exposed skin.

Mosquitoes become infected with the virus when they feed on infected birds, and the insects can then spread the disease to humans and other animals.