Dead birds in two more Northern California counties have tested positive for West Nile Virus. Health officials said today that they found the disease in four birds in Sacramento County and one in Tehama County.

Yesterday they said that a bird had been found with the disease in Santa Clara County.

The virus is carried by mosquitoes and can also strike humans, usually creating flu-like symptoms. But it can also cause neurological problems and in rare cases death.

So far the virus has infected more than two dozen people in Southern California.