Fifteen counties have reported cases of dead birds or mosquitos with West Nile Virus this year.
That's almost double the number of counties with the virus at this time last year.
No human infections have shown up, but Dr. Vicki Kramer with the California Department of Public Health says there is an increased risk.
KRAMER: "People should be concerned about the elevated West Nile Virus activity, and should take precautions especially when they're going to be outside at dawn and dusk when mosquitos are most active."
BROWN:"Of course, we had a very dry winter, we have a very suseptible bird population but we also have a number of adult infected mosquitos and in large part that's because we haven't been able to get around and be as efficient at controlling the larval mosquitos as we have in the past."
Health officials say most people bitten by infected mosquitos don't become ill, but some may develop flu-like symptoms and a small minority can become severely ill.