A dead crow found in La Jolla tested positive for West Nile virus, the county's vector control office announced Tuesday.
Officials did not name the exact location of the bird, which is the first detected case reported in San Diego County this year.
County environmental health officials urged residents protect themselves from mosquitoes that can spread the potentially-deadly disease.
The virus tends to appear in warmer, summer-like temperatures. Residents in San Diego County have mostly avoided the nationwide epidemic, with the exception of a 19-year-old in Escondido, who was found to have the virus during a routine blood screening in 2009.
This year, about 4,700 people have gotten the virus nationwide and 219 people have died from it. In California, 15 people have died from West Nile virus this year.
"This is a good reminder that West Nile virus is here, but that it can be prevented," said Jack Miller, Director of the County Department of Environmental Health. "We want to remind people that they can take some simple steps to protect themselves."
Miller gave a few tips to avoid getting bit by mosquitoes potentially carrying the virus.
Click here for more information about West Nile virus or to find locations to get free mosquito fish.