West Nile virus makes first 2011 appearance in Los Angeles County

File photo: A mosquito sits on a stick April 9, 2009 in Martinez, California.
File photo: A mosquito sits on a stick April 9, 2009 in Martinez, California.
Justin Sullivan/Getty Images

A dead crow found in West Covina has tested positive for West Nile virus, the first indication of the virus in Los Angeles County this year, the San Gabriel Valley Mosquito & Vector Control District announced today.

The crow was found Tuesday near San Bernardino and Azusa Canyon roads.

District officials noted that dead birds are often the first indication of West Nile activity, adding that warmer temperatures mean ideal conditions for the spread of the virus.

Mosquitoes obtain the virus by feeding on infected wild birds.

The virus is spread to humans through the bite of an infected mosquito. The virus is not spread through person-to-person contact, or directly from birds to humans. In most cases, people who are infected with West Nile virus never become sick, or have only very mild symptoms that include fever, headache, nausea, body aches, and a mild skin rash.

Symptoms of West Nile virus could appear within three to 12 days after infection. Fewer than one in 150 people who are bitten by an infected mosquito become severely ill, according to the Centers for Disease Control and Prevention (CDC).

In these rare cases, the virus can cause encephalitis and death. The elderly are most at risk for severe cases of the disease. There is no specific treatment for West Nile virus. However, individuals with severe symptoms may be hospitalized.

People can decrease their risk of infection by following these recommendations:

Residents who see dead birds were urged to call (877) WNV-BIRD, or (877) 968-2473.