A dead crow found some 20 miles west of Los Angeles County's east end border cities has tested positive for West Nile virus.
The bird was found in Sierra Madre and is the first indication of the virus in the San Gabriel Valley this year, vector control officials said Sunday.
Officials with the San Gabriel Valley Mosquito & Vector Control District plan to test mosquitoes trapped in the area, with results expected by Monday. District officials said the warmer temperatures provide ideal conditions for the spread of the virus.
The virus is generally transmitted by mosquitoes who obtain it from dead birds. Residents were urged to report dead birds to a state hotline at (877) 968-2473 or online at www.westnile.ca.gov.
Residents were also urged to remove any standing water from their property that might attract mosquitoes.