San Fernando Valley residents are being urged to take extra precautions against mosquitoes as the threat of
Three Valley neighborhoods -- Canoga Park, Sherman Oaks and Encino -- have had nine or more mosquito samples that tested positive for the virus this year, said Levy Sun, a spokesman for the Greater Los Angeles County Vector Control District.
"It's definitely higher than average for those communities," he said.
A San Fernando Valley man in his 60s was the first in the county to die from the virus this year, county health officials confirmed last month.
The Valley historically has higher rates of West Nile virus than the rest of Los Angeles County, Sun said.
The area "tends to be a little hotter than the rest of the county," Sun said. "Sometimes due to residents not taking care of their backyards and leaving water behind, combined with the heat we've had … it contributes to increased numbers of virus activity."
The vector control district urged residents to wear mosquito repellant containing EPA-registered active ingredients such as DEET, Picaridin, oil of lemon eucalyptus or IR3535.
It also asked people to drain stagnant water from outdoor containers and to reduce lawn water runoff to prevent mosquitoes from laying eggs in the water.
"We do tell residents that this is a shared responsibility for all of us," Sun said. "If one bad pool in the neighborhood turns green, it affects the entire community."
The warnings come amid an explosion of West Nile cases throughout the state, with 375 people infected as of Wednesday. Fifteen people have died this year because of the virus, according to state data.
Earlier this month, the California Department of Public Health said the proportion of mosquitoes infected with the virus had reached the highest level ever detected.
The vast majority of the cases have been in Orange and Los Angeles counties. There have been 150 human infections in Orange County and three deaths, according to state and local data.
The city of Santa Ana, in particular, has been hard hit with 54 reported cases, according to Orange County public health officials.
Three people have died in Los Angeles County, where there have been 69 human cases reported, according to state and local data.
The Greater Los Angeles County Vector Control District -- the largest of five vector control districts in the county -- said residents should report dead birds, which "play an important role in maintaining and spreading the virus." They can be reported at www.westnile.ca.gov.