Mosquitoes Test Positive For West Nile Virus In LA County

LOS ANGELES, CA — Mosquitoes in the San Gabriel Valley recently tested positive for West Nile virus, which is potentially deadly to humans, officials said Monday. It comes after the disease was discovered in other parts of the county earlier this summer.

The virus was detected in a sample collected from a trap set near Morgan Park in Baldwin Park. Officials said it marks the first time this year the virus has been detected in the San Gabriel Valley Mosquito & Vector Control District, which covers much of Los Angeles County northeast of downtown LA.

“West Nile virus can be transmitted by the native Culex mosquito species which is most active at dusk and dawn,” district Director of Scientific Programs Tristan Hallum said. “There is no cure or human vaccine for West Nile virus. Therefore, the best method of protection is to prevent mosquito bites and reduce potential mosquito sources.”

West Nile virus can be transmitted to humans by the bite of an infected mosquito. It's the most common cause of mosquito-borne disease in the continental U.S., according to the Centers for Disease Control and Prevention.

There are no vaccines or treatment for West Nile in people. Most people who become infected with the virus do not become sick. But about 20 percent develop a fever and other symptoms. And one in 150 develop a serious illness that can become fatal, the CDC said.

Those at greatest risk include seniors and people with compromised immune systems.

West Nile virus is typically detected in the county in the summer. The season's warm overnight temperatures contribute to mosquito populations and disease activity, district officials said.

West Nile-positive mosquitoes have also been found this summer in the San Fernando Valley and Inglewood.

"The district will continue monitoring disease activity and controlling mosquitoes in public spaces through routine inspections and necessary treatments, but residents should take precautions to protect their health," the district said in a release.

Officials said residents should take precautions to reduce conditions in which mosquitos proliferate and protect themselves from getting bitten:

• Dump out stagnant water around the home weekly, as mosquitos can lay their eggs in as little as a quarter-inch of standing water
• Remove unused containers that can hold standing water
• Use insect repellent that contains CDC-recommended ingredients: picaridin, DEET, oil of lemon eucalyptus (or PMD), or IR3535

Last year, there were 70 infections recorded by the LA County Department of Public Health. Of those, 61 people were hospitalized and three people died.