West Nile Virus Activity Surges Above 5-Year Average In SGV: Breakdown By City

West Nile virus activity has climbed above normal levels across the San Gabriel Valley, prompting mosquito control officials to urge residents to take additional precautions outdoors.

The San Gabriel Valley Mosquito and Vector Control District has detected 105 West Nile virus-positive mosquito samples across cities and unincorporated communities within its service area so far this year, district officials said Thursday.

West Nile Virus-Positive Mosquito Samples:

Although West Nile virus is endemic to the region, this year's activity has surpassed the district's five-year average, officials said.

The virus is transmitted through the bite of an infected Culex mosquito, which is most active around dusk and dawn.

Vector control technicians are monitoring and treating known mosquito sources while searching for additional breeding sites in communities experiencing elevated mosquito activity. The district has also increased surveillance and public education efforts.

“Although current WNV activity is higher than usual, our teams are purposely equipped to deal with this challenge,” Director of Scientific Programs Tristan Hallum said. “We strongly encourage residents to tip out any stagnant water around their homes, toss out any unused containers that can collect water, and protect themselves with mosquito repellent when outdoors during this holiday weekend.”

Local and state agencies are also seeing higher-than-average West Nile virus activity this year, according to the district.

There is no human vaccine or cure for West Nile virus, making prevention especially important, officials said.

Residents can reduce mosquito breeding by eliminating standing water from rain gutters, barrels, tires, buckets, watering troughs and other containers that hold water for more than a week. Swimming pools, spas and ponds should also be properly maintained.

Water in pet dishes, birdbaths and other small containers should be changed weekly, and neglected swimming pools can be reported to local vector control officials.

To prevent bites, residents are encouraged to apply mosquito repellent before going outdoors and reapply it according to label instructions. Officials recommend repellents containing EPA-registered ingredients such as DEET, picaridin, IR3535 or oil of lemon eucalyptus.

Wearing light-colored, long-sleeved shirts and long pants can also help reduce exposure to mosquitoes.