A San Fernando Valley resident died from complications caused by the West Nile virus, marking the first death from the mosquito-borne illness in 2026, the Los Angeles County Department of Public Health confirmed on Thursday.
Public health staff said the resident was hospitalized with a neurological illness caused by the virus.
“We extend our heartfelt condolences to the family and friends grieving the loss of a loved one due to West Nile virus,” LA County Health Officer Muntu Davis said. “This tragic loss is a reminder of the serious threat posed by mosquito-borne diseases, including West Nile virus and dengue.”
DPH said West Nile Virus is native to LA County and is the most common mosquito-borne disease in the area. With 15 cases documented so far this year, public health staff said the number of people infected with West Nile virus, half of whom live in the San Fernando Valley, outpaces the five-year average for this time period.
California state officials warned residents that mosquito populations would explode in size after an uncharacteristically warm winter
“After experiencing the warmest winter on record, West Nile virus amplification and consequently detection in Los Angeles County started almost two months early this year, leading to widespread activity countywide,” said Susanne Kluh, general manager of the Greater Los Angeles County Vector Control District.
Vector control districts said they have seen more mosquito pools and dead birds testing positive for West Nile Virus than expected.
“Although mosquito abundance has been suppressed, virus detections continue to be frequent, and we urge residents to wear repellent when spending time outside, especially during dawn and dusk when West Nile virus carrying mosquitoes are most active,” Kluh said.
LA County Public Health urges residents to use mosquito repellents containing DEET, picaridin, IR3535, 2-undecanone, and oil of lemon eucalyptus because these products are the longest-lasting and most effective, and recommends wearing long-sleeved clothes and pants whenever they go outside.
It also recommends that residents make sure that their screens fit tightly to their windows and doors to keep out mosquitoes and to clear standing water around their homes.
“Small actions like these can make a big difference in preventing illness,” Davis said.
West Nile virus disease is caused by bites from infected mosquitoes. The virus lives within several types of birds and spreads through the region when mosquitoes feed on the infected birds.
Public health staff said people over 50 and residents with health problems are at a greater risk of serious illnesses, including meningitis, encephalitis and limb paralysis.
There is no specific treatment for the disease and no vaccine to prevent infection
Most people infected with West Nile virus do not experience any symptoms but about 20% develop a fever with symptoms like:
- Headaches
- Body aches
- Joint pains
- Vomiting
- Diarrea
- Rash
Public health staff said about 1 in 150 will have severe symptoms, such as high fever, stiff neck, muscle weakness and sometimes a rash, about 3 to 14 days after being infected. They urged anyone with these symptoms to call their doctor right away.
