CA's First Dengue-Positive Mosquito Found In LA County

LOS ANGELES, CA — Health officials on Thursday confirmed the presence of dengue in mosquitoes in Los Angeles County, and began deploying targeted control measures to reduce the risk of spreading the disease transmission caused by the bugs.

The Greater Los Angeles County Vector Control District collected a dengue-positive Aedes mosquito — also known as the "ankle biter" — from surveillance traps in Sun Valley in the east San Fernando Valley, officials said.

It marks the first confirmed detection of dengue in an Aedes mosquito in both the county and state, according to county officials.

County public health officials have previously confirmed seven infections of locally acquired dengue this year, in La Puente, Sun Valley and North Hollywood.

In a presentation delivered at a U.S. Centers for Disease Control and Prevention conference earlier this year, an LA County public health official described the presence of locally acquired dengue infections as "unprecedented."

While the risk for widespread dengue virus transmission in the county remains low, the Los Angeles County Department of Public Health encouraged residents to take proactive steps to prevent mosquito breeding and mosquito bites.

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The detection of dengue-positive mosquitoes indicates an increased risk of human infection in the east Valley, county officials said.

"The District is conducting enhanced surveillance, community outreach, and mosquito control efforts, including intensive door-to-door inspections and targeted treatments to reduce mosquito populations and limit further spread," Susanne Kluh, the vector control district's general manager said in a statement.

Kluh urged residents to use insect repellent and remove all standing water around their homes, as puddles and non-moving water can serve as breeding grounds for mosquitoes.

People can be infected with the virus from invasive Aedes mosquitos, which differ from common Southern house mosquitoes. They're typically found in tropical and subtropical climates such as the Caribbean, Puerto Rico, Central and South America, Southeast Asia and the Pacific Islands.

Since they were first detected in California over the last decade, Aedes mosquitos have entrenched themselves statewide.

Symptoms of dengue include fever, nausea, vomiting, rash and body aches. Symptoms usually last two to seven days and most people recover after about a week, though severe and life-threatening illness can occur, according to health officials.

About one in 20 people with dengue can develop severe disease, which can be life threatening.

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"During 2024, ongoing transmission, combined with an unexpected spike in dengue cases, resulted in a historic high of over 14.6 million cases and more than 12 000 dengue-related deaths reported," the World Health Oraganization reported. "From January to July 2025, over 4 million cases and over 3000 deaths have been reported to WHO from 97 countries."

The Greater Los Angeles County Vector Control District recommended people get rid of all standing water. Most mosquitos lay eggs on the surface of the water, but Aedes mosquitos lay their eggs on the sides of containers, so simply dumping out the water may not eliminate the bugs.

It's recommended that residents do away with plant saucers and keep repellent handy to help control the spread of the Aedes mosquito.

DPH recommends that residents who are experiencing symptoms or who have recently been ill should visit their primary care providers and discuss dengue testing.

Sun Valley residents without access to a provider can get a nursing appointment for dengue testing at a Public Health Clinic. To make an appointment, people in the area can call the Public Health InfoLine at 833-540- 0473, available seven days a week from 8 a.m. to 8 p.m.

City News Service contributed to this report.