Aedes aegypti (Yellow Fever Mosquito) Now Found in Los Angeles County

October 15, 2014

Los Angeles County, Calif. — The Greater Los Angeles County Vector Control District (GLACVCD) and San Gabriel Valley Mosquito & Vector Control District (SGVMVCD) are urging residents to keep a close eye out for small, black-and-white striped mosquitoes that are invasive to California and considered major vectors of public health concern in their native countries. On October 7th and 8th, the GLACVCD discovered Aedes aegypti (yellow fever mosquito) in the cities of Commerce and Pico Rivera, respectively.

“This is the latest in a series of identified mosquito introductions into the southland,” said Levy Sun, the District’s public information officer. In just three years, three new invasive Aedes species mosquitoes have been found in Los Angeles County: Aedes albopictus (Asian tiger mosquito) – A native of Southeast Asia, this species was first identified in El Monte and South El Monte in September 2011.

Since then, this mosquito has spread to 10 neighboring cities despite aggressive measures to eradicate the population. Aedes notoscriptus (Australian backyard mosquito) – A native of Australia, this mosquito was found in two neighborhoods in Montebello and Monterey Park this summer. Aedes aegypti (yellow fever mosquito) – A tropical and subtropical species now found worldwide was first identified in California’s central valley and central coast in June of 2013, and last week in Los Angeles County.

It is difficult to determine the origins of these Aedes introductions into California, but transport of dormant eggs, via imported tires and plants, have been associated with introductions of these mosquito species in the past. In addition, individuals moving materials via planes, ships, cars, or other vehicles from infested areas to non-infested areas may also facilitate spread. Vector control officials are concerned about this rapid change in the public health landscape in Los Angeles County.

All three mosquitoes are aggressive day-biting mosquitoes that thrive in urban environments because they prefer to lay eggs in small man-made containers that hold water. The adults are approximately 1/4 inch long and have distinctive black-and-white stripes across the body and legs.

The Asian tiger mosquito and the yellow fever mosquito are both capable of transmitting dengue, chikungunya and yellow fever viruses. The Australian backyard mosquito can transmit canine heartworm and is the primary vector for Barmah Forest and Ross River viruses in Australia. “While these debilitating viruses, so far, aren’t locally transmitted in L.A. County, the mosquitoes that can transmit them are now here,” said Susanne Kluh, director of Scientific-Technical Services. “Infected travelers can bring these viruses to Los Angeles County.”

The districts are working closely with the Los Angeles County Department of Public Health, which tracks imported human cases. Vector control specialists use this information to promptly reduce the risk of local disease transmission. “Both agencies have specialized teams that target these invasive species,” said Jason Farned, public information officer at SGVMVCD. “We’re aggressively attacking the populations wherever we find them.”

In order to stop the spread of these species in Los Angeles County, vector control is calling upon all residents to do their part by following these steps:

• REPORT any sightings of small, black-and-white mosquitoes or if you are being bitten by mosquitoes during the day! Residents can contact SGVMVCD at 626-814-9466 or GLACVCD at 562-944-9656 or online at

• Dump and drain all stagnant water around your home. Eliminate plant saucers and other unnecessary containers and thoroughly scrub outdoor pet water dishes weekly to remove eggs.

• Do not transport or share plant stems rooted in water. Do not keep outdoor buckets full of water.

• Use insect repellent containing EPA-registered active ingredients such as DEET, Picaridin or oil of lemon eucalyptus to avoid bites.