Invasive Mosquitoes Now Found in North County

For the second time in a week, County environmental health officials have found evidence of the Aedes aegypti mosquito, an aggressive, day-feeding invasive mosquito that has the potential to carry serious diseases.

San Diego County vector control officials reported finding Aedes larvae this week in Escondido, after responding to a resident’s complaint. It’s the first detection of the insect in North County.

Last week, officials said they found an adult mosquito in Chula Vista, near the same areas where the invasive mosquito was found for the first time locally in October.

County officials again urged people to check inside and outside their homes, apartments and properties and to empty out any standing water where these small, black-with-white-striped mosquitoes can breed.

“It’s very important that we get the public to help fight to keep this mosquito out of the county by eliminating standing water,” said County Environmental Health Director Elizabeth Pozzebon. “This includes inside your home. This mosquito will live and breed indoors.”

The diseases the Aedes mosquito is known for carrying are not native to San Diego County and are rarely seen here unless travelers contract them elsewhere and return home.

Despite that, environmental and public health officials are working to keep the Aedes mosquito — also known as the yellow fever mosquito — from establishing itself here because it can carry serious diseases including yellow fever, dengue and chikungunya.

County officials said they have not discovered how the mosquito had spread from South County to North County, but that it was likely transported by people in cars or material being moved. Officials said Aedes mosquitoes do not spread rapidly on their own.

The Aedes mosquito is fairly easy to identify. That’s because it differs from most native San Diego County mosquitoes in several important ways:

  • It usually feeds during the day and is an aggressive biter. Most native mosquitoes prefer to feed between dusk and dawn.
  • It likes to live in urban areas — feeding and laying eggs not only outside, but inside people’s homes in almost anything that can contain water, including plant saucers, cups and flowerpots.
  • It is small and black with white stripes.

County vector control teams have been putting up and monitoring traps for the Aedes mosquito in the areas where it has been found and handing out information to urge the public to be on the lookout for the pest.

Officials said the public should remember to follow the general “Prevent, Protect, Report” mosquito-fighting message they’ve used for the County’s “Fight the Bite” West Nile virus prevention campaign.

Prevent Mosquito Breeding: Dump out or remove any backyard or indoor item that can hold water, such as plant saucers, rain gutters, buckets, garbage cans, toys, old tires, and wheelbarrows. Mosquito fish, available for free, may be used to control mosquito breeding in backyard water sources such as unused swimming pools, ponds, fountains and horse troughs.

Protect Yourself from Mosquito Bites: Protect yourself from mosquito bites that can transmit disease. Wear long sleeves and pants when outdoors. Use insect repellent containing DEET, picaridin, oil of lemon eucalyptus or IR3535 when outside. Make sure screens on windows and doors are in good condition and secured to keep insects out.

Report Green Swimming Pools and Mosquitoes Biting During the Day Indoors: Report incidents of neglected swimming pools or areas of standing water that could be mosquito breeding areas — and mosquitoes biting indoors during daylight hours — to the Vector Control Program at (858) 694-2888 or vector@sdcounty.ca.gov.

For more information about County Vector Control, go to the program’s website.

Gig Conaughton is a communications specialist with the County of San Diego Communications Office. Contact