Invasive Aedes aegypti mosquito found in several counties across California, including in San Diego County


SAN DIEGO (FOX 5/KUSI) — An invasive mosquito species that can carry dangerous diseases has been identified in several counties across California, including in San Diego County.

Invasive Aedes aegypti mosquitoes, also known as the yellow fever mosquito, usually bite several times, and are active during the day. They can transmit Zika, dengue, yellow fever, and chikungunya viruses, according to San Diego’s Vector Control Program.

The small black mosquitoes have distinctive white stripes on their legs and back. 

The California Department of Health has been monitoring invasive Aedes mosquitoes throughout California for the past several years part of a statewide vector-borne disease surveillance system.

The San Diego Vector Control Program’s map shows invasive Aedes mosquitoes have been found in all areas in San Diego County.

Across California, the below counties are reporting the presence of invasive Aedes mosquitoes, while just a few counties in the state have found both Aedes aegypti and Aedes albopictus (also known as the tiger mosquito):

According to the California Department of Health, limited local transmission of dengue virus has happened in California, typically from mosquitoes biting people who have previously traveled to areas where those viruses are more prevalent.

The update on Dengue Infections in California by CDPH reports infections by county so far in 2024 as of April 1:

  • Kings County — 1
  • Napa — 1
  • Riverside — 1
  • San Francisco — 3
  • San Mateo — 1
  • Santa Cruz — 2
  • Sonoma — 1
  • Ventura — 2
  • Yolo — 1

In other parts of the country, the CDC’s map shows the Aedes aegypti mosquito across the entire southern half of the U.S., with less of a concentration in the southwestern states of Arizona and New Mexico.

Invasive Aedes mosquitoes lay their eggs in small containers of water. When it’s warm, the mosquitoes can go from egg to adult in less than one week.

Tips for protecting your home from Aedes mosquitoes — dump or treat any standing water around your property, check screens on doors and windows to insure they won’t get inside, wear long sleeves and pants, and use insect repellant.

To request an inspection, or for questions and advice contact the San Diego Vector Control Program at 858-694-2888 or

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