HAYWARD, CALIF. – Alameda County Mosquito Abatement District has discovered one non-native Aedes aegypti mosquito in a residential area of the city of Pleasanton. The district is working to find the invasive mosquito, which is capable of spreading diseases such as dengue, Zika and yellow fever. The district will be conducting door-to-door inspections and applications, inspect and treat all catchbasins and storm drains, and will conduct intensive follow up trapping

The Pleasanton detection is the first in Alameda County since 2015. The district staff will be speaking with residents in the neighborhood on Thursday, October 10th to quickly address the issue and find any possible locations where the mosquito may be reproducing. Our ultimate goal is to stop the mosquito from establishing permanently in the neighborhood to the west of Amador Valley High School and east of Hopyard Rd. See map of area below.

“We take the threat of Aedes aegypti very seriously and we are working quickly to find possible sources in the area” said Ryan Clausnitzer, General Manager of Alameda County Mosquito Abatement District. “To do our job well, we need residents to cooperate with staff by allowing access to their properties to inspect for mosquitoes and/or potential mosquito habitats.” For residents who worry about their privacy, the district emphasizes staff who enter residential properties are not authorized to do anything besides check for mosquitoes and provide mosquito control as needed. The inspections are provided at no cost to residents.

The invasive species is about a quarter-inch in size with black and white stripes on its back and legs. It feeds almost exclusively on humans and does not fly long distances, venturing fewer than 500 feet from where it hatches. Aedes aegypti eggs are extremely small and difficult to notice, often they are mistaken for dirt or seeds.

It is important for residents to allow district staff to access their properties to check for mosquitoes and treat them as needed. The district urges residents in Pleasanton to inspect their properties for standing water, which provides breeding habitat for mosquitoes.

If Aedes aegypti gains a foothold in Alameda County, it will not only threaten public health but also affect our quality of life, as these mosquitoes are highly aggressive and active during the day, unlike native mosquito populations, which are most active in the morning and evening, when temperatures are cool. Mosquito activity is increasing in the Bay Area and beyond, and Aedes aegypti has now been detected, though it is not yet established, in four Bay Area counties, including neighboring counties Contra Costa and Santa Clara.

Though it is not native to California, Aedes aegypti is present in 19 counties throughout the state, mostly in the Central Valley and Southern California. It has the potential to transmit several viruses, including those that cause dengue, chikungunya, Zika and yellow fever. These viruses are not endemic to California, but there have been 6 cases of locally acquired dengue in Southern California in 2024 to date.

Aedes aegypti is aggressive and bites at any time of day. These mosquitoes are “container breeders,” preferring to lay their eggs just above the water line in small, artificial sources of water such as buckets, pet dishes, fountains and bird baths, plant pots and saucers, and old tires. Once laid, the eggs can last for more than a year without water.

The public plays a critical role in controlling the spread of this mosquito. Residents should look around their property and dump out even the smallest amount of standing water.

To protect yourself from mosquito bites:

·        Apply insect repellents containing EPA-registered ingredients such as DEET, picaridin, IR3535 or oil of lemon eucalyptus, always following label instructions.

·        Wear long-sleeve shirts, pants, socks and shoes when mosquitoes are most active.

·        Make sure your window and door screens are in good condition.

Residents experiencing mosquito bites during the day should report them immediately to the Alameda County Mosquito Abatement District at (510) 783-7744 or on the website at www.mosquitoes.org.

If you are sick with fever, headache and joint or muscle pain after returning from an area where dengue, chikungunya, yellow fever or Zika occurs, contact your doctor, and stay indoors as much as possible to avoid mosquito bites and help prevent the possible spread of the virus.

For more information visit: www.mosquitoes.org