Invasive, disease-spreading mosquito not seen in Alameda County in 10 years discovered in Pleasanton
A non-native mosquito capable of spreading diseases and hasn't been seen in Alameda County for a decade has been found in a Pleasanton neighborhood, county officials said Thursday.
Residents are being urged to check around homes for standing water after one Aedes aegypti mosquito was discovered Wednesday in an area west of Amador Valley High School and east of Hopyard Road.
It's the first time since 2014 that the mosquito species, which can spread diseases like dengue, Zika and yellow fever, has been detected in Alameda County, according to the Alameda County Mosquito Abatement District.
"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 the district.
The invasive mosquitoes are aggressive and bite at any time of day, and are considered "container breeders" that lay eggs just above the water line in small water sources like buckets, pet dishes, fountains and bird baths, plant pots and saucers, and old tires. The eggs can last for more than a year without water.
The district posted on its website that it would be speaking on Thursday with residents in the area where the mosquito was found. The district is planning door-to-door inspections and applications, to inspect and treat catch basins and storm drains, and follow-up trapping.
The aim is to stop the mosquitos from establishing permanently in the neighborhood.
The Aedes aegypti mosquito is about a quarter-inch in size, with black and white stripes on its back and legs. It feeds almost exclusively on humans and doesn't fly long distances, venturing fewer than 500 feet from where it hatches. The eggs are extremely small and difficult to see.
The district is urging residents to inspect properties for standing water, which provides a 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," the district said on its website.
To reduce the risk of mosquito bites, residents are encouraged to use an EPA-registered insect repellent containing active ingredients like DEET, picaridin, the repellent version of oil of lemon eucalyptus, or IR3535.
Wearing long-sleeve shirts, pants, socks and shoes when mosquitoes are most active is also advised, and residents should ensure that window and door screens are in good condition.
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, according to the district.
Aedes aegypti is present in 19 counties throughout the state, mostly in the Central Valley and Southern California. It can transmit several viruses, including those that cause dengue, chikungunya, Zika and yellow fever.
