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Fall Newsletter 2023

Stopping diseases before they spread in Alameda County

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The past few months have been incredibly busy for mosquito abatement districts throughout the country, and California is no exception with a very active West Nile virus season and invasive Aedes mosquitoes. While West Nile virus established itself in the United States in the early 2000’s and it is still the most frequently transmitted mosquito-borne virus here, recently two diseases, malaria and dengue, have been locally transmitted in the US. Local transmission means a person acquired the virus in the United States, not while traveling outside the states. Cases of local transmission of dengue have occurred in Arizona and Florida, and malaria has been found in Florida, Texas, and Maryland.

One way to prevent these diseases from occurring here in Alameda County is through our rapid disease response to imported cases of mosquito-borne viruses. Alameda County Public Health Department (ACPHD) informs the district of imported cases of malaria, dengue, and another mosquito-borne diseases. We then deploy traps around the area where the affected person resides to ensure the types of mosquitoes that vector the specific disease are not in the area. See examples of the traps in the images below.

Different species of mosquitoes can vector different diseases, so by learning which mosquitoes are in the immediate area we can assess the level of risk to the community. We report the results to ACPHD and confer on the next steps. Efforts like these help us stay ahead of imported mosquito-borne diseases and continue our mission to improve the health and comfort of Alameda County residents by controlling mosquitoes and limiting the transmission of mosquito-borne diseases.


Countering West Nile virus in Alameda County

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The entire state is finding more West Nile virus this year than the past five years.  You can track the activity in Alameda County on our website: West Nile virus activity. We encourage the public to call the West Nile virus hotline or go on the website to report any dead birds you find. Due to the number of dead birds and positive mosquitoes we found in Livermore with West Nile virus, we conducted adult mosquito control operations on three separate occasions to target hot spot areas. To learn more about what we did, see our press release page: Press releases. To receive notifications about adult mosquito control in Alameda County, sign up for our Fogging notifications on our website: Fogging Notifications. We appreciate the public’s willingness to work with us to reduce the risk of West Nile virus in our county.

Keeping your home mosquito free

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As the weather turns cold, several mosquito species begin to seek out a sheltered place to overwinter, which is similar to hibernation. To learn more about mosquito behavior during colder months, check out this study from our colleagues in Sacramento: Homes are a favorite destination for mosquitoes during fall and winter.

To harden your home against mosquitoes:

-       Eliminate standing water (areas such as bird baths, gutters, children’s toys, tire swings).

-       Empty watering cans, dishes under flower pots, and unused containers outside regularly.

-       Change automatic sprinklers to accommodate for colder and wetter weather.

-       Ensure window screens are whole, without tears or rips.

-       Check your sump pump regularly for mosquito larvae.

-       Add mosquitofish to ponds, unmaintained pools, or horse troughs.

-       Treat standing water with mosquito bits or mosquito dunks according to label instructions.

Events and Outreach

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We have been busy at different events and schools over the past few months. A few events for us this year include:

* Solano Stroll in Albany (check out the photos with Albany Trustee Robin Lopez and Emeryville trustee Courtney Welch)

* Peralta Hacienda ACE Camp in Oakland

* McKinley Elementary in San Leandro

And more! If you have an event or outreach opportunity for our team, connect with Public Outreach Coordinator Judith Pierce at

West Nile Virus Map

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