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Summer Newsletter 2020

Summer 2020

Quarterly Newsletter and Updates


May contain: pool, water, yard, nature, outdoors, and swimming pool
Green swimming pool


Green Swimming Pools

Unmaintained swimming pools can produce thousands of mosquitoes in a short amount of time and are a significant problem in Alameda County during the summer months. Each year our District conducts an aerial inspection of Alameda County to identify unmaintained swimming pools. We are continuing the notice program we implemented last year to contact each property owner at the identified locations to make sure their swimming pools are not breeding mosquitoes. Possible mosquito control efforts for unmaintained pools include short term pesticide treatment or providing mosquitofish as a long term solution. A properly maintained swimming pool, which receives regular chlorine treatments and has a working pump and filtration system, is not a mosquito issue. If you have an unmaintained pool or know of one in your neighborhood you can submit a request for service on our website here.


Maintaining our Services During the Pandemic

During the COVID-19 pandemic our District continues to operate critical programs to protect the health and comfort of Alameda County residents by reducing mosquito populations. While it is not possible to pick up mosquitofish from our office at this time as it is closed to the public, our staff will still deliver them directly to your residence. Even though we are still providing our regular services of addressing mosquito issues, providing mosquitofish, identifying insects, and inspecting standing water, we are limiting person to person contact for our field staff while providing mosquito control to residents. Our staff continues to take precautions in their professional and personal lives to make sure that not only their families are safe during this time, but also the Alameda County residents that the District serves.


Aedes Dorsalis

May contain: nature, outdoors, land, scenery, plant, grass, and landscape

Aedes dorsalis mosquitoes are sometime an annoying part of summer in the Bay Area. They lay their eggs in our local tidal salt marshes and hatch when they are filled by high tides. Our field staff tracks the high tide cycles so that they can plan when to do a treatment in the marsh to prevent the larvae from becoming adults. Aedes dorsalis adults are very aggressive, day biting mosquitoes. They have the ability to fly moderate distances, making residents who don't live directly next to the marsh susceptible to this mosquito also. Residents should always protect themselves from mosquito bites by using insect repellent on exposed skin and wearing long, loose-fitting clothing when possible.


West Nile Virus

May contain: plot

Our laboratory continues to test suitable dead birds for West Nile virus (WNV). So far this year we have tested 56 dead birds and they have all come back negative. If you come across a dead bird please report it online at The summer months are when the mosquitoes most effective at spreading WNV are most common. However, mosquitoes can breed all year long in the Bay Area so proper precautions to avoid mosquito breeding should always be taken. Now is a great time to check for standing water in your yard and drain or cover anything that will hold water longer than 4 days. Visit our backyard checklist to see common places where mosquitoes breed. It is also important to note that WNV has been found in other counties in California, and can show up in our county at any point. If you will be spending time outdoors, especially during peak mosquito biting times like dusk and dawn, wear insect repellent on exposed skin and long, loose-fitting clothing to prevent mosquito bites. Use an insect repellent that contains DEET, Picaridin, IR3535, or oil of eucalyptus.