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Quarterly Newsletter and Updates

Spring 2023

First West Nile Virus detection happened when?!

2023 is already off to an interesting start, with an early discovery of West Nile virus (WNV) positive mosquitoes for the year. In the past nine years we have typically detected WNV in summer months, not in early winter. However, this year in late January WNV positive Culex tarsalis mosquitoes were collected from one of our many traps along the marsh in Union City. This was Alameda County’s first detection of WNV in mosquitoes since 2018. Typically we find WNV first in dead corvids, such as crows and ravens, before we find the virus in mosquitoes. California Department of Public Health confirmed our detection was the first WNV detection in the state for this year.  


To determine if West Nile virus was more widespread, district staff placed additional traps in the area where the WNV positive mosquitoes were found. After testing all the mosquitoes caught in the traps, none had WNV. These results lead staff to believe the detection was likely localized to the marsh in Union City, and may have resulted from the mosquito resting over the winter months. Mosquitoes go through a process of overwintering which is similar to hibernation, so it is highly plausible the mosquito contracted West Nile virus before it settled in for the winter in 2022. To learn more about overwintering, read: Where Do Mosquitoes go in the Winter? The district continues to monitor the site and all of the county throughout the year with mosquito traps.    

Rain containers 101: How to save water without inviting mosquitoes  

With more rain activity than we have seen for years, many residents hope to store water and use it for gardening and other activities. Unfortunately, we have already had a few calls reporting mosquito larvae in water storage. So, what can you do if you find larvae or want to protect your water from becoming a source for mosquito production? 

  • Cover all containers with a tight-fitting lid or screen 
  • Screen all openings, including downspouts from roof gutters. Screens should be 1/16 inch fine mesh and should have no holes or tears.  To see a video demonstration, find it on YouTube from our friends at Contra Costa Mosquito and Vector Control District: In a Minute Episode 11 Rain Barrels Without Mosquitoes
  • Place a mosquito donut or mosquito dunk with Bti in the container. The Bti spores will release over 1 month, so you will need to replace the dunk every month. Bti is a bacteria that inhibits mosquitoes from completing their life cycle. Bti treated water is safe for gardening, and can be used in bird baths and for amphibians. To learn more, visit: EPA Guide to Mosquito Control

If you do find mosquito larvae in your rain container, either add Bti to the water or dump it out. Check around for standing water to see if mosquitoes are producing in other nearby areas.  

Social Media Moment

There is still a lot of water out there, and many sump pumps are working overtime. Make sure yours is functioning properly and drain away as much water as possible from your home or business. You don't want to host a mosquito breeding ground.

Changes at the District

We thank our outgoing board of trustee members, Preston Jordan from Albany, Shawn Kumagai from Dublin and Julie Testa from Pleasanton for their time and service to the district. We welcome our new trustees, Robin Lopez representing Albany, Valerie Arkin representing Pleasanton and Kashef Qaadri representing Dublin. We look forward to working with new trustees and to learn from their insights in their own communities.

New staff: Danny Sharkey is our new mosquito control technician for Zone 8, which is primarily Livermore. Danny joins us after working as a field technician and a seasonal lab technician in Southern California. He has a strong interest in entomology and is especially interested in communicating with the public on ways they can limit the production of mosquitoes in their area. Welcome, Danny!  


Staff from the district presented, wrote posters and moderated sessions at two large conferences, American Mosquito Control Association and Mosquito and Vector Control Association of California. Check out what we did below.

American Mosquito Control Association Annual Conference 

Eric Haas-Stapleton: Moderated the UAS in Mosquito Control Symposium  

Sarah Lawson: Teamwork, tech and taxes to tackle tidal mosquitoes presentation

Judith Pierce: Confronting SIT misinformation in Berkeley, CA presentation

Mark Wieland: ARGO trailer nurse tank for extended larvicide applications at remote sites poster


Mosquito and Vector Control Association of California conference 

Robert Ferdan spoke on the panel for Inspection and Enforcement of Unmaintained Swimming Pools

Erick Caesar-Martin Gaona: Resistance in the marsh- Methoprene and Aedes dorsalis poster

Eric Haas Stapleton moderated the Inspection and Enforcement of Unmaintained Swimming Pools panel

Sarah Lawson: Teamwork, tech and taxes to tackle tidal mosquitoes presentation 

Anam Meiraj Safoora: Testing artificial intelligence accuracy in mosquito identification poster

Sky Mihaylo: Measuring and distributing workload in mosquito abatement: Analysis for Alameda County Mosquito Abatement District presentation

Mark Wieland: ARGO trailer nurse tank for extended larvicide applications at remote sites poster

Special thanks to General Manager, Ryan Clausnitzer, Lab Director Dr. Eric Haas-Stapleton and Field Operations Supervisor Joseph Huston their support for developing, editing and submitting presentations and posters.

Mosquito Life Cycle Curriculum

Our district offers free in-class presentations about mosquitoes to any school in Alameda County. The goal of the lessons is to educate students about the public health threat of mosquitoes, their habitats and ways to decrease their risk of getting bitten. Students learn to remove standing water in their communities, and our hope is by cementing this social norm now, they will carry it forward throughout their lives. We have already presented in schools in Oakland, San Leandro, and Newark, and have dates scheduled for Livermore and Sunol. If you are interested, email Public Outreach Coordinator Judith Pierce at [email protected] to learn more and schedule a presentation. 

West Nile Virus Reminder

Alameda County was the first county to detect West Nile virus in an animal this year. As a best practice our lab continues to trap mosquitoes and test them for disease. We will also pick up dead birds and test them, since dead birds are often the first indicator of WNV circulating in an area. If you come across a dead bird please report it online at www.westnile.ca.gov.  Mosquitoes enjoy periods of rain followed by sunshine, which the county has experienced a lot of in the past few months. Preventative activities such as removing standing water, adding mosquito fish to ponds, troughs, and neglected swimming pools, reduce our risk of West Nile virus. Even though it is cold or raining, get into the habit of checking 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 produce.  

More WNV information

Alameda County Mosquito Abatement District


[email protected]


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