The Contra Costa County Grand Jury released its report this week on the Contra Costa Mosquito and Vector Control District.
According to the Grand Jury Report, they says the Contra Costa County has a well-run Mosquito and Vector Control District (MVCD). The problem is that county residents largely do not know about the MVCD, or they do not know what services the MVCD provides. The MVCD needs the public’s help and support to meet its public health goals.
They continue:
Public awareness is an essential first step in stopping the spread. The MVCD needs residents to report suspected Aedes mosquitos and to be at the forefront of the fight by learning how to eliminate breeding in their yards and homes.
City leaders, schools, and other local organizations need to be supportive of the MVCD and assist in that effort. In that way, mosquito and other vector-borne diseases can be controlled before they cause widespread and difficult to stop outbreaks. An ounce of prevention is worth a pound of pesticide
The report also highlights the Aedes mosquitos discoveries in the City of Antioch, City of Concord and City of Martinez. Invasive Aedes were first discovered in Contra Costa County in Martinez in August 2022 by MVCD inspectors who responded to a service request by a resident.
In August 2024, MVCD inspectors in Concord discovered four Aedes mosquitos in mosquito traps that MVCD routinely places throughout the county. No additional mosquitos were found upon subsequent trapping and door-to-door inspections, which indicated to the MVCD that the four mosquitos were “hitchhikers” who were accidentally transported from elsewhere.
Then, in September 2024, an Antioch resident requested a mosquito inspection. It was during that inspection that an MVCD inspector collected the first female Aedes mosquito identified in Antioch. Further trapping and extensive door-to-door inspections revealed an infestation covering an approximately 1.5 square mile boundary, as opposed to the one quarter square mile boundary in Martinez. It was the largest undertaking to stop a vector of disease to date for the MVCD. And in Antioch, as in Martinez, search warrants were obtained in cases of homeowner resistance.
The effort to stop the spread of Aedes in Antioch was the largest vector-control undertaking in Contra Costa County by the MVCD. It included 1,524 service requests, treatment of 298 acres with larvicide, 4,750 individual letters to residents, news releases, and community educational events.
Who is MVCD? The grand jury shared that polling down in 2021, showed only 45 percent of the public even knew about MVCD. It also highlighted that incomplete content on websites can contribute to this misdirection and lack of proper information. Residents often confuse the MVCD with the County’s Animal Services Department, contacting one for the services provided by the other. At the same time, there is no explanation or link to Animal Services on the MVCD website, even if you type it in the search function. Similarly, there is no explanation or link to the MVCD on the Animal Services website.
FINDINGS
- F1. The Mosquito and Vector Control District (MVCD) uses state-of-the-art Integrative Vector Management, which includes physical, biological and chemical control of vectors, in addition to vector surveillance and public education.
- F2. The MVCD had an excess of revenues over expenditures of more than two million dollars in each of the past three fiscal years.
- F3. Awareness by residents of how to identify and report Aedes mosquitos can assist in Aedes control.
- F4. Promotion of the MVCD’s residential inspection service will aide in detection of invasive Aedes.
- F5. Public education in how residents can eliminate Aedes eggs in their yards will assist in stopping the spread of invasive Aedes.
- F6. MVCD uniformed inspectors sometimes encounter a level of misunderstanding regarding their mission, resulting in denial or delay of entry to property.
- F7. When residents deny inspections, it delays mosquito identification and eradication efforts.
- F8. The Antioch vacancy on the MVCD Board of Trustees contributed to a delay in the MCVD presentation on Aedes to the Antioch City Council.
- F9. The MVCD website does not explain what activities should be reported to the Animal Services Department as opposed to the MVCD.
- F10. The MVCD website does not have a link to the Animal Services Department.
- F11. There are no prominent, direct links for reporting mosquitos on the home page of the MVCD website or the Animal Services Department website.
- F12. The MVCD does not currently leave their educational “Invasive Mosquito Species of California” identification brochure during home inspections for other vectors.
- F13. There are no current marketing partnership agreements with other counties to explore cost- effective public education and awareness.
- F14. The MVCD does not currently distribute their existing Aedes information through relevant retail establishments and other public agencies unless requested.
- F15. As of May 2025, the MVCD social media presence is limited to Facebook (60 followers), Instagram (232 followers), Nextdoor, and 1,432 followers on X.
- F16. The MVCD does not cross-market educational or promotional YouTube videos on other social media platforms
RECOMMENDATIONS
- R1. By February 1, 2026, the MVCD Board of Trustees should consider directing the MVCD to explore additional avenues to educate residents on how to recognize and report Aedes mosquitos.
- R2. By February 1, 2026, the MVCD Board of Trustees should recruit to ensure a complete Board of Trustees.
- R3. By February 1, 2026, the MVCD Board of Trustees should consider directing the MVCD to work with the Animal Control Services Agency to provide a link on their websites for reporting suspected Aedes mosquitos to the MVCD.
- R4. By February 1, 2026, the MVCD Board of Trustees should consider directing the MVCD to offer their existing brochure, “Invasive Mosquito Species of California” to residents during all requested home inspections for vectors.
- R5. By February 1, 2026, the MVCD Board of Trustees should consider directing the MVCD to explore the costs of coordinating public information campaigns with neighboring counties during Aedes infestations.
- R6. By February 1, 2026, the MVCD Board of Trustees should consider directing the MVCD to offer their existing brochure, “Invasive Mosquito Species of California” or other informational material to other public agencies and relevant retail establishments (for example garden and pool stores).
- R7. By February 1, 2026, the MVCD Board of Trustees should consider directing the MVCD to provide an opt-in/opt-out email service to send alerts and news releases when Aedes infestations are discovered.
GLOSSARY
- CHIKUNGUNYA—The Chikungunya virus is spread by an infected Aedes mosquito. Symptoms include fever, joint pain, headache, muscle pain, joint swelling, or rash.
- DENGUE FEVER—Dengue (break-bone fever) is a viral infection spread by Aedes mosquitoes. Symptoms are high fever, headache, body aches, nausea, and rash. Severe cases can be fatal.
- YELLOW FEVER—Yellow fever is spread by infected Aedes mosquito and can be a mild febrile illness to severe, sometimes fatal disease. Vaccinations are available.
- ZIKA—The Zika virus is spread by the Aedes mosquito and can then be spread through sex or to a fetus during pregnancy. Infection during pregnancy can cause birth defects.
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- May 29 – Grand Jury Releases Report on Clayton City Council Shenanigans
- May 14 – Richmond Slammed in Grand Jury Report
- July 2, 2024 – Grand Jury Finds Evidence Antioch City Council Committed Brown Act Violations
