San Joaquin County Mosquito & Vector Control District

09/10/2026

Today, San Joaquin County Mosquito & Vector Control District Public Information Officer Sumiko De La Vega had the opportunity to present to the Rotary Club Of Manteca with District Manager Omar Khweiss and Manteca Trustee and Board President Richard Silverman also in attendance.

The presentation covered mosquito control in San Joaquin County, including West Nile virus, the spread of the invasive Aedes aegypti mosquito, and the important role residents play in reducing mosquito breeding around their homes.

During the meeting, Manager Khweiss also presented Trustee Silverman with a gavel lapel pin in recognition of his role as President of the San Joaquin County Mosquito & Vector Control District Board of Trustees.

Thank you to the Manteca Rotary Club for the opportunity to share important mosquito prevention information and connect with members of the community.

Effective mosquito control takes all of us.

Spot the source. Stop the swarm!

09/08/2026

On Saturday, September 5, the San Joaquin County Mosquito & Vector Control District participated in the Del Webb Health & Safety Fair, sharing important mosquito prevention information with local residents.

Our team talked with attendees about the invasive mosquito species, Aedes aegypti, how it differs from our native mosquito species, and simple steps residents can take around their yards to help prevent mosquitoes from developing. We also distributed mosquito repellent wipes, flyers on how to screen yard drains, and brochures to help residents protect themselves from mosquitoes.

Thank you to the Del Webb community for inviting us to participate and to everyone who stopped by our booth, asked questions, and learned more about mosquito prevention!

Effective mosquito control takes all of us!

09/04/2026

NEWS RELEASE 9-4-26 (Stockton, CA): West Nile Virus Is Active in San Joaquin County — Use EPA-Registered Repellent When Outdoors for Labor Day

West Nile virus (WNV) remains active throughout San Joaquin County as we head into Labor Day weekend. So far in 2026, the San Joaquin County Mosquito & Vector Control District has detected WNV in 108 mosquito samples and 7 dead birds, and San Joaquin County Public Health has reported one human case.

If your Labor Day plans take you outdoors, protect yourself from mosquito bites by using an EPA-registered insect repellent containing DEET, picaridin, oil of lemon eucalyptus, PMD, or IR3535.

Residents can also help reduce mosquitoes around their homes:

• Dump, drain, or remove standing water around your yard each week

• Screen yard and patio drains to prevent mosquito access

• Wear long sleeves and pants when practical, especially at dawn and dusk

• Ensure window and door screens are in good repair

• Report neglected swimming pools or request a yard inspection from the District

In addition to the native Culex mosquitoes that transmit WNV, the invasive Aedes aegypti mosquito is established in many residential neighborhoods throughout the county. While this aggressive daytime-biting mosquito does not transmit WNV locally, it can develop in very small amounts of water around homes, making weekly yard checks especially important.

The District continues mosquito surveillance, disease testing, larval control, and targeted truck and aerial mosquito control treatments based on surveillance data. There is no fee for requesting District services.

View the full news release here:
https://www.sjmosquito.org/News-Spray-Alerts/News-Releases

09/03/2026

In observance of Labor Day, the San Joaquin County Mosquito & Vector Control District office will be closed Monday, September 7, 2026. Our office will reopen for regular business hours on Tuesday, September 8.

🦟 Spending time outdoors this Labor Day weekend? West Nile virus is active in San Joaquin County this summer, so remember to protect yourself from mosquito bites.

Use an EPA-registered insect repellent and ensure the label has one of these effective ingredients:
• DEET
• Picaridin
• IR3535
• Oil of lemon eucalyptus (OLE)
• PMD

Always follow the product label directions when applying repellent.

Have a safe and enjoyable Labor Day!

09/02/2026

🦟 𝐒𝐞𝐩𝐭𝐞𝐦𝐛𝐞𝐫 𝟐𝟎𝟐𝟔 𝐖𝐞𝐬𝐭 𝐍𝐢𝐥𝐞 𝐕𝐢𝐫𝐮𝐬 𝐔𝐩𝐝𝐚𝐭𝐞

West Nile virus (WNV) remains active in San Joaquin County and across California as we head into September.

So far in 2026, the San Joaquin County Mosquito & Vector Control District has detected WNV in 108 mosquito samples and 7 dead birds.

⚠️ 𝐂𝐚𝐥𝐢𝐟𝐨𝐫𝐧𝐢𝐚 𝐢𝐬 𝐜𝐮𝐫𝐫𝐞𝐧𝐭𝐥𝐲 𝐞𝐱𝐩𝐞𝐫𝐢𝐞𝐧𝐜𝐢𝐧𝐠 𝐚 𝐟𝐢𝐯𝐞-𝐲𝐞𝐚𝐫 𝐡𝐢𝐠𝐡 𝐢𝐧 𝐖𝐞𝐬𝐭 𝐍𝐢𝐥𝐞 𝐯𝐢𝐫𝐮𝐬 𝐚𝐜𝐭𝐢𝐯𝐢𝐭𝐲. As of the California Department of Public Health website's August 28 update, 65 human cases, including 5 fatalities, have been reported statewide this year. In 𝐒𝐚𝐧 𝐉𝐨𝐚𝐪𝐮𝐢𝐧 𝐂𝐨𝐮𝐧𝐭𝐲, 𝐨𝐧𝐞 𝐡𝐮𝐦𝐚𝐧 𝐖𝐍𝐕 𝐜𝐚𝐬𝐞 has been reported by San Joaquin County Public Health Services to date, announced August 5.

District staff continue to trap mosquitoes and test mosquitoes and dead birds for WNV each week. This surveillance provides an early warning of virus activity and helps guide additional targeted mosquito control measures in areas with an increased risk of disease transmission.

📍 This updated map (as of September 2, 2026) shows the areas where the District has detected West Nile virus activity so far this year:

• Clements
• Delta Islands
• Escalon
• Linden-Peters (new)
• Lockeford
• Manteca
• Stockton
• Thornton
• Tracy

The map legend identifies the type of sample in which WNV was detected: 𝘊𝘹. 𝘱𝘪𝘱𝘪𝘦𝘯𝘴 (Northern house mosquito), 𝘊𝘹. 𝘵𝘢𝘳𝘴𝘢𝘭𝘪𝘴 (Western encephalitis mosquito), or a dead bird. Larger circles indicate areas with a greater number of positive samples.

West Nile virus season isn't over yet. Warm temperatures can keep mosquitoes and virus activity going into the fall, so continue taking precautions against mosquito bites:

✅ Apply an EPA-registered insect repellent before spending time outdoors. Ensure it contains one of the following ingredients for effectiveness: DEET, picaridin, IR3535, oil of lemon eucalyptus (OLE), or PMD.
✅ Wear loose-fitting, layered long sleeves and pants, particularly around dawn and dusk, when mosquito species that spread West Nile virus are most active.
✅ Check your yard every week and dump, drain, or treat standing water where mosquitoes can develop and multiply.

💻 Learn more about West Nile virus or sign up for District news and mosquito control spray alerts at www.sjmosquito.org

09/01/2026

😾 The look your pet gives you when they find out their water bowl has become a mosquito nursery…

Mosquitoes don’t need much standing water to complete their life cycle. Water bowls, whether indoors or outdoors can become the perfect place for them to develop. District staff found this source while conducting inspections for mosquito problems. 🦟

Refresh water bowls daily, and scrub mosquito eggs off the sides before refilling.

While you’re at it, check the rest of your yard for anything holding water - even as little as a teaspoon! Dump, drain, or dispose of anything that can collect water.

🔎💧Spot the source. Stop the swarm! 🚫🦟

08/28/2026

🦟 One small container can collect thousands of mosquito eggs each week!

Yesterday, our District Manager, Entomologist, and Public Information Officer attended the San Joaquin Council of Governments meeting to share information about West Nile virus, mosquito control, and the invasive mosquito species, 𝘈𝘦𝘥𝘦𝘴 𝘢𝘦𝘨𝘺𝘱𝘵𝘪, during public comment.

Our District Manager explained how we conduct surveillance and mosquito control throughout rural, urban, and suburban areas of the county and shared that West Nile virus activity in California is at a five-year high. He emphasized that our adult mosquito treatments do not kill eggs and the most effective residential mosquito prevention remains residents checking their yards to eliminate standing water on a weekly basis.

Our Entomologist displayed the contents from a single "ovi cup" trap from a residential yard that collected more than 2,000 invasive mosquito eggs in one week, showing how multiple overlooked water sources across backyards can quickly contribute to large mosquito populations.

With more than 250,000 private residences in our county, District staff are unable to routinely inspect every backyard. The District PIO explained why residents are such an essential part of the solution: check your yard weekly, remove standing water, and scrub containers to eliminate mosquito eggs. All mosquitoes start their life in the water and preventing them from developing into the flying adults is key.

Spot the source. Stop the swarm!

Effective mosquito control takes all of us.

08/28/2026

08/27/2026

🦟 Let’s Talk Mosquitoes with Manteca Mayor Gary Singh: Part 1

Why does it seem like we’re getting more mosquito bites in recent years?

A major reason is the invasive species, Aedes aegypti, a mosquito new to our area that behaves differently from the mosquitoes we’re used to. It aggressively bites during the day, lays eggs in items and on the edge of water sources in the yard, and can develop in the tiniest amounts of standing water in our neighborhoods.

In Part 1, we show Mayor Singh some of the common backyard items where our technicians find these mosquitoes developing and share simple steps residents can take to help prevent them.

But what does it take to reduce mosquitoes and what does the District do to protect residents from mosquitoes and the diseases they can spread? Follow our account for Part 2, where we’ll take a closer look at prevention and control methods we use —and why effective mosquito control takes all of us.

Thank you to Mayor Singh for visiting our District, asking important questions, and helping us share this information with the community!

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