Press Releases

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Invasive Aedes aegypti Mosquitoes Detected in Hayward for the first time

HAYWARD, Calif. August 25, 2026 — The Alameda County Mosquito Abatement District (ACMAD) has confirmed the discovery of multiple Aedes aegypti mosquitoes in Hayward. This marks the first detection of the invasive species in the city. The District is working with city officials and agencies to inform residents and inspect properties. Aedes aegypti is not native to California and can transmit…

The image shows a map of the Irvington area, highlighting streets, businesses, and landmarks like schools and parks.

Aedes aegypti mosquitoes in Fremont require larval treatments on August 14th

HAYWARD, CA August 13, 2026 - On August 12 multiple invasive Aedes aegypti mosquitoes were found in the Irvington neighborhood of Fremont. In response, Alameda County Mosquito Abatement District staff have increased mosquito monitoring and control efforts in the area and will conduct a truck-mounted larval treatment on August 14th during early morning hours to prevent additional adult mosquitoes…

The image shows a map of a residential area outlined in purple, near Castro Valley Boulevard and surrounding streets.

Invasive Aedes aegypti Mosquito Detected in Castro Valley; District to Conduct Larval Treatment July 23

HAYWARD, CA July 22, 2026 - On July 20th, the invasive mosquito Aedes aegypti was detected for the first time in Castro Valley. In response, Alameda County Mosquito Abatement District staff have increased mosquito monitoring and control efforts in the area and will conduct a truck-mounted larval treatment during nighttime hours on July 23 to prevent additional adult mosquitoes from emerging.

The image depicts a map of a Newark area, highlighting streets, parks, and a mobile service area.

Adult Mosquito Control Scheduled in Newark to Suppress West Nile Virus Activity

HAYWARD, Calif. July 9, 2026 – Due to increased West Nile virus activity in the Newark area, the Alameda County Mosquito Abatement District (ACMAD) will conduct two adult mosquito control treatments to affected areas centered near Mayhews Landings Park and Birch Grove Park on Friday July 10th.

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Alameda County Mosquito Abatement District Launches an Innovative Mosquito Reduction Program Using Wolbachia Male Mosquitoes to Reduce Invasive Aedes aegypti Mosquitoes

HAYWARD, CA. June 22, 2026 – In response to ongoing detections of the invasive mosquito species Aedes aegypti, known as the yellow fever mosquito, the Alameda County Mosquito Abatement District (ACMAD) is launching a new program to help reduce populations of this mosquito in Livermore.

The image shows a map highlighting an area around Newark Junior High School, including Mayhews Landings Park with a basketball court.

Adult Mosquito Control Scheduled in Newark Area to Suppress West Nile Virus Activity

HAYWARD, Calif. June 17, 2026 – Due to increased West Nile virus activity in the Newark area, the Alameda County Mosquito Abatement District (ACMAD) will apply an adult mosquito control treatment to the affected areas between Newark Blvd, Cedar Blvd and Mayhews Landings Rd starting at 11:00pm on Wednesday, June 17th.

Alameda County reports first West Nile virus in mosquitoes this year; learn more at www.mosquitoes.org.

First WNV positive mosquito of 2026 in Alameda County

First West Nile Virus-Positive Mosquito Sample Detected in Alameda County in 2026

Alameda County detected its first West Nile virus in 2026; one bird tested positive in Newark. Learn more at www.mosquitoes.org.

First West Nile positive dead bird found in 2026

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