CONCORD, CALIFORNIA – The Contra Costa Mosquito and Vector Control District (District) reports another group of trapped mosquitoes has tested positive for West Nile virus (WNV) in Contra Costa County.
The District is also confirming the collection of another invasive, non-native Aedes aegypti mosquito in North Concord. The WNV+ mosquitoes were collected in a trap in the City of Martinez. The invasive mosquito was collected during additional surveillance following the discovery of the first Aedes aegypti mosquito in North Concord (City of Concord) earlier this week.
In addition to the WNV+ mosquitoes this week, there have already been six groups of mosquitoes and six dead birds that have tested positive for WNV, and eight sentinel chickens have tested positive for antibodies in 2024. In response to the newest WNV activity, the District is conducting additional inspections and mosquito surveillance in Martinez.
In response to the collection of Aedes aegypti mosquitoes in North Concord, the District has conducted door-to-door inspections and treatments in the area and will continue to conduct inspections and trapping to reduce the risk that the invasive mosquito population becomes established in Contra Costa County.
“Aedes aegypti, commonly known as the Yellow Fever Mosquito, is an aggressive day-biting mosquito that can transmit pathogens that cause dangerous diseases including dengue fever, Zika virus, and chikungunya. In areas with established populations, particularly in Southern and Central California, these mosquitoes have changed the quality of life. They are well-adapted to living in small water-filled containers like plant saucers in urban and suburban backyards, and bite people during the day, typically around the legs and ankles. Due to the high nuisance potential and disease risks associated with these mosquitoes, the District is working very hard to find and eradicate them, but we need the public’s help. Report day-biting mosquitoes to the District and dump out and scrub any water-filled containers on your property to reduce the risk that these mosquitoes become established here, ” said Steve Schutz, Ph.D., Scientific Programs Director.
Contra Costa County residents can report these mosquitoes to the District and request the District’s mosquito service by calling (925) 685-9301 or visiting www.ContraCostaMosquito.com.
To reduce the risk of mosquito bites, the District recommends residents use an EPA-registered insect repellent with one of the following active ingredients:
- DEET
- Picaridin
- The repellent version of Oil of Lemon Eucalyptus
- IR3535
Always follow the instructions on the label when using insect repellent.
The invasive non-native Aedes aegypti mosquitoes lay sticky eggs. The District urges Contra Costa County residents to dump out standing water and scrub the inside of the plant saucer or other container to knock off the eggs at least once a week. And when residents take steps to reduce the risk of invasive mosquitoes for themselves and their families, they join the District in our mission to protect public health.
Contra Costa County residents can report dead birds by phone at (877) WNV-BIRD (968-2473) or online. County residents can also request a District service for residential property by calling (925) 685-9301 or online.
Recent Stories:
- Aug 27 – More West Nile Virus-Infected Mosquitoes Confirmed in Contra Costa County
- Aug 16 – West Nile Virus Activity Continues in Contra Costa County
- Aug 12 – Again… Adult Mosquito Control to Occur Monday in Oakley
- Aug 9 – West Nile Virus-Infected Mosquitoes Confirmed in Oakley
- Aug 9 – Tonight: Adult Mosquito Control to Take Place in Oakley
- July 26 – First West Nile Death Since 2006 Reported in Contra Costa County
- June 21 – West Nile Virus-Infected Birds Confirmed in Concord
- April 27 – First West Nile Virus Positive Dead Bird of 2024 Found in Contra Costa County
