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June 7, 2018 - Mosquito Adulticiding Scheduled to Suppress West Nile Virus Activity. Adulticiding treatment planned in Union City neighborhood. 

HAYWARD, JUNE 7- Mosquitoes and birds infected with West Nile virus have been detected near Ponderosa Cove Park in Union City, CA. In response, the Alameda County Mosquito Abatement District will be treating for adult mosquitoes on Friday, June 8th from approximately 10pm to 12am, weather permitting. District personnel will be applying Pyrenone 25-5 Public Health Insecticide, registered by the US Environmental Protection Agency (EPA) and California EPA for use in mosquito control and routinely used throughout the United States to control mosquitoes. The area targeted for the treatment is shown in the map below.

"The presence of multiple West Nile virus infected mosquitoes and birds in this area are a threat to the health of people living in nearby neighborhoods," said General manager Ryan Clausnitzer. "The District is dedicated to protecting the health of Alameda County residents and based on our assessment of infected mosquitoes and from the public's assistance in locating infected birds by calling the dead bird hotline, we feel that action is needed to reduce the presence of adult mosquitoes in this area."

To date in Alameda County, 2 West Nile virus positive dead birds and 2 groups of positive mosquitoes have been detected. No human cases have been reported. The District continues its surveillance and larval control program throughout the county. Residents are urged to be proactive by eliminating sources of water where mosquitoes can breed and protecting themselves from mosquito bites. If you come across a dead bird please report it by calling (877)WNV-BIRD or online at

As of June 1st, California has had 9 dead birds and 3 mosquito samples test positive for West Nile virus. 

West Nile virus is transmitted to people and animals through the bite of an infected mosquito. There is no cure for West Nile virus. Approximately one in five people who are infected with West Nile virus will develop symptoms such as fever, headache, body aches, joint pains, vomiting, or rash. Less than one percent will develop a serious neurologic illness such as encephalitis or meningitis. Adults over 50 years old and people with compromised immune systems are at increased risk of serious complications. Anyone who develops symptoms should seek medical care immediately. For information concerning West Nile virus symptoms or testing please contact the Alameda County Public Health Department at (510)267-3250.

Since horses are very susceptible to West Nile virus and vaccines are available, horse owners are advised to contact their veterinarians immediately about timely vaccinations.

For information about mosquitoes, West Nile virus, or the fogging operation please visit our website: Residents can request mosquitofish for their fish ponds, horse troughs, etc. by contacting our District office. We are located in Hayward at 23187 Connecticut St. Our phone number is (510)783-7744.

Target Treatment Area #1

Adulticiding Frequently Asked Questions