Mosquito samples found in Tracy and Ripon have tested positive for West Nile virus, marking the first sighting of the disease in San Joaquin County in 2019.

The samples were part of the San Joaquin County Mosquito & Vector Control District's mosquito-borne surveillance program.

“This serves as a reminder that mosquitoes carry disease that can harm humans,” the district’s public information officer, Aaron Devencenzi, said in a statement released Thursday. “The district does its part in controlling mosquitoes, however mosquito control is everyone’s responsibility. Adult mosquito control activities will increase in accordance with our surveillance results.”

A section of central Tracy is scheduled for ground spraying Friday morning between 4 and 6 a.m. with Evergreen 5-25 due to increased adult mosquito activity.

Warmer temperatures speed up the life cycle of mosquitoes and the replication of the disease inside their bodies.

The vector control district urges people to protect themselves from mosquito bites to reduce the risk of West Nile virus and other mosquito-borne diseases:

– Remove all sources of standing water that support mosquito development.

– Use an insect repellent with active ingredients that can include DEET, Picaridin, oil of lemon eucalyptus or IRr3535.

– Avoid spending time outdoors at dusk and dawn, when mosquitoes are most active.

– Wear loose-fitting long-sleeve shorts and long pants when outdoors.

– Keep mosquitoes out of homes with tight-fitting screens on doors and windows.

Everyone is asked to report daytime-biting mosquitoes or heavy infestations of mosquitoes to the vector control district at, 982-4675 or 800-300-4675.

People should also look out for birds that have fallen victim to West Nile virus. Dead birds can be reported at 877-WNV-BIRD or

Contact the Tracy Press at or 835-3030.

(0) comments

Welcome to the discussion.

Keep it Clean. Please avoid obscene, vulgar, lewd, racist or sexually-oriented language.
Don't Threaten. Threats of harming another person will not be tolerated.
Be Truthful. Don't knowingly lie about anyone or anything.
Be Nice. No racism, sexism or any sort of -ism that is degrading to another person.
Be Proactive. Use the 'Report' link on each comment to let us know of abusive posts.
Share with Us. We'd love to hear eyewitness accounts, the history behind an article.