By allowing ads to appear on this site, you support the local businesses who, in turn, support great journalism.
Four Stanislaus County residents positive for West Nile Virus
west nile
Infected mosquitoes spread West Nile Virus to humans and other animals when they bite. - photo by Photo courtesy of CDC

Four Stanislaus County residents have all been confirmed to have West Nile Virus and all four have developed the fairly uncommon neurological illness, known as neuroinvasive West Nile Virus, the Stanislaus County Health Services Agency reported on Tuesday.

The four cases are the first human cases of the virus in the county for the year.

As of Friday, California had 31 counties with West Nile Virus activity. There were 26 cases, which does not include the four cases recently confirmed in Stanislaus County. Two cases in the state have been fatal.

The number of human cases in California this season is higher than the same time period last year, which had 16 cases. It’s also higher than the five-year average of 17.6 cases for the same time frame, according to

Some of the increased West Nile Virus activity is attributable to the increased rainfall this year that lasted longer into spring, which gave mosquitoes more breeding grounds.

Stanislaus County has reported two dead birds and 155 positive mosquito samples. Of those, 86 have been in the Turlock Mosquito Abatement District’s territory. SCHSA and the local mosquito abatement districts announced the first pools of mosquitoes positive for West Nile Virus in June of 2023. One case of equine West Nile Virus was also recently identified.   

Mosquitoes become infected with West Nile Virus when they feed on infected birds. Infected mosquitoes can then spread West Nile Virus to humans and other animals when they bite, according to the Centers for Disease Control.

Approximately 1 in 5 people who are infected with West Nile virus will develop symptoms such as fever, headache, body aches, joint pains, vomiting, diarrhea, or rash. Less than 1 percent will develop a serious neurologic illness such as encephalitis or meningitis (inflammation of the brain or surrounding tissues). About 10 percent of people who develop neurologic infection due to West Nile virus will die, according to the CDC. People over 50 years of age and those with certain medical conditions, such as cancer, diabetes, hypertension, kidney disease, and organ transplants, are at greater risk for serious illness.

There are no medications to treat or vaccines to prevent West Nile Virus infection. People with milder illnesses typically recover on their own, although symptoms may last for several weeks or months. In the neuroinvasive forms, patients can suffer severe and sometimes long-term symptoms.

"Because there is no vaccine and no specific treatment for West Nile Virus, it is important for people to take steps to protect themselves and their families from mosquito bites,” said Dr. Thea Papasozomenos, Stanislaus County Public Health officer. “We also urge residents to help control the mosquito population by dumping and draining any standing water around their homes, and reporting neglected swimming pools, as these can serve as mosquito breeding sites.”

Mosquitoes like to breed in stagnant water, preferring weedy areas that provide cover. The lagoons at dairy farms make for perfect breeding grounds, but so do flooded fields, uncared for swimming pools, urban catch basins, overwatered lawns, and pretty much anything that holds water and allows it to stagnate.

The District will continue with their treatment and surveillance programs by identifying mosquito breeding sources and mosquito borne disease activity. They will perform treatments according to their surveillance results. The District would like to remind residents that they can help by taking the following precautions:

• Dump or drain standing water. These are places mosquitoes like to lay their eggs.

• Defend yourself against mosquitoes by using repellants containing DEET, Picaridin or Oil of Lemon Eucalyptus.

• Avoid being outdoors at dusk and dawn. These are the times when WNV carrying mosquitoes are generally most active.

•Report neglected swimming pools to your local mosquito abatement district.

• Use tight fitting door and window screens to keep mosquitoes from entering your home.

• Contact your veterinarian for information on vaccinating equine against WNV.

For additional information or to request service, Turlock residents should contact the Turlock Mosquito Abatement District at (209) 634-1234 or (

Reporting and testing of dead birds are important steps in preventing West Nile Virus. A confirmed case of the virus in dead birds or mosquito samples helps to identify areas that need treatment to reduce mosquito activity. To report a dead bird, call the California State hotline at 1-877-WNV-BIRD or report it online at Birds of particular interest are crows, ravens, magpies, jays and raptors (hawk or eagle).