The Stanislaus County Health Services Agency has reported the first case of West Nile Virus in a person for this season.

The agency said the individual is an adult male with a non-neuroinvasive form of the virus but did not say what town he resides in.

“We want to remind all residents to take precautions to protect themselves and their families from mosquito bites, especially during the summer months when mosquito activity is at its peak,” said Dr. Thea Papasozomenos, Stanislaus County Public Health Officer.

This could be the first human case of the virus in the state for the year. California’s official West Nile Virus website keeps track of cases but was last updated on Friday and does not reflect the current Stanislaus County case. Three asymptomatic WNV-positive blood donors have been reported from Fresno County.

Last year at this time the state had one human case. In total, the 2023 season saw 433 cases of the virus, of which 18 were fatal.

Stanislaus County has had six mosquito samples test positive for the virus, according to the westnile.ca.gov site. Two of those have come from the Turlock area and one from Hilmar.

The temperature increases typically bring an increase in mosquitoes which in turn increase the rate of the virus in the area.

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. West Nile Virus first appeared in California in 2003 and by 2004 it was in all 58 counties.

Approximately one in five 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 one 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 

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 local mosquito abatement districts 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 Districts 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, local residents should contact the Turlock Mosquito Abatement District at (209) 634-1234 or (www.turlockmosquito.org). 

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 www.westnile.ca.gov. Birds of particular interest are crows, ravens, magpies, jays and raptors (hawk or eagle).