Mosquitoes test positive for West Nile Virus in Visalia

(Rigo Moran)

Delta Mosquito and Vector Control District reports two positive mosquito samples for WNV, one positive sample for St. Louis Encephalitis virus

VISALIA – The Central Valley’s summer woes are on the rise as a recent spike in mosquito-borne illnesses have added to the season’s challenges.

On July 2 and 3, the Delta Mosquito and Vector Control District reported two positive mosquito samples for West Nile virus (WNV), and one positive mosquito sample positive for St. Louis Encephalitis virus (SLEV). This is Tulare County’s first indication of West Nile virus this year. The mosquito was collected from the northwest border of Visalia and tested at the District laboratory.

West Nile virus is transmitted to people and animals through the bite of an infected female mosquito. Mosquitoes become infected when they feed on infected birds and then spread West Nile virus to people and other animals by biting them.

While most infected people will have no symptoms, others will develop fever, headaches and body aches. Some cases require hospitalization and, in rare cases, death occurs. People with symptoms should contact their health care provider. Adults over 50 years old and people with compromised immune systems are at increased risk of serious complications. However, anyone who develops symptoms should seek medical care immediately.

Efforts are being made to locate areas of standing water where mosquitoes may breed, including but not limited to catch basins, storm drain systems and neglected swimming pools. Neglected swimming pools continue to be a mosquito breeding issue in the District. Neglected swimming pools can be reported to the District anonymously for treatment at 559-732-8606.

To reduce the risk of contracting mosquito-borne diseases such as West Nile virus, the Delta Mosquito and Vector Control District recommends these guidelines. To prevent mosquito bites, use an EPA-registered insect repellent when going outside around dawn and dusk when mosquitoes are most active. Make sure to follow the instructions listed on the EPA-registered insect repellent product label.

To reduce bites, residents are recommended to cover up by wearing long sleeve shirts and long pants when mosquitoes are most active. Residents are also instructed to check window and door screens to prevent mosquitoes from entering homes.

To prevent mosquitoes around your home, inspect your yard for standing water sources. Make sure to drain water that collects under potted plants, bird baths, tires and any other water-holding containers. Residents are recommended to screen the openings of lawn drains and clean and scrub pet dishes and water features weekly.

Swimming pools, ponds and fountains require working pumps and regular maintenance so report neglected swimming pools anonymously to Delta Mosquito and Vector Control District for treatment. Residents can request free mosquito fish for backyard ponds, horse troughs or neglected swimming pools, which are available at the District office located in Visalia at 1737 W Houston Ave. All services provided by Delta Mosquito and Vector Control District are free of charge to the residents in the District.

Reporting and testing of dead birds is one way to check for the presence of West Nile virus in the environment. Horses are very susceptible to West Nile virus and can be vaccinated. Horse owners are advised to contact their veterinarians regarding timely vaccinations.

For information about mosquitoes, West Nile virus or to request District services, visit or call 559-732-8606. 

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