Mosquito district advises residents to use precautions as temperatures rise

As pleasant spring temperatures transition into sultry summer days and nights, mosquitoes become more active and try to cook a meal out of every arm, leg, neck, etc. they can find. Along with their cravings, there is a risk of contracting West Nile virus and St. Louis encephalitis.

Both Turlock and Eastside Mosquito Control Districts want to remind residents to take measures like “dump and drain” to prevent mosquitos and mosquito-borne diseases.

In 2020, California recorded 231 cases of West Nile virus in humans and 20 cases in horses. Of the 231 cases in humans, 11 were fatal, according to the California Department of Health.

In Stanislaus County, 36 cases of West Nile virus have been observed in humans and three in horses. The county also recorded one human case of St. Louis encephalitis.

No cases of West Nile virus were reported in California as of April 23.

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

About 1 in 5 people infected with West Nile virus develop symptoms such as fever, headache, body aches, joint pain, vomiting, diarrhea, or a rash. Less than 1 percent develop a serious neurological condition such as encephalitis or meningitis (inflammation of the brain or surrounding tissue). According to the CDC, about 10 percent of people who develop neurological infection from the West Nile virus die. People over the age of 50 and people with certain medical conditions like cancer, diabetes, high blood pressure, kidney disease, and organ transplants are at higher risk of serious illness.

There are no drugs to treat or vaccines to prevent West Nile virus infection. People with milder illnesses usually recover on their own, although symptoms can last for weeks or months. In the neuroinvasive forms, patients can experience severe and sometimes long-term symptoms.

It is not just the West Nile virus transmission that affects mosquito areas in the region. The breed of mosquito responsible for transmitting the Zika virus was discovered in Stanislaus County. Aedes aegypti mosquitoes, which are invasive to the region, can transmit viruses such as St. Louis encephalitis, chikungunya, dengue, yellow fever, and Zika.

In contrast to the native amber-colored Culex mosquitoes, whose peak bite times are dawn and dusk, Aedes aegypti mosquitoes are black and white, bite aggressively during the day and feed almost exclusively on humans. In addition, the larvae of Aedes aegypti mosquitoes require much less water. Women lay their eggs just above the waterline in small containers and vessels that hold water, such as dishes, potted plants, bird baths, ornamental fountains, tin cans, or discarded tires. The eggs can survive for up to eight months after the water has dried out.

Most people infected with St. Louis encephalitis have no symptoms, according to the CDC. People who get sick may experience a fever, headache, nausea, vomiting, and fatigue. Some people can develop neuroinvasive conditions such as encephalitis or meningitis. In rare cases, long-term disability or death can result. There are no preventive vaccines or drugs to treat St. Louis encephalitis.

The mosquito control districts encourage residents to drain and drain standing water around their property.

“If you prevent mosquitoes from multiplying in your home, you and your family can be better protected,” said David Heft, general manager of the Turlock Mosquito Abatement District. This allows mosquitoes to develop. ”

With large amounts of stagnant water such as neglected swimming pools, ponds, water troughs or ornamental ponds, the districts encourage residents to put mosquito fish in them. Residents can contact the Turlock or Eastside Mosquito Abatement offices to arrange mosquito fish collection or delivery.

The districts will continue their monitoring programs to identify sources of mosquito breeding and mosquito-borne disease activity. They will treat according to their monitoring results. Districts expect more WNV and mosquitoes in the coming months and would like to remind residents that they can help by taking the following precautions:

• Drain or drain off standing water. These are places where mosquitoes like to lay their eggs.

• Defend yourself against mosquitoes by using repellants containing DEET, picaridin, or lemon eucalyptus oil.

• 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 control district.

• Use tight-fitting door and window grilles to prevent mosquitoes from entering your home.

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

For additional information or to request service, please contact the local Stanislaus County MADs:

• North of the Tuolumne River Contact: Eastside Mosquito Abatement District at (209) 522-4098 (

• South of the Tuolumne River Contact: Turlock Mosquito Abatement District at (209) 634-1234 (

Reporting and testing dead birds are important steps in preventing West Nile virus. A confirmed case of the virus in dead birds or mosquito samples will help 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 birds of prey (falcon or eagle).

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