As the summer progresses and more people turn to the outdoors, the area’s mosquito abatement districts are reminding residents that West Nile Virus is a serious threat in the region and precautions should be taken to avoid the potentially deadly bites of mosquitoes.
“High temperatures and a wet spring have caused mosquito populations to rise in the county,” said Turlock Mosquito Abatement District Manager David Heft. “It’s important for people to reduce their risk of being bitten by mosquitoes.”
As of yet, the county has not reported any human cases of West Nile Virus, but there have been two mosquito samples and two dead birds test positive for the virus in the Turlock district. A total of 15 mosquito samples have tested positive for West Nile Virus in Stanislaus County, according to the California Department of Public Health.
In 2015, Stanislaus County had 13 human cases of West Nile Virus, along with 14 dead birds and 84 mosquito samples.
Statewide the virus has been detected in 23 counties, with 433 mosquito samples and 372 dead birds testing positive for the virus. There has not been any human cases of the virus reported in California as of July 1.
Most often, West Nile Virus is spread by the bite of an infected mosquito. Mosquitoes become infected 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 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 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.
A 2015 CDC report indicates that for every one diagnosed case of West Nile Virus another 150 people have the disease and are either undiagnosed or misdiagnosed.
In the United States, most people are infected from June through September, and the number of these infections usually peaks in mid-August, according to the Centers for Disease Control. Seasonal outbreaks often occur in local areas that can vary from year to year. In Stanislaus County West Nile Virus typically starts to appear in April or May and will continue to have a presence through October. The weather can also be a significant factor in West Nile Virus outbreaks. The CDC reported higher number of cases during periods of abnormally high temperatures.
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 area’s mosquito abatement districts have been conducting aerial photography to locate potential mosquito breeding sites and rely on residents to report neglected swimming pools and ornamental ponds.
The California Department of Public Health recommends that individuals prevent exposure to mosquito bites and West Nile virus by practicing the “Three Ds:”
DEET – Apply insect repellent containing DEET, picaradin, oil of lemon eucalyptus or IR3535 according to label instructions. Repellents keep the mosquitoes from biting you. DEET can be used safely on infants and children 2 months of age and older.
DAWN AND DUSK – Mosquitoes bite in the early morning and evening so it is important to wear proper clothing and repellent if outside during these times. Make sure that your doors and windows have tight-fitting screens to keep out mosquitoes. Repair or replace screens with tears or holes.
DRAIN – Mosquitoes lay their eggs on standing water. Eliminate all sources of standing water on your property, including flower pots, old car tires, rain gutters and pet bowls. If you know of a swimming pool that is not being properly maintained, please contact your local mosquito and vector control agency.
Reporting and testing of dead birds is an important step 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).
To report mosquito-breeding problem areas, Stanislaus County residents should contact one of the two mosquito abatement districts that serve the county. For Stanislaus County addresses north of the Tuolumne River, residents should call the Eastside Mosquito Abatement District at 522-4098 (www.eastsidemosquito.com) and all others should contact the Turlock Mosquito Abatement District at 634-1234 (turlockmosquito.org).