The Stanislaus County Health Services Agency confirmed Thursday that a 52-year-old female county resident has tested positive for West Nile Virus.
The confirmation marks the first human case in the county, while California has reported 10 cases. Last week the California Department of Public Health reported the death of a Sacramento County senior citizen that had died from the virus.
CDPH has reported ten human cases of WNV from eight California counties this year. In addition, 851 dead birds from 29 counties have tested positive for WNV in 2016 and 1,841 mosquito samples from 30 counties have also tested positive for WNV this year.
The number of WNV positive dead birds and mosquito samples exceeds the numbers at this same time last year, but the number of human cases is down from the same time this year. In 2015, there were 53 deaths from West Nile Virus in California, which was the highest rate since the virus first appeared in the state in 2003.
There have been six dead birds found in Stanislaus County that tested positive for the virus, four of which were found within the Turlock Mosquito Abatement District. In Turlock one dead bird was found near Stanislaus State, between Crowell Road and N. Walnut Road. Another was found in a neighborhood between N. Denair Avenue and N. Olive Avenue, and a third in a neighborhood between E. Monte Vista Avenue and Christoffersen Parkway. Other dead birds have been found in the Patterson and Ceres areas.
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 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.
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).