FRESNO, Calif. (KFSN) -- A dangerous trend has showed up in the Central Valley over the last few weeks. Every county in the Valley -- except Mariposa -- has West Nile virus activity. Tulare and Fresno are among the counties where it's spread to humans. And even though there are still only a few cases, health officials say it's spreading at an alarming rate.
In Fresno County, they say this could be the worst year ever for the virus, which first showed up here 10 years ago. They've already identified five human cases -- with four of them classified as "neuroinvasive," which is the worst type of infection. That's already double the number from last year, and oddly, this extreme drought is part of the reason.
In the gutter in front of a Central Fresno apartment complex, in the storm drain along a neighborhood road, and in a giant puddle in the middle of Fresno's Vinland Park -- mosquito abatement crews find standing water, and with it, the threat of mosquitoes and the spread of the West Nile virus.
"So even though there's not a lot, there are water sources around and mosquitoes are finding them," said Steve Mulligan, district manager of the Consolidated Mosquito Abatement District. "It also concentrates, in a drought year, it concentrates the water sources, so that both the mosquitoes and the birds come together."
Mosquitoes and birds are confined to the same small sources of water, giving the Culex mosquito easy targets for feeding and spreading the potentially deadly virus. If you look closely, you'll see it swimming around in its pupal stage in water scooped up from the gutter. Without treatment, a mosquito will emerge and the virus will have a vector. Dormant pools can be the worst breeding grounds, putting neighbors at risk.
"Mosquitoes will find this, they'll come in, lay their eggs, and produce tens of thousands of mosquitoes, so something like this can infest an entire neighborhood," said Mulligan.
About 20 percent of people bitten by an infected mosquito will actually develop the virus. One percent will get meningitis or encephalitis.
"Those are folks that usually have severe issues," said David Luchini, the assistant director of the Fresno County Department of Health. "They usually become hospitalized. And from those that sometimes can lead to death and we have had death from the West Nile virus in the last several years, so it is very serious."
If you report standing water in your neighborhood, mosquito controllers will come out to treat the water.
Tips for cutting down the West Nile virus:
- Apply insect repellents that contain DEET, picaridin, oil of lemon eucalyptus or IR 3535 according to label instructions.
- Use repellent, especially in the early morning and in the evening, when mosquitoes that carry WNV are most active, or anytime mosquitoes are noticed.
-Make sure that doors and windows have tight-fitting screens to keep out mosquitoes. Repair or replace screens that have holes.
- Eliminate standing water and containers that can hold water from around the home or places of business
- Contact mosquito abatement districts to report poorly maintained swimming pools or water features that appear green. Neglected pools are a primary source of mosquito breeding in residential areas. Over 2,000 neglected swimming pools have been reported in Fresno County.
- Get FREE mosquito fish for backyard ponds or horse troughs from mosquito abatement districts. For information about mosquito fish, call 559-896-1085.
- Report dead birds and dead tree squirrels at www.westnile.ca.gov.
- Residents can visit the Fresno County Department of Public Health website at www.fcdph.org to download a "Heard the Buzzzzz?" brochure which contains steps to protect their family, their home, and their community from WNV. Click "Mosquito Season Has Arrived" on the main page.
- Residents can also call 1-800-821-1577 to speak to a mosquito abatement district representative or visit www.mosquitobuzz.net and/or www.fresnomosquito.org.
For additional information about WNV or to report dead birds and dead tree squirrels, visit the California Department of Public Health website at www.westnile.ca.gov or call 1-877-WNV-BIRD.