Here’s how West Nile is spread — and what symptoms to look for after a mosquito bite
The first bird of the season has tested positive for West Nile virus in Sacramento County, and officials said they are on alert for the mosquito-borne disease that killed 11 people and infected more than 200 in California last year.
A yellow-billed magpie found dead last week near Elverta in north Sacramento County tested positive for the virus, the Sacramento-Yolo Mosquito and Vector Control District confirmed Monday in a news release.
“Finding the first positive bird is always significant because it provides an early warning sign for the disease,” said Gary Goodman, manager of the district, which covers Sacramento and Yolo counties. “It confirms that the virus is present, provides a good indication of where we may find positive mosquito samples and where human cases may develop later in the season.”
Other California counties have started to register activity, too, according to the California West Nile virus website “Fight the Bite.” Possibly the first reported human case of West Nile in the state was confirmed near Modesto this June. This year, 471 mosquito samples from 10 counties have tested positive for the virus. Monday afternoon, the latest mosquito sample collected in Olivehurst in Yuba County also tested positive.
In addition to the Sacramento County case, 18 birds have been confirmed killed by the virus in or near Fresno, Visalia, Bakersfield, Manteca, Los Angeles and San Diego, according to an interactive Cal Survey map. Just last week, five new West Nile virus-positive birds were reported from Orange County.
“In response to the detection of WNV activity, the District will increase its mosquito trapping and surveillance in the area to find sources where mosquitoes may be breeding,” the Sacramento-Yolo district reported in the release.
The chief of infectious diseases at UC Davis Medical Center in Sacramento told The Bee in April that a cure for West Nile virus has still not been found. No vaccine is available.
About 80 percent of people infected with the virus never exhibit symptoms, according to the U.S. Centers for Disease Control and Prevention. However, about 20 percent of those infected may experience fever with symptoms including fatigue, body aches, joint pain, vomiting, diarrhea and rash. And about 1 in 150 of those infected develop severe inflammation of the brain or membranes surrounding the brain and spinal cord. Among those with severe central nervous system illness, 1 in 10 die, the CDC says.
The only way to stay safe is to avoid mosquito bites, officials say. The district recommends:
- Wear an effective mosquito repellent with ingredients such as DEET, picaridin, oil of lemon eucalyptus, or IR3535.
- Stay indoors at dawn and dusk, when mosquitoes are most active.
- Make sure door and window screens are intact
- Drain any standing water, which creates a breeding ground for mosquitoes
- Wear long sleeves and pants outdoors
Officials encourage the public to report dead birds to the California Department of Public Health hotline at 877-968-2473, and visit www.fightthebite.net to stay informed on mosquito treatments. You can also file a report online at fightthebite.net or westnile.ca.gov.