West Nile virus continues to surge in Sacramento. Watch out for mosquitoes in the heat
West Nile virus activity is increasing intensely in “many” parts of Sacramento and Yolo counties, local mosquito control officials said Wednesday, as California’s capital region has recorded dozens of new virus cases in mosquitoes and dead birds within the past two weeks.
“Virus activity continues to be widespread and very intense,” Gary Goodman, manager of the Sacramento-Yolo Mosquito and Vector Control District, said in a news release.
“While this is not uncommon during the summer, we are seeing an increase in the overall abundance of mosquitoes collected in our traps.”
The district reported that 69 mosquitoes and 43 dead birds have tested positive in Sacramento County this year to date. Those totals are up from 34 and 18, respectively, in the previous update from July 3. Officials first detected the virus this year in mid-May, in dead birds found near Florin Road in south Sacramento.
In Yolo County, the tallies have jumped to 33 mosquitoes and two dead birds, up from six mosquitoes and one bird on July 3.
Areas of concern include the South Natomas, Tahoe Park and Elder Creek areas within the city of Sacramento; as well as Davis and Woodland within Yolo County, according to Wednesday’s news release.
“We are closely monitoring all these areas and evaluating the best plan of action,” Goodman said in the release. “We need to do everything we can to ensure residents are protected.”
State and local mosquito control officials urge residents to drain standing water to limit mosquito breeding; wear insect repellent that contains DEET, picaridin, oil of lemon eucalyptus or IR3535; secure doors and window screens in good working condition; avoid being outdoors at dawn and dusk if possible; and wear long sleeves and pants when outside.
Winter rain, summer heat combine for high West Nile risk
The California Department of Public Health issued a warning in late June noting that record rain totals this past winter have led to increases in mosquito populations.
Extreme heat also exacerbates West Nile activity by speeding up the hatching of mosquitoes, officials say. The Sacramento region is forecast to reach triple digits Friday through Monday, according to the National Weather Service, peaking Saturday at about 110 degrees.
Local mosquito control officials note that virus activity is increasing statewide. CDPH as of last Friday reported nearly 350 cases: 283 in mosquito samples and 65 in dead birds. Both are higher than the same point in 2022, with the dead bird total more than triple last year’s 20.
No human cases have been reported by state health officials in 2023 as of Wednesday. Last year, California detected 216 human cases including 15 fatalities.
What are West Nile virus symptoms in humans?
West Nile virus in humans often results in mild or no symptoms, but in severe cases the disease can be deadly. Many people can recover from West Nile virus at home, but about 20% of those bitten develop symptoms of West Nile fever.
Roughly one out of every 150 people bitten by an infected mosquito gets the most severe form of the disease, West Nile encephalitis.
Symptoms of severe West Nile virus include sudden onset of high fever, severe headache, nausea, vomiting, sore throat, backache, joint pain, aches and weakness in prominent muscles, prolonged fatigue and swollen lymph nodes. Those with West Nile fever may also get a rash.
