Health & Medicine

West Nile virus activity reported in Yolo County mosquitoes for first time this year

Yolo County is finally seeing the first signs of West Nile virus activity this year in two mosquito samples, one from Winters and the other from Zamora, the Sacramento-Yolo Mosquito & Vector Control District announced Wednesday.

Mosquitoes carry the deadly West Nile virus and can transmit it to birds, humans and other mammals when they bite them. The illness can cause overwhelming fatigue, terrible muscle aches and headaches, according to doctors, and people who survive severe cases of the illness report ongoing problems with fatigue and neurological problems. Those most vulnerable to illness are people age 65 or older, physicians say.

“With the warmer temperatures we’ve seen recently West Nile virus activity continues to increase,” said Gary Goodman, manager of the Sacramento-Yolo district.

Sacramento County saw its initial signs of activity in early July, and it has continued to spread. Since then, the Sacramento-Yolo mosquito district has reported West Nile virus activity in 16 mosquito samples and 12 dead birds. Those numbers include five dead birds and seven mosquito samples found just this week.

In Sacramento County, dead birds found in Elk Grove, Herald, Carmichael, Elverta and Sacramento’s Pocket neighborhood have tested positive for the virus, and positive mosquito samples were found in Herald, Elk Grove’s Sheldon Heights community, south Sacramento, just west of Sacramento International Airport and near Diablo Park in Sacramento County.

In the Placer Mosquito & Vector Control District, four mosquito samples have tested positive for West Nile, and officials have been spraying in agricultural areas, as recently as Wednesday this week. Placer County residents can sign up for information on planned treatments at

“While we have seen a significant decrease in WNV activity this season as compared to previous years,” Goodman said, “it’s extremely important that residents take proper precautions to protect themselves from mosquito bites especially as they enjoy outdoor evening activities when mosquitoes are most active.”

The California Department of Public Health reported that one person has died from the disease in Imperial County. As of Friday, the agency stated, four human cases of West Nile virus have been reported statewide – one each in Fresno, Imperial, San Bernardino and Stanislaus counties.

Around California, 43 birds and 1,371 mosquito samples have tested positive for the virus. Last year, the West Nile death toll was 11 in California. The virus was detected in 217 people, 501 birds and 1,963 mosquito samples last year.

To report dead birds, call the hotline for the California Department of Public Health at (877) 968-2473.

Residents can take several steps to eliminate breeding grounds for mosquitoes, district officials said: Drain any stagnant water near homes and report any unattended swimming pools at (800) 429-1022. The district also will send out technicians to help find the source of unusually high mosquito activity and help with abatement.

When mosquito activity rises to a level considered dangerous for public health, Sacramento-Yolo mosquito district officials have conducted aerial spraying in the past. To sign up for email notifications about spraying, go to spray notifications at the district’s website at

To prevent mosquito bites, experts suggest wearing clothes that cover the arms and legs, especially at dusk or when near stagnant water. At home, look for holes in screens or windows that allow pests to get indoors. Use mosquito repellent, district officials said, and be mindful that you may need to apply more over the course of an evening.

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Cathie Anderson covers health care for The Bee. Growing up, her blue-collar parents paid out of pocket for care. She joined The Bee in 2002, with roles including business columnist and features editor. She previously worked at papers including the Dallas Morning News, Detroit News and Austin American-Statesman.