Mosquito pools test positive for West Nile in Butte County

OROVILLE - The first two mosquito pools to test positive for West Nile Virus in Butte County were collected in the areas of Dayton and Nelson.

It's common for the virus to pop up right around the Fourth of July and it becomes more aggressive in warm weather. Aaron Lumsden, assistant manager for the Butte County Mosquito and Vector District, iterated that mosquitoes are most commonly active during the mornings and evenings.

"We want people to be aware that West Nile is active in the area," Lumsden said.

Lumsden urged the public to wear long sleeves and long pants when outdoors during these hours, and to use bug repellents, ideally those with DEET. Additionally, standing water should be drained. If the water can't be drained, mosquito fish are available for free by calling the district at 530-533-6038 or 530-342-7350.

The district is working on various tactics against mosquitoes, particularly in farmland areas throughout the valley.

"We're basically trying to fly over as much rice as we can in the area and trying to take as many countermeasures as we can," Lumsden said.

A press release put out by the district also detailed methods of preventing mosquito bites such as checking doors, windows and screens to make sure they are sealed and in good shape, preventing mosquitoes from getting into the house.

District Manager Matthew Ball offered a statement warning the public of West Nile Virus.

"It's imperative that county residents be aware that (West Nile Virus) is active and to avoid mosquito bites by whatever means necessary," Ball said. "Residents are urged to do their part to prevent mosquitoes from breeding by inspecting and eliminating all standing water from their properties."

The virus generally stays active through October in Butte County, or as long as higher temperatures persist.

Lisa Almaguer, public information officer for Butte County Public Health, confirmed that as of Monday, there have been no reported cases of West Nile Virus in humans in Butte County in 2026. She added that most symptoms appear between three and 14 days of being bitten.

"Less than 1%% of individuals, about 1 in 150 people, infected with WNV will develop severe neurological illnesses, such as encephalitis or meningitis: inflammation of the brain or surrounding tissue," Almaguer said. "Serious symptoms may last several weeks, and neurological effects may be permanent."

Other symptoms of West Nile Virus include headache, body aches, nausea, vomiting, fever, swollen lymph glands and rashes, Almaguer said.

"There is no vaccine or cure for (West Nile Virus)," Almaguer said. "Most people who have (West Nile Virus) will recover on their own at home and may consider using a fever reducer to ease symptoms. Those who experience extreme symptoms should go to the hospital immediately."

Extreme symptoms would include high fevers, neck stiffness, tremors or loss of vision, Almaguer said.

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