Frey Spray flies over the Bently Trail in northern Carson Valley on Saturday morning.
A test for a possible human case of West Nile Virus came back negative on Tuesday afternoon, health officials said.
Carson City Health and Human Services Epidemiologist Dustin Boothe notified the Douglas County Mosquito District of the negative test, according to Director Krista Jenkins.
The reported victim, a 67-year-old Minden woman, is recovering at home after what her boyfriend said they were told was a case of the virus carried by mosquitoes.
Mosquitoes in three spots in Carson Valley, including Genoa, Carson Valley Golf Course and Kirman Field east of Silver City RV Park tested positive for the virus last week, prompting the district to spray and fog. Results from testing conducted Monday in those locations have not yet returned, Jenkins said on Tuesday night.
On Friday and Saturday mornings, an aircraft operated by Frey Spray spread adulticide on both sides of Muller Lane and north where the Carson River passes through Kirman Field north of Stephanie Way.
Fogging was completed in Genoa on Friday. Jenkins said Martin Slough Trail, Winhaven and Westwood were next on the agenda to spray.
The district trapped and tested mosquitoes at Topaz Lake Park and Campground last week, where camper Jill Hettrick said she was bitten a half dozen times in three hours.
“I think it’s very important that people are aware of how bad it is at Topaz,” she said on Monday, thanking Jenkins for working on it.
Douglas County Chief of Staff Melissa Elges said plans are for the mosquito district to spray the area around the campground 5:30-11 a.m. Aug. 19.
“Visitors and campers are asked to temporarily vacate the premises during this time and stay away for at least two hours after the application,” Elges said.
The last time The Record-Courier reported a human with the virus was in 2018 when health officials said a Gardnerville resident received a less severe version.
“For the past few years, we did not trap any positive mosquitoes,” Jenkins said. “There is no real indicator of how or when we get positives.”
The 2018 case occurred the year after the record 2016-17 winter.
“Each year is different based on the snowfall, spring melt, irrigation and temperature,” she said. “There were plenty of mosquitoes last year and we ended up fogging the Topaz area, excluding the campground, a couple of times.”
It has been 20 years since dying crows, magpies and jays in Carson Valley first alerted residents to West Nile virus.
“Birds are the host and the mosquitoes are the vectors for disease, so each year can be totally different from the next,” Jenkins said. “There is a lot of speculation as to why, but no definitive answer.”
One weather factor might be the warm temperatures this summer. Minden experienced a solid week of temperatures of 95 degrees or warmer that barely ended on Monday.
“Heat drives the mosquito population, and … it gives the virus ample time to populate,” Jenkins said. “We are seeing early hot temperatures both in the day and the night lasting later into the fall. This creates a perfect storm for the virus to amplify.”
She said it’s critical for people to wear and rotate mosquito repellant.
“Because you just never know when a mosquito will be positive,” she said.
