Nearly 14,000 mosquitoes – captured in traps and counted by hand – were among those that plagued Licking County last year.
After their careful counting, the workers of Licking County Health Department’s outdoor environmental health created a mosquito “juice” that can be tested for West Nile Virus — a virus which is far more prevalent in Licking County than one might guess.
Behind the interns work of hand counting and mosquito juicing are Scott Morris and Alexander Kimball.
Morris and Kimball sat together in Morris’ plainly decorated office at the Licking County Health Department. A map of Licking County stretched out behind the pair and hung next to a poster with the phrase “Fight the Bite” on proud display.
Morris is the director of outdoor environmental health at the Licking County Health Department (LCHD), where he has managed the mosquito program for the last four years. Kimball has been involved since the beginning. Kimball, a registered environmental health specialist, is in charge of helping spray and trap mosquitoes while also managing the interns which the health department hires for the outdoor environmental health division.
In 2024, LCHD captured and counted 13,709 mosquitoes within the county, according to the annual health report released by the department in March this year.
“Our mosquito program typically picks up at the beginning of the year, usually around the beginning of May and goes sometimes into October. So typically starts out with identifying notorious areas that are mosquito breeding habitats,” Morris said.
The division has locations marked throughout the county where they capture or treat mosquitoes. Some areas such as Buckeye Lake always receive treatment as they are prone to having higher mosquito counts. Other treatment areas can include past hotspots or places that reached out to the program.
However, the main goal of the division is to monitor the mosquito population and prevent overpopulation. While mosquitoes are essential to the environment because of their biomass as a food source and ability to act as pollinators, the work the LCHD is doing does not have enough of an impact to negatively affect these functions. Instead, their work seeks to prevent the spread of West Nile Virus – a virus spread by mosquitoes that can cause fever and in rare cases, severe and fatal illness – and improve quality of life for those living in Licking County.
The division has a small fleet of trucks equipped with sprayers that can essentially fog large areas in Licking County.
“The sprayer sprays up and behind as you’re driving at a slow pace,” Kimball explained. “You can only go like 10 miles per hour. We shut the sprayer off when we approach people.”
Kimball said the department is required to give at least 24-hour notice to neighbors before spraying for mosquitoes.
And two years ago, the department made the switch from an oil-based spray to a water-based one, which is supposed to have a smaller environmental impact.
The traps used by the division are called gravid traps and are designed to be placed in hotspots where mosquitoes lay their larva. With the use of some dirty water, a fan and some netting, the mosquitoes lay their larva and are imprisoned by the system. Later, those trapped mosquitoes are hand-counted by interns back at the LCHD. After mosquitoes are counted, they are ground into a “juice” to be tested for West Nile Virus.
If a population recovered from the traps tests positive for the West Nile Virus, that area is treated by sprayers as soon as possible. Most trapping focuses on West Nile Virus and the discovery of carrier-mosquito populations.
“We had 54 total West Nile Virus-positive pools last year. So we had 11 in July, 14 in August, and then 29 in September,” Morris said. “We haven’t had a [reported] human case of West Nile virus in the county – I don’t think in quite some time.”
According to Morris, the symptoms of West Nile Virus are mild and often present as a cold or flu. The vast majority of people infected would not need to seek professional medical care due to the virus. The only way for a human case of West Nile Virus to be reported is by a doctor after a patient has been tested.
Although the West Nile Virus can be severe, Denison University professor and entomologist Susan Villarreal notes that Ohio has a very low rate of incidence. Culex Pipiens – one of more than 3,500 species of mosquitoes – is the primary vector of this virus and what the health department hopes to detect and contain.
At Denison, Villarreal studies insect behavior and ecology, cultivating a colony of mosquitoes for her research. She is the Licking County Health Department’s “resident-mosquito-expert.”
Villarreal provides in-depth presentations on identifying mosquitoes and the discrepancies between the different species and sexes.
“Since the Health Department is looking for West Nile Virus, I wanted to ensure they can identify them, so at the very least, [they] won’t be wasting time running mosquitoes through the processor that won’t have West Nile because they’re not Culex,” she explained.
Oftentimes, gnats and flies can be confused and pooled together with mosquitoes as other annoying pests, so for these tests, Villarreal’s basic mosquito breakdown is that they are larger and have a piercing mouthpart, a specific mouth that is designed for sucking fluid.
The Culex Pipiens is uniformly brown with bare patches on its sides, she’ll point out to interns and Health Department employees. The health department has a specific emphasis in this work: putting mosquito traps where Licking County citizens are most bothered and surveying the disease transmission rates.
“I have a very specific point of view as an entomologist and biologist,” she said. “And there’s only so much you can do with the size of the health department.”
The Culex Pipiens are strictly bird-feeders and rarely stray to human hosts, Villarreal said, so the chances of someone contracting West Nile virus from Culex are pretty low.
That being said, Villarreal understands the need for spraying and forms of mosquito control similar to it.
It’s essential to stay ahead of the curve, especially with rising temperatures and climate change, which affects the migration patterns of mosquitoes, drawing them further north.
“As things get warmer, even through the winter, they can stay [north] in the winter now, and they can subside. This is a problem because these are bridge vectors. Aedes aegypti is the bad one that’s got all the diseases that are pulling further north, and now we have endemic cases of Zika in Texas and California,” Villarreal said.
The Aedes aegypti is capable of transmitting more than 50 kinds of viruses, including yellow fever, dengue, Zika and chikungunya, as well as two species of parasites. And they’re moving further north, with dozens reported in southern Oregon – further north than central Ohio – late last year.
Villarreal stood in the crisp, white laboratory. Upon entering, a faintly sour smell from the cultivations and experiments greeted her, but she never seemed to react, having grown accustomed to the aromas of her second home.
She undid the elastic knot at the opening of a glass cube, revealing a sleeve of material to put her forearm through. When she did, a hundred mosquitoes zipped around the cube, narrowly avoiding Villarreal’s hand.
“See!” she said excitedly, “The culex pipiens are not aggressive. If these were Aedes mosquitoes, that’d be a different story.”
Brin Glass and Andrew Theophilus write for TheReportingProject.org, the nonprofit news organization of Denison University’s Journalism program, which is supported by generous donations from readers. Sign up for The Reporting Project newsletter here.