County spraying to kill insects

Despite cooling weather, mosquitoes in Jay County still could carry West Nile virus until they’re killed off by the first hard freeze of the winter.

In July, one case of West Nile virus was found in a batch of mosquitoes tested by the state department of health. Since then, there have been no additional positive tests in Jay County. But in neighboring Delaware County, there has been a human case, one of only nine human cases in Indiana this year, as well as five in mosquitoes.

Jay County Health Department employees are continuing to take action to reduce the risk of infection for the county’s residents.

Donald Cooke Sr. started working in the evenings seven years ago driving a health department spray truck through the county’s population centers. Three years ago, his granddaughter Jenna Caroll joined him working three to four nights a week to exterminate mosquitoes near the majority of Jay County’s residents.

The spraying unit they use is a far cry from the equipment of the past that billowed clouds of smoke. This one is simply mounted on the back of a pickup truck and controlled using a remote inside the cab.

Heath Butz, environmentalist for the health department, is a licensed sprayer who oversees the extermination of mosquitoes in Redkey, Dunkirk, Pennville, Bryant, Salamonia and New Corydon. Portland’s spraying is handled by city employees.

“Generally we have two people, one driving and one watching for people (walking) and shutting the sprayer off,” Butz said.

The synthetic pyrethroid that the department sprays isn’t dangerous to humans, but proves lethal to mosquitoes by attacking their nervous system.

Cooke and Carroll spray Monday through Thursday evenings throughout the county, provided the weather cooperates.

“We don’t spray during the day, mosquitoes aren’t active. We want to spray in the evenings when they start coming out,” Butz said. “We make sure it’s not going to rain, check wind conditions.”

Rain washes away the spray after it settles on leaves and grass, effectively wasting that day’s application. Wind can cause drift of the fine mist and make it difficult to evenly cover a populated area.

“We try to hit everything once a week,” Cooke said.

Butz also adjusts the frequency and location of the sprays with existing West Nile threats. Because of the prevalence in Delaware County, spraying has been increased on the west side of Jay County in Redkey and Dunkirk.

The health department uses gridded routes in each municipality, to ensure good coverage and make sure that areas aren’t over-covered with spray. The spray Cooke and Carroll use creates about a 300-foot swathe of synthetic pyrethroid behind the truck.

Though the county health department handles extermination of large mosquito populations, the testing of mosquitoes for West Nile virus is conducted by the Indiana State Department of Health. Some more populated counties conduct their own testing.

Butz said that as the weather cools down, mosquito activity will decrease. But spraying will continue until the insects die off at the first hard freeze of the year.

Because of the human case of West Nile in Delaware County, and the positive results for the virus in mosquitoes for Jay and all surrounding counties, he said extra precautions should still be taken to protect against infection. Butz said residents should still wear long sleeves and apply DEET insect repellent during the evenings, and that they should empty containers that could hold water, like bird baths and old tires, once a week.

“At the end of the day, if people aren’t cleaning out containers that could hold water, we’re fighting against that,” Butz said. “That’s where larva are breeding, in stagnant water.”