Fight against West Nile-carrying mosquitoes goes underground - 13 WTHR Indianapolis

The nation's deadliest outbreak of West Nile virus is in Texas, with nearly 90 cases of the most severe form of the disease. Nine people have died in the state.

In Indianapolis, there are two confirmed cases of West Nile virus in humans.

The fight to control the pesky bugs of summer has gone underground. Technicians from Marion County Mosquito Control are spraying storm sewer catch basins with a chemical to kill both adult mosquitoes and larvae.

Matt Sinsko of Mosquito Control says his office has found an usually high number infected. "There's definitely more virus out there compared to other years, as far as numbers go," he said. "This is much higher positive mosquito pools than we normally have. We usually have fewer, this is a whole month earlier," said Sinsko.

The hot dry summer has helped keep mosquitoes from becoming a problem, but recent rains have changed that in some areas. 

Mosquito Control technicians are on the hunt for larvae. During daylight hours, the fight against mosquitoes is with a plastic dipper on a stick. Once he has found at least one larvae, a biodegradable oil is applied to the water surface. The oil will stay on top of the water long enough to stop larvae from reaching adulthood.

At sunset, the tools change to a specially-designed fogger sprayer that puts out a chemical designed to kill adult mosquitoes. Areas with confirmed West Nile cases are sprayed twice. But the fight is countywide. Mosquito Control has found adult mosquitoes in every part of the county infected with the virus.

The Marion County Mosquito Control Office says the cooler nights will help keep the adult population down. Adult mosquitoes slow down as the temperature drops. That, however, coincides with more outdoor activities for humans, potentially exposing more to infected mosquitoes.