November 26, 2008 By Andy Opsahl
GIS is the archenemy of West Nile Virus and all mosquitoes in Valdosta, Ga. The city's Mosquito Population Control Program records data from about 35 mosquito traps within the city limits, each trap set in one-mile radius intervals.
Students from Valdosta State University collect the mosquitoes each week to count, type, and test them for West Nile Virus - a potentially deadly affliction contracted primarily by the bites of infected mosquitoes. The data is then entered into a GIS tool that directs John Whitehead, the deputy city manager for operations, where to spray for mosquitoes.
"The GIS system has helped us tremendously to pinpoint where we need to put our resources, instead of just going out, like in the past, when we were spraying the entire city every week," Whitehead said.
Spraying only targeted areas saves the city roughly $70,000 annually in cost avoidance. The GIS and spraying program now costs $30,000 each year. Reductions in labor, overtime pay, and chemical and vehicle expenses produced the savings, said Whitehead.
A child in Valdosta contracted West Nile from a mosquito in 2001, which drove Whitehead to create the GIS tool in collaboration with experts at Valdosta State. There are no known cases in Valdosta since then of humans testing positive for West Nile.
The initial goal of the GIS tool was to spot earlier the mosquitoes that are carrying West Nile, but the presence of fewer mosquitoes was an additional benefit. Whitehead said that West Nile Virus always appears in the same location, which enables him to focus his spraying efforts.
"I immediately go aggressively into the chemical spraying. There are two components to a program. You have your larvaciding and your adulticiding," Whitehead said.
The GIS program matches each trap with data on nearby nursing homes, recreational facilities, schools, and day-care centers - places where at-risk people congregate. South Georgia is home to many honeybee growers, and the GIS program also shows Whitehead where to avoid spraying bee farms.