MEDDAC builds readiness through mosquito surveillance
By Zach RehnstromJune 14, 2017
The mosquito surveillance program at MEDDAC chronicles and identifies the different species of mosquitos found in the field. Next, a unique profile is built on each mosquito larvae captured that can be then further studied at the lab to determine whether it carries disease causative agents.
"Surveillance of any type is important because it gives you a historical base line," Beasley said. "It's important to know what's out there in any regard before a problem comes up, and when you have that history and that base line information when a problem comes up, it helps you resolve that problem."
To capture the information needed to provide an accurate profile of the mosquitos that populate Fort Stewart, Beasley utilizes a trap system which has a sophisticated network of sensory triggers that attract them.
"We put dry ice in here which is frozen carbon dioxide and it leaches out of the pores and that attracts them," Beasley said. "It's like us [as humans] exhaling."
After the mosquitos approach the trap, the power of the fan inside snares them until they can be retrieved by Beasley.
"They're attracted here because of carbon dioxide," Beasley said. "And there's a chemical lure in here that mimics our skin smell."
The woodland habitat around the Fort Stewart, MEDDAC foot print can provide the perfect breeding ground for mosquito larvae. According to 2017 statistics from the Center for Disease Control and Prevention, 123 symptomatic Zika virus disease cases were reported within U.S. States and 499 symptomatic Zika virus disease cases were reported within U.S. Territories.
"You have emerging diseases that infrequently come and therefore can be established here because we have mosquitos that are capable of vectoring those pathogens," Beasley said. "Although we usually see a problem in people or animals first, we may see a problem in the mosquitos first. We do screen the mosquitos for certain pathogens, Zika, Chikungunya, Dengue, Equine Encephalitis, West Nile are the top emerging diseases we care about right now, so we screen these mosquitos that I trap for those pathogens."
One of the tools in Beasley's arsenal is Gambusia Affinis or most commonly referred to as the mosquito fish. This guppy like minnow has a fondness for eating small arthropods like mosquito larvae.
"It's a biological control that keeps the mosquito population down. It works better than treating the water with pesticides," Beasley said.
These groups of mosquito fish were harvested from a body of water directly behind Winn Army Community Hospital, and will be used to populate the ditches, creeks, lakes and estuaries around the designated problem areas on Fort Stewart, with the hopes of curbing the mosquito threat before it begins.
"The mosquito fish are working 24/7, but the pesticide that gets put out only lasts minutes, hours, or days, depending on the situation," Beasley said. "So this is a far better process than coming out and spraying."
Any areas on or around the Winn foot print that are encountering a mosquito threat have the ability to request mosquito surveillance from USA MEDDAC Environmental Health. It's as easy as filling out the Fort Stewart and Hunter Army Airfield Mosquito Surveillance survey at www.surveymonkey.com/r/XDWHFH2.