Wyoming

Researchers are studying whether a mosquito can be given a special synthetic insecticide "hot-foot" treatment before it has a chance to suck blood--and potentially transmit diseases--in a project at the Sustainable Agriculture Research and Extension Center (SAREC) near Lingle.

The study will be explained during a July 26 open house at SAREC. Irrigated row crop research is also part of the open house. Participants will begin gathering at 9:30 a.m., and tours start at 10 a.m. at the center two miles south and west of Lingle on Highway 157.

Ed Schmidtmann, Agricultural Research Service research entomologist with the U.S. Department of Agriculture's Arthropod-Borne Animal Diseases Research Laboratory in Laramie on the University of Wyoming campus, and fellow mosquito "hot-foot" researchers Professor Jack Lloyd and Associate Professor Jim Waggoner, both of the UW Department of Renewable Resources, are not being practical jokers. If successful, the method could be a quick and economical answer to protect the livestock industry from mosquito-transmitted pathogens introduced by bioterrorism--or by chance, like West Nile virus.

"It's well-recognized that the United States livestock industry is vulnerable to the introduction of insect-transmitted viruses," said Schmidtmann. "West Nile virus is a good example of the vulnerability. It was introduced in 1999 and spread rapidly across the country with little to keep it from happening. There are other viruses much more damaging to livestock than West Nile virus. If these were introduced into the United States, it could be catastrophic to livestock production."

The SAREC study will run approximately six weeks. A spray containing a synthetic pyrethroid insecticide, which has been tested and deemed approved for use on livestock in the U.S. by the Environmental Protection Agency, is applied to cattle.

"The insecticide has a hot-foot repellency," said Schmidtmann. "The mosquito contacts the animal, but leaves the animal before it can feed. The material acts rapidly on an insect's nervous system and interferes with the behavior of the mosquito."

The treatment could also work against black flies and biting midges.

Researchers will have two herds of 20 Holstein steers at SAREC. Half will be treated and half not. Twice a week, special cages will be dropped over selected animals, and mosquitoes will be collected to determine how many have fed and how many have not on the non-treated and treated animals.

West Nile virus doesn't cause disease problems in cattle, he said, "But if exposed to the virus, they will develop antibodies. We will test blood samples at 10-day intervals looking for antibodies, and this will tell us whether they have been bitten by an infected mosquito."

Schmidtmann said his lab is being redirected toward more Homeland Security issues. "The livestock industry is highly vulnerable, and we need tools to counteract or protect our industry," he said.

Nasty pathogens such as Rift Valley fever, African horse sickness, exotic bluetongue, Japanese encephalitis and others could be devastating.

A spray offers a quicker response time than vaccinations to pathogens that could quickly rampage through livestock.

"Some of these viruses will decimate cattle or cause high levels of abortion or death in young animals," he said. "If we can't protect with vaccines, which can take two weeks to become effective, are there other methods that could be used? This is something that could be used right away."

On the Web: www.uwyo.edu/uwexpstn/Centers/SAREC.asp, or www.ars.usda.gov/main/site_main.htm?modecode=54100000.

Date: 8/25/05