The New World screwworm (NWS) is causing trouble and costing dollars in Texas and New Mexico. As of June 25, 20 cases have been found, and I figure if there have been 20 cases found in livestock and pets, there are probably another 20 cases or more in wildlife.
Female screwworms will find an open wound on any warm-blooded animal to lay its eggs, and the larvae eat the flesh surrounding the wound. If left untreated, the animal eventually dies.
The good part about releasing sterile male flies in affected areas is female flies only mate once, and if the wild female flies mate with a sterile partner, the pest’s life cycle stops. This control method worked to many years ago during an outbreak in the U.S. and Mexico.
The potential path of the pest looks to go north and northeast from South Texas, especially along the coast from Texas to Florida.
The High Plains Region looks to be safe from NWS, unless it shows up as larvae in an infected wound on an animal.
Weather patterns and temperatures will influence the movement of the NWS. Pupae development cannot live below about 58 degrees, and the adult fly’s favorite temperature is around 81 degrees. It looks like cool nighttime temperatures will control NWS.
Along with our temperatures, I hear rainfall and moisture will dictate to what extent the pest lives. If some do get to our region, they will soon be a dead this year with our drought.
Besides Mexico and the Central America, the U.S. Department of Agriculture (USDA) is doing a heck of a job controlling the fly. We have to work closely with these countries to control NWS in our states. Other countries live with NWS, while the U.S. doesn’t want the pest at all.
The USDA currently produces sterile flies in Panama and is investing $21 million to support Mexico. Moore Air Base near Edinburg, Texas currently has a fly dispersal facility where pupae from Panama arrive and are readied for distribution. USDA is also constructing a production facility at Moore Air Base which should be operational in the fall of 2027.
As of June 17, the number of sterile flies released in Texas and New Mexico was 135,623,026 via aerial dispersal, 12,079,200 via ground dispersal and 5,238,496 via vehicular dispersal.
In Wyoming, Gov. Mark Gordon convened an ad hoc animal health panel with state veterinary and public health officials to strengthen communication and preparedness efforts surrounding NWS.
The governor said, “The goal was to expand outreach ahead of Wyoming’s peak summer travel, backcountry recreation and rodeo season.”
Gordon also said, “There are no reported cases in Wyoming. However, Texas and New Mexico are tracking instances, so it is important to keep all citizens informed, including pet owners, campers, rodeo athletes and sportsmen, in addition to our ag, ranching and wildlife communities.
I’m satisfied with the extensive outreach regarding NWS which has been outgoing to our ag, livestock and wildlife professionals.”
We applaud the governor and members of the group for being so proactive.
Dennis Sun is the publisher of the Wyoming Livestock Roundup, a weekly agriculture newspaper available online and in print.
