We have been covering the battle to control the New World Screwworm (NWS, Cochliomyia hominivorax), a flesh-eating parasitic fly whose larvae infest open wounds of warm-blooded animals, including livestock, wildlife, pets, and occasionally humans, causing severe tissue damage and often death if left untreated. The pest appears to be infesting Mexico and heading north.
In the fall, we noted that the state of California warned people that more infestations of this particular parasite were possible.
Well, Texas is not waiting around. Texas Governor Greg Abbott has issued a statewide disaster declaration to prevent an invasion of NWS, which officials warn could severely damage Texas’s cattle herd and drive up beef prices if the parasite reaches the state.
Although the New World screwworm has not yet been detected inside Texas or elsewhere in the United States, state and federal officials have been closely monitoring confirmed cases in northern Mexico. Multiple infestations have been documented in Mexican states near the Texas border, including a confirmed case roughly seventy miles from the border in Nuevo León.Governor Abbott made clear that the declaration is intended to prevent harm rather than respond after damage has occurred. He stated that state law authorizes him to act before an infestation reaches Texas and that waiting until livestock and wildlife are affected would be irresponsible given the scale of potential losses.
As I have noted previously, NWS are controlled using the sterile insect technique, in which large numbers of lab‑reared male flies are sterilized with ionizing radiation and then released over affected or at‑risk areas. Because female NWS flies mate only once in their lifetime, mating with sterile males results in eggs that do not hatch, causing the wild population to shrink generation by generation until it collapses.
There was a move to create a plant for sterilized flies in Mexico. Now, a facility for insect dispersal has opened up in Texas.
A new sterile fly production facility has opened in Edinburg, Texas, as part of efforts to protect livestock from the New World screwworm.Secretary of Agriculture Brooke Rollins announced the facility opening on Monday, saying, “This facility strengthens our ability to stop this dangerous pest before it reaches U.S. soil by expanding sterile fly operations, improving response time, and reinforcing border protections.”The U.S. Department of Agriculture (USDA) built the facility to disperse sterile insects, marking the first time the USDA will extend its dispersal efforts into Texas, covering 50 miles along the U.S.-Mexico border near Tamaulipas.
The U.S. used this technique successfully in the 1970’s, during the last incursion of this pest. Rollins notes we have even more technology available for this response.
This isn’t the first time the U.S. has battled screwworm flies in this way. Between the late 1950’s and late 1970’s, the U.S. utilized similar dispersal facilities when screwworm outbreaks impacted the country. Since then, those facilities have been discontinued as the country has been without screwworm flies for decades.Now, combined with other safeguards, including improved surveillance, traps, and lures outlined in the USDA’s response plan, U.S. Secretary of Agriculture Brooke Rollins believes the country is ready to respond if those flies reach U.S. soil.“We have tools available today that we didn’t have in the 50’s and the 60’s and the 70’s that I sincerely believe if it does cross our border, we are ready.” Secretary Rollins said during the unveiling ceremony Monday.“I don’t want to underplay it because it is a big threat to our country, but I believe we’re as prepared as we can possibly be if that happens, we can deal with it and move towards eradication.”
The New World screwworm might be a formidable and nasty menace. However, it’s up against a potent defense…our own high-tech version of a “Venus flytrap”, using the insects’ sex drive to stop its incursion into this country cold.
Between the USDA’s sterile‑fly arsenal, state‑level vigilance, and a wall of new technology lining up close to our border, this pest may find itself out-of-luck even before it ever crosses the Rio Grande.
That means America’s cattle can keep grazing in peace, and Americans can continue to enjoy nutrient‑rich steaks worthy of the Lone Star State itself. I, for one, am grateful!
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