Texas agencies are ganging up on a bad, bad worm. According to a release, the Texas Animal Health Commission and Texas Parks and Wildlife Department will team up to combat the New World screwworm (NWS) prior to its arrival in Texas, following a directive from Governor Greg Abbott.
Abbott issued a letter warning that the spread of the New World screwworm from Central America into southern Mexico poses “a serious threat to Texas livestock and wildlife” and directed the two agencies to form a Texas New World Screwworm Response Team with a mission to prevent the reemergence of this destructive parasite.
“Texas played a critical role in eradicating this pest from the United States in the 1960s and will do so again if the need arises,” Abbott said in his directive.
They are called screwworms because they screw into the flesh, worsening injuries and causing a painful condition called NWS myiasis. Flies lay eggs in open wounds or orifices such as nostrils, eyes, or mouth. These eggs hatch into parasitic larvae. The maggots burrow or screw into flesh with sharp mouth hooks. Wounds can become larger, and an infestation can often cause serious damage or death.
After feeding, larvae drop to the ground, burrow into the soil, and emerge as adult NWS flies. Adult NWS flies can fly long distances, and the movement of infested livestock or wildlife can increase the rate of spread.
NWS primarily infests livestock but can also affect humans and wildlife, including deer and birds.
The parasite was last eradicated from the U.S. in 1966, with costly efforts by federal and state animal health officials, livestock producers, and veterinary practitioners. Eradication efforts have continued in Central America, but the pest is widespread in Cuba, Haiti, Dominican Republic, and South American countries.
In 2022, NWS broke through an established eradication border in Panama and began spreading north through Central America. NWS reached the southern states of Mexico in November 2024 and has continued to spread in multiple Mexican states as far north as Oaxaca. Due to Texas’ vast border with Mexico, extensive animal agriculture industry, and abundant wildlife, the risk of NWS reemergence in Texas is still of strong concern.