After making its way through South America and Mexico, the New World screwworm (NWS) has arrived in the U.S. — a month ahead of the busy July 4th holiday and grilling season — with the USDA stating, the “U.S. food supply is safe” in a press release.
USDA’s Animal and Plant Health Inspection Service reported that NWS larvae were found in a three-week-old calf in Zavala County, Texas. Adult NWS lay their larvae in the flesh of living animals – livestock, wildlife, pets, and sometimes, people and birds.
Zavala County residents are encouraged to look for signs of NWS by inspecting body openings (nose, ears, genitalia) of pets and livestock and identifying any enlarged or draining wounds or signs of discomfort in animals, the agency stated in a press release.
Once eradicated from North America, the NWS re-emerged in Mexico around Nov. 2024, with the U.S. suspending live animal imports from Mexico several times over NWS concerns. Also, the USDA revealed last year its multi-pronged NWS Response Playbook, laying out how the Trump administration planned to combat the pest.
The biggest defense against NWS is the use of sterile fly technology, which reduce the NWS population over time. The USDA opened a sterile fly facility in Tampico, Mexico, with assistance from the Mexican government, and is working to open a facility in Edinburg, Texas, that would produce 100 million flies per week once operational.
Additionally, the USDA opened a livestock insect research facility in Kerrville, Texas, nearly a week before the first case of NWS in the U.S.
Ag suppliers are also stepping up in the fight against NWS, including Elanco Animal Health, which received USDA emergency authorization for a coumaphos, propoxur, sulfanilamide topical powder called Negasunt and a coumaphos- and propoxur-based NWS preventive and treatment called Tanidil, as AgNavigator reported.
These treatments will be available from the USDA’s National Veterinary Stockpile, which provides resources for producers.
“Protecting our livestock industry is a national security issue of the utmost importance, and USDA is wasting no time in taking action. USDA invested heavily in the tools needed to eliminate NWS ever since cases started increasing in Central America and Mexico. The United States has defeated this pest before, and we will do it again,” said Under Secretary for Marketing and Regulatory Programs, Dudley Hoskins, in a press release.
