FOOD SECURITYBugs, Beef, and Blame: New World Screwworm is Back
American cattle can’t catch a break. For the first time this year, highly pathogenic avian influenza has been detected in Texas dairy cows. And now, the biggest story this week is the confirmed re-introduction of New World Screwworm (NWS) into the United States.
American cattle can’t catch a break. For the first time this year, highly pathogenic avian influenza has been detected in Texas dairy cows; meanwhile14 dairies in Idaho have also confirmed cases in the last 30 days. However, bird flu will have to take a back seat as the biggest story this week is the confirmed re-introduction of New World Screwworm (NWS) into the United States.
Six confirmed NWS cases have been reported in the last week: four calves and a goat in Texas and a dog in New Mexico. Unlike many types of maggots that feed on dead tissue, larvae of Cochliomyia hominivorax, a parasitic fly, burrow into and consume the living flesh of warm-blooded animals, causing severe wounds that can be fatal if untreated. NWS was eradicated from the U.S. in the 1960s but has been creeping north through Central America and Mexico, where over 27,000 animal cases have been confirmed since November 2024.
Beef at a Breaking Point
Many fear the impact NWS may have on the US cattle industry, as herd numbers are already at their lowest point in 75 years and beef prices have risen roughly 75% since 2020. A broad NWS outbreak could cause calf deaths, weight loss in adult cattle, and widespread movement restrictions, pushing prices even higher. Such restrictions are already underway both internationally and domestically, with Canada implementing import restrictions on livestock from Texas and US states like Louisiana restricting interstate animal travel. Mexico has also blocked import of almost all animal species from the U.S. following confirmation of the NWS cases in Texas. More restrictions are expected in the coming weeks if additional cases are detected.
Playing the Blame Game
Unsurprisingly, the NWS outbreak has already turned political, with Democrats and Republicans clashing over who is to blame. USDA Secretary Brooke Rollins and some Republican lawmakers are pointing fingers at Joe Biden, arguing the parasite’s northward migration is the result of border security failures of the previous administration.
Democrats, meanwhile, have highlighted that the Musk-led Department of Government Efficiency (DOGE) cut USAID funding for a Central American screwworm monitoring program early last year, just days before the US temporarily lifted a suspension on Mexican cattle imports. Whether those funding cuts directly contributed to the current outbreak remains unclear. The USDA maintains there were “no cuts to any staff used on the response to this issue”, though many have pointed out that the department saw one of the largest workforce reductions under this administration. Nearly 27% of USDA employees separated between September 2024 and December 2025, with nearly three-quarters taking the “deferred resignation” option pushed by DOGE. Additionally, the staffing shortage is expected to worsen soon as the USDA continues forward with its plan to significantly reorganize the department, including moving its headquarters from Washington D.C. to Salt Lake City and closing dozens of research facilities, a plan Senate Democrats argue will only weaken the department’s ability to combat the NWS threat.
What’s Being Done?
In response to the outbreaks, the USDA has established 12-mile quarantine zones around each confirmed case and is releasing millions of sterile male flies weekly in affected areas. The sterile insect technique, in which sterile males are released to mate with wild females to prevent offspring, was the cornerstone of the original eradication effort and remains the primary containment strategy. More than 8,000 traps have been set along the US-Mexico border, and tens of thousands of fly samples are under analysis.
Texas Agriculture Commissioner Sid Miller has urged faster action, pushing for a combined approach using sterile flies alongside broader insecticide use. USDA officials have pushed back, calling the suggestion “dangerous.”
Anticipating a potential US arrival, the FDA’s Center for Veterinary Medicine spent the past year working to authorize treatments for NWS myiasis across species. Currently, there are 3 conditionally approved products, two for cattle and one for dogs, and nine emergency use authorizations (EUAs) covering dogs, cats, cattle, horses, sheep, goats, swine, deer, and exotic and zoo animals.
The situation is still evolving, and officials are urging livestock owners to inspect animals frequently and report suspicious wounds to their veterinarian immediately. NWS myiasis can be treated with authorized products, but prompt veterinary or medical intervention is critical.
Further Reading
● New World Screwworm Confirmed Detections Tracker: USDA Animal and Plant Health Inspection Service
● “What to know about the New World screwworm fly and its reappearance in the US,” John Hanna and Russ Bynum, AP News
● “What screwworm means for your beef prices,” Ramishah Maruf, CNN
● “US plans to fight flesh-eating screwworm outbreak with flies and dogs,” Max Matza, BBC
Margeaux Malone, Pandora Report Associate Editor. This article is published courtesy of the Pandora Report.
