The Food and Drug Administration has granted emergency use authorizations for additional medications that can prevent and treat infestations of the New World screwworm, a parasitic fly whose larvae burrow into living tissue. The authorizations come as the flesh-eating parasite continues spreading northward from Central America along the U.S.-Mexico border.
New World screwworm (Cochliomyia hominivorax) infestations can be fatal in animals if untreated, with larvae feeding on living tissue and potentially causing severe infections or death. The pest, which was eradicated from the United States in 1982 after a decades-long eradication program, has been detected in wildlife in southern Texas and has raised concerns among ranchers and pet owners.
What the Right Is Saying
Conservative groups have expressed cautious support while raising questions about federal overreach. The American Farm Bureau Federation called the FDA's action 'a pragmatic step' but urged the administration to avoid creating regulatory barriers that could slow treatment access for ranchers in border states. RNC Committee member and Texas rancher Brett H. McGuire told Politico that local livestock managers need 'flexibility to respond quickly without waiting on Washington paperwork.'
Some Republican lawmakers have framed the outbreak as an immigration policy issue, arguing that increased border activity has contributed to the spread of pests from Central and South America. Representative Chip Roy (R-TX) said the screwworm resurgence 'underscores the broader consequences of unsecured borders' in a post on social media. The USDA's Animal and Plant Health Inspection Service has deployed teams to monitor wildlife populations in affected areas along the Rio Grande Valley.
What the Left Is Saying
Animal welfare advocates and public health groups have largely welcomed the FDA's action as a necessary response to an emerging threat. The Humane Society called the emergency authorizations 'a critical tool for protecting pets and livestock from a preventable disease.' Dr. Michael Topper, president of the American Veterinary Medical Association, said the medications provide veterinarians with 'additional options when confronting active infestations or protecting animals in high-risk areas.'
Progressive lawmakers have emphasized that screwworm outbreaks disproportionately affect small ranchers and rural communities who lack resources for expensive treatments. Representative Jasmine V. Brown (D-MI), a member of the Congressional Animal Protection Caucus, said in a statement that 'federal intervention ensures family farmers aren't left to bear the cost of controlling a pest that crossed our border due to conditions beyond their control.' The CDC has not issued guidance specifically for human cases, though the agency notes humans can be infected through open wounds.
What the Numbers Show
According to data from APHIS, New World screwworm was detected in 33 counties across Texas as of July 2026, up from confirmed cases in just two counties in late 2025. The agency has documented more than 1,200 animal fatalities attributed to screwworm infestations in the past 12 months, with cattle, deer, and feral hogs among affected species. USDA officials have released approximately 800 million sterile male flies as part of a containment program aimed at disrupting breeding cycles.
The FDA's emergency use authorizations cover three additional topical and injectable medications not previously approved for screwworm treatment in the United States. Pet owners should consult their veterinarians about appropriate preventive measures, particularly for animals that spend time outdoors in affected regions. The EPA has separately authorized permethrin-based products for use on livestock.
The Bottom Line
The FDA's expansion of available treatments represents a regulatory response to what officials describe as an evolving animal health threat along the southern border. The authorizations give veterinarians and ranchers additional tools, though experts emphasize that prevention—including avoiding exposure in high-risk areas—remains the most effective strategy for pet owners.
What to watch: USDA is expected to release updated infestation maps next month. Congress may consider supplemental funding for screwworm containment efforts during fall budget negotiations. Pet owners in Texas, New Mexico, Arizona, and Florida—which receives occasional introductions via international travel—are encouraged to consult veterinarians about risk assessment and preventive options.