U.S. moves to import Brazil-made screwworm treatment

The federal New World screwworm response is adding a Brazil-made treatment to its arsenal, but not quickly enough to change the near-term risk picture. USDA’s Animal and Plant Health Inspection Service announced that EPA granted a Section 18 emergency exemption for Tanidil, a topical powder from Elanco used to treat or prevent New World screwworm, as U.S. officials prepare for possible additional cases near the border. APHIS said the product now has to be imported from Brazil and relabeled, a process expected to take roughly 90 to 100 days once the official order is placed. (aphis.usda.gov)

The move comes during the first U.S. New World screwworm detections in decades. USDA confirmed the first case on June 3, 2026, in a calf in Zavala County, Texas, followed by additional detections soon after. APHIS’ confirmed-detections page says the dashboard is intended to provide a current snapshot of both animal and wild fly detections, underscoring that the response has shifted from contingency planning to active surveillance and control. CDC also activated a Level 3 emergency response in June and has told veterinarians to report suspicious animal cases immediately to state animal health officials and APHIS. (direct.aphis.usda.gov)

Tanidil fills a specific gap in that response. According to the EPA exemption document, the product contains 2% propoxur and 3% coumaphos, and may be used on open wounds of livestock, horses, other domestic ungulates, and captive or temporarily captured wild and exotic ungulates and canids. APHIS’ pesticide guidance lists Tanidil as an additional wound-treatment product under a Section 18 emergency exemption, separate from already registered pesticides and separate from FDA’s growing list of animal drugs authorized or conditionally approved for New World screwworm myiasis. (texasagriculture.gov)

Just as important as the authorization itself is how tightly the product will be controlled. APHIS said Tanidil will be available only through the National Veterinary Stockpile and distributed in coordination with state animal health officials and federally recognized tribal agencies. If an incursion occurs, it may be used only by federal, state, local, or tribal agencies, and people working under their supervision, including veterinarians, certified applicators, and wildlife professionals. APHIS also noted that some states will need separate registration, which could limit availability in certain jurisdictions even after the importation window closes. (aphis.usda.gov)

Outside experts have been warning that the U.S. needs more response capacity, not just more products. A recent Nature Ecology & Evolution comment by Jason Andrews, J. Scott Weese, and Isaac Bogoch said renewed investment is needed as screwworm returns to the U.S., pointing to the overland spread from Central America and Mexico and the importance of sustained eradication infrastructure. USDA has already broken ground on a new sterile fly production facility in Edinburg, Texas, framing it as a cornerstone of its longer-term strategy, but that project won’t solve immediate field-treatment needs during the current transmission season. (nature.com)

Why it matters: For veterinary professionals, Tanidil’s authorization is useful, but it’s operationally different from a product that can simply be ordered through normal clinic supply chains. Large animal, mixed animal, equine, zoo, and wildlife veterinarians in affected or adjacent states may be asked to work inside a more formal incident-response structure, where case recognition, wound management, specimen submission, movement controls, and communication with state and federal officials matter as much as drug access. Companion animal clinicians should also keep watching the broader FDA response, because the agency has separately authorized multiple products for dogs, cats, horses, and food animals as officials try to build a cross-species toolkit. (aphis.usda.gov)

What to watch: The next milestones are practical ones: when APHIS places the import order, which states complete any needed registrations, whether confirmed detections continue to move geographically, and how quickly federal agencies can bridge the gap until larger infrastructure, including sterile-fly capacity, comes online. (aphis.usda.gov)