National Cattlemen July 2026 | Page 10

When New World screwworm( NWS) was detected in southern Mexico in 2024, NCBA quickly made response and preparedness a top priority. On June 3, 2026, the U. S. Department of Agriculture( USDA) confirmed a case of NWS in a calf in South Texas, signifying the first case of the pest in the U. S. in decades. NCBA has worked with the USDA, Food and Drug Administration, and Environmental Protection Agency to ensure these agencies recognize the serious animal health threat NWS poses and the economic implications on the supply chain. NCBA pushed these agencies to take action to provide resources livestock producers can access to mitigate the threat of NWS. As a result, these federal agencies moved quickly to expand prevention and treatment options that producers and veterinarians can use to protect cattle.

To date, the best defense against New World screwworm is still the sterile insect technique( SIT), which was discussed in the June National Cattlemen. This method uses gamma radiation to irradiate NWS pupae and create sterile male flies. When the sterile males are produced and released, they mate with female flies to lay unfertilized eggs, therefore reducing the population over time and eradicating the pest. SIT has been successfully used in the past to eradicate NWS in the 1960s and is the cornerstone of the U. S.’ s response plan.

In addition to SIT, agencies are fast tracking approvals for additional tools producers can use at the animal level. Several products are now available under emergency or conditional approval that can help prevent infestation, treat future active cases, or protect wounds that attract screwworm flies.

WHAT DOES THE APPROVAL STATUS SIGNIFY?

Conditional Approval: Only animal drugs for minor species or minor uses in a major species( horses, dogs, cats, cattle, pigs, turkeys, and chickens) are eligible for FDA conditional approval. For major species conditional approve a drug must( 1) Be used infrequently and in only a small number of animals each year or( 2) Used in a limited geographic area and in only a small number of animals each year. For conditional approval, the drug company must show that the drug has a“ reasonable expectation of effectiveness,” but has not yet proven that it meets the“ substantial evidence” standard of effectiveness for full approval.

Emergency Use Authorization( EUA): When the Secretary of Health and Human Services declares an emergency use authorization is appropriate, FDA may authorize unapproved medical products or unapproved uses of approved medical products for emergency use to diagnose, treat or prevent serious or life-threatening diseases or conditions when certain criteria are met, including there are no adequate, approved, and available alternatives. As of August 18, 2025, the HHS Secretary declared NWS as justification for EUA with certain animal drugs.

Emergency Exemption: EPA allows Emergency Exemptions for unregistered uses of pesticides to address“ emergency conditions.”“ Emergency condition” is met when an urgent, non-routine situation that requires the use of a pesticide. EPA allows limited use of the pesticide in a defined geographic area for a finite period of time.

Approval Status Product Drug Manufacturer Purpose Application

Beef Cattle Withdrawal Time

Emergency Use Authorization

Ivomec 1 % Ivermectin Boehringer Ingelheim Prevention Injectable 35 days

* When treating anything on an animal’ s hide other than injection sites and / or tag wounds, the withdrawal period for Tanidil is 28 days. However, the EPA has placed additional restrictions on the use of this product to protect human safety. Read the full restrictions here: https:// assets-us-01. kc-usercontent. com / e4748d51-2c24-00f7- fc54-65f3864ee8b1 / 7fbaa3ce-39ff-47ff-a509-1a382d259f5f / Tanidil % 20New % 20World % 20Screwworm % 20EUA % 20Section % 2018 _ Apr-29-2026. pdf

10 JULY 2026 www. NCBA. org