HELENA, MT – The Montana Department of Livestock (MDOL) has issued an emergency order restricting the importation of certain animals from areas affected by New World Screwworm (NWS) following the confirmation of the pest in Texas.

The action comes after the U.S. Department of Agriculture confirmed a case of New World Screwworm in Zavala County, Texas, on June 3. State Veterinarian Dr. Tahnee Szymanski determined the detection poses an imminent threat to Montana’s livestock industry and animal health, prompting Official Order No. 26-01.

New World Screwworm is a parasitic fly that lays eggs in open wounds and body openings of warm-blooded animals. Once the eggs hatch, the larvae feed on living tissue, causing severe injury and potentially death. The pest was eradicated from the United States in 1966, but officials warn its reintroduction could have significant economic consequences for livestock producers nationwide.

The emergency order applies to all warm-blooded animals, including cattle, horses, sheep, goats, swine, bison, poultry, pets, wildlife, and alternative livestock.

USDA confirms New World Screwworm in Texas calf; livestock industry goes on high alert

Under the order, animals originating from areas designated as NWS-infested zones must obtain an import permit from the Montana Department of Livestock and meet strict entry requirements. These include veterinary inspection, official identification, treatment with approved anti-parasitic products, and documentation verifying animals are free of wounds and signs of infestation.

Additional requirements also apply to livestock and equine species originating from 44 counties in southern and central Texas surrounding the affected area, even if those animals are located outside an officially designated infestation zone.

The order specifies that certificates of veterinary inspection issued before the initial detection of NWS in an affected state will not be accepted for entry into Montana. Equine owners also may not use extended equine health certificates for travel from infested states.

Montana officials emphasized that any shipment containing an animal suspected of carrying New World Screwworm will be denied entry until all animals have received required treatment and any wounds have healed.

The emergency order took effect immediately and will remain in place unless modified or rescinded by the Montana Board of Livestock. The board is scheduled to review the order at its next regular meeting on August 27.

State officials say the measures are intended to protect Montana’s livestock industry, wildlife populations, companion animals, and public health from the potentially devastating impacts of New World Screwworm infestation.