New screwworm cases in Texas and New Mexico alarm dog owners

A road trip to a dock-diving meet, hunt test, or summer trial weekend just picked up a new layer of risk. New World screwworm detections in southwest Texas and New Mexico have turned a livestock parasite into a travel-planning problem for owners moving high-drive dogs across state lines, especially when a dog has a wound, a packed schedule, or a certificate of veterinary inspection to secure before departure.

The first U.S. animal case in the current outbreak was confirmed June 3 in a calf in Zavala County, Texas. USDA later reclassified an Andrews County, Texas dog case as New Mexico’s first confirmed case because the dog actually lived in Lea County, New Mexico. State officials said that dog was detected June 7 and that they established a 12-mile infested zone around the affected animal for surveillance, treatment, and safe animal movement.

For handlers, the timing matters as much as the geography. The American Kennel Club warned that dogs may be at risk if they have open wounds or come into contact with infested animals or contaminated areas, and it urged owners to check interstate requirements before crossing state lines. That warning lands squarely on the summer circuit, when dogs are hauled to shows, training camps, field events, and weekend competitions with little margin for paperwork delays.

Florida moved quickly after the Texas detections, issuing Emergency Rule 5CER26-7 on June 5 and then strengthening it after the later Texas and New Mexico cases. The rule blocks or restricts some rescue and shelter dogs and cats from states with confirmed screwworm detections, a reminder that a change in one part of the country can alter entry rules far beyond the outbreak zone.

Treatment options also shifted fast. On June 11, the Food and Drug Administration issued an Emergency Use Authorization for generic nitenpyram tablets for New World screwworm infestations in dogs, puppies, cats, and kittens weighing at least two pounds and at least four weeks old. The agency had already authorized NexGard for dogs and NexGard COMBO for cats for screwworm treatment. The Centers for Disease Control and Prevention also activated a Level 3 emergency response on June 11.

The federal response is moving alongside a parasite that has been advancing northward through Central America and Mexico since 2023. CDC said no locally acquired human infestations had been reported in the United States as of June 4, but it also noted more than 1,190 human cases and seven deaths in Central America and Mexico in its January advisory. USDA says it is adjusting sterile fly dispersal areas based on science and modeling, a sign that this is an active containment campaign, not a static alert. For anyone loading crates and coolers for the next run to the ring, the checklist now starts with health status, then paperwork, then the route.