Canada blocks Texas livestock after second screwworm case; 21-day rule

A second New World screwworm case in Texas moved the event from a single detection to a cross-border livestock-trade issue on June 6. CNBC's RSS feed published the update at 19:33:38 GMT, after the USDA's Animal and Plant Health Inspection Service confirmed the second detection in a one-month-old calf in Zavala County, about 5.6 miles from the first confirmed case.

The trade action is the market catalyst. Canada said it would temporarily restrict imports of livestock, including horses, from affected U.S. areas, and animals that originated in or were present in Texas within 21 days before arrival at the Canada-U.S. border would not be accepted. That turns an animal-health event into a regulatory constraint for ranchers, feedlots, transporters, and cross-border livestock buyers.

USDA's June 5 APHIS release said samples from the surrounding area had tested negative so far. It also said the second detection sits inside the established movement-control zone and an enhanced sterile-insect dispersal area. APHIS and Texas officials are maintaining a 20-km infested zone, quarantines, movement controls, heightened surveillance, border trapping, and outreach to producers and veterinarians.

The response numbers matter because they define the containment cost and timeline. USDA began aerial releases on June 4 and plans to disperse 2 million sterile screwworms twice a week. It is also shipping another 4 million sterile flies per week to Texas for deployment through 24 ground release chambers. The agency has moved treatment supplies to Texas and deployed two 24-foot response cargo trailers that can convert into operational and laboratory space.

The commodity link is cattle supply rather than food safety. USDA said the U.S. food supply remains safe because screwworms do not infest meat, fruits, vegetables, or other food products, and affected animals would be identified during inspection. The market issue is movement control: fewer eligible animals can cross borders or leave restricted zones while the response is active, and that matters in a cattle market already sensitive to herd size, feedlot placement, and beef-price pressure.

The next checks are APHIS updates to the confirmed-detection dashboard, any expansion of Canada's import restriction geography, and whether additional Zavala County samples remain negative. A third confirmed case outside the existing zone would raise the trade-risk profile; continued negative tests would keep the story contained to movement controls and sterile-fly logistics.

Not investment advice. Verify all figures with primary sources before acting.