Canada has imposed a temporary ban on livestock imports from Texas after U.S. officials confirmed a second case of the flesh-eating New World screwworm in South Texas. This move reflects growing concerns over the parasite’s reappearance and the threat it poses to North America’s livestock industries.
The second case emerged in a young calf in Zavala County, located just a few miles from where the first detection in decades was identified earlier this month. The New World screwworm larva attacks living tissue by hatching in open wounds or body orifices of warm-blooded animals, including livestock, wildlife, pets, and occasionally humans. Left untreated, infestations can cause severe injury or death.
After the parasite was declared eradicated in the United States in 1966, this resurgence signals a significant challenge. The U.S. Department of Agriculture (USDA) has responded by establishing a stringent 20-kilometer control zone around the infected area and deploying sterile insect release programs designed to limit spread. Federal and state agencies had prepared for this eventuality following the parasite’s progression through Central America and Mexico.
While several samples taken from surrounding regions have tested negative, officials remain vigilant. USDA officials emphasized their agency’s readiness and prior success eradicating the screwworm, pledging swift action to control the outbreak.
In response, the Canadian Food Inspection Agency ordered that all cattle, horses, and other livestock originating from or present in Texas within the preceding three weeks be barred from entering Canada. Canadian authorities noted that the country's cooler climate reduces the likelihood of permanent screwworm establishment but stressed the necessity of precaution during warmer months.
The robust livestock trade between the U.S. and Canada, including cross-border movement for breeding and slaughter, makes these restrictions significant. Officials from both countries continue to monitor the situation closely, aiming to prevent the screwworm’s further spread and safeguard animal health across the continent.