NASHVILLE, TENN. (RFD-TV) — A new case of New World screwworm was detected in Mexico, about 120 miles south of the U.S. border. According to the U.S. Department of Agriculture (USDA), the dangerous cattle parasite was found in a 2-year-old bovine that was moved from Veracruz to a feedlot in Nuevo León. This is the second detection at that facility since October.
The detection comes as the U.S. Food & Drug Administration (FDA) approves a new topical drug to help protect U.S. cattle. The product developed by Merck, Exzolt Cattle-CA1, is designed to prevent and treat New World screwworm and control cattle fever ticks. The prescription-only treatment must follow a 98-day slaughter withdrawal period. While screwworm has not been detected in the United States, fever ticks remain a threat to herds.
The FDA’s approval gives producers a new, fast-acting tool that is absorbed through the skin and approved for calves, heifers, bulls, and lactating cows. The agency says the topical drug is safe and shows promise, giving producers a much-needed tool as they work to safeguard animal health and the food supply.
Texas Agriculture Commissioner Sid Miller called the decision a landmark step for herd protection, emphasizing coordination with USDA, Mexican authorities, and state partners to prevent northward spread. State officials are urging producers near the border to monitor animals carefully for unhealed wounds or maggot activity and to report suspicious cases immediately.
While Texas remains free of detection, state officials warn that livestock movement, wildlife traffic, and existing fever tick pressure demand increased vigilance. Texas shares approximately 1,254 miles of border with Mexico, and its beef industry heavily depends on feeder cattle imports from the Southern trade partner. Currently, the U.S.-Mexico border is closed. U.S. Secretary of Agriculture Brooke Rollins met with Mexican President Claudia Sheinbaum in Mexico City at the end of October to coordinate biosecurity efforts, but left the positive meeting and decided it was not the time to reopen the cattle trade.
USDA officials told RFD-TV News earlier this year that it remains focused on its five-point plan to combat screwworm in Mexico and reopen the border for trade, including aerial releases of sterile flies. Officials urge producers to watch for suspicious wounds and maggots.
For more information about the USDA’s biosecurity plan to combat New World screwworm and access to producer resources, visit screwworm.gov.
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