USDA confirms – The U.S. Department of Agriculture confirmed a second New World screwworm case in Texas on June 5, this time in Zavala County—5.6 miles from the first positive case reported this week. With larvae found in a one-month-old calf and added testing continuing arou
The alarm bells in South Texas weren’t just loud — they were close.
On June 5, the U.S. Department of Agriculture confirmed a second case of New World screwworm in Texas. with experts finding the parasite’s larvae in a one-month-old calf. The new detection came in Zavala County. on a ranch located 5.6 miles from the first positive screwworm case in the state. which was confirmed this week. That first case was reported in nearby La Pryor, a town roughly 30 miles northeast of the U.S.-Mexico border.
The second infestation was found after the USDA said it tested a number of suspect cases. according to a press release from the department’s Animal and Plant Health Inspection Service. APHIS also said officials are continuing to collect and test additional samples from the surrounding area. and that those samples have come back negative so far.
The second case was reported earlier on Friday by Reuters, citing sources. It was confirmed by the USDA on June 5, with the department describing the affected calf and the follow-up testing underway in the nearby area.
Screwworms are parasitic flies that lay eggs in open wounds or mucous membranes of warm-blooded animals. After the eggs hatch, larvae penetrate living tissue, feed on the host, and can cause fatal damage if treatment does not happen in time.
For ranchers, the timing and geography matter. Friday’s case and the initial detection in La Pryor have dealt a setback to U.S. cattle ranchers who have been preparing for the pest’s movement north through Mexico over the past year.
In earlier decades, screwworm outbreaks in U.S. border states in the 1960s devastated wildlife and caused heavy financial losses for ranchers. A widespread resurgence now could carry a major economic threat in Texas. the country’s largest cattle-producing state. through animal deaths as well as higher labor and treatment costs.
To keep the risk contained. Washington has kept the U.S.-Mexico border closed to live cattle imports for more than a year. The government has also spent millions of dollars aimed at stopping the pest’s spread northward. including funding sterile fly production. expanding trapping programs. and stepping up livestock monitoring.
Even as the second Texas case marks a new confirmed foothold. APHIS says testing in the surrounding area has returned negative results for now — a point that may determine how quickly officials can narrow the outbreak’s edges. For cattle operators, that gap between a confirmed case and wider spread is where the economic stakes live.
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