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Mexico has confirmed a new case of New World screwworm in a Mexican city, less than 70 miles from the Texas-Mexico border.
New World screwworm (NWS) fly larvae burrow into the flesh of a living animal and are considered a threat to livestock, pets, and wildlife.
The case was identified in Sabinas Hidalgo in the Mexican border state of Nuevo León. Sabinas Hidalgo is located near the major highway from Monterrey, Nuevo León to Laredo — a heavily trafficked commercial route.
The U.S. Department of Agriculture said this is now the northernmost detection of the screwworm.
"This is a national security priority," said U.S. Secretary of Agriculture Brooke L. Rollins in a news release. "We are firmly executing our five-pronged plan and will take decisive action to protect our borders, even in the absence of (Mexico's) cooperation. Furthermore, we will pursue aggressive measures against anyone who harms American livestock."
The previous northernmost detection was reported in July in Veracruz, approximately 370 miles farther south.
Preliminary reports indicate that the affected 8-month-old cow had been moved to a certified feedlot in Nuevo León from a region in southern Mexico with known active NWS cases.
The U.S. has responded to the threat by closing its ports to cattle, bison, and horse imports from Mexico — part of the agency's sweeping plan to protect against NWS.
The USDA has already begun construction on an $8.5 million domestic sterile fly dispersal facility in Edinburg. It's expected to be completed by the end of this year and will be capable of dispersing up to 100 million sterile flies per week.
Plans are also underway with the U.S. Army Corps of Engineers for the construction of a domestic sterile fly production facility in South Texas.
To date, no NWS flies have been detected in traps along Texas, Arizona, and New Mexico.
Earlier this year, the U.S. confirmed its first human case of the New World screwworm. Health officials said the patient became infected after traveling in Central America and was diagnosed after returning home.
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