New World screwworm resurfaces in New Mexico

The New World screwworm, a parasitic fly whose larvae feed on living tissue, has resurfaced in the United States. A recent case was confirmed in a horse in Grant County, New Mexico, according to the U.S. Department of Agriculture. This detection comes as the USDA prepares to reopen the Santa Teresa port, a major gateway for Mexican cattle imports.

While nearly 2,000 cases remain active in Mexico, there have been 50 reported cases in the U.S., mostly in Texas, with only three currently active. Agriculture Secretary Brooke Rollins stated that the agency will delay port reopening if safety protocols are not fully assured. The source of the New Mexico infestation is currently under investigation.

Researchers at the University of California San Diego and the San Diego County Health and Human Services Agency have developed a tracking dashboard to estimate screwworm risk across U.S. counties. The tool uses confirmed detections and environmental data to help public health officials monitor the parasite's movement. The screwworm poses a significant threat to livestock, wildlife, pets, and occasionally humans, as larvae can cause deep wounds and secondary infections.