USDA Reports Multiple Screwworm Cases in US

The U.S. Department of Agriculture (USDA) has reported five cases of screwworms in the United States, with three new cases identified recently. These incidents mark a reemergence of the flies after breaching containment barriers.

Four of the confirmed cases involve calves located in Texas. Two of these were found in Zavala County, and another two were reported in La Salle County. The fifth case was detected in a dog, which is a resident of New Mexico. While the dog's infection was reported in Texas, its origin remains unclear, and it may have recently traveled to Mexico, where screwworm infestations are also reportedly spreading.

The primary concern surrounding the screwworm's resurgence is the significant threat it poses to livestock, particularly the cattle industry. The larvae of the screwworm fly are known for their voracious feeding habits, which can be fatal to cattle without intense vigilance and preventive measures.

Economically, the USDA has provided estimates on the potential impact if the flies establish a comeback comparable to past outbreaks. It is projected that such a resurgence could cost Texas producers approximately $732 million annually, with the broader Texas economy facing an estimated annual impact of $1.8 billion.

While the main focus is on livestock, Ars Technica indicates that the human risk associated with screwworms in the U.S. is considered low, though not entirely absent, and notes the larvae's capability to burrow through tissue.