A second case of the flesh-eating screwworm fly has been confirmed in Texas, prompting a disaster declaration from Governor Greg Abbott as authorities intensify efforts to contain the parasite. The US Department of Agriculture (USDA) verified the new infection days after the first case was detected in a one-year-old calf, marking the first resurgence of the new world screwworm (NWS) in the United States since the 1960s.
The two infections were found approximately five miles apart in Zavala County, south-west of San Antonio. In response, officials are releasing millions of sterile male screwworm flies in the area to prevent wild females from reproducing. The Texas Animal Health Commission (TAHC) confirmed the initial case on Wednesday, detecting NWS in a three-week-old calf with an umbilical lesion, and has established an infested zone with animal movement restrictions.
NWS larvae are parasitic maggots that burrow into the living flesh of warm-blooded animals, causing a painful condition called myiasis and potentially killing the host if untreated. The USDA stressed that the US food supply remains safe, as the pests do not infest meat, fruit, vegetables or other food sources.
The TAHC said it had been preparing for a resurgence for over two years, and its director, Dr Bud Dinges, urged animal owners to remain vigilant and report any suspicious larvae in wounds. The combination of sterile fly releases, enhanced surveillance, movement controls, wound treatment and public education is considered a proven method for eradicating the pest, according to the commission.
The outbreak poses a significant economic threat to Texas, the leading cattle-producing state. The US-Mexico border has been closed to live cattle imports for more than a year, shrinking the $100bn beef industry to a 75-year low. Canada has now temporarily banned livestock from Texas, though officials noted the parasite is unlikely to establish there due to the colder climate.
