USDA reports two additional screwworm cases in Texas cattle and dog

The U.S. Department of Agriculture announced Monday that two more New World screwworm infestations have been confirmed in Texas, a calf in La Salle County and a dog in Andrews County. The discoveries raise the state’s total to four confirmed cases, following earlier reports of two calves infected in south Texas last week.

Screwworm larvae, which feed on living flesh, are deposited by female flies in open wounds of warm-blooded animals. A sterile-male release program, historically used to contain the pest in Panama, is being expanded as a long-term control strategy.

University of Florida entomologist Edward Burgess said the recent detections likely reflect heightened surveillance rather than rapid spread, noting that “when you are looking for something, you are more likely to see it.”

Federal officials said they are sampling suspected cases and working to eradicate the parasite. The USDA plans to increase sterile fly production at facilities outside the United States and to construct a large-scale production plant in Texas.

Texas Agriculture Commissioner Sid Miller criticized the federal response as too slow and suggested a poison bait could eliminate the problem within months, though USDA scientists warned the bait has not been proven effective and could harm non-target insects, animals and humans.

Canada has temporarily halted imports of cattle, horses and other livestock from Texas. The USDA Secretary Brooke Rollins is scheduled to hold a news conference on the issue later Monday.