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A confirmed New World screwworm case in Texas triggers movement restrictions and heightened livestock monitoring

Now that New World screwworm has been confirmed in the United States, what happens next? 

Dr. Bud Dinges, the state veterinarian for Texas and executive director of the Texas Animal Health Commission, says a 12-mile radius infested zone has been established around the operation where the lone case of New World screwworm was detected in a three-week-old calf.  “That infested zone, we are not allowing animal movements up to 36 hours initially,” he says. “We want to get in there and make sure that animals are safe to move. Animals can move out of the infested zone. They just need to be inspected, treated.”  He says the process was modeled after the state’s Cattle Fever Tick eradication efforts.  

Dinges says the infected calf has been treated. “They looked at the cattle on the premises, and didn’t find any other infested animals,” he said. “From our epidemiology investigation, there is no evidence of a recent movement of animals onto or off of the premises.”  

Dr. Lucas Hinojosa, a veterinarian in Edinburg, Texas, says the most important thing for producers to do right now is monitor their livestock and pets. “Checking any wounds that they might have for potential sites for the screwworm fly to land and then lay an egg and then you get the screwworm process started,” he says. “Another common area is the newborn calves of the umbilical area.” 

And he says there are other indicators outside of what producers might see. “There’s also a very horrible odor that comes from these wounds,” he says.  “I remember as a kid treating calves on the ranch, the smell that comes out of these wounds is just horrific, and you’ll never forget it. Once you smell it, you know it’s around.” 

He tells Brownfield sterile flies are key to controlling and eradicating New World screwworm.  But currently sterile flies are only being produced at the COPEG facility in Panama.  “You need over a million flies to cover a large area,” he says.  “We’re trying to get these flies to areas where we know the screwworm is that so that they can mate with a female and sterilize these eggs.” 

AUDIO: Dr. Lucas Hinojosa, Edinburg, Texas

A second facility, located in Metapa, Mexico is set to come online this summer and a third facility, at Moore Air Field in Texas is expected to start producing flies in late 2027.