The U.S. Department of Agriculture has detected the second incident of a New World screwworm infecting a calf in southwest Texas – approximately 5.6 miles from the first case.
On Friday, a federal government response team posted on social media that the new case was in a 1-month-old calf in Zavala County.
“An APHIS Strike Team is on-site, we have deployed mobile response trailers, and sterile fly releases are underway,” the New World Screwworm Rapid Response group said. “We have defeated this pest before, and we will do it again.”
Earlier this week, the flesh-eating larvae was discovered for the first time in the U.S. in a calf in South Texas. Screwworm flies pose a threat to the state’s $17 billion cattle industry, but can also spread to any warm-blooded animals, including wildlife and pets.
LEARN MORE: Greg Abbott pledges state resources to fight spread of ‘extraordinarily challenging’ screwworm flies
The federal response team said it has already acted to control the movement of cattle where the infected calf was found and is providing treatment supplies. The team said it also is releasing sterile flies – 2 million by air and 4 million on the ground per week – to ensure the screwworm flies only encounter sterile mates and do not reproduce.
Federal and state officials, as well as cattle industry leaders, have been sounding the alarm about the fly’s movement through Mexico and toward the U.S. since a case was confirmed in southern Mexico in November 2024.
As of Wednesday, more than 171,700 cases were reported in animals outside of the country, and more than 2,070 cases in people.
Gov. Greg Abbott issued a disaster declaration last year about the bug. He expanded it Friday to authorize “all available resources of state government to respond to this disaster.”
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This article originally published at A second cow in Texas has been found infected with screwworm.