Holy crap — the USDA just confirmed that New World screwworm has officially breached into US territory for the very first time! Beth Mole at Ars Technica reported Wednesday night (June 3rd, updated to 10:45 PM ET) that they sent a sample from South Texas all the way out to their National Veterinary Services Laboratories in Ames, Iowa — and Agriculture Secretary Brooke Rollins later announced that confirmatory testing has officially verified an infection found in just a 3-week-old calf located in Zavala County. It's wild to think these ravenous flesh-eating flies have been inching up through Central America for years now (their biological barrier finally breached back in 2022), and we've watched case after case pile up in Coahuila, Mexico — including one on May 28th just 25 miles from the border in a 5-year-old goat.
Screwworms are legitimately terrifying little parasites when you think about it: females lay hundreds of eggs directly into wounds and openings of warm-blooded creatures (livestock most commonly, but even humans can get them), then their larvae feed on living tissue, creating deep, festering infections that can be life-threatening. Rollins told the press call Tuesday "there is no doubt" this represents an extremely serious livestock threat — though she also disputed some of the claims flying around that had rattled cattle producers all week! Rep. Don McLaughlin (R-Texas) claimed on social media Monday they'd found a case just one mile from the border, which Rollins pushed back against saying false information "causes significant panic," and while he's suspected further detections in calves at La Pryor ranch (in Zavala County!) with images showing larvae inside bloody circular wounds that Reuters couldn't immediately verify but looked promising — technically unconfirmed until now. What made me stop mid-scroll was this: the USDA estimates screwworms had cost zero since being eliminated from US herds back in 1960s via their incredible Sterile Insect Technique (aerial bombing of sterile male flies), saving livestock producers roughly $900 million per year ever since.
And here's where it gets even cooler: the USDA announced they're setting up a full unified Incident Command Team with Texas Animal Health Commission, mobilizing response personnel straight to Zavala County and establishing quarantine zones covering 20 km (~12 miles) around detection points with tight movement restrictions and enhanced trapping; plus their $750 million sterile fly production facility in South Texas is already pushing out roughly 4 million by air this week while they deploy ground release chambers, all adding up to about 100 million total insects released per week across Mexico near border regions — an absolutely massive campaign! "The United States has defeated this pest before and we will do it again," Under Secretary Dudley Hoskins said in the Wednesday night USDA presser. For me personally, as someone obsessed with biological warfare stories (that aerial bombing program still blows my mind), watching screwworms try to reclaim territory after their decades-long absence is genuinely exciting stuff — I'll be following this closely!
Source: https://arstechnica.com/health/2026/06/flesh-eating-screwworm-infection-detected-in-south-texas-usda-says/
Screwworms are legitimately terrifying little parasites when you think about it: females lay hundreds of eggs directly into wounds and openings of warm-blooded creatures (livestock most commonly, but even humans can get them), then their larvae feed on living tissue, creating deep, festering infections that can be life-threatening. Rollins told the press call Tuesday "there is no doubt" this represents an extremely serious livestock threat — though she also disputed some of the claims flying around that had rattled cattle producers all week! Rep. Don McLaughlin (R-Texas) claimed on social media Monday they'd found a case just one mile from the border, which Rollins pushed back against saying false information "causes significant panic," and while he's suspected further detections in calves at La Pryor ranch (in Zavala County!) with images showing larvae inside bloody circular wounds that Reuters couldn't immediately verify but looked promising — technically unconfirmed until now. What made me stop mid-scroll was this: the USDA estimates screwworms had cost zero since being eliminated from US herds back in 1960s via their incredible Sterile Insect Technique (aerial bombing of sterile male flies), saving livestock producers roughly $900 million per year ever since.
And here's where it gets even cooler: the USDA announced they're setting up a full unified Incident Command Team with Texas Animal Health Commission, mobilizing response personnel straight to Zavala County and establishing quarantine zones covering 20 km (~12 miles) around detection points with tight movement restrictions and enhanced trapping; plus their $750 million sterile fly production facility in South Texas is already pushing out roughly 4 million by air this week while they deploy ground release chambers, all adding up to about 100 million total insects released per week across Mexico near border regions — an absolutely massive campaign! "The United States has defeated this pest before and we will do it again," Under Secretary Dudley Hoskins said in the Wednesday night USDA presser. For me personally, as someone obsessed with biological warfare stories (that aerial bombing program still blows my mind), watching screwworms try to reclaim territory after their decades-long absence is genuinely exciting stuff — I'll be following this closely!
Source: https://arstechnica.com/health/2026/06/flesh-eating-screwworm-infection-detected-in-south-texas-usda-says/