USDA Confirms Seven U.S. Screwworm Cases As Outbreak Reaches New Mexico
USDA confirmed seven New World screwworm cases in the United States as of Monday, June 8, 2026, including at least one in New Mexico, officials said.[1]
USDA had earlier confirmed screwworm larvae in a 3-week-old calf in La Pryor, Zavala County, after larvae were found in its umbilical area.[2] Texas State Veterinarian Bud Dinges established a 12-mile quarantine around La Pryor, and USDA formed an Incident Command Team with the Texas Animal Health Commission to coordinate eradication.[2] Federal officials said they are ramping up releases of sterile male flies and expanding sterile-fly production to stop the pest from establishing.[3]
On Wednesday, June 3, USDA announced the La Pryor calf case, marking the first confirmed U.S. screwworm detection since the 1960s and the first Texas case since 1966.[4] The pest was largely eliminated from the U.S. in the 1970s using sterile-male releases, but outbreaks that began in Panama have moved north into Mexico, where tens of thousands of cases have been reported.[5]
Early coverage stressed the finding appeared limited to a single calf and officials said properly treated animals are expected to recover.[2] As more cases surfaced, reporting shifted to warn of broader industry risk, and officials expanded quarantines, surveillance and emergency operations to try to stop spread.[6]
Canada temporarily halted imports of cattle and other livestock from Texas, and experts say increased testing will likely identify additional cases in coming days.[3] Officials have stressed the larvae do not infest meat or produce and say the U.S. food supply is not at risk.[5]
Show source details & analysis (11 sources)
📌 Key Facts
- On Wednesday, June 3, 2026, USDA confirmed New World screwworm larvae in a 3‑week‑old calf in La Pryor (Zavala County), Texas, after larvae were identified in its umbilical area (3‑week‑old calf).
- Texas State Veterinarian Bud Dinges established a 12‑mile quarantine/"infested zone" around La Pryor that restricts movement of warm‑blooded animals without inspection, and USDA has increased trapping along the U.S.–Mexico border to contain the detection (12‑mile quarantine zone).
- By Monday, June 8, 2026, authorities announced three additional detections — bringing the U.S. total to seven confirmed screwworm cases — with at least one new case reported in New Mexico, showing the outbreak has spread beyond Texas (seven confirmed U.S. screwworm cases).
- USDA has activated coordinated response measures, including forming an Incident Command Team with the Texas Animal Health Commission and intensifying surveillance and quarantine protocols to eradicate the pest (Incident Command Team).
- Federal officials say they are ramping up sterile‑male fly tactics and other eradication tools — including plans to expand overseas production and build a large sterile‑fly facility in Texas — and Agriculture Secretary Brooke Rollins has described intensified surveillance of South Texas herds (Rollins warns ranchers face 'really scary time').
- Officials emphasize that screwworm larvae do not infest food, affected animals are expected to recover with treatment when detected, and the risk to humans and the U.S. food supply remains low (larvae do not infest food).
- Experts warn the parasite threatens the $113 billion U.S. cattle industry (Texas accounts for about $17 billion of that value), and if not contained the pest could push up beef costs (113 billion U.S. cattle industry).
- Screwworm was largely eradicated from the U.S. in the 1970s using sterile‑male releases; its reappearance follows outbreaks that moved north from Panama into Mexico (roughly 26,216 cases reported across Mexico with ~2,700 still active), and this episode is being described as the first confirmed U.S. screwworm case since the 1960s (and the first Texas case since 1966) (first confirmed U.S. screwworm case since the 1960s).
- The outbreak has prompted trade and political reactions: Canada temporarily halted imports of livestock from Texas effective Friday, June 5, 2026, and Texas Agriculture Commissioner Sid Miller publicly urged use of an unproven poison‑bait approach that USDA scientists warn could harm non‑target species (Canada temporarily halted imports of cattle).
📰 Source Timeline (11)
Follow how coverage of this story developed over time
June 08, 2026
10:45 PM
News Wrap: 3 more screwworm cases found in Texas and New Mexico
New information:
- On Monday, June 8, 2026, authorities reported three additional New World screwworm cases in the United States, bringing the total to seven.
- The new detections include at least one case in New Mexico, indicating the outbreak has spread beyond Texas.
- The additional cases were announced the same day USDA and state officials were already responding to earlier confirmations in Texas.
5:41 PM
WATCH LIVE: Rollins holds update as USDA confirms more screwworm cases in Texas
New information:
- On Monday, June 8, 2026, USDA announced two additional New World screwworm cases in Texas, in a calf in La Salle County and a dog in Andrews County, bringing the state total to four confirmed cases.
- USDA said the new cases are hundreds of miles apart, underscoring the difficulty of stopping the pest's spread and that officials are sampling suspected cases and working to eradicate the parasite entirely.
- University of Florida entomologist Edward Burgess said on June 8 that scientists expect a handful of new cases in coming days and weeks and cautioned that increased vigilance can make detections appear like rapid spread.
- USDA reiterated that the long-term solution remains ramping up production and release of sterile male screwworm flies, with expanded production at overseas plants and plans for a large sterile-fly facility in Texas.
- Texas Agriculture Commissioner Sid Miller on June 8 publicly criticized USDA's approach as too slow, urged use of an unproven poison bait he says could eliminate screwworm within months, and complained the U.S.-Mexico border has not been closed to pets.
- USDA and other experts warned that the poison-bait idea Miller favors has not been proven effective and could poison non-target insects, other animals and potentially humans.
- Canada temporarily halted imports of cattle, horses and other livestock from Texas as of Friday, June 5, 2026, in response to the screwworm detections.
- The article notes that although the parasite attacks live cattle, it does not infest meat or fruit, there are around a dozen approved livestock treatments, and that beef prices, already near record highs due to a smaller U.S. herd, have not yet been significantly affected by screwworm's reappearance.
2:15 PM
Rollins warns ranchers face 'really scary time' as flesh-eating screwworm resurfaces in Texas cattle
New information:
- Agriculture Secretary Brooke Rollins said on Sunday, June 7, 2026, that USDA has confirmed a second New World screwworm case in Texas cattle, in addition to the initial La Pryor calf.
- Rollins stated that approximately 10 million sterile screwworm flies are currently being released each week in Texas as part of the eradication program.
- She described intensified visual surveillance of South Texas herds, saying 'we've got eyes on the cattle in South Texas' and urged ranchers to promptly report suspected cases.
- Rollins reiterated that affected animals are expected to recover with treatment, that the food supply will not be affected, and that the risk to humans in the United States remains historically low.
- She publicly framed the federal goal as beating the parasite back 'south of the border, back across the Darien Gap,' indicating an expanded cross-border eradication strategy beyond Mexico.
June 05, 2026
7:39 PM
First U.S. Screwworm Case Since 1960s Prompts Texas Emergency Response
New information:
- The New York Times reports this is the first confirmed U.S. screwworm case since the 1960s, expanding earlier framing that emphasized first Texas case since 1966.
- Article details that Texas Gov. Greg Abbott has activated or expanded specific state emergency-response mechanisms in coordination with USDA beyond the initial quarantine zone around the infected calf.
- The piece describes additional federal-state operational steps such as surge deployment of sterile-fly releases and expanded aerial surveillance over parts of south Texas beyond the initial 12‑mile infested zone.
- Reporting adds that Texas ranchers and local officials are being briefed on potential economic impacts and contingency plans for cattle movement and trade if further cases are detected.
6:42 PM
Flesh-eating New World screwworm fly is not a food safety or virus issue, Texas officials say
New information:
- On Friday, June 5, 2026, Texas Gov. Greg Abbott and other state officials held a public briefing about the New World screwworm detection in a 3‑week‑old calf in Zavala County, Texas.
- During that June 5 briefing, Texas officials said the parasite poses no food-safety risk and emphasized that it is not transmissible like a virus.
- Officials framed the screwworm as a localized livestock health issue that is addressed through quarantine and eradication measures rather than consumer food-safety actions.
5:48 PM
What to know about the New World screwworm fly and its U.S. reappearance
New information:
- The article reiterates that the New World screwworm fly has now reappeared in U.S. cattle with an infestation confirmed in a single 3‑week‑old calf in La Pryor, Texas, about 100 miles southwest of San Antonio and 50 miles from the Mexico border, the first Texas case since 1966.
- It quantifies the potential economic exposure by noting the parasite is threatening the $113 billion U.S. cattle industry and that Texas alone is home to $17 billion worth of cattle, making it the No. 1 cattle state.
- University of Notre Dame researcher Lee Haines explains that standard cattle-handling practices such as shearing, de‑horning, and moving animals through corrals create wounds that make livestock vulnerable to screwworm infestation, and that birth itself is a high‑risk moment for cows and calves.
- Texas & Southwestern Cattle Raisers Association president Stephen Diebel is quoted saying that even wounds "as small as a tick bite" can put cattle at risk of infestation.
- The article emphasizes that New World screwworm larvae eat live flesh and fluids, unlike most flies, and that females mate only once in their monthslong lives and lay eggs in open wounds and mucous membranes of any warm‑blooded animal, including wildlife, pets and occasionally humans.
- It adds historical detail that in past decades screwworm infestations caused tens of millions of dollars in losses to U.S. ranchers (potentially billions in today’s dollars) before the U.S. eradication campaign that bred and aerially released sterile male flies.
- The piece notes that deadly flies were detected in Mexico in late 2024 after years of being contained at the southern end of Panama, and that a 2023 outbreak in Panama led to a state of emergency, with spread to Costa Rica and Nicaragua later that year.
- University of Florida entomologist Edward Burgess is cited explaining that the screwworm reproduces quickly and is carried across wide areas by hosts such as deer, and that outside Panama many sterile-fly production programs have largely shut down.
- Agriculture Secretary Brooke Rollins reiterates that the larvae do not infest food and says screwworm is unlikely to damage U.S. beef production, which is important as consumers already face record beef prices.
- The article reinforces that about a dozen treatments are approved for screwworm across species and that death can result if infestations are not treated.
1:21 PM
Flesh-eating screwworm fly is reemerging in Texas after decades, threatening livestock
New information:
- CBS reports that the flesh-eating screwworm fly is now characterized as "threatening the U.S. cattle industry," emphasizing the potential economic risk beyond the initial single-calf detection.
- The segment reiterates that this is the first time in decades the parasite has posed an active threat to the U.S. cattle industry, underscoring the historical significance of the reemergence.
- The report frames the situation as a broader livestock threat in Texas, not just an isolated animal health incident.
June 04, 2026
11:41 PM
Flesh-eating screwworm could drive up cost of beef if not contained
New information:
- In a June 4, 2026 CBS News video segment, USDA officials said they are "taking immediate action" to contain the screwworm detection in southwest Texas.
- The CBS report emphasizes that the flesh‑eating parasite threatens cattle by burrowing into their flesh and that failure to contain it could drive up the cost of beef.
6:50 PM
Screwworm fly detected in Texas decades after cattle threat was largely eradicated in U.S.
New information:
- USDA said Wednesday, June 3, 2026, that the detection involves the New World screwworm fly itself reaching south Texas, not just larvae in a single animal.
- Agriculture Secretary Brooke Rollins said the case was found in a 3-week-old calf in La Pryor, Texas, about 50 miles from the Mexico border, and called it the first confirmed Texas case since 1966.
- Texas State Veterinarian Bud Dinges established a 12-mile quarantine zone around La Pryor that prohibits movement of any warm-blooded animal, including pets, outside the zone without inspection.
- Rollins said there have been no other detections in the U.S. and stated USDA is confident its preparations mean there is "no threat of mass infestation" and "no reason to believe this incursion will result in establishment of the pest" in the country.
- Officials emphasized the larvae do not infest food and that, if properly treated, the infested calf is expected to recover.
- The article notes that this is only the third U.S. appearance of New World screwworm since its eradication in the 1970s, referencing a 2016 Florida Keys outbreak and a 2025 Maryland human case linked to travel.
2:00 AM
Flesh-eating New World screwworm found in Texas calf, USDA says
New information:
- On Wednesday, June 3, 2026, the USDA confirmed New World screwworm in a 3-week-old calf in Zavala County, Texas, after larvae were identified in its umbilical area.
- USDA established a 12-mile "infested zone" around the detection site in Zavala County and is implementing quarantines there.
- USDA said it is increasing screwworm trapping along the U.S.-Mexico border and has formed an Incident Command Team with the Texas Animal Health Commission to coordinate eradication.
- USDA Under Secretary Dudley Hoskins said the United States "has defeated this pest before, and we will do it again," citing prior federal investments in eradication tools.
- USDA reiterated that at least 26,216 New World screwworm cases have been identified across Mexico, with about 2,700 still active, and described the Texas case as currently limited to a single calf.
June 02, 2026