New World Screwworm
New World screwworm (Cochliomyia hominivorax) has breached its historical containment line in the Darién and spread up through Central America into southern and central Mexico. USDA has suspended live cattle, bison and horse imports across the southern border and is ramping sterile-insect production to re-establish an eradication barrier. Texas and Gulf-state livestock face direct exposure, with beef supply and price effects propagating through North American markets.
Why it matters — This matters because a flesh-eating parasite is spreading north through Mexico toward Texas, and USDA's halt on live-cattle imports is already tightening North American beef supply and pushing prices up for ranchers and consumers.
Why now — The screwworm front has breached its historical Darién containment line and pushed into central Mexico, prompting USDA to suspend southern-border cattle imports and scale up sterile-fly releases.
WHAT CHANGED · LAST 72H
- —US case tally reaches 32; 30 in Texas, one in New Mexico.
- —Texas opens Infested Zone 10 after Jim Hogg County bovine tests positive.
- —Crockett County bovine case bypasses active containment barriers.
KEY CLAIMS ON THE RECORD · 19 TOTAL
| Texas established Infested Zone 10 covering parts of Jim Hogg, Starr, and Zapata counties after a bovine tested positive in Jim Hogg County. | ASSESSED · 0.70 · 2 EVID |
| USDA awarded the University of Arizona a $3.74 million Grand Challenge grant to strengthen state preparedness for New World screwworm. | VERIFIED · 0.65 · 1 EVID |
| US New World screwworm cases reached 31, with 30 in Texas and one domestic animal case in Lea County, New Mexico. | ASSESSED · 0.65 · 1 EVID |
| USDA APHIS lists 31 confirmed New World screwworm cases in the US, with 21 active and 9 shifted to inactive status. | ASSESSED · 0.65 · 1 EVID |
| University of Arizona project will validate a PCR-based diagnostic tool to expand New World screwworm testing capacity beyond morphological identification. | VERIFIED · 0.62 · 1 EVID |
| Project includes economic-impact assessment and benefit-cost analysis of response strategies, including a proposed Arizona-based sterile fly distribution facility. | VERIFIED · 0.62 · 1 EVID |
| Texas DSHS confirmed no human cases of New World screwworm in Texas. | ASSESSED · 0.60 · 1 EVID |
| By end of June 2026, USDA tallied 20 active and seven inactive NWS cases, all but one in south Texas. | ASSESSED · 0.60 · 1 EVID |
OPEN FORECASTS · SCORED CROWD
- Will USDA APHIS report at least 100 cumulative confirmed New World screwworm cases in the United States by September 30, 2026?no forecasts yet · closes 2026-09-30
- Will a confirmed New World screwworm case be reported in a US state other than Texas or New Mexico by November 30, 2026?no forecasts yet · closes 2026-11-30
DOWNSTREAM EFFECTS · WATCH INDICATORS
- North American beef prices — USDA's suspension of live cattle, bison and horse imports across the southern border removes Mexican feeder-cattle supply from a market already tight, pushing wholesale and retail beef prices up. Watch: CME live cattle futures and USDA weekly retail all-fresh beef price
- Texas and Gulf-state cattle herds — The screwworm front has bypassed containment barriers into central Mexico and now Texas counties, so larvae infest livestock wounds directly, forcing herd inspections, treatment and culling. Watch: USDA APHIS confirmed US case tally and active-vs-inactive split
- Mexican cattle-export economy — The border import halt strands Mexican ranchers' primary US market, collapsing cross-border cattle revenue until the eradication barrier is re-established. Watch: Monthly Mexican live-cattle export volumes to the US via SADER/USDA data
- US household food-inflation politics — Rising beef prices lift the grocery component of CPI, which then makes food affordability a salient campaign attack line in contested 2026 races. Watch: CPI food-at-home index and beef price mentions in midterm ad spending