---
title: "Screwworm Watch — New World screwworm in the United States"
url: https://stovall.report/screwworm
publisher: "The Stovall Report"
dossier_last_updated: "August 22, 2026"
detections_as_of: 2026-09-29
license: "© The Stovall Report. All rights reserved. Short quotations with attribution and a link are welcome."
---

# Screwworm Watch — New World screwworm in the United States

As of 2026-09-29, 52 New World screwworm detections confirmed in the United States (auto-extracted, medium confidence; source: New World screwworm cases climb to 52; first wild fly detected in U.S. trap).

Source statement: [New World screwworm cases climb to 52; first wild fly detected in U.S. trap](https://news.google.com/rss/articles/CBMiygFBVV95cUxOWlRCUVk3d0ROSGk4S0xoYVRDZWNVRzc3dGk2cGFqY3dKQ3ljWEhOT25kWlhOY3JrVndGdDNxaHQ3S3dkNm1zaVZLVHlGN2hUVTl0ZVVaSzYwYzNjdGVTcjRPRGpqclFidW1PNmtKMW9NVXpaVy1yaHFoNy1CR1ZfWDhQclRuckNjNmJZeU1Yd0I1b1RhcXVKbjl6VWhBNkdLYUZ2c2NBc0R6dzVsMzhOcjFfUG5sa01kMjVGc0hhRThLdXBYTWhJZHln?oc=5)

_Auto-extracted nightly from the latest official statement; verify with USDA APHIS._ Fact page: https://stovall.report/facts/screwworm-us-detections/2026-09-29 · API: https://stovall.report/api/v1/screwworm/status

## Today's update (Wednesday, October 21, 2026)

**Screwworm Watch daily check**

U.S. detections: 52 confirmed as of September 29, 2026. Up 3 since September 15, 2026. 0 new reports in the last 48 hours.

The sections below are the hand-verified dossier as of August 22, 2026. Where its figures differ from the automated figure above, the automated figure is newer but less verified.

## Hand-verified status (dossier of August 22, 2026)

### U.S. status: 45 detections; 5 active, all in Texas

The first U.S. detection since the 1982 eradication was confirmed on June 3, 2026 in a calf in Zavala County, Texas. Since then USDA APHIS has logged 45 confirmed U.S. detections — 44 in Texas and one dog in Lea County, New Mexico. As of August 2026, only five cases remain active, all in Texas: Terrell, Sutton, Starr, and Brewster (two) counties.

As of Aug 2026 · Source: [USDA APHIS — Current Status of New World Screwworm](https://www.aphis.usda.gov/animals/animal-health/livestock-and-poultry-disease/current-status)

### Where it's been found: 23 TX counties under movement controls

Movement restrictions now cover parts of 23 Texas counties, from the Rio Grande Valley through West Texas and the Hill Country. The five currently active cases are in Terrell, Sutton, Starr, and Brewster (two) counties. The only U.S. detection outside Texas remains a dog in Lea County, New Mexico. This follows the parasite's northward spread from Central America and Mexico through 2024–2025.

As of Aug 2026 · Source: [Medical Daily — Texas Adds a New Screwworm Zone in Terrell County as Active U.S. Cases Fall to Five (Aug 2026)](https://www.medicaldaily.com/screwworm-terrell-county-infested-zone-45-detections-august-2026-477052)

### Federal response: Emergency response active

USDA APHIS activated an emergency response and expanded its sterile insect technique (SIT) barrier to slow and push back the parasite's northward spread.

As of 2025–2026 · Source: [USDA APHIS — New World screwworm](https://www.aphis.usda.gov/livestock-poultry-disease/screwworm)

### Highest-risk state: Texas

Texas is considered the highest-risk U.S. state because of its long border with Mexico and its large livestock population.

As of 2026 · Source: [Texas Animal Health Commission](https://www.tahc.texas.gov)

### Texas response: Multiple infested zones + movement controls

TAHC first designated "Infested Zone 01" across Zavala and Uvalde counties after the June 2026 detections. As the footprint spread, additional infested zones were added — most recently in Terrell County in early August 2026, after New World screwworm was confirmed in a sheep. Warm-blooded animals cannot leave an infested zone without TAHC authorization and inspection. Gov. Greg Abbott's New World screwworm disaster proclamation remains in effect.

As of Aug 2026 · Source: [Medical Daily — Texas Adds a New Screwworm Zone in Terrell County as Active U.S. Cases Fall to Five (Aug 2026)](https://www.medicaldaily.com/screwworm-terrell-county-infested-zone-45-detections-august-2026-477052)

### Border livestock ports: Phased reopening begins Aug 24

On July 24, 2026, USDA announced a phased reopening of southern livestock ports. The Douglas, Arizona port reopens to cattle trade on August 24, 2026, with Santa Teresa and Columbus, New Mexico to follow pending a risk review. Every animal entering the U.S. is inspected for New World screwworm, and USDA says the timeline stays contingent on Mexico meeting joint action-plan milestones.

As of Aug 2026 · Source: [USDA — Phased Reopening of Southern Ports for Livestock Trade (Jul 24, 2026)](https://www.usda.gov/about-usda/news/press-releases/2026/07/24/usda-announces-phased-reopening-southern-ports-livestock-trade)

### Risk to people: Possible but rare

Screwworm primarily affects livestock and other warm-blooded animals. Human infestation (myiasis) is possible but rare, and is treatable when caught early.

As of 2026 · Source: [CDC — New World screwworm](https://www.cdc.gov)

## The sterile-fly barrier

### Panama barrier (COPEG): Permanent sterile-fly barrier

The U.S. maintains a permanent biological barrier in Panama's Darién Gap through COPEG — the Commission for the Eradication and Prevention of Screwworm, jointly run by the U.S. and Panama — releasing sterile flies to keep the parasite from moving north.

As of 2026 · Source: [USDA APHIS — New World screwworm](https://www.aphis.usda.gov/livestock-poultry-disease/screwworm)

### Sterile insect technique: Barrier expanded

In response to the 2024–2025 northward spread, USDA expanded its SIT operations, releasing lab-raised, sterilized male flies further north to reinforce the barrier.

As of 2025–2026 · Source: [USDA APHIS — New World screwworm](https://www.aphis.usda.gov/livestock-poultry-disease/screwworm)

### How SIT works: Sterile males, no offspring

Sterile males are released in overwhelming numbers. Because females typically mate once, matings with sterile males produce no larvae — sustained releases drive the wild population down and eventually out.

As of — · Source: [USDA APHIS — New World screwworm](https://www.aphis.usda.gov/livestock-poultry-disease/screwworm)

## What is New World screwworm?

The New World screwworm (Cochliomyia hominivorax) is a parasitic fly whose larvae (maggots) feed on the living tissue of warm-blooded animals. Female flies lay eggs at the edge of a wound or a natural body opening; the hatching larvae burrow into living flesh, creating a wound that grows progressively larger and draws still more flies. It affects all warm-blooded animals — cattle, horses, sheep, goats, deer, dogs, and, rarely, people. The United States eradicated it decades ago, which is why any renewed threat is treated as a serious event.

**Why it matters:** Texas runs the largest cattle herd in the country, and screwworm threatens cattle, sheep, goats, horses, wildlife such as deer, and household pets. For ranchers it can mean sick animals, costly treatment, and movement restrictions on livestock; for pet owners it means any open wound on an outdoor animal needs closer attention if the parasite reaches the U.S. Early detection and prompt reporting are what keep a few cases from becoming a regional infestation.

## How to identify an infestation

- **A wound that grows instead of healing.** An enlarging wound that gets worse over time rather than healing the way an ordinary cut would — a hallmark of screwworm infestation.
- **Foul-smelling wounds with larvae.** Infested wounds give off a distinctive foul odor and contain visible maggots feeding in the living tissue.
- **Maggots burrowed into living flesh.** Screwworm larvae burrow head-down into living tissue and are often partly buried, with spiny bands around the body. Look in and around wounds.
- **Eggs or larvae around body openings.** Check the nose, ears, eyes, and genitalia — and especially the navel of newborn animals, a common site of infestation.

## What to do if you suspect a case

1. If you see a wound with maggots — especially a foul-smelling wound that is getting larger instead of healing — treat it as a possible screwworm case and act immediately.
2. Call your local veterinarian, the Texas Animal Health Commission (1-800-550-8242), or the USDA Screwworm Hotline (1-800-USDA-SOS / 1-800-872-7367).
3. If directed, collect 10 or more larvae from the wound and place them in rubbing alcohol (isopropyl) to preserve them for identification.
4. Do not move the animal off your property until you have guidance — movement of animals out of an affected area may be restricted.
5. If you think a person may be infested, seek medical care right away.

### Who to call

- **USDA Screwworm Hotline** — Phone: 1-800-USDA-SOS (1-800-872-7367) ([USDA APHIS — New World screwworm](https://www.aphis.usda.gov/livestock-poultry-disease/screwworm))
- **Texas Animal Health Commission** — Phone: 1-800-550-8242 ([Texas Animal Health Commission](https://www.tahc.texas.gov))
- **Your local veterinarian** — First call: Evaluates the animal and reports on your behalf

## Recent developments

- **Late 2024 — Screwworm detected in Mexico near the U.S. border.** New World screwworm was detected in Mexico near the U.S. border, raising concern about a northward spread of a parasite the U.S. eradicated in 1982. ([USDA APHIS — New World screwworm](https://www.aphis.usda.gov/livestock-poultry-disease/screwworm))
- **2024–2025 — Cases confirmed in southern Mexico and Central America.** Confirmed cases across southern Mexico and Central America underscored that the parasite was moving north toward established livestock regions. ([USDA APHIS — New World screwworm](https://www.aphis.usda.gov/livestock-poultry-disease/screwworm))
- **2025 — USDA APHIS activates emergency response and expands the sterile-fly barrier.** USDA APHIS activated an emergency response and expanded the sterile insect technique barrier — the same approach that eradicated screwworm from the U.S. decades ago. ([USDA APHIS — New World screwworm](https://www.aphis.usda.gov/livestock-poultry-disease/screwworm))
- **Jun 2026 — Texas Gov. Abbott issues a screwworm disaster proclamation.** Gov. Greg Abbott issued a New World screwworm disaster proclamation, directing state agencies to prepare and respond as the highest-risk U.S. state. ([Office of the Texas Governor — NWS disaster proclamation (Jun 2026)](https://gov.texas.gov/news/post/governor-abbott-issues-new-world-screwworm-disaster-proclamation-in-june-2026))
- **Jun 3, 2026 — FIRST U.S. case since 1982 — confirmed in Zavala County, Texas.** USDA APHIS confirmed New World screwworm in a three-week-old calf with an umbilical-area infestation near La Pryor, Zavala County, TX — verified by the National Veterinary Services Laboratories in Ames, Iowa. It is the first U.S. detection since the 1982 eradication. TAHC issued an Executive Director Order restricting animal movement in Zavala and Uvalde counties the same day. ([USDA APHIS — Confirms presence of NWS in the United States (Jun 3, 2026)](https://www.aphis.usda.gov/news/agency-announcements/usda-confirms-presence-new-world-screwworm-united-states))
- **Jun 4, 2026 — Sterile-fly dispersal and containment begin around the detection zone.** Animal-health officials began targeted sterile-fly releases and stood up "Infested Zone 01" (Zavala & Uvalde counties), expediting the sterile insect technique alongside enhanced surveillance and movement restrictions to eliminate any reproducing population. ([Texas Animal Health Commission — New World Screwworm response](https://www.tahc.texas.gov/emergency/nws.html))
- **Jun 5, 2026 — Second Texas case confirmed in the same county.** USDA APHIS confirmed a second detection — a roughly one-month-old calf about 5.6 miles from the first case, inside the existing infested zone. TAHC issued a Modified Executive Director Order tightening movement controls; Gov. Abbott expanded the state disaster declaration. ([USDA APHIS — Officials respond to second NWS detection (Jun 5, 2026)](https://www.aphis.usda.gov/news/agency-announcements/animal-health-officials-respond-second-detection-new-world-screwworm))
- **Jun 8, 2026 — Cases spread to four Texas counties and a New Mexico dog.** USDA APHIS confirmed three more detections, bringing the U.S. total to five: a calf in La Salle County and a goat in Gillespie County, Texas, plus a dog in Lea County, New Mexico — the first U.S. case outside Texas. Mexico halted most U.S. animal imports, including pet dogs, in response. ([USDA APHIS — First NWS case in a New Mexico dog (Lea County) & fourth Texas case (Jun 8, 2026)](https://www.aphis.usda.gov/news/agency-announcements/usda-confirms-first-case-new-world-screwworm-dog-lea-county-new-mexico))
- **Jul 15, 2026 — FDA authorizes a drug for short-term screwworm prevention in horses.** The FDA issued an Emergency Use Authorization for an ivermectin oral solution for the short-term prevention of New World screwworm infestation in horses, administered at the time of initial wound care. It is part of a widening set of federal countermeasures as detections continue in Texas. ([FDA — Issues Emergency Use Authorization for Drug for Short-Term Prevention of New World Screwworm in Horses (Jul 2026)](https://www.fda.gov/news-events/press-announcements/fda-issues-emergency-use-authorization-drug-short-term-prevention-new-world-screwworm-horses))
- **Jul 24, 2026 — USDA announces a phased reopening of southern livestock ports.** USDA announced that the Douglas, Arizona port would reopen to cattle trade on August 24, 2026 — the first step in a phased reopening of southern livestock ports closed during the screwworm response, with Santa Teresa and Columbus, New Mexico to follow pending a risk review. Every animal is inspected for New World screwworm on entry, and the timeline stays contingent on Mexico meeting joint action-plan milestones. ([USDA — Phased Reopening of Southern Ports for Livestock Trade (Jul 24, 2026)](https://www.usda.gov/about-usda/news/press-releases/2026/07/24/usda-announces-phased-reopening-southern-ports-livestock-trade))
- **Jul 29, 2026 — USDA commits $25M to a new Arizona sterile-fly dispersal facility.** Agriculture Secretary Brooke Rollins announced a $25 million commitment for a new sterile-fly dispersal facility in Douglas, Arizona during a visit to the Douglas port of entry. It would be only the second such facility in the U.S. (the other is in southern Texas) and would strengthen response capacity along the Southwest border as the Douglas port prepares to reopen to cattle trade on August 24. ([USDA — Announces $25 Million Commitment for New Arizona Sterile Fly Dispersal Facility (Jul 29, 2026)](https://www.usda.gov/about-usda/news/press-releases/2026/07/29/usda-announces-25-million-commitment-new-arizona-sterile-fly-dispersal-facility-secretary-rollins))
- **Aug 2026 — New infested zone in Terrell County as active U.S. cases fall to five.** Texas designated a new infested zone in Terrell County after New World screwworm was confirmed in a sheep, tightening movement controls there. Since June, U.S. detections have totaled 45, with only five still active — all in Texas (Terrell, Sutton, Starr, and Brewster). Movement restrictions now touch parts of 23 Texas counties. ([Medical Daily — Texas Adds a New Screwworm Zone in Terrell County as Active U.S. Cases Fall to Five (Aug 2026)](https://www.medicaldaily.com/screwworm-terrell-county-infested-zone-45-detections-august-2026-477052))

## Modern New World Screwworm Eradication Plan

_Using historical TTPs, updated for 2026 conditions. Opinion and analysis by The Stovall Report; not an official USDA plan._ Full page: https://stovall.report/screwworm/plan

### Strategic intent

The goal should not be "control screwworm in Texas." The goal should be: Re-establish New World screwworm freedom in the United States and Mexico, push the eradication front south through Central America, and restore the Panama/Darien barrier as the permanent continental shield.

That is the lesson from the original eradication campaign. The U.S. was not made permanently safe by treating ranches one by one; it became safe after sterile-insect release, surveillance, quarantine, and international eradication moved the population front southward and established a maintained barrier.

### 1. Operating Assumptions

Current Situation:
As of early June 2026, New World screwworm has reached Texas again. USDA's current-status page tracks U.S. detections, Mexico cases, movement restrictions, and response actions. The current response includes sterile-fly dispersal, border controls, movement restrictions, public reporting, and expanded production/dispersal infrastructure. USDA has invested in Moore Air Base in Texas as a domestic sterile-fly dispersal site.

Historical Lesson:
The historical eradication program worked because it combined:
1. Sterile insect technique, released continuously and at scale
2. Rapid case detection through rancher reports and larval identification
3. Animal movement controls and inspection lines
4. Wound prevention and wound treatment
5. Aerial release logistics using grids, swaths, and release-density planning
6. International rollback from the U.S. southward through Mexico and Central America
7. A permanent biological barrier in Panama/Darien

### 2. Mission Objectives

Objective 1 — Stop establishment in the United States
Prevent the Texas detections from becoming a self-sustaining U.S. population.

Objective 2 — Suppress northern Mexico and the U.S.–Mexico border zone
The U.S. border cannot function as the final barrier if the fly is abundant just south of it.

Objective 3 — Expand sterile-fly production and release capacity
SIT only works when sterile males greatly outnumber fertile wild males. Production capacity is the strategic center of gravity.

Objective 4 — Push the eradication front south
Once northern Mexico is stabilized, operations should move south in stages until the Panama/Darien barrier is restored.

Objective 5 — Build permanent readiness
After eradication, do not dismantle all capacity. Maintain production, surveillance, contracts, and contingency plans.

### 3. Command Structure

Create a Unified Screwworm Eradication Command — a formal joint command, not an informal coordination group.

Core participants:
• USDA APHIS
• Texas Animal Health Commission
• State animal-health agencies in border and livestock-heavy states
• Mexico SENASICA
• COPEG / Panama-U.S. screwworm commission
• FAO / IAEA technical advisers
• U.S. Fish and Wildlife Service
• Texas Parks and Wildlife Department
• U.S. Customs and Border Protection
• State veterinary diagnostic labs
• Land-grant university extension services
• Cattle, sheep, goat, horse, wildlife-ranching, dairy, and pet-industry representatives

### 4. Geographic Concept of Operations

Zone 1 — Infested Zone (area around confirmed cases):
• Mandatory reporting of suspect wounds
• Veterinary inspection of livestock and high-risk domestic animals
• Immediate wound treatment
• Ban or permit-only movement of susceptible animals
• Larval sample submission before disposal
• High-density sterile-fly release
• Adult suppression around high-risk locations
• Trap deployment
• Daily situation reporting

Zone 2 — Surveillance Zone (buffer around infested zone):
• Market, sale barn, feedlot, dairy, ranch, veterinary clinic, wildlife facility, and border-corridor surveillance
• Sampling kits distributed to producers
• Weekly trap review
• Targeted sterile-fly release if trap or case data show risk
• Movement certification for animals leaving the zone

Zone 3 — Sterile-Fly Barrier Zone (broad band along invasion front):
• Continuous aerial sterile-fly dispersal
• Release density adjusted by season, case data, trap data, animal density, wind, and terrain
• Buffer releases on both sides of the border
• Rapid surge when cases move north

Zone 4 — Rollback Zone (areas farther south):
• Sequential suppression
• Intensive SIT
• Local movement controls
• Producer education
• Field diagnostics
• Transition from emergency response to verification of freedom

### 5. Sterile Insect Technique Plan

Core Principle: Treat sterile flies like ammunition. Production, quality, storage, transport, and release must be managed as an integrated supply chain.

Production Targets:
• Minimum North American capacity: 500 million sterile flies per week (floor, not ceiling)
• Surge capacity goal: 750 million to 1 billion per week during continental emergency

Production Facilities:
Immediate: Maximize Panama output, accelerate Mexico Metapa renovation, use Moore Air Base for Texas/northern Mexico, contract aircraft and ground-release crews.
Medium term: Bring Texas production online, establish modular backup insectaries, stockpile critical inputs, maintain redundant irradiation.
Long term: Maintain standby domestic production, keep at least one fully operational U.S. dispersal hub, keep Mexico and Panama facilities funded.

### 6. Sterile-Fly Release Tactics

Aerial Release (default for broad coverage):
• Grid-based dispersal
• Release density adjusted by risk
• Denser release around confirmed cases
• Wider release barrier along movement corridors
• Repeated release cycles, not one-time drops

Ground Release for: ranch clusters, livestock markets, sale barns, dairies, feedlots, veterinary hospitals, border inspection stations, wildlife rehabilitation facilities, urban/peri-urban pet clusters.

Release Density determined by: confirmed cases, trap counts, larval submissions, temperature/humidity, rainfall, wind, livestock density, wildlife density, animal movement data, terrain, proximity to source zones.

Quality Control — every batch monitored for: emergence rate, flight ability, longevity, mating competitiveness, sterility, sex ratio, release survival, dye/marking performance, geographic release accuracy.

### 7. Surveillance Plan

Channel 1 — Producer Reporting:
Every livestock owner receives: larval collection vials, wound-inspection instructions, QR-code reporting links, hotline numbers, prepaid sample mailers, approved wound-treatment guidance, movement-restriction explanations.

Channel 2 — Veterinary Reporting:
Required for: cattle, sheep, goats, horses, dogs, cats, exotic hoofstock, wildlife ranch animals, zoo animals, wildlife rehabilitation cases.

Channel 3 — Trap Network:
Deploy at: confirmed-case ranches, neighboring ranches, sale barns, feedlots, dairies, slaughter facilities, livestock-event grounds, border crossings, quarantine stations, river corridors, wildlife migration corridors, high-density deer areas, illegal dumping/offal sites.

Channel 4 — Wildlife Surveillance:
Priority: white-tailed deer, exotic deer, feral hogs, coyotes, wildlife ranches, hunting preserves, wildlife rehabilitation centers, roadkill clusters, areas with high tick burden.

Channel 5 — Human and Pet Surveillance:
Public-health and veterinary channels should be linked for travel-associated cases, pets, and wound myiasis.

### 8. Movement-Control Plan

Animals covered: cattle, sheep, goats, horses, swine, dogs, cats, camelids, exotic hoofstock, zoo animals, wildlife rehabilitation animals, captive deer and game animals.

From Infested Zones:
• No movement without inspection
• Wounds must be treated
• Suspect wounds require sample submission
• Infested animals require treatment and hold period
• Movement certificates required
• Destination notification required

From Surveillance Zones:
• Inspection before movement
• Wound-free certification
• Record retention
• Event-specific requirements for rodeos, fairs, shows, auctions

Border Controls:
• Suspend or restrict live-animal imports from affected regions
• Require inspection and certification
• Target illegal animal movement and smuggling
• Use detector dogs where feasible
• Maintain livestock port protocols tied to current risk

### 9. Wound-Prevention and Herd-Management Plan

The fly needs wounds. Reducing wounds reduces reproduction.

Postpone in high-risk zones: castration, dehorning, branding, ear tagging if avoidable, elective surgery, shearing when injury risk is high, invasive wildlife handling.

Required practices:
• Inspect newborn navels daily
• Treat wounds immediately
• Control ticks and biting flies
• Separate animals with suspicious wounds
• Use veterinary-approved larvicidal/wound treatments
• Document wound cases
• Submit larvae before destroying evidence

Producer Incentives — reimburse: veterinary farm calls, sample submission costs, quarantine losses, additional labor for inspection, wound-treatment supplies, losses from movement restrictions.

A reporting system that punishes the first rancher who reports will fail. A system that pays for early reporting will work.

### 10. Adult Suppression Plan

Use adult suppression selectively around: confirmed premises, neighboring premises, livestock concentration points, sale barns, feedlots, dairies, slaughter-adjacent areas, offal/disposal sites, high-risk wildlife corridors, border choke points.

Do not overuse broad insecticide campaigns — they create environmental, political, resistance, and non-target risks. Purpose is to support SIT, not replace it.

Modern SWASS-style program includes: attractant-baited stations, trap-and-kill units, adulticidal bait deployment, monitoring of non-target effects, GIS tracking, strict label/legal compliance, removal after suppression objective is met.

### 11. Data and Intelligence Plan

Create a Screwworm Common Operating Picture — all partners see the same map.

Data Layers: confirmed cases, suspect cases, negative submissions, trap results, sterile-fly release polygons, release density, wind/weather, livestock density, wildlife density, animal movement permits, markets/sale barns, vet clinics, feedlots/dairies, border crossings, quarantine zones, lab turnaround times.

Analytics — predict: fly dispersal, livestock movement spread, weather-favored reproduction, insufficient sterile-fly density, weak trap coverage, anomalously low reporting.

Key Metrics: days from wound detection to report, days from report to lab confirmation, days from confirmation to sterile-fly surge, larval submissions, percent negative submissions, trap-positive rate, wild-to-sterile ratio, new premises per week, distance of newest case from previous front, release density by zone, movement violations, producer reimbursement speed.

### 12. Public Communication Plan

Messaging Principles: Be direct. Avoid panic. Tell people exactly what to look for. Make reporting easy. Emphasize pets and wildlife, not just cattle.

Ranchers: "Inspect wounds and navels. Treat wounds. Save larvae. Report immediately. You will not be punished for early reporting."

Veterinarians: "Report suspicious myiasis immediately. Submit samples. Treat aggressively. Document animal movement."

Hunters and Wildlife Managers: "Report animals with foul-smelling wounds, visible larvae, abnormal behavior, or head/ear/genital/navel lesions."

Pet Owners: "Check wounds, ears, noses, and surgical sites. Seek veterinary care if larvae are present."

Local Officials: "Support movement controls, carcass disposal, public reporting, and producer assistance."

### 13. Research and Modernization Priorities

1. Better Sterile Strains: higher mating competitiveness, better flight performance, longer field survival, genetic sexing strains, gene-editing approaches if safe/legal/accepted.

2. Better Lures and Traps: more sensitive adult detection, species-specific attractants, low-maintenance field traps, automated image recognition, eDNA or environmental surveillance.

3. Faster Diagnostics: field PCR, mobile lab confirmation, image-assisted larval ID, veterinary clinic sample kits.

4. Better Release Systems: drone release for small areas, precision aircraft release, GPS/telemetry verification, automated temperature tracking.

5. Better Wound Therapeutics: approved larvicides, long-acting wound protectants, producer-safe treatment protocols, wildlife-compatible delivery.

### 14. Phased Eradication Campaign

Phase 0 — Immediate Containment (Days 0–30):
1. Activate Unified Command
2. Define infested/surveillance/buffer zones
3. Restrict animal movement from infested zones
4. Surge sterile-fly release around detections
5. Deploy traps and mobile response teams
6. Distribute sample kits
7. Create producer reimbursement mechanism
8. Inspect livestock markets, feedlots, dairies, events, border corridors
9. Begin daily GIS reporting
10. Launch public education campaign
Success: No unlinked cases outside surveillance zone, reporting increases, lab confirmation <48h, releases verified, movement compliance >95%.

Phase 1 — Border Stabilization (Months 1–6):
1. Expand sterile-fly release polygons along border
2. Coordinate U.S.–Mexico surveillance data
3. Enforce permitted livestock movement
4. Deploy adult suppression around clusters
5. Increase trap density
6. Expand wildlife surveillance
7. Pre-position emergency fly shipments
8. Producer outreach in English and Spanish
9. Contract additional aircraft/pilots
10. Independent review of sterile-fly quality
Success: Cases decline weekly, no sustained US trap positives, wild-to-sterile ratio favors sterile, Mexican northern front declines, no movement-related jumps.

Phase 2 — Mexico Rollback (Months 6–36):
1. Divide Mexico into eradication blocks
2. Pair sterile release with movement controls
3. Maintain barrier behind the front
4. Use SWASS ahead of releases
5. Certify zones after surveillance proves freedom
6. Keep border releases active until northern Mexico stable
7. Increase public-private cost sharing
8. Use mobile labs in outbreak regions
9. Integrate wildlife/free-ranging livestock surveillance
10. After-action reviews every 90 days
Success: Case front moves south, northern Mexico maintains freedom, border release demand declines, reinfestations detected/extinguished quickly.

Phase 3 — Central America Rollback (Years 2–7):
1. Support COPEG and national vet services
2. Maintain high-output sterile-fly production
3. Staged eradication blocks
4. Support small producers
5. Strengthen movement controls
6. Control illegal livestock movement
7. Maintain permanent sterile barrier at Panama/Darien
8. Build local diagnostic/surveillance capacity
Success: Panama barrier restored, Central America north of barrier free, routine surveillance replaces emergency response, permanent funding established.

Phase 4 — Permanent Prevention (Year 7+):
1. Keep U.S. sterile-fly production/dispersal capability
2. Maintain Panama barrier releases
3. Fund Mexico/CA surveillance
4. Keep emergency aircraft contracts
5. Maintain trained response teams
6. Annual exercises
7. Keep producer reporting kits updated
8. Maintain lab proficiency
9. Preserve legal authorities for rapid movement control
10. Maintain public-facing reporting tools

### 15. Equipment and Capability List

Production: insectaries, larval rearing systems, diet production, environmental controls, irradiation equipment, quality-control labs, emergence rooms, sterile-fly marking/dye systems, packaging lines, backup power, redundant water/HVAC.

Distribution: refrigerated trucks, aircraft loading facilities, fly release boxes/automated release machines, GPS-tracked aircraft, ground-release vehicles, temporary forward operating bases, cold-chain monitoring.

Surveillance: larval sample kits, adult traps, bait/lure supplies, mobile diagnostic labs, microscopes/molecular diagnostic tools, sample chain-of-custody system, GIS platform, mobile reporting app, hotline/call center.

Field Response: PPE, wound-treatment supplies, animal-handling equipment, portable corrals/chutes, veterinary medications, approved larvicides, carcass/offal disposal equipment, biosecurity supplies, signage/checkpoint supplies.

Enforcement/Logistics: movement permits, inspection stations, detector-dog teams, livestock transport tracking, law-enforcement liaison, bilingual field teams, reimbursement/payment system.

### 16. Budget Architecture

Bucket 1 — Emergency Containment: response teams, aircraft, sterile-fly dispersal, traps, mobile labs, producer reimbursement, quarantine enforcement.

Bucket 2 — Production Capacity: Moore Air Base production, Metapa expansion, Panama support, modular backup facilities, irradiation redundancy.

Bucket 3 — Mexico and Central America Rollback: bilateral field operations, movement-control support, surveillance, producer education, mobile labs, regional sterile-fly distribution.

Bucket 4 — Innovation: better lures, better traps, genetic sexing, improved sterile strains, precision release technology, diagnostics, therapeutics.

Bucket 5 — Permanent Prevention: Panama/Darien barrier, standby U.S. capacity, annual exercises, surveillance maintenance, staff training.

### 17. Decision Points

Decision Point A — Is the U.S. outbreak contained?
Criteria: no new cases outside known zone for two fly generations, traps show no wild-fly expansion, all suspect premises investigated, movement tracing complete, sterile release verified.
If yes: continue barrier release and surveillance.
If no: expand infested zone, increase release density, tighten movement restrictions.

Decision Point B — Is northern Mexico suppressed?
Criteria: declining cases, low wild-fly trap counts, effective movement controls, release density adequate, no repeated border-adjacent detections.
If yes: begin rollback south.
If no: increase sterile-fly capacity and adult suppression.

Decision Point C — Is sterile-fly capacity adequate?
Criteria: release plan fully supplied, reserve capacity available, no skipped release cycles, quality metrics acceptable.
If no: prioritize production over almost every other expenditure.

### 18. Practical Recommendations for Immediate Adoption

Federal Level:
1. Declare a multi-year eradication campaign, not a temporary emergency response
2. Fully fund Texas, Mexico, and Panama production/dispersal capacity
3. Set a public sterile-fly production target
4. Build a national screwworm GIS dashboard
5. Create a producer indemnity/reimbursement program
6. Expand border and wildlife surveillance
7. Establish a standing scientific advisory panel
8. Fund Mexico/CA operations as U.S. prevention infrastructure

State Level:
1. Activate state animal-health emergency authorities
2. Restrict animal movement from infested zones
3. Coordinate sale barn and event inspections
4. Train veterinarians and extension agents
5. Push reporting kits to producers
6. Integrate wildlife agencies
7. Reimburse compliance costs quickly

Producer Level:
1. Inspect animals daily in high-risk zones
2. Treat wounds immediately
3. Watch newborn navels
4. Save larvae for identification
5. Report suspicious wounds
6. Delay elective wound-causing procedures
7. Control ticks and biting flies
8. Follow movement restrictions

Veterinary Level:
1. Treat suspect cases immediately
2. Submit larvae
3. Report cases
4. Educate clients
5. Document animal movement
6. Help verify wound-free movement status

### 19. The Single Most Important Principle

Do not let the wild population outrun sterile-fly capacity.

Everything else supports that principle. Reporting, trapping, movement control, wound prevention, adult suppression, aircraft logistics, production plants, border coordination, and international rollback all exist to keep the sterile-to-wild ratio high enough for SIT to collapse the population.

The historical program proved the method works. The modern challenge is whether we can rebuild the scale, speed, discipline, and international coordination fast enough.

## Resources

- [USDA APHIS — New World screwworm](https://www.aphis.usda.gov/livestock-poultry-disease/screwworm)
- [USDA APHIS — Current Status of New World Screwworm](https://www.aphis.usda.gov/animals/animal-health/livestock-and-poultry-disease/current-status)
- [USDA APHIS — Confirmed Detections of New World Screwworm](https://www.aphis.usda.gov/animals/animal-health/livestock-and-poultry-disease/current-status/us-confirmed-cases-new-world)
- [USDA APHIS — Confirms presence of NWS in the United States (Jun 3, 2026)](https://www.aphis.usda.gov/news/agency-announcements/usda-confirms-presence-new-world-screwworm-united-states)
- [USDA APHIS — Officials respond to second NWS detection (Jun 5, 2026)](https://www.aphis.usda.gov/news/agency-announcements/animal-health-officials-respond-second-detection-new-world-screwworm)
- [USDA APHIS — First NWS case in a New Mexico dog (Lea County) & fourth Texas case (Jun 8, 2026)](https://www.aphis.usda.gov/news/agency-announcements/usda-confirms-first-case-new-world-screwworm-dog-lea-county-new-mexico)
- [USDA — Phased Reopening of Southern Ports for Livestock Trade (Jul 24, 2026)](https://www.usda.gov/about-usda/news/press-releases/2026/07/24/usda-announces-phased-reopening-southern-ports-livestock-trade)
- [Medical Daily — Texas Adds a New Screwworm Zone in Terrell County as Active U.S. Cases Fall to Five (Aug 2026)](https://www.medicaldaily.com/screwworm-terrell-county-infested-zone-45-detections-august-2026-477052)
- [FDA — Issues Emergency Use Authorization for Drug for Short-Term Prevention of New World Screwworm in Horses (Jul 2026)](https://www.fda.gov/news-events/press-announcements/fda-issues-emergency-use-authorization-drug-short-term-prevention-new-world-screwworm-horses)
- [USDA — Announces $25 Million Commitment for New Arizona Sterile Fly Dispersal Facility (Jul 29, 2026)](https://www.usda.gov/about-usda/news/press-releases/2026/07/29/usda-announces-25-million-commitment-new-arizona-sterile-fly-dispersal-facility-secretary-rollins)
- [Texas Animal Health Commission — New World Screwworm response](https://www.tahc.texas.gov/emergency/nws.html)
- [Office of the Texas Governor — NWS disaster proclamation (Jun 2026)](https://gov.texas.gov/news/post/governor-abbott-issues-new-world-screwworm-disaster-proclamation-in-june-2026)
- [Texas Parks & Wildlife — NWS confirmed in Zavala County calf (Jun 3, 2026)](https://tpwd.texas.gov/newsmedia/releases/?req=20260603c)
- [Texas Animal Health Commission](https://www.tahc.texas.gov)
- [Texas A&M AgriLife Extension](https://agrilifeextension.tamu.edu)
- [CDC — New World screwworm (people)](https://www.cdc.gov)

## Links

- Dashboard: https://stovall.report/screwworm
- National detection total (citable fact page): https://stovall.report/facts/screwworm-us-detections
- Plan of action: https://stovall.report/screwworm/plan
- Methodology and data sources: https://stovall.report/screwworm/methodology
- JSON status: https://stovall.report/api/v1/screwworm/status
- JSON history: https://stovall.report/api/v1/screwworm/history