Weekly New World Screwworm Status Update_2026-June-15

Between June 8 and June 15, 2026, the U.S. situation has expanded materially. On June 8, the working count was approximately 5 confirmed U.S. animal cases: Texas calves/goat plus the reclassified New Mexico dog. Since then, official Texas/USDA sources show additional detections in La Salle, Zavala, Edwards, Tom Green, and Sutton counties, and Texas now reports 6 Texas counties with cases and 10 Texas premises with cases. A June 15 media summary citing the USDA detection dashboard reports 12 total U.S. confirmed cases: 11 in Texas and 1 in New Mexico, but because the APHIS dashboard itself is dynamic and not fully visible in the static page text, I would treat the official TAHC county/premises counts as the most defensible written count and the 12-case count as a dashboard/media-reported current count requiring dashboard confirmation before publication. (Texas Animal Health Commission)

There are still no confirmed locally acquired human infestations reported in the United States on CDC’s situation page. CDC continues to note one prior travel-associated human case in a person returning after travel to El Salvador. (CDC)

Newly confirmed U.S. animal cases since June 8

Confirmed / official written records

Current U.S. working count

The strongest official written source available in this search is TAHC, which says: 6 Texas counties with cases and 10 Texas premises with cases. It also lists quarantine/infested-zone counties including Coke, Edwards, Gillespie, Kerr, Kimble, La Salle, Schleicher, Sutton, Tom Green, Uvalde, Val Verde, Webb, and Zavala, though not all of those counties necessarily have confirmed cases; some are included because they fall within infested or surveillance zones. (Texas Animal Health Commission)

For a blog update, I would write: “As of June 15, official Texas records identify cases in six Texas counties and ten Texas premises; media reports citing USDA’s dynamic dashboard describe 12 total U.S. cases, including 11 in Texas and one in New Mexico. The dashboard count should be checked directly before final publication.” That wording is cautious and defensible.

Human cases in the United States

CDC’s current situation page still says no locally acquired human infestations have been reported in the United States. CDC also says one case was confirmed in August 2025 in a person who returned to the U.S. after travel to El Salvador. (CDC)

So for U.S. human status:

Mexico status and trend

USDA’s current-status page says Mexico case maps/lists for detections within 400 miles are updated Tuesdays and Thursdays at 5 p.m. ET, and cases within 100 miles are added each business day. USDA also says isolated detections outside known affected areas in Mexico are “not unexpected” and that rapid identification and response are evidence that the U.S.–Mexico NWS Action Plan is functioning. (APHIS)

The trend remains northward pressure with active containment, not stabilization. CDC states the outbreak that began in Panama and Costa Rica in 2023 has moved northward through Central America and Mexico. (CDC) SENASICA’s alert system reported on June 9 that Mexico temporarily suspended imports of live animals from the U.S. to preserve the zoosanitary status of Baja California, Baja California Sur, Chihuahua, Sinaloa, and Sonora, after confirmations in Texas and New Mexico. (SENASICA)

USDA says it continues to disperse 100 million sterile insects per week in Mexico and along the U.S.–Mexico border, adjusting the sterile-insect release polygon based on case locations and modeling. (APHIS)

Central America / Panama status

COPEG reports that NWS remains in the eradication phase, with positive cases in all provinces of Panama except Guna Yala, and regional cases reported in Costa Rica, Nicaragua, Honduras, Guatemala, El Salvador, Belize, and Mexico. (COPEG)

COPEG’s visible statistics are not as current as today; the page displays epidemiologic week 19, 2026, covering data through May 16, 2026. At that point, COPEG listed 488 new cases, 66,061 cumulative cases since the start of the outbreak, and 34 weekly dispersion flights, with dispersion operations noted for Tapachula and Tuxtla, Mexico. (COPEG)

A key operational detail: COPEG states that, because the outbreak spread beyond the old Panama barrier, a new biological barrier farther north became necessary, and sterile-fly dispersal in Panama was stopped starting in May 2024 to support the northward barrier strategy. (COPEG)

USDA/APHIS and state control actions

U.S. actions
USDA’s confirmed-detections page says APHIS and state partners are tracking individual animal cases by county/state, animal type/species, confirmation date, and status, and also tracking wild-fly detections by county/state and date. (APHIS)

USDA and TAHC response activities include epidemiologic investigations, case tracing, surveillance, testing, trapping, sterile-insect releases, and outreach to animal owners. (APHIS) TAHC states that federal and state partners are working jointly in infested zones on animal and fly surveillance, epidemiological investigations, and response protocols. (Texas Animal Health Commission)

Quarantine / movement controls
TAHC says a quarantine is in place for established NWS infested zones in parts of multiple Texas counties. Warm-blooded animals in an infested zone may not move out of the zone without prior TAHC authorization; animals must be inspected and treated as required, and hides, carcasses, and animal parts capable of serving as hosts require inspection/treatment before removal. (Texas Animal Health Commission)

USDA’s current-status page says all southern ports of entry are closed to livestock trade at this time. (APHIS) Mexico also suspended imports of live animals from the U.S. after U.S. detections in Texas and New Mexico. (SENASICA)

Treatment and pet-related update
FDA issued an Emergency Use Authorization on June 11, 2026 for generic nitenpyram tablets to treat NWS myiasis in dogs, puppies, cats, and kittens weighing at least two pounds and at least four weeks old. FDA says most U.S. dogs and cats remain at low risk, but risk is elevated for pets recently in areas with confirmed NWS cases. (U.S. Food and Drug Administration)

Summary of Changes since June 8

The significant changes since June 8 are:

1. U.S. case geography expanded. As of June 8, known confirmed U.S. cases were concentrated in Zavala, La Salle, Gillespie, and Lea County, NM. Since then, Texas detections have expanded to additional counties including Edwards, Tom Green, and Sutton, with TAHC reporting six Texas counties with cases. (Texas Animal Health Commission)
2. Case count increased. USDA announced on June 9 that a new La Salle County calf case brought the U.S. total to six at that time. By June 15, local reporting citing the USDA dashboard described 12 total U.S. cases, though I would verify the dashboard directly before using that number in a formal public-facing post. (APHIS)
3. Texas quarantine footprint expanded. TAHC now lists infested-zone quarantine areas across parts of 13 Texas counties, though some are zone counties rather than counties with confirmed cases. (Texas Animal Health Commission)
4. FDA added a pet-treatment tool. FDA authorized generic nitenpyram tablets for dogs/cats on June 11. (U.S. Food and Drug Administration)
5. Trade restrictions broadened. USDA southern livestock ports remain closed, and Mexico suspended importation of live animals from the U.S. to protect northern Mexican states. (APHIS)

Practical implications
For veterinarians, the immediate issue is fast recognition, proper larval collection/identification, reporting within state channels, and careful management of wounds in animals from or near infested zones. TAHC says suspected livestock cases should be reported to TAHC within 24 hours of suspicion. (Texas Animal Health Commission)

For livestock owners, daily wound surveillance is now a serious operational requirement in affected zones. TAHC advises monitoring animals for larvae/eggs, body-opening lesions, drainage, wound enlargement, and signs of secondary infection. (Texas Animal Health Commission)

For pet owners, the risk remains low nationally, but risk is higher for animals recently in affected areas or with open wounds. The new FDA nitenpyram EUA helps treatment access, but it does not replace veterinary wound care and larval removal when needed. (U.S. Food and Drug Administration)

For public health, the main message remains vigilance rather than alarm: CDC reports no locally acquired human infestations in the U.S., but clinicians should consider NWS in suspicious myiasis-like lesions, especially after exposure to affected areas. (CDC)

For entomologists, the priority is reliable species confirmation, trapping/surveillance, and careful separation of true NWS from other wound-associated flies. USDA’s dashboard explicitly tracks both animal cases and wild-fly detections, which will matter for determining whether the U.S. is seeing isolated animal infestations versus local fly activity. (APHIS)

Uncertainties and discrepancies

The biggest uncertainty is the exact current U.S. case count by individual animal, because USDA’s confirmed-detections dashboard is referenced as current but its tabular details were not fully visible in the static page text I could access. TAHC’s written page gives strong official counts for Texas counties and premises, while media reports citing the dashboard give a higher, more granular current count. (APHIS)

A second issue is terminology: “infested zone county” does not equal “county with confirmed cases.” TAHC lists quarantine zones that include neighboring or partially affected counties. Your blog map should distinguish case counties from quarantine/surveillance counties. (Texas Animal Health Commission)

A third issue is Mexico/Central America data freshness. COPEG’s visible statistics are through May 16, while USDA points to SENASICA and COPEG for current regional data but some of those data are dashboard-based or difficult to extract into static text. (COPEG)

Map generated by ChatGPT using USDA, CDC, and state agency data. For full data sources, see the associated article.