Confirmed U.S. Screwworm Case Sparks Urgent Push for Sterile Fly Capacity

On August 04, 2025, health officials confirmed the first U.S. human case of New World Screwworm (NWS) in decades. A Maryland resident who had recently returned from Guatemala was diagnosed with the flesh-eating parasite. After breaking containment in Panama in mid-2023, the pest advanced steadily through Central America and Mexico. While the Maryland case marked the first confirmed human identification in the U.S., it is along the southern border where vigilance remains highest, as ranchers, veterinarians, and agricultural communities focus on protecting the health and welfare of livestock and wildlife.

The screwworm fly’s larvae infest open wounds in livestock, wildlife, and at times people, consuming living tissue and causing swift deterioration. Without treatment, infestations can be fatal in only a few days. USDA economists estimate that an outbreak in Texas could cost nearly $2 billion. Testimony before the Texas Agriculture and Livestock Subcommittee added that when wildlife and exotic animals are factored in alongside cattle, annual losses could exceed $13 billion if the parasite becomes established across the state.

The Maryland case underscores the challenges of detecting and responding to screwworm, reinforcing why ranchers, veterinarians, and policymakers are pressing for stronger immediate defenses and longer-term safeguards.

USDA’s Two-Pronged SIT Response

On August 15, 1025, Secretary of Agriculture Brooke Rollins stood at the Texas State Capitol to announce the largest federal initiative against screwworm in U.S. history.

• Permanent capacity: A $750 million sterile fly production facility at USDA’s Moore Air Base in Edinburg, Texas, designed to produce 300 million sterile flies per week. This facility will provide the U.S. with a domestic production hub for the first time in decades and increase response capacity alongside sister facilities in Panama and Mexico.
  
• Rapid innovation: A $100 million investment fund to accelerate deployable technologies, including modular rearing units, non-radioisotopic sterilization methods, and novel traps and baits.
  

Rollins framed the decision in stark terms:

“… we must construct an additional sterile fly production facility in the United States to stop the northward advancement of this terrible pest that is threatening American cattle production… The construction of a domestic sterile fly production facility will ensure the United States continues to lead the way in combating this devastating pest.”.

The strategy balances scale with adaptability: permanent infrastructure for stability, and rapid innovation to meet threats as they unfold.

Bridging the Gap: M3 Modular Sterile Fly Units

Permanent facilities form the backbone of eradication. But construction takes time, and a single point of failure—a power outage, supply disruption, or equipment breakdown—can halt production overnight. Wayne Cockrell, representing the 148-year-old Texas & Southwestern Cattle Raisers Association and its 28,000 members, welcomed the federal commitment of $750 million for a new sterile fly facility in Texas, calling it a “landmark step.” He praised Secretary Rollins, Governor Abbott, and state agencies for elevating the issue, but cautioned that funding alone is not enough. Drawing on visits to the COPEG plant in Panama and USDA’s research station in Kerrville, he stressed that large facilities face long lead times and infrastructure vulnerabilities. During his recent testimony before the Texas House Agriculture & Livestock Committee on August 19, 2025, he recalled learning that during a power outage at COPEG, “the power went off… [for] 15 minutes, [and] killed 25 million flies.” His story underscores that resiliency is critical to success in sterile insect technique programs. Modular units can reinforce and bolster large facilities, providing backup capacity and ensuring the system does not fail when pressure is greatest. That is why USDA’s second prong, rapid innovation, is essential.

One of the most promising tools is M3 Agriculture Technologies’ Sterile Fly Rearing & Release Modules. These are portable production modules, each housed inside a climate-controlled unit. Within each module, operations can be brought online quickly. Highly mobile and self-contained, they are capable of producing sterile insects within weeks rather than the months or years needed for fixed facilities.

By situating production close to outbreak zones, these modules cut transport delays and allow rapid adjustments in output. If surveillance detects intensifying activity in a hotspot, additional modules can be moved in and production scaled up within days. When conditions shift, the units can be relocated just as quickly.

These units can output 25M per week. That output may seem modest compared to a fixed plant designed for hundreds of millions, but the advantage lies in speed and adaptability. Units can be trucked or railed to high-risk areas, activated on-site, and used to flood an outbreak zone with sterile flies in time to make a difference.

Unlike older facilities that relied on radioactive isotopes for sterilization, modular units use X-ray irradiation. This avoids dependence on scarce Cobalt-60 sources and eases regulatory and security concerns. Developed with support from the Department of Energy and Sandia National Laboratories, the system represents a shift toward safer, decentralized production.

Why Scale Requires Modularity

Even with a new plant in Edinburg, the U.S. faces structural vulnerabilities. Concentrating production in one or two sites creates bottlenecks: a mechanical failure, a severe storm, or supply chain disruption could cripple output.

Producers in Texas have raised alarms about escalating biosecurity risks. In typical years, as many as 20,000 head of cattle per week enter from Mexico, and even during restrictions, incomplete inspection coverage and gaps have been noted, particularly at some border crossings. This ongoing movement has rapidly expanded the corridor for New World screwworm introduction, intensifying biosecurity risks for Texas producers. At the same time, the Darién Gap’s once-impenetrable rainforest has seen accelerated deforestation, with illegal land clearing for ranching and new road construction documented by conservation and news agencies. These environmental changes have enabled both legal and clandestine cattle drives to bypass historic natural barriers, creating livestock highways that significantly increase NWS spread. Despite the ongoing release of more than 100 million sterile flies weekly from the Panamanian COPEG facility, experts warn that unregulated animal movements and altered landscapes now threaten to overwhelm traditional SIT-based control strategies and jeopardize national and continental eradication investments.

For ranchers, the lesson is direct: permanent facilities are essential, but they cannot stand alone. Backup systems and mobile options are needed to match the pace of an outbreak and absorb shocks when conditions change suddenly.

Innovation as a Bridge

This is where modular units become indispensable. They provide an immediate surge capacity, reinforcing eradication campaigns while permanent infrastructure scales up.

Each modular system functions as a field-ready production line, supporting localized outbreaks with sterile fly releases tailored to regional needs. When deployed near the border, they can blunt incursions. When placed deeper in the interior, they can protect valuable herds or wildlife populations from infection.

At the same time, advances in traps and baits offer complementary suppression. Improved attractants can reduce wild fly populations in parallel with sterile releases, shrinking the overall breeding base and improving SIT efficiency. Together, these tools extend the reach of sterile insect technique into areas where reliance on a single central facility would be too slow or inflexible.

A Layered Defense

The confirmed Maryland case points to a concerning future. It confirms that screwworm is no longer a distant threat but an active danger. USDA’s two-pronged plan acknowledges that America needs both scale and speed:

• Scale from permanent facilities designed to produce hundreds of millions of sterile flies each week.
• Speed from innovations such as modular rearing units and new monitoring methods, which can be fielded immediately and redeployed as outbreaks evolve.

For decades, sterile insect technique has been the proven method for eradicating screwworm. The challenge today is timing. If sterile flies are not available quickly enough, outbreaks can spread beyond containment. The Maryland case shows just how thin that window has become.

The Clock Is Already Ticking

Renewed capacity supported by federal dollars and a broad coalition of stakeholders points to an industry prepared for the difficult work ahead.

Permanent infrastructure, paired with rapid innovation, will help the U.S. and North America regain control of this pest. Just as the screwworm was eradicated in the past, it can be contained again. Despite the challenges, producers, scientists, and policymakers are moving in the same direction, committed to building the layered defense needed to safeguard livestock, wildlife, and rural communities.