What is the New World Screwworm?
The recent resurgence of the New World screwworm (NWS), Cochliomyia hominivorax, has prompted renewed regulatory action by the U.S. Department of Agriculture (USDA) and raised concerns across the livestock industry.NWS is a parasitic fly whose larvae infest open wounds and feed on the living tissue of cattle, wildlife, pets, and other warm-blooded animals, causing serious injury and economic losses. Unlike most fly larvae, which feed on dead tissue, NWS larvae feed on living tissue, making them particularly harmful to livestock and other warm-blooded animals.[1] While the United States successfully eradicated NWS in 1966 through the use of the sterile insect technique, a renewed detection in Texas in June 2026[2] has resulted in expanded surveillance, animal movement restrictions, and trade controls intended to prevent further spread.
What’s the Current Regulatory Landscape?
In response to the renewed detection of NWS, USDA's Animal and Plant Health Inspection Service (APHIS) has implemented a series of measures designed to contain the pest and protect the domestic livestock industry.
APHIS recognizes the animal health status of foreign regions when determining whether animals and animal products may be imported into the United States.As outbreaks occur, APHIS may administratively impose temporary trade restrictions on affected regions, restricting the importation of certain animals and animal products until the associated risks have been addressed.
In addition to these import restrictions, USDA has also closed all southern ports of entry to livestock trade while eradication efforts continue.[3] Together, these measures are intended to reduce the risk of introducing or spreading NWS into the domestic livestock population, but they also have practical consequences for businesses that depend on cross-border livestock movement and related agricultural commerce.
A complete list of regions the USDA recognizes as affected by NWS and any temporary trade restrictions can be found here.
Why Companies Throughout the Supply Chain Should Pay Attention
Although NWS primarily affects livestock, the federal response has implications throughout the supply chain.Processors, distributors, importers, retailers, transportation providers, and food manufacturers may face supply shortages and delayed shipments.Companies that rely on imported livestock or animal products may need to identify alternative sourcing arrangements or adjust inventory and production schedules to account for disruptions in the supply chain.
These challenges may also create legal considerations.Businesses should consider reviewing existing supplier, distribution, and importer agreements to evaluate how potential supply disruptions may affect their contractual obligations and commitments.For example, given the evolving import restrictions and animal movement regulations, companies should pay particular attention to whether these hurdles could affect their ability to meet delivery timelines, maintain supply commitments, or otherwise fulfill their contractual responsibilities.
By proactively reviewing contracts, monitoring regulatory developments, and assessing operational risks, companies can better position themselves to respond as USDA's eradication efforts continue.
How Companies Can Continue to Stay Informed
Because the federal response to NWS continues to evolve, businesses should regularly monitor updates issued by the USDA.The USDA maintains a dedicated NWS resource page that provides tools and information such as reference guides, guidance documents, and additional information regarding the USDA's response strategy, policies, and ongoing eradication efforts.[4]
Sheppard can help businesses operating throughout the livestock and agricultural supply chain incorporate these resources into their compliance and risk management programs and help assure that they remain attentive to future announcements regarding import restrictions, quarantine requirements, and other regulatory developments as conditions change.