New World Screwworm: Fact Sheet & SHIC Article 6/10/2026 & USDA NWS Website & SHIC/AASV NWS Webinar (8/4/2026)
New World Screwworm: Fact Sheet & SHIC Article 6/10/2026 & USDA NWS Website & SHIC/AASV NWS Webinar (8/4/2026)
The Swine Health Information Center, launched in 2015 with Pork Checkoff funding, protects and enhances the health of the US swine herd by minimizing the impact of emerging disease threats through preparedness, coordinated communications, global disease monitoring, analysis of swine health data, and targeted research investments.
During an August 4 webinar, the latest information on the USDA NWS Response Playbook and its impact on producers, current products available to treat animals affected by the parasitic larvae, including product categories and requirements for use, and insights regarding efforts in Texas to manage and control NWS were shared.
Presenters included: Dr. Lindsey Holmstrom, director of national preparedness and incident coordination with USDA APHIS Veterinary Services, Amber McCoig, DVM, senior veterinary medical officer with FDA’s Center for Veterinary Medicine, Dr. Eric Bohnenblust, U.S. Environmental Protection Agency, and Jeff Wiegert, PhD, Texas A&M AgriLife Extension associate professor and extension specialist.
Click here to access the webinar recording.
Read more about webinar presentations in the recap article below.
In this episode of SHIC Talk, host Barb Determan is joined by SHIC Executive Director Dr. Megan Niederwerder and guests Dr. Montse Torremorell and Mark Schwartz of the University of Minnesota to discuss a recent study investigating the development and evaluation of an electrostatic precipitator (ESP) prototype to mitigate the airborne spread of pathogens under farm conditions. The study evaluated the utility of ESP to remove airborne particles from aerosols, including PRRSV. ESP demonstrated high effectiveness, comparable to or slightly exceeding that of a MERV-16 filter, in removing airborne particles and achieving over 99% removal of PRRSV. While the analysis showed potential for ESP as a biosecurity tool, economic considerations, challenges related to scalability, adapting the design to swine farms, and maintenance protocols will require further commercial exploration.
Click here to listen to the episode.
Find more information on the ESP study here.
Preparedness—not panic—was the central message delivered during a Swine Health Information Center-sponsored webinar bringing together federal regulators, extension specialists, and animal health experts to help pork producers prepare for the potential impacts of New World screwworm. The webinar, presented in collaboration with the American Association of Swine Veterinarians on August 4, 2026, focused on response planning, regulatory pathways, available resources, and practical producer outreach. The webinar had 240 registrants with 159 individuals attending live from across 11 countries, and it is now available for on demand viewing.
Watch the webinar here.
While NWS has been detected in Texas and New Mexico, speakers emphasized that no cases have been identified in swine to date, and the pork industry has an opportunity to prepare before the parasite becomes a swine health issue. Throughout the program, presenters stressed the importance of early detection, prompt reporting, wound management, and coordinated response among producers, veterinarians, regulators, and extension personnel.
Find SHIC’s NWS fact sheet here.
New World Screwworm Response Built Around Rapid Detection and Eradication
Dr. Lindsey Holmstrom, director of national preparedness and incident coordination with USDA APHIS Veterinary Services, outlined the federal response strategy and emphasized several key facts producers should understand about NWS.
Unlike infectious diseases such as African swine fever or PRRS, NWS is a parasite rather than a virus. It does not spread directly from animal to animal, nor is it transmitted through meat, milk, or other animal products. Instead, adult flies lay eggs in wounds on warm-blooded animals, where larvae feed on living tissue.
Dr. Holmstrom noted that USDA confirmed the first US detection during the current outbreak on June 3, 2026, in a calf in Zavala County, Texas. USDA maintains a publicly available dashboard, updated daily, tracking all confirmed detections.
To support response activities, USDA developed a comprehensive New World Screwworm Response Playbook, providing a national framework that can be adapted by states while remaining flexible enough to incorporate new information and response experience as conditions evolve. The playbook focuses on eradication through surveillance, movement controls, treatment guidance, and coordinated response activities.
Among the important operational elements described by Dr. Holmstrom were:
Swine Husbandry Creates Opportunities for Vigilance
Although NWS has not been detected in pigs, Dr. Holmstrom explained that routine swine management practices can create wounds that could become sites for infestation.
Examples include tail docking, castration, ear tagging, ear notching, tattoos, post-farrowing wounds, pressure sores, tail biting, and injuries from aggressive interactions among animals.
Rather than asking producers to identify adult flies, USDA recommends focusing on frequent animal inspections and wound management. Because many fly species resemble screwworm flies—and sterile flies released during eradication efforts may also be present—identifying adult insects is not a practical surveillance strategy for producers.
Instead, producers should:
FDA Explains Regulatory Pathways for Animal Drugs
Amber McCoig, DVM, senior veterinary medical officer with FDA’s Center for Veterinary Medicine, reviewed the agency’s role in rapidly making treatment options available while protecting animal welfare and food safety.
Dr. McCoig explained that FDA is working closely with USDA APHIS, international regulators, industry, and pharmaceutical companies to facilitate product development while providing emergency access when appropriate.
She described several regulatory pathways available for NWS products, including:
One of Dr. McCoig’s most important messages concerned extra-label drug use. Only fully approved animal drugs may be used extra-label under veterinary oversight. Products available only through conditional approval or Emergency Use Authorization are not eligible for extra-label use unless specifically authorized. Likewise, products containing the same active ingredient are not automatically approved simply because another formulation has received authorization for NWS.
She also reviewed differences among product claims for treatment, prevention of myiasis, and prevention of reinfestation, noting that producers and veterinarians should carefully follow label indications because formulations, routes of administration, and intended uses are not interchangeable.
Dr. McCoig emphasized that FDA evaluates food safety for products used in food animals, establishing withdrawal times as needed to ensure pork entering the food supply remains safe. She cautioned that prolonged reliance on antiparasitic drugs alone is not a sustainable strategy because resistance has already been reported for some compounds, including ivermectin. Sterile insect release remains the cornerstone of long-term eradication.
EPA Reviews Emergency Pesticide Options
Representatives from the U.S. Environmental Protection Agency described how pesticide products may become available during emergency situations.
Dr. Eric Bohnenblust reviewed EPA’s emergency exemption process under Section 18 of the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA), which allows temporary use of otherwise unregistered pesticide applications when urgent conditions exist and no effective alternatives are available.
He explained that EPA evaluates emergency requests through a multidisciplinary scientific review, considering biological effectiveness, human health, environmental impacts, and economic consequences before authorizing emergency use. For food-producing animals, EPA must also establish appropriate residue tolerances to protect consumers.
Dr. Bohnenblust also outlined the Section 24(c) Special Local Need registration process, which allows states to authorize additional uses of federally registered pesticides when local pest management needs cannot be adequately addressed through existing labels.
Texas Experience Highlights Importance of Producer Education
Jeff Wiegert, PhD, Texas A&M AgriLife Extension associate professor and extension specialist, concluded the webinar with observations from ongoing outreach efforts in Texas. He reported that as of August 3, 2026, no NWS cases had been identified in pigs, despite confirmed cases in other livestock species.
Dr. Wiegert described Texas’ swine industry as a mix of large commercial operations concentrated in the Panhandle and thousands of smaller show pig producers across the state. These smaller operations often feature mixed-species facilities, varying biosecurity practices, open-air housing, and frequent animal movement, creating unique educational challenges.
Among the most common questions extension personnel receive are whether concrete flooring interrupts the screwworm life cycle, whether producers should search for adult flies, and whether every maggot found in a wound is New World screwworm.
His answers were straightforward: Concrete does not eliminate risk because larvae can pupate anywhere protected and warm. Producers should focus on finding larvae rather than adult flies, which are rarely observed. And not every maggot represents NWS, making proper diagnostic submission essential.
Dr. Wiegert also noted that educating producers about quarantine terminology has required substantial outreach because many producers associate quarantines with highly contagious foreign animal diseases or COVID-19 restrictions. Extension, USDA, the Texas Animal Health Commission, and allied organizations have worked together to explain how movement controls differ for NWS.
Texas A&M AgriLife has developed an extensive library of preparedness resources, including online training modules covering screwworm biology, inspection procedures, treatment, movement requirements, and enforcement. County Extension agents remain the primary local resource for producer education, specimen collection, permitting assistance, and ongoing response support.
Links Shared by Dr. Wiegert
Agrilifeextension.tamu.edu/new-world-screwworm
Preparation Before Detection
Across every presentation, one consistent message emerged: Preparedness today will determine the effectiveness of tomorrow’s response.
Federal agencies have established response plans, regulatory pathways, and treatment authorizations, while extension specialists continue educating producers and veterinarians. For pork producers, the most valuable actions remain routine wound inspection, prompt reporting of suspicious infestations, understanding movement requirements, and utilizing trusted educational resources before NWS becomes a swine health challenge.
The webinar underscored that protecting the US swine industry will require coordinated action across government, veterinary medicine, extension, and producers—but with preparation and rapid response, NWS eradication remains the goal.
The Swine Health Information Center funded the development and expansion of the Standardized Outbreak Investigation Program (SOIP) to address a critical gap in swine biosecurity. Dr. Derald Holtkamp, Iowa State University, leads the program, which offers online access, standardized resources, and reporting of outcomes for producers and their veterinarians to use in the event of a disease outbreak. While many biosecurity control measures exist, little research has focused on identifying the specific hazards and pathogen entry routes those measures are intended to prevent. Consequently, biosecurity resources are often applied inefficiently. SOIP uses disease outbreak investigations as opportunities to conduct systematic biosecurity hazard analyses, identify likely pathways of pathogen introduction, and prioritize risks that warrant intervention.
Find the entire project report for SHIC project #25-053 here.
SOIP strengthens the infrastructure needed to translate outbreak investigation findings into practical biosecurity improvements across the US swine industry. By improving data collection, training, reporting, and industry participation, SOIP provides a framework for identifying significant risks, prioritizing interventions, and improving preparedness for emerging and transboundary animal diseases. The long-term goal is to enhance herd health, productivity, and the global competitiveness of the US pork industry through more effective, evidence-based biosecurity practices.
Launched in January 2024, SOIP enables veterinarians and producers to conduct standardized outbreak investigations and securely store findings in a centralized database. By aggregating information across multiple investigations, the system allows the swine industry to identify recurring biosecurity risks and learn from collective experiences. The recently completed project’s objectives were to provide ongoing support for the SOIP platform, improve training resources, increase adoption of the application, enhance database and data extraction capabilities, and develop company- and industry-level benchmarking reports.
The SOIP web-based application and investigation database are maintained and supported by Iowa State University’s Department of Veterinary Diagnostic and Production Animal Medicine. Supported activities include user management, technical troubleshooting, software improvements, and maintenance of a dedicated support email address ([email protected]). Adoption of the platform continues to grow. As of June 1, 2026, there have been 124 investigations conducted using the SOIP web-based application.
To assist with the use and application of SOIP, training resources were developed through collaboration with SES Inc., resulting in two comprehensive training modules, including 17 videos covering both application use and outbreak investigation methodology (Table 1).
Table 1. SHIC training videos available for SOIP.
Module 1
Episode 1: The Organization of the SOIP
Episode 2: How to Add a Company Representative in the SOIP
Episode 3: Who Can Delete Sites, Users, and Companies in the SOIP
Episode 4: How to Set Up Sites and Build Site Maps in the SOIP
Episode 5: How to Delete or Edit Existing Sites in the SOIP
Episode 6: Overview of the Pre-Investigation Survey Section of the SOIP
Episode 7: Overview of the Questionnaire Section of the SOIP
Episode 8: How to Edit an Existing Investigation in the SOIP
Episode 9: How to Update Master Mapping Information in the SOIP
Episode 10: How to Unlock a Locked Investigation in the SOIP
Episode 11: How to Interpret a Detailed Report in the SOIP
Episode 12: How to Interpret an Executive Summary in the SOIP
Module 2
Episode 1: The Purpose of the SOIP
Episode 2: Terminology Used in the SOIP
Episode 3: The Process for Conducting an Outbreak Investigation – The Investigation Phase
Episode 4: The Process for Conducting an Outbreak Investigation – The Investigation Form
Episode 5: The Process for Conducting an Outbreak Investigation – The Post-Investigation Phase
SOIP adoption is encouraged through industry engagement, including meetings, demonstrations, outreach articles, and direct collaboration with producers and veterinary clinics. A widely distributed article, Lessons Learned from SHIC’s Standardized Outbreak Investigation Program to Date, summarized major findings from completed investigations and highlighted opportunities for improving biosecurity across the industry.
A written document, the SOIP User Support Guide, covers the same contents as the Module One video. The written guide is available here.
SOIP database functionality has been enhanced to allow users to export investigation data directly to Excel with customizable filters. Additionally, company- and industry-level benchmarking reports were developed to compare the frequency of pathogen entry events and associated hazard ratings (Figure 1). These reports help companies identify strengths, weaknesses, and opportunities for improvement in their biosecurity programs. Preliminary work also demonstrated the potential to use artificial intelligence tools to analyze narrative investigation data and identify common themes.
Figure 1. Frequency of hazard ratings by entry event, ranked by the number of times rated high.
The web-based application can also allow for aggregation of investigation data that can help identify and characterize hazards for key areas of production such as cull sow transportation. Examples of information that can be gained from industry reporting include the identification of risks for disease entry such as lack of decontamination procedures in Figure 2 and for high-risk trailers due to limited auditing or assessment of truck wash procedures noted in Figure 3.
Figure 2: Industry summary of the decontamination procedures used to haul cull sows.
Figure 3: Industry summary of biosecurity procedures at cull sow trailer/vehicle truck washes.
In addition, the program can identify information for key biosecurity areas such as assessment of risks and hazards associated with cull sow removal which are consistently identified as:
An inherently high-risk process driven by:
▪️Human compliance variability
The greatest vulnerabilities occur at:
▪️Loadout areas (failure to prevent pathogen entry into barns)
The SOIP provides a systematic, standardized, and comprehensive outbreak investigation and biosecurity hazard analysis for veterinarians and pork producers both pre and post pathogen introduction. Utilizing the collective findings, gaps in US swine herd biosecurity can now be identified more rapidly, and solutions applied, to decrease the incidence of disease outbreaks over time, increase herd productivity, and improve global competitiveness. This improvement in biosecurity will help prevent the introduction of transboundary diseases to the US, and when transboundary diseases are introduced, veterinarians and pork producers will be ready to respond by identifying the most significant biosecurity hazards and routes of transmission to help slow spread.
A Swine Health Information Center-funded project at Iowa State University developed a data-driven etiology index to help characterize the relative activity of endemic swine pathogens in the US. The work, led by Drs. Giovani Trevisan and Daniel Linhares, uses confirmed tissue-based diagnoses from the Iowa State University Veterinary Diagnostic Laboratory to rank disease activity and identify emerging changes over time.
The full study has been published in Transboundary and Emerging Diseases here.
The industry summary for SHIC project 24-016 can be found by searching here.
The disease index was also the subject of the Swine Disease Reporting System Bonus Page here (p 10-11).
This initiative aimed to provide a transparent, automated, and reproducible method to help veterinarians, producers, and stakeholders prioritize disease threats based on real-world diagnostic data. The research analyzed 59,950 porcine tissue cases submitted to the ISU-VDL between 2020 and 2024, including evaluation of 81 bacterial, viral, parasitic, and metabolic/intoxication etiologies. Rather than relying solely on the number of diagnoses, the resulting index combines four measures: disease occurrence, co-diagnosis with other etiologies, geographic distribution across states, and Early Aberration Reporting System (EARS) alarms. The variables are weighted according to their contribution to the overall index, with disease occurrence receiving the greatest weight (0.50), followed by EARS alarms (0.26), state occurrence (0.15), and co-diagnosis (0.09).
The resulting index (Table 1) ranges from 0.01 to 1 and is designed to show relative etiology activity and changes in ranking over time—not national disease prevalence or incidence. This distinction is important because diagnostic laboratory submissions can be influenced by factors such as producer awareness, sample submission practices, logistics, and economic conditions. In addition, some diseases are more commonly identified through diagnostic methods other than confirmed tissue diagnoses and therefore may be underrepresented in this dataset.
Table 1. The 10 diseases/etiologies that received the highest indexes in 2024 after multiplying each variable’s results by its respective weight.
Results demonstrated strong year-to-year stability in the index. PRRSV and Streptococcus suis consistently ranked among the highest-activity etiologies, while Pasteurella multocida and influenza A virus also remained important. At the same time, the index identified changes that may warrant additional attention. Porcine sapovirus and porcine astrovirus showed increased activity and geographic distribution, indicating risks for potential emergence, while PCV2 demonstrated a notable decline in ranking and fell outside the top 10 by 2024. Bootstrap analysis also identified PCV2’s 2024 activity as an atypical change relative to the expected distribution based on previous data.
An important strength of the approach is its ability to integrate multiple dimensions of diagnostic information into a single, interpretable measure. The index can help distinguish pathogens that consistently represent a substantial endemic burden from those showing more recent or unusual changes in activity. It also provides a framework that can be adapted to additional diagnostic laboratories, pathogens, production systems, or livestock species.
The index results are available through an interactive Power BI dashboard (scroll to bottom of SDRS dashboard page) that allows users to examine individual etiologies and compare their index values across years. The dashboard is designed to be updated as new diagnostic data become available, providing a mechanism for continued monitoring rather than a one-time assessment.
The completed research provides a scalable and reproducible framework for using routinely collected diagnostic information to support evidence-based swine health decision-making. By combining frequency, geographic distribution, co-diagnosis, and signals of unusual activity, the etiology index offers another tool for identifying changing disease priorities and strengthening surveillance of endemic and reemerging swine pathogens.
Overall, the index presents a transparent foundation for swine disease prioritization, enabling continuous, longitudinal monitoring that differentiates between stable endemic pathogens and volatile or emerging threats.
Reference: Cezar, Guilherme A., Zhang, Danyang, Main, Rodger G., Burrough, Eric R., Nicolino, Rafael R., da Costa, Maria Rodrigues, Silva, Gustavo, Linhares, Daniel C. L., Trevisan, Giovani, Generation of an Etiology Index Based on Confirmed Tissue Diagnosis Data to Assess Endemic Swine Etiology Activity in the United States of America, Transboundary and Emerging Diseases, 2026, 9910689. https://doi.org/10.1155/tbed/9910689
The Allen D. Leman Swine Conference, an annual educational event for the global swine industry, is set for September 19 – 22, 2026, at the RiverCentre in St. Paul, Minnesota. Swine veterinarians, pork producers, and other stakeholders attend the annual meeting to learn about the latest information and research outcomes in swine production, biosecurity, and animal health management. The Swine Health Information Center, a Leman Conference Program Partner, will again be actively engaged in the meeting through an informational display at booth #25 near the registration desk as well as the support of researchers presenting their SHIC-funded projects during the Conference. In addition, Drs. Megan Niederwerder and Lisa Becton will each chair different breakout sessions sponsored by SHIC.
On Monday, September 21, from 1:30 – 3:00 p.m., Dr. Niederwerder will chair a session titled, Practical applications of on-farm biosecurity research, including one SHIC-sponsored presentation.
Find the full 2026 Leman Conference program here.
Coordinated communication and broad dissemination of swine health information is one of SHIC’s main priorities. Working with the Leman Conference team offers the opportunity to expand SHIC’s reach by sharing outcomes from work conducted because of the Center’s research priorities. In addition to the sponsorship and chairing sessions, SHIC’s display table provides the opportunity to offer information and connect with Conference participants. All these efforts directly support the SHIC mission to share swine health information broadly across the industry.
This month’s Domestic Swine Disease Monitoring Report highlights several key findings: PRRSV showed a seasonal, moderate increase in wean-to-market detections in August. Mycoplasma hyopneumoniae case positivity also increased, reaching 26% in wean-to-market – the highest level observed in 2026 – while overall activity remained within the expected range. PEDV and PDCoV activity exceeded expected levels in August, with a moderate increase in PEDV detections among wean-to-market, especially at the end of the month. IAV case positivity in adult/sow farms declined to its lowest level since 2014. This month’s bonus page highlights the inclusion of Illinois Veterinary Diagnostic Laboratory data in SDRS. The accompanying podcast features Dr. Baumgartner and Dr. Lowe (University of Illinois), who discuss the complementary roles of IL-VDL and SDRS, ongoing disease elimination efforts, the importance of continuous surveillance, and the potential role of host response in future disease control strategies.
PRRS Cumulative Incidence for MSHMP
PEDV Cumulative Incidence for MSHMP
Four PRRSV variants are currently classified as Variants Under Monitoring (VUM) Category 2 or higher this month. Lineage 1C.5.32 remains at Category 4, while lineages 1A.13.49 and 1C.5 have been downgraded from Category 4 to Category 3. Lineage 1C.2 holds steady at Category 3. Historical reports for all variants that have reached Category 2 or higher are archived and available for review.