New World Screwworm: Fact Sheet & SHIC Article 6/10/2026 & USDA NWS Website
Pseudorabies Resources: Latest PRV Fact Sheet (Updated June 2024) & Additional PRV Resources/Links & Statement
New World Screwworm: Fact Sheet & SHIC Article 6/10/2026 & USDA NWS Website
Pseudorabies Resources: Latest PRV Fact Sheet (Updated June 2024) & Additional PRV Resources/Links & Statement
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.
The Swine Health Information Center, in collaboration with the American Association of Swine Veterinarians, will host a webinar titled “New World Screwworm Response Planning, Available Resources, and Outreach Strategies for Pork Producers.” The webinar will be held on Tuesday, August 4, 2026, from 1:00 to 2:30 pm CDT. Register for the webinar here.
USDA’s Animal and Plant Health Inspection Service confirmed the detection of NWS in a 3-week-old calf in Zavala County, Texas, on June 3, 2026. NWS is a parasitic fly whose larvae feed on the living tissue of warm-blooded animals, causing serious wounds, infestation, and even animal death if left untreated.
USDA APHIS stated in its press release that, “USDA and Texas officials are taking immediate action to contain and eradicate NWS from the United States, following the strategies and actions outlined in the NWS Response Playbook.” In response to the detection, actions taken by authorities include the establishment of a unified incident command structure and implementation of a comprehensive containment strategy, including quarantines, movement controls, enhanced surveillance, increased sterile fly release, expanded trapping efforts, wildlife monitoring, and targeted local outreach. These measures are designed to contain NWS infestation, prevent its spread, and accelerate eradication efforts. Additional resources can be found on USDA’s NWS website at www.screwworm.gov.
The intent of the August 4 webinar is to provide the latest information on the USDA NWS Response Playbook and its impact on producers, review the current products available to treat animals affected by the parasitic larvae, including product categories and requirements for use, and hear insights regarding efforts in Texas to manage and control the pest. Join experts during this webinar as they share critical information on NWS preparedness, response, and mitigation strategies, as well as insight into how NWS may impact the US pork industry.
Confirmed presentations to date include:
Lindsey Holmstrom, DVM, director of national preparedness and incident coordination, USDA APHIS Veterinary Services
Tristan Colonius, DVM, MPA, chief veterinary officer and deputy director for science policy, Center for Veterinary Medicine, U.S. Food and Drug Administration
Jeff Wiegert, PhD, swine extension specialist, Department of Animal Science, Texas A&M University
The Swine Health Information Center welcomed a new board member during its June 22–23, 2026, meeting. Trish Cook, an Iowa pork producer and member of the National Pork Producers Council Board of Directors, joined the SHIC Board, filling the NPPC-appointed seat previously held by Jeremy Pittman, DVM. During the meeting, the board recognized Dr. Pittman, Smithfield Hog Production, for his dedicated service and contributions to SHIC.
The SHIC Board of Directors also held an election of officers. Joe Dykhuis of Dykhuis Farms, Hamilton, Michigan, was elected president of the SHIC Board. Jay Miller, DVM, The Maschhoffs, will serve as vice president. Kent Bang retains his position as secretary/treasurer and Paul Ruen, DVM, will now serve as past-president. Other board members include veterinarians Seth Krantz and Pete Thomas. Pork producers Alayne Johnson and Sarah Pillen round out the SHIC Board. SHIC staff includes Megan Niederwerder, DVM, PhD, executive director, Lisa Becton, DVM, MS, DACVPM, associate director, and Rhea Schirm, grant and contract administrator.
Sustaining the Mission
As SHIC transitions its board composition and leadership, the consistent theme from both incoming and outgoing members is a steadfast commitment to the organization’s mission. The combined experience and perspectives of the board are poised to strengthen SHIC’s strategic initiatives in disease preparedness, global monitoring, and targeted research, ultimately enhancing the resilience and profitability of the US swine industry.
Cook: Farm-focused Perspective
Cook brings a valuable on-farm perspective to SHIC’s mission of protecting and enhancing the health of the US swine herd. As the newest member, Cook joins a board comprised of veterinarians, fellow producers, and industry leaders, adding the practical insights of a producer with more than three decades of experience raising pigs and serving in pork industry leadership roles.
Cook and her family operate CBL Farms, Inc. and Cook Brothers Ltd., a diversified farrow-to-finish pork and crop operation in Iowa. She has also served in leadership positions with the Iowa Pork Producers Association and has participated in numerous national pork industry initiatives. While recognizing the scientific expertise already represented on the SHIC Board, Cook said she is eager to contribute the producer’s perspective. “I am a farmer, so I bring a producer’s perspective at the farm level regarding raising pigs,” she said. “I look forward to working with the SHIC Board and staff to enhance the health of the U.S. swine herd.”
From her viewpoint as a pork producer, Cook sees SHIC as a trusted and reliable source of swine health information. She noted that producers benefit from the organization’s investment in research and its commitment to delivering timely, science-based resources through fact sheets, webinars, podcasts, and newsletters. “Farmers on their own do not have the resources to investigate emerging diseases and report on disease monitoring,” Cook said. “It is comforting to know that SHIC is doing this for our industry every single day.”
Looking ahead, Cook believes SHIC’s ability to identify emerging disease threats, coordinate research, and communicate critical information will remain essential to the industry’s success. Although future challenges cannot always be predicted, she said producers can have confidence knowing SHIC is prepared to respond. “As a pig farmer, the health of our animals is the top priority,” she said. “I feel fortunate that SHIC is a partner in this goal.”
Pittman: Concluding Service
Dr. Pittman reflects on an experience marked by collaboration, industry leadership, and a shared commitment to protecting the health of the US swine herd. Among the most rewarding aspects of his service, Dr. Pittman points to the relationships built with fellow board members and the opportunity to contribute to work that benefits producers and veterinarians across the country. “Personally, it has been the interaction with other members of the board, some of whom I may have never met if not for the board,” he said. “Professionally, it is the work the organization has done to generate and provide information to the swine industry; information that I hope has or will provide some real benefit to producers and veterinarians.”
During Dr. Pittman’s tenure, he witnessed growth in the scope and volume of SHIC’s activities, enabling the organization to address emerging disease challenges with greater effectiveness. Pittman believes SHIC’s ongoing evolution has strengthened its ability to serve the industry through research, preparedness efforts, and timely dissemination of critical information.
Looking back, Pittman is proud to have represented the swine industry through SHIC’s involvement in national and international discussions shaping the future of animal health. “Being at the table” stands out as a defining accomplishment, he said. Through SHIC and other industry leadership roles, he participated in conversations that influenced policy, preparedness, and disease response strategies. He noted that SHIC consistently brought valuable information and support to these discussions, ensuring the interests of the US swine industry were represented. Dr. Pittman also emphasized SHIC’s unique role in helping the industry stay ahead of emerging threats by focusing attention on potential challenges before they become major issues.
As he concludes his board service, Dr. Pittman encourages current and future directors to continue working collaboratively on behalf of the entire swine industry. Having served alongside incoming board member Trish Cook in other leadership capacities, he expressed confidence in the experience and expertise of SHIC’s leadership team. He believes maintaining SHIC’s role within an integrated national swine health strategy will be critical as new disease threats emerge. For Dr. Pittman, SHIC’s mission is deeply personal. “I am a swine veterinarian,” he said. “So SHIC’s mission, at its core, is what my profession is about.”
Industry Emphasizes Continued Vigilance Against Feral Swine
The Swine Health Information Center, along with US pork industry partners including the National Pork Producers Council, National Pork Board, and American Association of Swine Veterinarians, continues to monitor and communicate information regarding the recent detection of pseudorabies virus antibodies in small swine herds in Iowa and Texas.
Pseudorabies does not present a food safety concern and is not considered a risk to human health. This detection does not affect the safety of the commercial pork supply, which remains secure. Learn more about PRV through the SHIC fact sheet, including potential clinical signs in affected pigs such as reproductive failure in sows, neurologic problems in piglets, and respiratory disease in grow-finish pigs.
In a press release dated June 15, 2026, the Iowa Department of Agriculture and Land Stewardship announced that the state had successfully completed the pseudorabies response protocol. Iowa Secretary of Agriculture Mike Naig stated that the response was completed in accordance with USDA Animal and Plant Health Inspection Service guidelines, allowing both Iowa and the US to retain their pseudorabies disease-free trade status.
According to USDA APHIS, the PRV detection involved a limited number of animals tied to a known risk factor—exposure to feral swine. The Iowa Department of Agriculture and Land Stewardship reported that the affected small commercial swine facility in Iowa had received swine from the affected Texas herd in recent months. The Texas herd was housed outdoors with potential contact with feral swine. Although pseudorabies was eliminated from US commercial swine herds in 2004, the virus remains present in feral swine populations, creating an ongoing risk for domestic pigs.
Federal and state animal health officials acted quickly to contain the situation through animal depopulation, surveillance activities, epidemiologic investigations, and implementation of response protocols designed to protect commercial swine herds and maintain disease-free status.
In a statement following completion of the response, the National Pork Producers Council said, “We appreciate the swift, coordinated response by USDA, state animal health officials, veterinarians, and producers to identify, contain and address the pseudorabies occurrence. Their efforts—and this situation—demonstrate the value of robust surveillance, proactive biosecurity and close collaboration in protecting US herd health.”
The successful resolution of this event reinforces the effectiveness of established disease response plans and surveillance systems. However, concern regarding feral swine and their ability to impact herd health remains high. The recent pseudorabies detection serves as an important reminder that feral swine continue to represent a significant disease transmission risk to domestic swine populations including outdoor or transitional herds.
Since PRV eradication was achieved in US commercial swine herds more than two decades ago, occasional detections have continued to occur in non-commercial or outdoor-raised swine due in part to the increased opportunity for contact with feral swine.
The Secure Pork Supply (SPS) program provides guidance to help producers reduce the risk of disease introduction from feral swine. Recommended biosecurity practices include:
▪️Installing and maintaining fencing around the farm perimeter to prevent contact between domestic and feral swine.
▪️Keeping doors, gates, and other access points closed and in good repair to prevent unwanted entry of feral swine.
▪️Promptly cleaning up grain and feed spills to avoid attracting wildlife.
▪️Requiring farm personnel to wear dedicated farm clothing and footwear when working inside the operation.
▪️Disposing of mortalities in a manner that prevents attracting wildlife and scavengers.
These practices are important components of a comprehensive farm biosecurity plan and can help reduce opportunities for disease transmission from feral swine and other wildlife reservoirs. Additional resources to enhance farm biosecurity and prevent herd exposure to feral swine can be found on the SPS biosecurity site found here. Other SPS resources include the Feral Swine Mitigation Plan checklist focused on biosecurity practices for outdoor-raised swine.
SHIC encourages producers to remain vigilant; review biosecurity plans regularly and utilize available industry resources to protect herd health. The recent response demonstrates the value of preparedness, coordinated communication, surveillance, and collaboration in safeguarding the US swine industry from emerging and re-emerging disease threats.
New World Screwworm resources for livestock producers and veterinarians are available and continue to be shared widely. The Swine Health Information Center continues to closely monitor the outbreak and provide information for pork producers regarding NWS. Prior to NWS re-emergence in Texas with the first detection in a calf on June 3, 2026, SHIC reported on Mexico cases through global disease monitoring, hosted a webinar on the pest, and developed a swine-specific NWS fact sheet for pork producers and other industry stakeholders.
Swine producers can prepare for NWS by understanding the fly’s behavior and life cycle, identifying production and housing conditions that increase the risk of myiasis, implementing effective biosecurity, environmental, and wound management practices, knowing the response procedures for suspected infestations, and developing an NWS disaster management plan.
Monitoring for clinical signs of NWS in swine remains critical, including nonhealing wounds that appear to deepen, wounds with a foul odor, biting or licking at wounds, depressed behavior, reduced appetite, and visible larvae in wounds. Specific areas to monitor include ear notches or tags, castration sites, docked tails, needle injection sites, tattoos, umbilicus of newborn piglets, and any skin abrasions. Any suspect cases of NWS should be reported immediately to state and/or federal animal health officials.
The USDA website, Screwworm.gov, contains important and useful information for livestock producers, veterinarians and other stakeholders.
When you click the “Information for…” button on the Screwworm.gov website, you will find a menu of resources for producers, veterinarians, animal health officials, and other stakeholders. By clicking the desired category, you will be directed to relevant information.
Beyond these resources, the website also features the Current Status Dashboard which is regularly updated with new cases listed by date, species, and location along with a map. Potential detections are divided into inactive and active domestic animal cases, wildlife & feral animal cases, and fly trap detections.
For more information, additional NWS resources are available here:
Visit the Mexican government NWS dashboard here for the latest reporting data.
The Center for Food Security & Public Health (CFSPH) at the Iowa State University College of Veterinary Medicine is hosting a three-part webinar series this summer to raise awareness of emerging and transboundary mosquito-borne diseases. The Swine Health Information Center is collaborating with CFSPH by participating in the webinar series. SHIC’s interest in monitoring and mitigating the threat of mosquito-borne Japanese encephalitis virus grew when outbreaks occurred in Australian piggeries in 2022. Research, preparedness, and prevention activities soon followed and continue today.
JEV is a mosquito-borne virus which has waterbirds as a natural reservoir host but can infect many species, including swine, horses and humans. While JEV is not currently in the US, incursion risk remains a concern given the virus’s recent global expansion. The presence of JEV in the US could have devastating outcomes for the swine industry because of its severe disease presentation in neonatal piglets and pregnant sows. Learn more about JEV as an emerging threat to the US swine industry through the SHIC JEV fact sheet.
Thanks to funding from USDA NADPRP, CFSPH’s “One Health, One Threat: Preparing for Japanese Encephalitis Virus” webinar series brings together animal health, public health, vector control, apiculture, and emergency response professionals. These webinars will explore detection, prevention, and coordination using One Health response strategies to help individuals and agencies prepare for this virus should it be introduced to the US. Attendees will be encouraged to interact with presenters through an active question and answer component.
All are welcome to join these important conversations, which will be held:
Each live, interactive webinar has been approved to provide one hour (scientific) of continuing education credit by the Iowa Board of Veterinary Medicine and the Oklahoma State Board of Veterinary Medical Examiners. Veterinary personnel in California, Kansas, Michigan, Minnesota, and other states may be able to obtain CE credit using the Course Completion Certificate emailed to registered attendees after each live webinar. Register now to strengthen preparedness across your network: Japanese encephalitis preparedness.
The Swine Health Information Center and the Foundation for Food & Agriculture Research funded six research projects totaling $1.3M to enhance US prevention, preparedness, mitigation, and response capabilities for Japanese encephalitis virus. Results can be found by searching for JEV on the SHIC website. As a transboundary disease risk for US introduction, JEV is transmitted through the bite of infected mosquitoes and can cause reproductive failure, abortions, stillbirths, and weak piglets in swine breeding herds.
Foundation for Food & Agriculture Research
The Foundation for Food & Agriculture Research (FFAR) builds public-private partnerships to fund bold research addressing big food and agriculture challenges. FFAR was established in the 2014 Farm Bill to increase public agriculture research investments, fill knowledge gaps and complement the U.S. Department Agriculture’s research agenda. FFAR’s model matches federal funding from Congress with private funding, delivering a powerful return on taxpayer investment. Through collaboration and partnerships, FFAR advances actionable science benefiting farmers, consumers, and the environment.
Swine Health Information Center
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. As a conduit of information and research, SHIC encourages sharing of its publications and research. Forward, reprint, and quote SHIC material freely. For more information, visit http://www.swinehealth.org or contact Dr. Megan Niederwerder at [email protected] or Dr. Lisa Becton at [email protected].
Porcine reproductive and respiratory syndrome virus continues to cause significant challenges to the US swine industry. Recent surveillance data indicates that PRRSV variant 1C.5.32, a highly virulent emerging strain, has rapidly expanded across multiple production systems and geographic regions since its initial detection in late 2023. Swine Health Information Center disease monitoring tools provide important insights into the variant’s growth, spread, and consequences in support of the National Swine Health Strategy.
Key Takeaways
The 1C.5.32 variant, commonly associated with the 1-4-4 restriction fragment length polymorphism pattern, has become one of the most dominant wild-type PRRSV lineages circulating in the US swine herd. Due to its rapid spread and significant production impact, the SHIC-funded Morrison Swine Health Monitoring Project designated 1C.5.32 as a Variant Under Monitoring (VUM) Category 4 in August 2025. Category 4 status is reserved for variants demonstrating sustained growth and widespread dissemination, affecting more than 100 new production sites within six months.
While variant 1C.5.32 was initially detected in late 2023, it was not until August 2025 that it reached the threshold for VUM Category 4 designation. Since then, the variant has continued to expand rapidly. Although 1C.5.32 has been identified across more than 15 states, approximately 90% of cases are concentrated in Iowa and Minnesota, with nearly two-thirds of Iowa counties and one-third of Minnesota counties affected. Roughly 80% of cases have occurred in growing pig sites.
Analysis conducted through MSHMP has identified at least four distinct waves of transmission, with peaks in new cases during spring 2024, winter 2024, spring 2025, and winter 2025. Ongoing analyses of MSHMP-monitored herds have identified four significant space-time clusters. The first occurred within a 42-mile radius in central Iowa during winter 2023, followed by a 60-mile radius cluster in southern Minnesota and a 10-mile radius cluster in central Iowa during spring 2025. Most recently, a 35-mile radius cluster was detected in northeast Iowa during winter 2025.
From November 2023 through February 2026, the cumulative incidence of 1C.5.32 was estimated at 10% among growing pig sites and 6% among breeding herds. These findings underscore the rapid regional spread of the variant and highlight the critical importance of maintaining strict biosecurity protocols, particularly in growing pig populations throughout the Midwest.
Recent surveillance data underscores the continued expansion of the variant. According to the June 2026 National Surveillance Report on PRRSV VUM, 1C.5.32 remains the most significant variant currently tracked, accounting for 411 newly affected sites during the previous six months. This total far exceeds the next highest variant, 1A.13.49, which was associated with 116 new sites during the same period.
The June report identified seven PRRSV variants classified as VUM Category 2 or higher. While 1A.13.49 recently advanced to Category 4 status, 1C.5.32 remains the variant with the greatest overall impact and geographic reach. Variants 1C.5 and 1C.2 continue to meet criteria for Category 3 classification, while variants 1H.18, 1C.5.35, and 1C.2.45 are currently classified as Category 2.
Additional data from the SHIC-funded Swine Disease Reporting System further illustrates the variant’s dominance. Among all wild-type PRRSV detections reported during 2026 through June 19, the L1C.5 lineage accounted for more than 62% of detections. At the variant level, 1C.5.32 represented 44.6% of all wild-type detections, accounting for 2,205 of 4,943 cases. Across 11 states evaluated by SDRS, 1C.5.32 was the most prevalent variant in Iowa, Illinois, Kansas, Minnesota, Missouri, and Oklahoma.
Although first recognized in the Midwest, particularly in Iowa and Minnesota, 1C.5.32 has now been identified across more than 15 states and within more than 20 major swine production systems. Its widespread distribution illustrates the interconnected nature of modern swine production and reinforces the importance of surveillance, biosecurity, and rapid response measures.
Beyond its prevalence, the variant is attracting significant attention because of its association with severe production losses. Data from the PRRS Outbreak Management Program (POMP), coordinated through the Swine Disease Reporting System at Iowa State University (SHIC Domestic Swine Disease Monitoring Report), provides valuable insight into the real-world consequences of 1C.5.32 outbreaks.
POMP was established to improve understanding of the factors and management practices that influence recovery from PRRS outbreaks. The program systematically collects and analyzes outbreak data from commercial breeding herds while providing participating producers with diagnostic support, sequencing services, and benchmarking tools.
Recent POMP analyses demonstrate that outbreaks associated with 1C.5.32 result in substantially higher piglet losses than outbreaks attributed to other PRRSV lineages. One key metric used by the program is piglet losses per 1,000 sows, which measures the number of piglets not weaned during an outbreak and standardizes losses across herd sizes.
Among all POMP-enrolled outbreaks evaluated, piglet losses associated with 1C.5.32 were more than twice those observed in outbreaks caused by older L1A lineages. Median losses reached 4,761 piglets per 1,000 sows for 1C.5.32 outbreaks, compared with 2,240 piglets per 1,000 sows for L1A-associated outbreaks.
The trend remained evident when researchers compared 1C.5.32 with other variants within the same L1C.5 family. In herds classified as American Association of Swine Veterinarians status IA or IB at the time of outbreak, median piglet losses reached 3,545 piglets per 1,000 sows for 1C.5.32, approximately 19% higher than losses associated with other 1C.5 variants. Similarly, in herds with AASV II or II-vx status, median losses climbed to 5,701 piglets per 1,000 sows, roughly 32% higher than losses observed with other 1C.5 variants.
These findings suggest that the impact of 1C.5.32 extends beyond its ability to spread rapidly. Even when compared with genetically related variants, outbreaks involving 1C.5.32 appear to result in greater production losses and more severe consequences for affected breeding herds.
Recent SDRS analyses also suggest that 1C.5.32 may be diverging into two distinct genetic groups. Researchers are continuing to evaluate whether these emerging subgroups may contribute to differences in clinical presentation and production impacts observed under field conditions. Continued surveillance and sequencing efforts will be important for understanding the evolution of this variant and its implications for disease control strategies.
The continued emergence and expansion of variants such as 1C.5.32 highlight the value of coordinated surveillance efforts. Programs including MSHMP, the Swine Disease Reporting System, and POMP provide producers and veterinarians with critical information about variant distribution, disease trends, and production impacts. These tools help identify emerging threats, support informed decision-making, and strengthen industry preparedness.
This month’s Domestic Swine Disease Monitoring Report highlights several key findings. PRRSV case detection had a moderate decrease, but overall case positivity continues to be relatively high, especially in grow-finish populations. Similarly, PEDV and PDCoV case positivity declined; however, PEDV activity in June was above expected levels. MHP case positivity showed an uptick in June in both adult/sow farms and wean-to-market categories, following the expected seasonal trend. Regarding PRRSV genotype trends, variant 1C.2 split and the subsequent variant 1C.2.45 became the most detected in North Carolina. The split of 1C.2 moved variant 1A.13.49 into the top three most frequently detected variants, with five first-state detections reported in the SDRS database in 2026. This month’s bonus page provides an update on the ongoing evolution of variant 1C.2 and the creation of variant 1C.2.45. The accompanying podcast features Drs. Baliellas and Abella, swine veterinarians and production specialists from Spain, who discuss PRRSV surveillance and emerging variants, Spain’s experience with strain dynamics, and the value of coordinated disease control efforts and data sharing to support decision-making in the swine industry.
In this month’s report, read about African swine fever being confirmed on a commercial farm in Hungary. Hungarian authorities reported the first-ever outbreak of ASF in domestic pigs at a facility housing 3,166 head, which is located less than a mile from the Romanian border. In Africa, foot-and-mouth disease remains a major regional concern. Ongoing SAT1 and SAT2 outbreaks of FMDV have been reported across Botswana, Lesotho, Eswatini, and South Africa. Canada and Japan signed an ASF zoning agreement that will allow pork trade to continue from unaffected regions in the event of an ASF outbreak in Canada. Japan, Canada’s largest pork export market by value, imported approximately $1.3 billion USD in Canadian pork products in 2025, representing 31% of the country’s pork export value.
PRRS Cumulative Incidence for MSHMP
PEDV Cumulative Incidence for MSHMP
This month’s report continues to identify seven PRRSV variants as VUM Category 2 or higher. Variant 1C.5.32 remains classified as Category 4, while 1A.13.49 shifted from Category 3 to Category 4. Variants 1C.5 and 1C.2 continue to meet the criteria for Category 3. In contrast, variants 1H.18 and 1C.5.35 are now classified as Category 2, following a Category 3 classification in the previous report, and 1C.2.45 continues to be classified as Category 2. These changes are detailed in the current situation reports. All historical reports for variants previously reaching Category 2 or higher remain available for review.
SHIC NWS Fact Sheet