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.
The Swine Health Information Center, in collaboration with the Foundation for Food & Agriculture Research and the Pork Checkoff, recently funded five additional projects addressing research priorities and topics for the H5N1 Risk to Swine Research Program. Goals of the program are to enhance prevention, preparedness, mitigation, and response capabilities for H5N1 influenza in the US swine herd. The first request for proposals for this program was announced in November 2024 and resulted in funding of 10 H5N1 research projects in 2025 totaling $2.2 million. A second RFP was announced in January 2026 outlining seven priorities not yet adequately addressed by the first 10 projects. By March 2026, a total of 42 proposals were received from 26 different organizations across three countries.
The priority areas addressed through the newly funded projects include diagnostic surveillance, introduction and transmission risks, biosecurity, pork safety, and production impact. Funding timely research is an essential component of SHIC’s mission to provide project outcomes that drive action for emerging disease prevention, preparedness, mitigation, and response for the US swine industry.
SHIC/FFAR/NPB H5N1 Risk to Swine Research Program projects funded and initiated in response to the second RFP include:
Diagnostic Surveillance
Beyond the Snout: Validating Oral, Mammary, and Environmental Sampling for Rapid H5N1 Incursion Detection
Introduction and Transmission Risks
A Multi-Level Analysis of H5N1 Introduction and Persistence in Swine
Biosecurity
Addendum to: Enhancing Biosecurity in Swine Operations: Investigating Wildlife Interactions on Swine
Pork Safety
Inactivation of Avian Influenza Virus (H5N1) in Pork Products
Production Impact
Impact of Endemic Infections (PRRSV, PCV2, and Mycoplasma hyopneumoniae) on HPAI H5Nx Pathogenesis and Transmission in Swine
Critical research investments are necessary to understand and prevent H5N1 incursion on swine farms, ensure rapid detection of H5N1 if introduced, protect animal and caretaker health, inform pork industry stakeholder response, mitigate production losses on farm, identify effective control measures, and develop clear messaging to consumers on the safety of pork. Outcomes from the funded projects will provide critical information that producers, veterinarians, and industry stakeholders can use to better prevent incursion and develop preparedness plans if H5N1 is identified in US commercial swine 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 US Department of 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. Connect: @FoundationFAR
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. Lisa Becton at [email protected].
The Swine Health Information Center funded a study to evaluate potential tools to protect swine health and mitigate the impact of Japanese encephalitis virus infection in pigs. Led by Dr. Thomas P. Monath with Substipharma Biologics SA, the study sought to determine whether an existing single-dose JEV vaccine for humans has the potential to be safe and effective to prevent infection, clinical disease in swine, and transmission of the virus.
Find the industry summary for SHIC project #24-056 here.
JEV is not currently established in the mainland United States, but its introduction could create significant animal health and public health concerns. Pigs can play an important role in the JEV transmission cycle by amplifying the virus, making the swine population an important consideration in an emergency response. JEV is transmitted principally by mosquitoes, using pigs and birds as amplifying hosts, with spillover to humans. JEV affects a wide area of temperate and tropical parts of the Asia–Pacific region. The 2022 expansion of JEV in continental Australia has raised awareness of the threat to the US.
Although routine JEV vaccination of swine is practiced in some Asian countries, there are no veterinary vaccines currently approved for use in the US. An effective swine vaccine could become an important tool to reduce the amount of virus circulating in a population and limit the role pigs play in JEV amplification during an outbreak.
Investigation of the impact of JEV vaccination in pigs
ImoJev® is a recombinant live, attenuated vaccine using the yellow fever 17D vaccine as a vector for expressing the prM-E envelope genes of an attenuated Japanese encephalitis vaccine strain SA-14-14-2 widely used in parts of Asia for human immunization. The study to investigate the potential impact of the use of this vaccine included three primary objectives 1) demonstrate the efficacy of ImoJev® in protecting pigs from challenge with JEV, 2) demonstrate the safety and immunogenicity of ImoJev® in swine, and 3) demonstrate the minimum effective dose for immunization with ImoJev®.
US crossbred pigs ranging from 6-8 weeks of age were utilized during the study and were tested to determine West Nile Virus serostatus. Rectal temperatures were tracked for all pigs. The virus for the pig challenge model used viremia as the indicator of protection against JEV (genotype IV) peripheral challenge which does not cause clinical illness. Samples collected during the study included blood (viremia, WNV serostatus and antibody detection), nasal, oral and rectal swabs (viral plaque assay) , and the brainstem (medulla) and cerebrum for tissue lesions, histology, and viral plaque assay.
The study identified important differences between humans and pigs
Across the studies, vaccinated pigs developed neutralizing antibodies and demonstrated substantially lower levels of JEV in their blood following exposure to the challenge virus. In one challenge study, all pigs receiving the two-dose intramuscular vaccination program were protected from detectable viremia, with only one animal showing a very low-level breakthrough infection. Lower virus levels in infected pigs could reduce the potential for pigs to amplify JEV and contribute to transmission and could protect pregnant sows from abortion and stillbirth.
The subsequent dose-range experiment reinforced the finding that pigs receiving two doses had significantly lower peak virus levels and overall virus exposure than unvaccinated control animals. The levels of viremia observed in vaccinated pigs were substantially below those considered necessary for efficient infection of mosquito vectors.
Neutralizing antibody levels against four JEV genotypes elicited by the vaccine exceeded the 1:10 threshold for protection (correlate of protection) established for humans.
No safety signals nor vaccine shedding were detected in pigs receiving the ImoJev® vaccine. The results indicated that two intramuscular doses were required for robust, consistent immunogenicity. Unlike the human vaccination program, pigs required a higher vaccine dose and a two-dose schedule to produce a robust and consistent immune response. Intramuscular administration also produced the most reliable results.
More work is needed before a vaccine could be used
Additional research is needed to demonstrate the protective threshold for all five JEV genotypes and to show protection against viremia and disease in pigs challenged with both homologous and heterologous JEV genotype viruses. It cannot be predicted which JEV genotype would be introduced into the US. A better challenge model system with adverse clinical outcomes (other than viremia) would be required to support experimental studies.
While the vaccine proved to be less immunogenic in pigs than in nonhuman primates and humans, it could potentially be utilized as a veterinary vaccine for emergency preparedness against a JEV introduction into the US swine population.
A study funded by the Swine Health Information Center Wean-to-Harvest Biosecurity Research Program, in partnership with the Foundation for Food & Agriculture Research and Pork Checkoff, sought to examine whether preventing trailer cross-contamination during unloading at a commercial harvest facility may help reduce viral transmission from positive to negative herds. Dr. Noelle Noyes, of the University of Minnesota, led the study to evaluate the efficacy of a commercial powder disinfectant to reduce trailer cross-contamination in this setting. PRRSV contamination was observed among treated trailers compared with control trailers following unloading. These results suggest that the use of a commercial powder disinfectant may reduce trailer contamination with PRRSV.
Find the industry summary for SHIC project #24-095 here.
Harvest facilities remain an important biosecurity consideration
Transportation is a recognized pathway for the movement of swine pathogens between farms, and trailers serving multiple sites can provide opportunities for indirect transmission. Trailers at harvest facilities can serve as a contact point between different farms and a contamination source when trailers return to pig farms. Harvest facilities are of particular interest because trailers from different sources converge at a common location, while pigs, drivers, and plant personnel move through unloading areas.
Preventing trailer cross-contamination during unloading may play a role in reducing viral transmission from positive to negative herds. The primary objective of this research was to test the efficacy of a commercially available powder disinfectant as a practical intervention to reduce negative-to-positive cross-contamination events during unloading of pigs at a commercial harvest facility. The secondary objective was to provide estimates of PDCoV, PEDV, and PRRSV prevalence and qPCR-based viral load of both inbound and outbound trailers at a commercial harvest facility under normal operating procedures over a 12-month period.
Samples were collected once a month from February 2025 through January 2026, during normal plant operating conditions at a harvest facility with five unloading docks. Trailers were sampled over a 12-month period, and each month 10 trailers were enrolled for testing with a total of 120 trailers tested. For each sample, the following data points were collected: time of powder application, time of sample collection, and trailer organic load (on a scale of 1-5, with 1 being completely clean and 5 being completely covered with organic material).
Powder disinfectant was applied directly behind treated trailers prior to unloading, while control trailers did not receive an intervention. The rear trailer deck was swabbed immediately before and after unloading. Samples were tested for PRRSV, PEDV, and PDCoV using real-time RT-PCR. Powder was reapplied for each additional trailer enrolled in the treatment docks.
Contamination increased during unloading
Across the 12-month study, incoming trailers tested positive for PDCoV, PEDV, and PRRSV at unexpectedly high rates. Among trailers that initially tested negative, approximately one-quarter became positive for at least one of the viruses during unloading. Crude prevalence across all samples was 60.4%, 50.4%, and 27.1% for PDCoV, PEDV, and PRRSV, respectively. When researchers compared samples collected before and after unloading, the prevalence of all three viruses increased. The increases were statistically significant for PEDV and PDCoV. Overall, approximately 25% of trailers that arrived negative for PEDV or PDCoV became positive after unloading, while the corresponding figure for PRRSV was 17.5%. Crude prevalence varied by month across all three viruses.
The most meaningful treatment effect was observed with PRRSV. Among trailers that were negative before unloading, 20% of control trailers became PRRSV-positive after unloading, compared with 15% of trailers receiving the powder intervention. The difference was statistically significant.
The intervention did not produce a statistically significant reduction in contamination events for PEDV or PDCoV. The researchers caution, however, that the study had fewer virus-negative trailers available for comparison than expected because the incoming prevalence of PEDV and PDCoV was unusually high. This limited the ability to detect differences between treated and control groups and and suggests that additional research with larger sample sizes is needed.
A practical intervention—but not a stand-alone solution
One of the study’s important industry considerations is practicality. Unlike a full trailer wash and disinfection process, which can require significant infrastructure, time, and cost, the powder intervention was incorporated into normal harvest-facility operations. The researchers estimated the material cost at approximately $1.50 per trailer and noted that application was quick enough to fit within commercial unloading operations.
This makes the approach potentially attractive as an additional layer of biosecurity, particularly where complete trailer cleaning and disinfection between loads is difficult to implement consistently.
At the same time, the researchers emphasize that the five-percentage-point reduction in PRRSV contamination observed in this study may or may not translate into a meaningful reduction in farm-level or regional disease transmission. The ultimate impact will depend on how trailers move among farms and the broader disease dynamics within the industry. Multiple interventions throughout the pork production chain are likely necessary to achieve meaningful reductions in disease risk.
Implications of results
For producers, the findings reinforce an important biosecurity principle: the risk associated with a market trailer does not necessarily end when pigs leave the farm. The harvest facility itself can be another point where a trailer may acquire contamination before returning to a production site. The researchers noted that the movement of people, pigs, and contaminated material from the dock or lairage area back into the trailer may be an important contributor to this risk.
The study provides evidence that trailers arriving at harvest facilities often have virus contamination and that virus prevalence increases during unloading. The results suggest that use of a commercial powder disinfectant may reduce trailer contamination for PRRSV. Future studies with larger sample sizes, particularly those enrolling sufficient numbers of initially virus-negative trailers, are warranted. For an industry challenged with PRRSV, PEDV, and PDCoV outbreaks, the addition of another biosecurity measure at a critical point in the transportation chain can be of value for potential reduction in disease transmission risks at the harvest plant.
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 US Department of 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. Connect: @FoundationFAR
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. Lisa Becton at [email protected].
The Swine Health Information Center funded a study led by Dr. Angela Bosco-Lauth and colleagues at Colorado State University to evaluate the potential for Japanese encephalitis virus to affect US swine production. Researchers assessed the ability of US mosquito species to transmit the virus, examined how different JEV genotypes affect domestic pigs, and evaluated whether vaccination against JEV or the related West Nile virus could prevent infection. Results indicate that if JEV was identified in the US, there are mosquito species that can transmit JEV to domestic pigs. Vaccination, particularly against JEV, showed promise as a strategy to reduce infection and limit transmission and could be a useful tool producers could use to prevent an outbreak.
Find the industry summary for SHIC study #24-055 here.
Key Producer Outcomes:
JEV poses a risk to US swine herds
Although JEV has not been detected in the United States, its geographic expansion and recent outbreaks in countries including Australia and China highlight the importance of preparedness and prevention strategies in the US. Pigs are susceptible to JEV, can serve as an amplifying host for the virus JEV, and an introduction could create animal and public health concerns. The objectives of this proposal were to evaluate the competence of mosquitoes in the US to carry and transmit the virus, determine how different genotypes of the virus behave in domestic swine, and evaluate the potential for vaccination against either JEV or related West Nile virus to prevent infection in pigs. Understanding these various factors is essential to understanding JEV transmission risk and limiting potential outbreaks.
The study had four main objectives 1) evaluate vector competence of JEV genotypes I-IV in the three primary WNV mosquito vectors in the U.S.: Culex pipiens, Cx. tarsalis, and Cx. quinquefasciatus, 2) determine susceptibility and pathogenesis of JEV genotypes I-IV in domestic swine, 3) assess protective efficacy of vaccination using a commercially available equine WNV vaccine and an attenuated vaccine strain of JEV (SA-14-14-2) against JEV infection in domestic swine, and 4) evaluate cross-neutralization of porcine antibodies against JEV genotypes I-IV, WNV, and SLEV.
To address whether the three US mosquito species were competent vector transmit JEV, mosquitoes were fed spiked bloodmeals each containing one of the four genotypes (GI, GII, GIII, GIV) and tested for the presence and dissemination of the virus. The next step was to perform experimental infections in pigs approximately five weeks of age to determine how different genotypes behaved in pigs. Pigs were observed daily for lethargy, ataxia, fever and seizure. Sampling of whole blood and tissues at necropsy were performed for each pig. For the vaccination studies, pigs were vaccinated at five weeks of age and again at eight weeks of age. Blood was collected pre- and post-vaccination against either JEV or WNV and subsequently infected them with JEV genotypes 1 or 4 after vaccination. Pigs were challenged with JEV 14 days post-final vaccination.
US mosquitoes can be competent vectors for JEV transmission
The study determined that there are three major US mosquito species competent to transmit multiple JEV genotypes, including genotype IV, which has been associated with established transmission in Australia. Transmission rates varied between 0-20% in both Cx. pipiens and Cx. quinquefasciatus and ranging from 8-28% in Cx. tarsalis. The mosquito species evaluated are distributed across the United States, indicating that the potential for transmission is not necessarily limited to one geographic region.
These findings reinforce the importance of mosquito management as a potential component of swine herd protection. If JEV were introduced, reducing mosquito exposure could help limit opportunities for the virus to move between susceptible animals and mosquito populations.
Pigs are susceptible, even when clinical signs are limited
Researchers found that domestic pigs were susceptible to all four JEV genotypes evaluated. In experimentally infected weanling pigs, however, for all genotypes, clinical disease was minimal or absent, and viremia (virus in blood) was present in the first few days post-infection with rapid clearance. Animals experienced temporary increases in body temperature, but these were resolved within several days, and researchers observed no other obvious clinical signs.
Researchers were able to detect viruses from brain tissue during acute infection and from tonsil tissue at later time points post-infection. Examination of brain tissues identified lesions in some infected pigs despite the limited outward signs of illness.
These findings have important implications for disease preparedness. The absence of pronounced clinical signs does not necessarily mean infection has not occurred. The researchers noted that neonatal pigs and pregnant sows may be more likely to experience clinical disease than the young pigs evaluated in this study. Further work would help clarify the effects of JEV across different production stages and animal populations.
Vaccination demonstrates protective potential
JEV vaccination protected against clinical disease and prevented viremia in JEV infected pigs. WNV vaccination prevented clinical disease and reduced viremia in infected pigs compared to controls. Cross-neutralization assays confirm that antibodies against either JEV or WNV provide at least partial protection against infection with the heterologous virus.
Pigs receiving the experimental live-attenuated JEV vaccine developed neutralizing antibodies and were protected against clinical disease and detectable viremia following challenge with JEV. No adverse vaccine reactions were observed in the study animals.
Researchers also evaluated a commercially available inactivated WNV vaccine developed for horses. While this vaccine did not completely prevent JEV infection in pigs, it reduced the amount of virus detected in the bloodstream compared with unvaccinated controls. The findings suggest that vaccination against a related virus could offer partial protection under certain circumstances.
Antibody testing further demonstrated cross-protection between JEV genotypes I and IV and between JEV and WNV. Pigs exposed to either JEV genotype developed antibodies capable of neutralizing the other genotype and WNV. This cross-reactivity may provide some protection against related viruses, although it also highlights considerations for diagnostic testing.
Implications for pork producers
The research confirms a credible pathway for JEV introduction and transmission in the United States while also identifying potential tools to mitigate risk. US mosquito populations can transmit viruses, domestic pigs are susceptible, and infection may occur without pronounced clinical signs in young animals.
For pork producers, the results support maintaining awareness of emerging foreign animal diseases and considering mosquito control as part of broader herd health and biosecurity planning. Vaccination could also become a useful intervention if JEV were detected, with the study demonstrating strong protection from JEV vaccination and partial protection from WNV vaccination.
Proactive preparation is valuable even though JEV is not established in the US. Understanding transmission risks and potential prevention strategies gives producers and veterinarians a stronger foundation for responding to a possible introduction and protecting herd health.
This month’s Domestic Swine Disease Monitoring Report highlights several key findings: PEDV case positivity in wean-to-market sites declined and returned to the expected range; however, facility detections increased noticeably in October compared with September. PRRSV activity continued to trend upward from July onward, driven by increasing detections in wean-to-market sites, where case positivity approached 45% in October. After two consecutive months of increasing activity, MHP PCR case positivity declined in October across both production phases, and the tissue-confirmed MHP diagnosis continued their steady decline, consistent with the five-year trend. This month’s bonus page summarizes key takeaways from the SDRS 2026 Winter Preparedness Call, where the SDRS Advisory Group and VDL collaborators revisited SDRS project priorities and discussed the current status of swine disease activity. The accompanying podcast features Dr. Hollis and Dr. Fombelle, discussing PEDV transmission risks, MHP control strategies, and biosecurity approaches to reduce PRRSV introductions during the winter season.
In this month’s report, read about African swine fever being confirmed in a wild boar in Brandenburg, Germany, the first detection in more than four years in the region. In Nigeria, ongoing ASF outbreaks have reportedly caused over $3.7 million USD in economic losses affecting more than 2000 pig farmers. Additional information on ASF outbreaks in Poland and the Philippines is included as well. Foot-and-mouth disease outbreaks in Namibia and Cyprus are detailed along with a significant classical swine fever outbreak in Japan.
PRRS Cumulative Incidence for MSHMP
PEDV Cumulative Incidence for MSHMP
Four PRRSV variants remain currently classified as Variants Under Monitoring (VUM) Category 2 or higher this month. Variant 1C.5.32 remains at Category 4 while variants 1A.13.49 and 1C.5 remain Category 3. Similarly, variant 1C.2 remains at Category 2. Historical reports for all variants that have reached Category 2 or higher are archived and available for review.