A 2019 grant from USDA’s Foreign Agricultural Service division, awarded to the Swine Health Information Center (SHIC) who applied with National Pork Producers Council assistance, funded multi-phase African swine fever (ASF) field projects in Vietnam. One completed study evaluated the performance of ASF serum and/or oral fluid ELISAs for use in the surveillance and monitoring of ASF outbreaks in commercial farms in Vietnam and in preparation for the virus becoming endemic in the US. This study shows there is no single best diagnostic approach for ASFV surveillance and demonstrates that the combined use of the Tetracore qPCR and indirect ELISA tests and serum/oral fluid sampling increase efficiency of ASF disease surveillance. Another completed study modeled the risk of introducing ASF to a sow farm as a result of semen movement from apparently healthy boar studs located in an ASF disease control area. Results indicated the risk is negligible to low given study parameters, however, several factors with the potential to impact these results were acknowledged.
Author Archives: Paul Sundberg
November Domestic Swine Disease Monitoring Report Now Available
The Swine Health Information Center’s (SHIC) November Domestic Swine Disease Monitoring Report is available. This month’s Domestic Swine Disease Monitoring Report shows a substantial increase in detection of porcine reproductive and respiratory syndrome virus (PRRSV) in the wean-to-market category was associated with a new wave of detection of PRRSV RFLP 1-4-4 L1C variant strain. Also, a moderate increase in PEDV detection in the age category wean-to-market was observed in October. The advisory group has suggested that there may be an opportunity for a national plan to control and eliminate PEDV. As a reminder, there are no approved viral mitigants that can legally be added to feed fed to swine. Levels of detection of M. hyopneumoniae by PCR are at expected levels for this time of year. In the podcast, the SDRS hosts talk with Dr. Brigitte Mason, health assurance veterinarian from Country View Family Farms, about her experience with animal health management, disease management, control, and her advice to the swine industry to better handle animal health interventions.
SHIC-Funded MSHMP and NCSU Project Models PRRS Dissemination Dynamics
Just in time to prevent and prepare for seasonal PRRS outbreaks, a team led by North Carolina State University researchers and funded by the Fats and Proteins Research Foundation, along with the University of Minnesota Morrison Swine Health Monitoring Project (MSHMP), funded by the Swine Health Information Center (SHIC), developed and calibrated a mathematical model for transmission of porcine reproductive and respiratory syndrome virus (PRRSV). Their recently published work demonstrated the contribution of multiple unmeasured routes of PRRSV dissemination, including for the first time the role of animal by-products delivered via feed meals, and multiple transportation vehicle networks. It also provides strong evidence to support the need for cautious, measured PRRSV control strategies for transportation vehicles and, to some degree, feed by-products. The project provides valuable information and opportunities for the swine industry to focus effort on the most relevant modes of PRRSV between-farm transmission.
SHIC: Newly Discovered Low Virulent, Genotype I, ASF Virus Causing Chronic Infections in China
Recently, Sun et al. (2021) describe in “Genotype I African swine fever viruses emerged in domestic pigs in China and caused chronic infection” the detection of a second African swine fever virus (ASFV) strain present in two Chinese provinces. The ASF viruses described are genotype 1 viruses, distinct from the currently circulating genotype 2 virus Georgia-07 and its derivatives. These virus isolates (hemadsorption negative) are of lower virulence characterized by a chronic disease presentation including necrotic skin lesions and joint swelling. Data presented suggest the viruses are readily transmissible to contact animals. Notably, pigs infected with these viruses could easily be missed early in a disease outbreak due to their reduced virulence. However, current diagnostic tools PCR (p72-based) or serologic (ELISA-based) should be adequate for detection of infected animals [Sun et al., 2021]. Given their reduced virulence and transmissibility characteristics, it is reasonable to assume these viruses also may be present in other regions of China and Southeast Asia.
SHIC Diagnostic Fee Support Program Provides Additional Resources
The Swine Health Information Center (SHIC) received a call when vesicles were observed in the snout area of pigs on multiple farms in Iowa and Minnesota from January to April 2021. Investigators Jianqiang Zhang, Pablo Piñeyro, and others from Iowa State University (ISU) College of Veterinary Medicine worked on the case. A total of 133 swine vesicular cases with pig ages of three to 6.5 months from Iowa farms were submitted to the ISU Veterinary Diagnostic Lab. All were foot-and-mouth disease virus (FMDV) PCR negative but they were also negative for Senecavirus A (SVA) and other known vesicular viral pathogens, leaving the causative agent(s) unidentified. When standard diagnostic protocols did not reveal satisfying information about the cause, a request for diagnostic fee support was reviewed and approved by SHIC.
SHIC-Funded Quantitative Risk Assessment Models US Risk of ASF Introduction in Feed
Evidence suggests African swine fever virus (ASFV) may survive under conditions similar to those observed in transoceanic transport models. In a Swine Health Information Center (SHIC)-funded study, researchers developed a quantitative risk assessment model to estimate the probability that one or more corn or soybean meal ocean vessels contaminated with ASFV would be imported into the US annually. Ultimately, this model can be used to evaluate risk mitigation strategies and critical control points for inactivating ASFV during feed ingredient processing, storage, and transport, and contribute to the design and implementation of biosecurity measures to prevent the introduction of ASFV into the US and other ASFV-free countries. Study authors are Rachel A. Schambow, Fernando Sampedro, Pedro E. Urriola, Jennifer L. G. van de Ligt, Andres Perez, and Gerald C. Shurson.
SHIC-Funded Swine Disease Reporting System Expands Near Real-Time Disease Information
The Swine Health Information Center (SHIC)-funded Swine Disease Reporting System (SDRS) initiative has completed another successful year. An aggregated database with diagnostic data from the Iowa State, Kansas State, University of Minnesota, South Dakota State, and Ohio State (beginning in October 2021) veterinary diagnostic labs (VDLs) is regularly updated, with monthly reports and podcasts to SHIC, as well as online interactive dashboards. The database now includes more than 950,000 distinct VDL submissions tested by PCR for the five US porcine endemic agents: porcine reproductive and respiratory syndrome virus (PRRSV), porcine epidemic diarrhea (PEDV), porcine deltacoronavirus (PDCoV), transmissible gastroenteritis (TGEV), and Mycoplasma hyopneumoniae. Monthly etiologic summaries of digestive, respiratory, and neurologic diagnostics from the Iowa State VDL are also reported. Interactive online dashboards with filtering capabilities for age category, specimen, geographic region, are kept updated and are available on the project website (https://www.fieldepi.org/sdrs).
Influenza Virus Fact Sheet Updated in SHIC Library
The Swine Health Information Center (SHIC) Fact Sheet on influenza viruses C and D has been updated. New information in the fact sheet on epidemiology, including host range, geographic distribution, and prevalence, as well as pathogenicity, all increase its relevance and value. Fact sheets are part of SHIC’s mission to protect the health of the US swine herd, providing guidance and resources for producers, practitioners, and diagnosticians who are on the front lines of swine health concerns is an ongoing effort. Influenza C virus (ICV) and influenza D virus (IDV) are potential emerging pathogens of pigs, although swine are not the primary host for either virus species. Swine can be naturally and experimentally infected with both ICV and IDV, but clinical illness occurs rarely. Currently, influenza A virus (IAV) is the only species of routine clinical significance in swine.
SHIC Funding Investigation of Feed Manufacturing Facility Decontamination Processes
There is field and/or experimental evidence that feed and/or ingredients may be potential vectors of African swine fever virus (ASFV) or foot-and-mouth disease virus (FMDV) introduction. And introduction of ASFV or FMDV in a domestic feed manufacturing facility has the potential to unknowingly disseminate those viruses widely. Research is needed to determine optimal methods for decontaminating feed manufacturing facilities, especially equipment that is not designed to be disinfected. The Swine Health Information Center (SHIC) has funded a study, proposed by a group of co-investigators including Dr. Chad Paulk of Kansas State University, to evaluate methods of decontaminating feed manufacturing equipment, using Senecavirus A (SVA), porcine epidemic diarrhea virus (PEDV), and porcine reproductive and respiratory syndrome virus (PRRSV) contamination as domestic, pathogenic surrogates for foreign animal diseases.
SHIC-Funded Research Helps Compare Pathogen Detection Methods in Feed
Interest in feed biosecurity has been increasing. Recent experimental evidence confirmed African swine fever virus (ASFV), PEDV, Senecavirus A (SVA), and foot-and-mouth disease virus (FMDV) can be transmitted through contaminated feed, providing an avenue for introduction to susceptible pigs via ingestion. One way of reducing the risk of pathogen transmission through feed is to test feed ingredients and feed before they are introduced onto farms and fed to pigs. This would only be possible if sampling and nucleic acid extraction methods would allow efficient detection of pathogens in feed. In a study funded by the Swine Health Information Center (SHIC), principal investigator Dr. Diego Diel, Cornell University, and colleagues focused on comparing the performance of three commercially available nucleic acid extraction kits (CORE, IndiMag, MVP II). Results show the CORE extraction kit outperformed the other two kits evaluated.