SHIC/AASV PORCINE CIRCOVIRUS-FOCUSED WEBINAR PROVIDES TIMELY UPDATES

Feb 26, 2024

On February 6, 2024, the Swine Health Information Center along with the American Association of Swine Veterinarians offered a webinar focused on emerging trends of porcine circovirus. Expert presenters provided the latest information on porcine circovirus including domestic and global distribution, new research updates, diagnostic trends, sample types submitted for surveillance, interpretation of test results, and practitioner perspectives for disease management strategies.

There were 311 people registered for the PCV webinar, conducted by the Swine Medicine Education Center at Iowa State University, which is now available online for review. The first presenter, Dr. Tanja Opriessnig, ISU, provided a general disease overview including domestic and global distribution, recent research outcomes, and an update on PCV4. She said although PCVs were first identified approximately 27 years ago, an improved understanding of circoviruses and their impact on swine health has continued to evolve over time.

PCV2 has been a significant health challenge for global pig producers for many decades. Dr. Opriessnig said PCV2-specific vaccines have worked remarkably well to prevent viral health impacts since global introduction in 2006. Modern PCV2 vaccines provide cross-protection against currently known PCV2 genotypes and are among the most widely used vaccine in growing pigs. Dr. Opriessnig shared evidence of the global distribution of PCV3 as well as the recent identification of PCV4 in Asia and Spain, saying a more field-based approach is needed for prevention, preparedness, and response to emerging PCVs. Dr. Opriessnig remarked that initial evidence shows that PCV3 vaccines are helpful for control and that monitoring for emerging strains, including porcine circovirus-like viruses, is ongoing.

Dr. Darin Madson, ISU Veterinary Diagnostic Lab, shared background information for PCV2, stating it is a globally distributed and ubiquitous virus with very few negative swine herds in the US. PCV2 is an economically important disease, ranking as one of the top three infectious agents in the swine industry. Dr. Madson remarked that infection generally occurs after waning of maternal antibodies in pigs 7- to 15-weeks of age. Transmission of PCV2 is possible both horizontally (pig to pig) and vertically (dam to offspring) through nasal-oral and fecal-oral routes. He pointed out a major route of transmission occurs through virus secreted and/or excreted in urine, ocular discharge, nasal discharge, saliva, and feces.

Fomites capable of transmission include needles, insects, and rodents. Aerosol transmission of PCV2 is possible as the virus has been detected in exhaust air and dust outside barns; however, infectivity is unknown. The virus is environmentally hardy and difficult to inactivate with disinfectants.

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Video: Swine Industry Advances: Biodigesters Lower Emissions and Increase Profits

Analysis of greenhouse gas (GHG emissions) in the Canadian swine sector found that CH4 emissions from manure were the largest contributor to the overall emissions, followed by emissions from energy use and crop production.

This innovative project, "Improving Swine Manure-Digestate Management Practices Towards Carbon Neutrality With Net Zero Emission Concepts," from Dr. Rajinikanth Rajagopal, under Swine Cluster 4, seeks to develop strategies to mitigate greenhouse gas emissions.

While the management of manure can be very demanding and expensive for swine operations, it can also be viewed as an opportunity for GHG mitigation, as manure storage is an emission source built and managed by swine producers. Moreover, the majority of CH4 emissions from manure occur during a short period of time in the summer, which can potentially be mitigated with targeted intervention.

In tandem with understanding baseline emissions, Dr. Rajagopal's work focuses on evaluating emission mitigation options. Manure additives have the potential of reducing manure methane emissions. Additives can be deployed relatively quickly, enabling near-term emission reductions while biodigesters are being built. Furthermore, additives can be a long-term solution at farms where biogas is not feasible (e.g., when it’s too far from a central digester). Similarly, after biodigestion, additives can also be used to further reduce emissions from storage to minimize the carbon intensity of the bioenergy.