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Pathways assessment: Entry Assessment for Exotic Viral Pathogens of Swine. Lisa A. Ferguson USDA, APHIS, Veterinary Services NIAA, Omaha April 2014. Objectives. Identify and describe pathways by which exotic viral pathogens of swine may enter the US
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Pathways assessment:Entry Assessment for Exotic Viral Pathogens of Swine Lisa A. Ferguson USDA, APHIS, Veterinary Services NIAA, Omaha April 2014
Objectives • Identify and describe pathways by which exotic viral pathogens of swine may enter the US • Estimate the likelihood that each identified pathway may introduce exotic viral pathogens of swine into the US
Virus in region NO no YES Infected or contaminatedproductselected for export NO no Virus survives process prior to export Product contaminated post-process YES NO no YES Virus survives transport to US no NO YES Virus survives import mitigation at border NO no ENTRY YES
Next steps • Pathways with non-negligible likelihood of introduction - estimate likelihood of exposure • Pathways with non-negligible likelihood of exposure – evaluate consequences • Pathways where consequences, overall risk of introduction, and overall risk of exposure are non-negligible – identify potential mitigation measures
Assumptions • One or more exotic viral pathogens are present • Infected animals are selected for slaughter and/or rendering • Current regulations and mitigation procedures effectively enforced
Representative viruses • Stand in for both single- and double-stranded RNA and DNA virus • Encompass a range of resistance to inactivation • Classical swine fever • Foot and mouth disease • Pseudorabies
Pathway groups • Airborne • Inanimate articles serve as fomites • Animal tissues or fluid and their products • Conveyances and containers • Equipments • Food and feed • Garbage • Live animals that may serve as vectors or fomites • Livestock/germplasm • Humans • Microorganisms or arthropod vectors • Other live animals
Feed ingredient origin • Animal (rendered products, marine, dairy, etc..) • Plant (forage, grain, by-products, fats/oils, vitamins, etc…) • Microbial culture (amino acids, minerals, vitamins, etc…) • Mined material (anticaking, colorants, minerals) • Synthetic (amino acids, antioxidants, flavors, minerals, vitamins, etc…)
Rendered animal proteins and fats, marine by-products • Includes blood products – none imported • Rendering process inactivates viruses • Post-processing contamination unlikely; transport times and conditions not conducive to virus survival • Negligible risk of entry
Milk and milk derivatives • Small amount of imports • Treatment sufficient to inactivate FMD • Post-processing contamination unlikely; transport times and conditions not conducive to virus survival • Negligible risk of entry
Animal manure • Virus could be present • Not allowed entry for purpose of feeding • Negligible risk of entry
Plants and plant products • Imports – Canada, Argentina, Mexico • Potential for contamination if contact with infected animals/excretions/fomites • ? Virus survival time • Negligible risk of entry if pelleted/treated; low risk of entry if unprocessed
Microbial culture • Amino acids (L-carnitine, lysine, etc..), probiotics, enzymes (phytase), vitamin (B2, B12), etc. • Contamination of culture (bacteria, fungi, bacteriophages) considered production failure; GMP control • Recovery of product – sterilization, centrifugation, filtration, crystallization, etc… - not conducive to virus survival • Negligible risk of entry
Chemical synthesis/mining • Amino acid (methionine), minerals, vitamins (A, B1, B3 or B5, B6, B7, B9, D, K; choline), etc.. • Viruses can’t propagate without living animal cells; contamination unlikely to survive manufacturing process • Post-processing contamination unlikely; transport times and conditions not conducive to virus survival • Negligible risk of entry