Phylogenetic evaluation of historic PRRSV isolates from air filtered sow herds in North America

摘要

Air filtration systems have been demonstrated to reduce the risk of introduction of PRRSV contaminated aerosol into susceptible herds.' Phy-logenetic analysis is the standard tool used for discriminating new PRRS introductions from 'resident' viruses,but the choice of "cut-off" in sequence homology is largely arbitrary and therefore questionable. The objective of this retrospective study was to assess the impact of phylogenetic cutoff on the estimated risk reduction achieved with air filtration systems.