Evaluation of positive pressure filtration to reduce aerosol transmission of PRRSV during an experimental challenge of farm access points

摘要

Since its discovery in the late 1980s, porcine reproductive and respiratory syndrome virus (PRRSV) continues to be one of the most economically important swine diseases in the United States.1 The virus's ability to spread via aerosol over large distances makes it difficult to control, especially for breeding herds located in pig-dense regions.2 Many farms have implemented air filtration as a method of reducing the risk of infection; however, filtration is expensive, requires significant maintenance to prevent intake of un-filtered air, and PRRSV transmission may still occur via retrograde air movement through open farm access points.3,4 Some systems are investing in positive pressure filtration (PPF) to reduce the risk of aerosol PRRSV transmissionvia retrograde air movement, but no research currently exists on the positive pressure air speed required to prevent aerosol PRRSV entry onto PPF farms. The objectives of this study were to 1) develop a technique to test aerosol PRRSV transmission on PPF farms, 2) assess the PRRSV aerosol transmission risk via retrograde air movement at PPF farm access points, and 3) provide best practices to prevent aerosol PRRSV entry.