Optimization of a sampling system for recovery and detection of airborne porcine reproductive and respiratory syndrome virus and swine influenza virus

The objective of this research was to optimize sampling parameters for increased recovery and detection of airborne porcine reproductive and respiratory syndrome virus (PRRSV) and swine influenza virus (SIV). Collection media containing antifoams, activated carbons, protectants, and ethylene glycol were evaluated for direct effects on factors impacting the detection of PRRSV and SIV, including virus infectivity, viability of continuous cell lines used for the isolation of these viruses, and performance of reverse transcriptase PCR assays. The results showed that specific compounds influenced the likelihood of detecting PRRSV and SIV in collection medium. A subsequent study evaluated the effects of collection medium, impinger model, and sampling time on the recovery of aerosolized PRRSV using a method for making direct comparisons of up to six treatments simultaneously. The results demonstrated that various components in air-sampling systems, including collection medium, impinger model, and sampling time, independently influenced the recovery and detection of PRRSV and/or SIV. Interestingly, it was demonstrated that a 20% solution of ethylene glycol collected the greatest quantity of aerosolized PRRSV, which suggests the possibility of sampling at temperatures below freezing. Based on the results of these experiments, it is recommended that air-sampling systems be optimized for the target pathogen(s) and that recovery/detection results should be interpreted in the context of the actual performance of the system.