Optimization of a Sampling System for Recovery and Detection of Airborne Porcine Reproductive and Respiratory Syndrome Virus and Swine Influenza Virus

Abstract

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. Airborne pathogens are detected by recovering the target microorganism in a collection medium (liquid, semisolid, or solid substrate) and then assaying the substrate for the presence of the target pathogen by using an appropriate microbiological assay. Various air-sampling devices are available, but "impingers" are generally used to collect airborne viruses. Impingers direct a converged stream of environmental air onto a liquid collection medium to recover airborne viral particles in the liquid phase of the collection system (1,11,12,14,16,17). Impingers are generally considered more effective than filters, bubblers, or impactors for capturing airborne viruses (18,19,20).A number of variables are known to affect impinger collection efficiency. These include impinger design (5, 13, 24), sampling time (28), and the composition of collection medium (31). In addition, specific compounds are sometimes added to impinger collection medium to preserve virus infectivity during the collection process (37,38,40).This research focused on specific aspects of optimizing the collection and detection of aerosolized porcine reproductive and respiratory syndrome virus (PRRSV) and swine influenza virus (SIV) in air-sampling systems. The first study (experiment 1) focused on virus detection. Compounds added to collection media to enhance collection efficiency (i.e., antifoams, bovine serum albumin, gelatin, mucin, activated carbon, and ethylene glycol) were evaluated for direct effects on virus infectivity, on the viability ...

Effect of temperature and relative humidity on the stability of infectious porcine reproductive and respiratory syndrome virus in aerosols

“…Previous research showed that Antifoam A Emulsion was non-virucidal for PRRSV [19]. The nebulizer was operated for 3 min on compressed air (Sears Roebuck, 00916734000, Hoffman Estates, IL, USA) at 40 P.S.I.…”

Analytical Methods for Virus Detection in Water and Food

“…After sampling the medium can be concentrated or directly decontaminated, purified, and analyzed. The recovery efficiency of this method is high because it avoids dehydration but flow rate and the composition of the collection fluid are again critical for virus recovery (Hogan et al 2005;Hermann et al 2006).…”

Development of A Rapid and Convenient Method for Sampling Airborne Virus Based on Nanoparticle Adsorption

“…We used a similar equipment designed by Hermann to test the recovery efficiency of air virus [15]. A 20 liter glass reservoir was modified to allow simultaneous sample collection at outlet ports.…”