New personal sampler for viable airborne viruses: feasibility study

Abstract

While various sampling methods exist for collecting and enumerating airborne bacteria and fungi, no credible methodology has yet been developed for airborne viruses. A new sampling method for monitoring the personal exposure to bioaerosol particles has recently been developed and evaluated with bacteria and fungi. In this method, bacterial/fungal aerosol is aspirated and transported through a porous medium, which is submerged into a liquid layer. As the air is split into numerous bubbles, the particles are scavenged by these bubbles and effectively removed. The current feasibility study was initiated to evaluate the efficiency of the new personal sampler prototype ("bubbler") with airborne viable viruses. Two common viral strains, Influenza (stress-sensitive) and Vaccinia (robust), were aerosolized in the test chamber and collected by two identical "bubblers" that operated simultaneously for a duration of upto 5 min. A virus maintenance liquid, proven to be the optimum collecting environment for the test organisms, was used as a collection fluid. After sampling, the collecting fluid was analyzed and the viral recovery rate was determined. The overall recovery (affected not only by the sampling but also by the aerosolization and the aerosol transport) was 20% for Influenza virus and 89% for Vaccinia virus. The new sampling method was found feasible for the collection and enumeration of robust airborne viruses. ᭧

Long-Term Sampling of Viable Airborne Viruses

“…The inter-sampler variation did not exceed 20% for all the tests. In our earlier study (Agranovski et al 2004c), we obtained about the same average recovery rate of Vaccinia virus when performing a short-term (5-min) sampling with the bubbler. The present finding allows extending the sampling period much further.…”

“…When challenged with the robust Vaccinia virus, the bubbler provided an 89% recovery after a 5-minute sampling (Agranovski et al 2004c). Although stress-sensitive Influenza virus recovered only at a 19% level (as reported in Agranovski et al 2004c), the "bubbling" technique showed promise, at least, for relatively stress-resistant viruses if they are collected during short-term intervals. This is remarkable given that viruses often exhibit much stronger response to stress than bacteria and fungi, making their collection from air environment especially challenging.…”

“…Similar to our earlier study (Agranovski et al 2004c), a fluorescence dye (C 20 H 10 NA 2 O 5 , Fluka AG, Buchs, Switzerland) was added to the suspension in the nebulizer. This enabled us to quantify the amount of the viral material in the initial suspension (before aerosolization) as well as in the collection fluid (after sampling) using the fluorescence-based method.…”

Highly efficient collection of infectious pandemic influenza H1N1 virus (2009) through laminar-flow water based condensation

“…Although known to be inefficient in collecting submicrometer-sized aerosols (Hogan et al, 2005), the BioSampler has been used as a reference sampler for many virus aerosol studies (e.g., Lednicky and Loeb [2013] and Dybwad et al [2014]). Additionally, impinger-based collection methods often inactivate viruses, especially "stress-sensitive viruses," reducing the usefulness of data acquired by these methods (Agranovski et al 2005). Hence, comprehensive understanding of the risk of airborne IFV transmission is limited by a lack of efficient samplers for the collection of airborne particles containing infectious influenza virus.…”

Personal Sampler for Monitoring of Viable Viruses; Modeling of Indoor Sampling Conditions

“…A new personal sampler has been developed and verified to be a very efficient tool for monitoring of viable airborne bacteria, fungi, and viruses (Agranovski et al 2002a(Agranovski et al , 2002b(Agranovski et al , 2005. The operation principle is based on aspiration of an air sample through peripheral holes located on the upper part of the sampler with following passing of air through porous media submerged into the layer of collecting liquid.…”