Long-Term Sampling of Viable Airborne Viruses

Abstract

A novel bioaerosol sampling technique, which utilizes the bubbling process in the collection fluid, has recently been developed and found feasible for a long-term personal sampling of airborne bacteria and fungal spores as it maintained high physical collection efficiency and high microbial recovery rate for robust and stresssensitive microorganisms. Further tests have shown that the new technique also has potential to collect viable airborne viruses, particularly when utilized for a short-term sampling of robust strains. As the short-term sampling has a limited application for assessing personal exposure in bioaerosol-contaminated environments, the present study was undertaken to investigate the feasibility of the "bubbler" for a long-term monitoring of viable airborne viruses. Liquid droplets containing Vaccinia virions (that simulate Variola, a causative agent of smallpox) were aerosolized with a Collison nebulizer into a 400-liter test chamber, from which the droplets were collected by three identical prototype personal samplers in the liquid medium during different time periods ranging from 1 to 6 hours. The viral content was measured in the collection fluid of the sampler and in the initial suspension of the nebulizer using the fluorescence-based method and by enumerating plaque-forming units per milliliter of the fluids. The relative recovery of viruses after the sampling act was determined. The results show that the "bubbling" technique has consistent collection efficiency over time and is capable of maintaining the viability of Vaccinia, for at least 6 hours, with a loss in recovery rate of about 10%. The data demonstrate a good potential of the new technique for measuring personal exposure to robust airborne viruses over a long period.

Standardization of a Protocol for Quantitative Evaluation of Anti-Aerosolized Influenza Virus Activity by Vapors of a Chemically-Characterized Essential Oil Blend

“…This is in agreement with previously documented works [40][41][42][43]. The success in collection of the virus in the second experiment was obtained at an air suspension time of 1.0 min, while shorter suspension times of 15.0, 30.0, and 45.0 sec failed in recovering the virus from the transport medium.…”

Electrospray versus Nebulization for Aerosolization and Filter Testing with Bacteriophage Particles

“…0.16% per minute of operation. This implies that although electrospray aerosol generation is much less variable than nebulization, it may not be as feasible for use in long-term virus aerosol studies, e.g., in calibration of long-term virus aerosol samplers (Agranovski et al 2005).…”

“…Nebulization is a common methodology used for aerosolizing biological particles, such as bacteria (Jensen et al 1992;Grinshpun et al 1997;Foarde et al 1999;Johnson et al 1999;Griffiths et al 2001;Li and Lin 2001;Mainelis et al 2005), fungi and fungal fragments (Lin and Li 2003), and viruses (Agranovski et al 2005;Balazy et al 2006a;Kim et al 2007) as it is a relatively inexpensive aerosolization technique and does not require extensive user training or trial and error for correct and reliable operation. Likewise, nebulization is a common aerosolization method utilized for filter testing, e.g., for aerosolizing bacteriophage MS2 (a non-enveloped icosahedral virus) to compare ultrafine inert and biological particle penetration through respirator filters (Balazy et al 2006a;Eninger et al 2008a;Eninger et al 2008b).…”

Real-time detection of airborne viruses on a mass-sensitive device

“…In fact because of these properties, it is regarded as a possible bioterrorism or biowarfare agent. 15 With this study, we demonstrate the potential of the QCM as a mass sensitive device to perform the detection of nanoscale entities in air. We use an electrospray aerosol generator as a means to generate the airborne virus particles.…”