Showing papers by "Thomas H. Kuehn published in 2013"

Association of Airborne Virus Infectivity and Survivability with its Carrier Particle Size

Abstract: Although laboratory generated virus aerosols have been widely studied in terms of infectivity and survivability, how they are related to particle size, especially in the submicron size range, is little understood. Four viruses (MS2 bacteriophage, transmissible gastroenteritis virus, swine influenza virus, and avian influenza virus) were aerosolized, size classified (100–450 nm) using a differential mobility analyzer (DMA), and collected onto gelatin filters. Uranine dye was also nebulized with the virus, serving as a particle tracer. Virus infectivity assay and quantitative reverse transcription-polymerase chain reaction were then used to quantify the amount of infectious virus and total virus present in the samples, respectively. The virus distribution was found to be better represented by the particle volume distribution rather than the particle number distribution. The capacity for a particle to carry virus increased with the particle size and the relationship could be described by a power law. Virus s...

Comparison of spike and aerosol challenge tests for the recovery of viable influenza virus from non-woven fabrics.

Abstract: Background To experimentally determine the survival kinetics of influenza virus on personal protective equipment (PPE) and to evaluate the risk of virus transfer from PPE, it is important to compare the effects on virus recovery of the method used to contaminate the PPE with virus and the type of eluent used to recover it. Methods Avian influenza virus (AIV) was applied as a liquid suspension (spike test) and as an aerosol to three types of non-woven fabrics [polypropylene (PP), polyester (PET), and polyamide (Nylon)] that are commonly used in the manufacture of PPE. This was followed by virus recovery using eight different eluents (phosphate-buffered saline, minimum essential medium, and 1·5% or 3·0% beef extract at pH 7, 8, or 9). Results For spike tests, no statistically significant difference was found in virus recovery using any of the eluents tested. Hydrophobic surfaces (PP and PET) yielded higher spiked virus recovery than hydrophilic Nylon. From all materials, the virus recovery was much lower in aerosol challenge tests than in spike tests. Conclusions Significant differences were found in the recovery of viable AIV from non-woven fabrics between spike and aerosol challenge tests. The findings of this study demonstrate the need for realistic aerosol challenge tests rather than liquid spike tests in studies of virus survival on surfaces where airborne transmission of influenza virus may get involved.