Bioaerosol sampling for the detection of aerosolized influenza virus.
BACKGROUND
Influenza virus was used to characterize the efficacy of a cyclone-based, two-stage personal bioaerosol sampler for the collection and size fractionation of aerosolized viral particles.


METHODS
A Collison single-jet nebulizer was used to aerosolize the attenuated FluMist vaccine into a calm-air settling chamber. Viral particles were captured with bioaerosol samplers that utilize 2 microcentrifuge tubes to collect airborne particulates. The first tube (T1) collects particles greater than 1.8 microm in diameter, while the second tube (T2) collects particles between 1.0 and 1.8 microm, and the back-up filter (F) collects submicron particles. Following aerosolization, quantitative PCR was used to detect and quantify H1N1 and H3N2 influenza strains.


RESULTS
Based on qPCR results, we demonstrate that aerosolized viral particles were efficiently collected and separated according to aerodynamic size using the two-stage bioaerosol sampler. Most viral particles were collected in T2 (1-1.8 microm) and on the back-up filter (< 1 microm) of the bioaerosol sampler. Furthermore, we found that the detection of viral particles with the two-stage sampler was directly proportional to the collection time. Consequently, viral particle counts were significantly greater at 40 minutes in comparison to 5, 10 and 20 minute aerosol collection points.


CONCLUSIONS
Due to a lack of empirical data, aerosol transmission of influenza is often questioned. Using FluMist, we demonstrated that a newly developed bioaerosol sampler is able to recover and size fractionate aerosolized viral particles. This sampler should be an important tool for studying viral transmission in clinical settings and may significantly contribute towards understanding the modes of influenza virus transmission.
Blachere
Francoise M
FM
Centers for Disease Control, National Institute for Occupational Safety and Health, Health Effects Laboratory Division, Allergy and Clinical Immunology Branch, Morgantown, WV 26505, USA. fblachere@cdc.gov
Lindsley
William G
WG
Slaven
James E
JE
Green
Brett J
BJ
Anderson
Stacey E
SE
Chen
Bean T
BT
Beezhold
Don H
DH
D000336:Aerosols; D006801:Humans; D053118:Influenza A Virus, H1N1 Subtype / Q000302:isolation & purification*; D053122:Influenza A Virus, H3N2 Subtype / Q000302:isolation & purification*; D012367:RNA, Viral / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000379:methods; D013048:Specimen Handling / Q000379:methods*; D013997:Time Factors
D000336:Aerosols; D012367:RNA, Viral