Abstract No:
1708
Abstract Type:
Student Poster
Authors:
A Adesina1, P Raynor2
Institutions:
1University of Minnesota, Falcon Heights, MN, 2University of Minnesota, Minneapolis, MN
Presenter:
Adepeju Adesina
University of Minnesota
Faculty Advisor:
Peter Raynor
University of Minnesota
Description:
Virus outbreaks, previously thought to be seasonal or occasional, have in recent times become a continual challenge. Workplace exposure to infectious viruses, such as influenza viruses, is common in certain workplaces, such as animal agriculture and health care settings. Viral infections and their associated illnesses exacerbate lost workdays and reduce productivity. Consequently, early and effective detection of infectious virus aerosols is necessary to protect workers. This research investigates a potential solution to this hurdle.
Situation/Problem:
The airborne route is an established transmission path for viral agents. However, limitations posed by conventional aerosol samplers have restricted our ability to effectively detect and quantify viable airborne viruses. These include particle loss due to bounce in conventional impactors, low flow rates in bioaerosol samplers, and infectivity loss associated with collection substrates. To overcome the limitations of conventional viral aerosol samplers, a size-separating air sampler, a novel 3-stage virtual impactor (VI), was designed to improve the detection and quantification of infectious viruses. The performance of the novel VI for detecting two non-pathogenic viruses was compared with that of several conventional samplers.
Methods:
An Andersen Cascade Impactor (ACI), AGI-30 impinger, AirPrep Cub filtration (ACF) sampler, and the VI were used to simultaneously collect aerosolized virus for 30 minutes. Laboratory-grown swine influenza virus (SIV) H1N1 was grown and titrated in Madin-Darby Canine Kidney (MDCK) cells and prepared in minimum essential medium. MS2 coliphage was propagated and titrated in Escherichia coli famp. Each virus was aerosolized at 20 psi using a 6-jet collison nebulizer in a negatively-pressure custom-made enclosure inside the Veterinary Isolation Facility at the University of Minnesota.
The aerosolized viruses were laced with fluorescein dye to quantify their physical collection efficiency. Three replicate tests were conducted with each virus. A total of 51 samples of each virus were collected and stored at -80°C until analysis. SIV was titrated in MDCK cells, and the 50% tissue culture infective dose (TCID50) was determined. Quantification of infectious MS2 coliphage was carried out using a double agar layer (DAL) procedure. Real-time RT-qPCR (reverse transcription-quantitative Polymerase Chain Reaction) was used to determine the cycle threshold (Ct) values. The Ct values were used to compute the viral genome copy number (SIV) and projected Plaque Forming Unit (PFU) (MS2) from a standard calibration curve. The total virus and infectious virus air concentrations for each virus were calculated, and the means were determined.
Results / Conclusions:
Results: For SIV, the VI operating at a flow rate of 300 LPM recorded the highest mean infectious virus, total virus, and fluorescein air concentrations of 308 TCID50/m3, 8.02E+12 RNA copies/m3, and 23200 ng/m3, respectively, with the highest concentrations in the after-filter collecting viruses less than 1µm. The ACF, ACI, and AGI-30 measured 3.25E+12, 3.76E+11, and 1.13E+12 RNA copies/m3, with fluorescein air concentrations of 7880, 6320, and 7360 ng/m3, respectively. The ACF, ACI, and AGI-30 operating at 200, 28.3, and 12.5 LPM recorded infectious virus air concentrations of 176, 17, and 218 TCID50 /m3, respectively. Likewise, the highest MS2 mean total virus air concentration of 2.11E+12 projected PFU/m3 was recorded by the VI. The ACF, ACI, and AGI-30 measured projected PFU/m3 of 5.75E+11, 4.23E+11, and 4.23E+11, respectively.
Discussion: The novel VI recorded the highest MS2 and SIV RNA copies. It also measured the highest SIV infectious virus and physical recovery among the tested air samplers. This can be attributed to its higher sampling flow rate. Generally, high-volume samplers enable better detection of infectious viruses. Each of the 3 stages of the VI and the after-filter detected infectious virus, providing information on the particle size of the collected infectious viruses. Limitations of this study include the bulky size of the VI and the requirement of a high-volume blower to power it. Also, the reported data is specific to the viruses used in this study.
Conclusions: These results suggest that the virtual separation of viruses in the novel impactor, combined with its high flow rate and the collection of viruses directly into liquid media through the impinger, offers an advantage for the detection and recovery of infectious viruses in the workplace.
Core Competencies:
Indoor Air Quality
Secondary Core Competencies:
Biological Hazards
Total Worker Health ®
Choose at least one (1), and up to five, (5) keywords from the following list. These selections will optimize your presentation's search results for attendees.
Aerosol and airborne particulate monitoring
Biological monitoring
Biosafety
Exposure Assessment
Indoor air quality
Based on the information that will be presented during your proposed session, please indicate the targeted audience practice level: (select one)
Professional: Professional is a job title given to persons who have obtained a baccalaureate or graduate degree in IH/OH, public health, safety, environmental sciences, biology, chemistry, physics, or engineering or who have a degree in another area that meets the standards set forth in the next section, Knowledge and Skill Sets of IH/OH Practice Levels, and has had 4 or more years of practice. One significant way of demonstrating professional competence is to achieve certification by a 3rd party whose certification scheme is recognized by the International Occupational Hygiene Association (IOHA) such as the Board of Global EHS Credentialing (BGC).
Was this session organized by an AIHA Technical Committee, Special Interest Group, Working Group, Advisory Group or other AIHA project Team?
No
Are worker exposure data and/or results of worker exposure data analysis presented?
No
How will this help advance the science of IH/OH?
It will protect workers' health by enabling early detection of viruses upon exposure.
Have you presented this information before?
No
I have read and agree to these guidelines.
Yes