Browsing by Author "Pan, Jin"

Now showing 1 - 6 of 6
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    Building Interdisciplinary Partnerships for Community-Engaged Environmental Health Research in Appalachian Virginia
    Satterwhite, Emily M.; Bell, Shannon E.; Marr, Linsey C.; Thompson, Christopher K.; Prussin, Aaron J. II; Buttling, Lauren G.; Pan, Jin; Gohlke, Julia M. (MDPI, 2020-03-05)
    This article describes a collaboration among a group of university faculty, undergraduate students, local governments, local residents, and U.S. Army staff to address long-standing concerns about the environmental health effects of an Army ammunition plant. The authors describe community-responsive scientific pilot studies that examined potential environmental contamination and a related undergraduate research course that documented residents’ concerns, contextualized those concerns, and developed recommendations. We make a case for the value of resource-intensive university–community partnerships that promote the production of knowledge through collaborations across disciplinary paradigms (natural/physical sciences, social sciences, health sciences, and humanities) in response to questions raised by local residents. Our experience also suggests that enacting this type of research through a university class may help promote researchers’ adoption of “epistemological pluralism”, and thereby facilitate the movement of a study from being “multidisciplinary” to “transdisciplinary”.
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    Environmental Stability of Enveloped Viruses Is Impacted by Initial Volume and Evaporation Kinetics of Droplets
    French, Andrea J.; Longest, Alexandra K.; Pan, Jin; Vikesland, Peter J.; Duggal, Nisha K.; Marr, Linsey C.; Lakdawala, Seema S. (American Society for Microbiology, 2023-04)
    Efficient spread of respiratory viruses requires the virus to maintain infectivity in the environment. Environmental stability of viruses can be influenced by many factors, including temperature and humidity. Our study measured the impact of initial droplet volume (50, 5, and 1 mu L) and relative humidity (RH; 40%, 65%, and 85%) on the stability of influenza A virus, bacteriophage Phi6 (a common surrogate for enveloped viruses), and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) under a limited set of conditions. Our data suggest that the drying time required for the droplets to reach quasi-equilibrium (i.e., a plateau in mass) varied with RH and initial droplet volume. The macroscale physical characteristics of the droplets at quasi-equilibrium varied with RH but not with the initial droplet volume. Virus decay rates differed between the wet phase, while the droplets were still evaporating, and the dry phase. For Phi6, decay was faster in the wet phase than in the dry phase under most conditions. For H1N1pdm09, decay rates between the two phases were distinct and initial droplet volume had an effect on virus viability within 2 h. Importantly, we observed differences in virus decay characteristics by droplet size and virus. In general, influenza virus and SARS-CoV-2 decayed similarly, whereas Phi6 decayed more rapidly under certain conditions. Overall, this study suggests that virus decay in media is related to the extent of droplet evaporation, which is controlled by RH. Importantly, accurate assessment of transmission risk requires the use of physiologically relevant droplet volumes and careful consideration of the use of surrogates. IMPORTANCE During the COVID-19 pandemic, policy decisions were being driven by virus stability experiments with SARS-CoV-2 in different droplet volumes under various humidity conditions. Our study, the first of its kind, provides a model for the decay of multiple enveloped RNA viruses in cell culture medium deposited in 50-, 5-, and 1-mu L droplets at 40%, 65%, and 85% RH over time. The results of our study indicate that determination of half-lives for emerging pathogens in large droplets may overestimate transmission risk for contaminated surfaces, as observed during the COVID-19 pandemic. Our study implicates the need for the use of physiologically relevant droplet sizes with use of relevant surrogates in addition to what is already known about the importance of physiologically relevant media for risk assessment of future emerging pathogens.
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    Filtration evaluation and clinical use of expired elastomeric P-100 filter cartridges during the COVID-19 pandemic
    Patolia, Harsh H.; Pan, Jin; Harb, Charbel; Marr, Linsey C.; Baffoe-Bonnie, Anthony W. (Cambridge University Press, 2020-05-27)
    To the Editor—The limited supply of more conventional disposable personal protective equipment (PPE), namely single-use N95 filtering facepiece respirators (FFRs), among hospital systems in the United States during the COVID-19 pandemic has been alleviated with the adoption of extended use and reuse policies by the Centers for Disease Control and Prevention (CDC).1 These measures, along with a variety of implemented decontamination methodologies (eg, ultraviolet germicidal irradiation, vaporized hydrogen peroxide, etc), have prolonged PPE supplies during pressing times. Another strategy adopted by the CDC and health systems to protect healthcare providers caring for COVID-19 patients and patients under investigation in limited resource settings includes the use of elastomeric FFRs with reusable cartridges. Although elastomeric respirators have not been approved by the Food and Drug Administration for fluid resistance, they have been endorsed by the CDC as reasonable alternatives for N95 FFRs during the COVID-19 pandemic due to their filtration approval by the National Institutes for Occupational and Safety Health (NIOSH).2 Subsequently, elastomeric respirators have formed a major arm of the COVID-19 pandemic response strategy in many hospital systems...
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    Infectious SARS-CoV-2 Is Emitted in Aerosol Particles
    Hawks, Seth A.; Prussin, Aaron J. II; Kuchinsky, Sarah C.; Pan, Jin; Marr, Linsey C.; Duggal, Nisha K. (American Society for Microbiology, 2021-10-19)
    Respiratory viruses such as SARS-CoV-2 are transmitted in respiratory droplets and aerosol particles, which are released during talking, breathing, coughing, and sneezing. Noncontact transmission of SARS-CoV-2 has been demonstrated, suggesting transmission via virus carried through the air. Here, we demonstrate that golden Syrian hamsters produce infectious SARS-CoV-2 in aerosol particles prior to and concurrent with the onset of mild clinical signs of disease. The average emission rate in this study was 25 infectious virions/hour on days 1 and 2 postinoculation, with average viral RNA levels 200-fold higher than infectious virus in aerosol particles. The majority of virus was contained within particles <5 μm in size. Thus, we provide direct evidence that, in hamsters, SARS-CoV-2 is an airborne virus.
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    Inward and outward effectiveness of cloth masks, a surgical mask, and a face shield
    Pan, Jin; Harb, Charbel; Leng, Weinan; Marr, Linsey C. (Virginia Tech, 2020-11-20)
    We evaluated the effectiveness of 11 face coverings for material filtration efficiency, inward protection efficiency on a manikin, and outward protection efficiency on a manikin. At the most penetrating particle size, the vacuum bag, microfiber cloth, and surgical mask had material filtration efficiencies >50%, while the other materials had much lower filtration efficiencies. However, these efficiencies increased rapidly with particle size, and many materials had efficiencies >50% at 2 μm and >75% at 5 μm. The vacuum bag performed best, with efficiencies of 54-96% for all three metrics, depending on particle size. The thin acrylic and face shield performed worst. Inward protection efficiency and outward protection efficiency were similar for many masks; the two efficiencies diverged for stiffer materials and those worn more loosely (e.g., bandana) or more tightly (e.g., wrapped around the head) compared to a standard earloop mask. Discrepancies between material filtration efficiency and inward/outward protection efficiency indicated that the fit of the mask was important. We calculated that the particle size most likely to deposit in the respiratory tract when wearing a mask is ∼2 μm. Based on these findings, we recommend a three-layer mask consisting of outer layers of a flexible, tightly woven fabric and an inner layer consisting of a material designed to filter out particles. This combination should produce an overall efficiency of >70% at the most penetrating particle size and >90% for particles 1 μm and larger if the mask fits well.
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    Presence and Stability of SARS-CoV-2 on Indoor Surfaces and Masks
    Pan, Jin (Virginia Tech, 2022-06-01)
    The emergence of coronavirus disease 2019 (COVID-19) has resulted in more than 300 million cases and 5 million deaths worldwide and innumerable economic losses. COVID-19 is acknowledged to transmit via air, but whether it is capable of transmitting via contaminated surfaces, also known as fomites, remains controversial. The overarching goal of this study was to investigate the presence and stability of SARS-CoV-2, the virus that causes COVID-19, on indoor surfaces and masks, and to provide insight into the possibility of fomite transmission. Since most transmission occurs indoors where humans spent 90% of their time, we first focused on quantifying the contamination level of SARS-CoV-2, including both viral RNA and viable virus, on commonly touched surfaces and in the heating, ventilation, and air cleaning (HVAC) systems in two university dormitories. Although we found up to 104 gene copies per ~10×10 cm2 on surfaces, we did not detect any viable virus, suggesting that the possibility of transmission via indoor surfaces is low. As universal masking has been recommended as an effective practice to prevent transmission of SARS-CoV-2, we shifted our focus to masks, both their effectiveness at filtering the virus from the air and their potential to serve as fomites. We evaluated the effectiveness of 11 face coverings for material filtration efficiency, inward protection efficiency on a manikin, and outward protection efficiency on a manikin. Masks made of filter materials, such as vacuum cleaner bag and HVAC filters, achieved a high material filtration efficiency whereas common textiles like cotton and acrylic usually showed the worst performance. The material filtration efficiency was generally positively correlated with either inward or outward protection effectiveness, but stiffer materials were an exception to this relationship as they did not fit as closely to the manikin's face and thus leaked substantially. Subsequently, we analyzed the survival of aerosolized SARS-CoV-2 in saliva on masks. Results suggested that the virus lost infectivity within one hour on an N95 respirator, surgical mask, polyester mask, and two types of cotton masks but not on a nylon/spandex mask. This study also highlighted the importance of applying virus in aerosols of realistic sizes when analyzing the stability of SARS-CoV-2 on surfaces.