Denise Freeburger

United States Department of Homeland Security

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Paul A. Dabisch

United States Department of Homeland Security

David Miller

University of Florida

Victoria Wahl‐Jensen

United States Department of Homeland Security

Michael Hevey

United States Department of Homeland Security

Michael Schuit

United States Department of Homeland Security

Gregory Williams

United States Department of Homeland Security

J. Kyle Bohannon

National Institute of Allergy and Infectious Diseases

Brian Holland

Battelle

Stewart Wood

Battelle

Jennifer Biryukov

United States Department of Homeland Security

Cooperative Institutions

United States Department of Homeland Security

Battelle

National Institutes of Health

National Institute of Allergy and Infectious Diseases

United States Army Medical Research Institute of Infectious Diseases

Scientific Consulting Group

Gojo (United States)

CollegeAmerica

Defence Science and Technology Laboratory

Johns Hopkins University

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Simulated Sunlight Rapidly Inactivates SARS-CoV-2 on Surfaces

The Journal of Infectious Diseases (2020)

Shanna Ratnesar-Shumate Gregory Williams Brian Green M Krause Brian Holland

Previous studies have demonstrated that SARS-CoV-2 is stable on surfaces for extended periods under indoor conditions. In the present study, simulated sunlight rapidly inactivated SARS-CoV-2 suspended in either simulated saliva or culture media and dried on stainless steel coupons. Ninety percent of infectious virus was inactivated every 6.8 minutes in simulated saliva and every 14.3 minutes in culture media when exposed to simulated sunlight representative of the summer solstice at 40°N latitude at sea level on a clear day. Significant inactivation also occurred, albeit at a slower rate, under lower simulated sunlight levels. The present study provides the first evidence that sunlight may rapidly inactivate SARS-CoV-2 on surfaces, suggesting that persistence, and subsequently exposure risk, may vary significantly between indoor and outdoor environments. Additionally, these data indicate that natural sunlight may be effective as a disinfectant for contaminated nonporous materials.

Sunlight

2019-20 coronavirus outbreak

Sars virus

Betacoronavirus

10.1093/infdis/jiaa274

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Citations (349)

The use of an Ebola virus reporter cell line in a semi-automated microtitration assay

Journal of Virological Methods (2021)

Michael Schuit Rebecca Dunning Denise Freeburger David Miller Idris Hooper

A variety of methods have been developed for quantification of infectious Ebola virus in clinical or laboratory samples, but existing methods often require extensive operator involvement, manual assay scoring, or the use of custom reagents. In this study, we utilize a recently developed Ebola-specific reporter cell line that expresses ZsGreen in response to Ebola virus infection, in conjunction with semi-automated processing and quantification techniques, to develop an unbiased, high-throughput microtitration assay for quantification of infectious Ebola virus in vitro. This assay was found to have equivalent sensitivity to a standardized plaque assay for quantifying viral titers. However, the new assay could be implemented with fewer reagents and processing steps, reduced subjectivity, and higher throughput. This assay may be useful for a variety of applications, particularly studies that require the detection or quantification of infectious Ebola virus in large numbers of samples.

Virus quantification

Ebolavirus

10.1016/j.jviromet.2021.114116

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Citations (3)

Comparison of Dose–Response Relationships for Two Isolates of SARS-CoV-2 in a Nonhuman Primate Model of Inhalational COVID-19

Journal of Aerosol Medicine and Pulmonary Drug Delivery (2022)

Paul A. Dabisch Jaleal Sanjak Jeremy A. Boydston John J. Yeager Artemas Herzog

As the COVID-19 pandemic has progressed, numerous variants of SARS-CoV-2 have arisen, with several displaying increased transmissibility.

Viral Shedding

Pandemic

Infectious dose

10.1089/jamp.2022.0043

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Citations (6)

Two-Center Evaluation of Disinfectant Efficacy against Ebola Virus in Clinical and Laboratory Matrices

Emerging infectious diseases (2017)

Sophie J. Smither Lin Eastaugh Claire Marie Filone Denise Freeburger Artemas Herzog

Ebola virus (EBOV) in body fluids poses risk for virus transmission. However, there are limited experimental data for such matrices on the disinfectant efficacy against EBOV. We evaluated the effectiveness of disinfectants against EBOV in blood on surfaces. Only 5% peracetic acid consistently reduced EBOV titers in dried blood to the assay limit of quantification.

Disinfectant

Peracetic acid

10.3201/eid2401.170504

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Citations (11)

Comparison of the performance of aerosol sampling devices with aerosols containing Ebola virus

Aerosol Science and Technology (2020)

Michael Schuit J. R. Taylor Rebecca Dunning David Miller Denise Freeburger

Previous laboratory studies of Ebola virus aerosols have used a variety of different sampling devices to collect viral material for analysis. However, sampling devices vary in their ability to collect aerosol particles and preserve the infectivity of collected viruses. If not accounted for, this variability has the potential to bias study outcomes and confound comparisons between studies in which different samplers are used. In the present study, five laboratory-scale aerosol samplers were assessed for their ability to collect and preserve the infectivity of Ebola virus at low and high relative humidities. Relative humidity did not affect physical collection efficiencies, but infectivity was preserved better at high relative humidity for most samplers. Overall, 25-mm gelatin filters were identified as the optimal sampler among those tested based on their physical and biological efficiency, ease of use, lack of glass components, and ability to be recovered in small volumes to produce a more concentrated final sample. Tests demonstrated that 25-mm gelatin filters recovered in 2.5-mL media and assayed by microtitration using an Ebola reporter cell line resulted in an approximately 10-fold improvement in sensitivity compared to other published methods. The data provided by this study will be useful to facilitate comparisons between different studies utilizing aerosolized Ebola virus and to inform sampler selection in future studies.

Aerosolization

Infectivity

10.1080/02786826.2020.1867310

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Citations (4)

Comparison of the performance of aerosol sampling devices for measuring infectious SARS-CoV-2 aerosols

Aerosol Science and Technology (2021)

Shanna Ratnesar-Shumate Kyle Bohannon Gregory Williams Brian Holland M Krause

To assess the risk of aerosol transmission of SARS-CoV-2, measurements of the airborne viral concentrations in proximity to infected individuals, the persistence of the virus in aerosols, and the dose of the virus needed to cause infection following inhalation are required. For studies aimed at quantifying these parameters, an aerosol sampling device needs to be employed. A number of recent studies have reported the detection of both genetic material and infectious SARS-CoV-2 virus in air samples collected in clinical settings. Previous studies have demonstrated that the efficiency of different samplers for collection and preservation of the infectivity of microorganisms can vary as a function of the specific microorganism. In the present study, the performance of eight common low-flow aerosol sampling devices were compared for their ability to collect and preserve the infectivity of airborne SARS-CoV-2 contained in small particle aerosols. The influence of sampling duration on recovery of infectious virus was also evaluated. Similar concentrations of infectious SARS-CoV-2 were measured in aerosols for the majority of the samplers tested, with the exception of the midget impingers, which measured significantly lower concentrations of SARS-CoV-2. Additionally, in three of the four impingers tested, additional clean airflow through the device following collection of infectious virus resulted in a decrease of the infectious concentration of virus over time, suggesting that virus was being inactivated and these devices may not be suitable for sampling for long durations. Further, RNA copies in the samples over time did not correspond with the losses of infectious SARS-CoV-2 observed in the impingers samples. These data can be utilized to inform interpretation of current studies on the SARS-CoV-2 viral loads in air samples, as well as inform sampling device selection in future studies.

Infectivity

Bioaerosol

Airborne Transmission

Aerosolization

Virus quantification

10.1080/02786826.2021.1910137

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Citations (37)

Seroconversion and fever are dose-dependent in a nonhuman primate model of inhalational COVID-19

PLoS Pathogens (2021)

Paul A. Dabisch Jennifer Biryukov Katie Beck Jeremy A. Boydston Jaleal Sanjak

While evidence exists supporting the potential for aerosol transmission of SARS-CoV-2, the infectious dose by inhalation remains unknown. In the present study, the probability of infection following inhalation of SARS-CoV-2 was dose-dependent in a nonhuman primate model of inhalational COVID-19. The median infectious dose, assessed by seroconversion, was 52 TCID50 (95% CI: 23-363 TCID50), and was significantly lower than the median dose for fever (256 TCID50, 95% CI: 102-603 TCID50), resulting in a group of animals that developed an immune response post-exposure but did not develop fever or other clinical signs of infection. In a subset of these animals, virus was detected in nasopharyngeal and/or oropharyngeal swabs, suggesting that infected animals without signs of disease are able to shed virus and may be infectious, which is consistent with reports of asymptomatic spread in human cases of COVID-19. These results suggest that differences in exposure dose may be a factor influencing disease presentation in humans, and reinforce the importance of public health measures that limit exposure dose, such as social distancing, masking, and increased ventilation. The dose-response data provided by this study are important to inform disease transmission and hazard modeling, and, ultimately, mitigation strategies. Additionally, these data will be useful to inform dose selection in future studies examining the efficacy of therapeutics and vaccines against inhalational COVID-19, and as a baseline in healthy, young adult animals for assessment of the importance of other factors, such as age, comorbidities, and viral variant, on the infectious dose and disease presentation.

Seroconversion

Infectious dose

10.1371/journal.ppat.1009865

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Citations (42)

The Influence of Simulated Sunlight on the Inactivation of Influenza Virus in Aerosols

The Journal of Infectious Diseases (2019)

Michael Schuit Sierra Gardner Stewart Wood Kristin Bower Greg Williams

Environmental parameters, including sunlight levels, are known to affect the survival of many microorganisms in aerosols. However, the impact of sunlight on the survival of influenza virus in aerosols has not been previously quantified.The present study examined the influence of simulated sunlight on the survival of influenza virus in aerosols at both 20% and 70% relative humidity using an environmentally controlled rotating drum aerosol chamber.Measured decay rates were dependent on the level of simulated sunlight, but they were not significantly different between the 2 relative humidity levels tested. In darkness, the average decay constant was 0.02 ± 0.06 min-1, equivalent to a half-life of 31.6 minutes. However, at full intensity simulated sunlight, the mean decay constant was 0.29 ± 0.09 min-1, equivalent to a half-life of approximately 2.4 minutes.These results are consistent with epidemiological findings that sunlight levels are inversely correlated with influenza transmission, and they can be used to better understand the potential for the virus to spread under varied environmental conditions.

Sunlight

Light intensity

10.1093/infdis/jiz582

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Citations (111)

Interferon-β and Interferon-γ Are Weak Inhibitors of Ebola Virus in Cell-Based Assays

The Journal of Infectious Diseases (2017)

Julie Dyall Brit J. Hart Elena Postnikova Yu Cong Huanying Zhou

Previous studies have demonstrated little efficacy of interferons (IFNs) in animal models of Ebola virus disease.However, these studies were limited to a small number of type I IFNs and, during the most recent outbreak of Ebola virus, questions regarding the suitability of the animal models to evaluate IFNs were raised.To address the potential that anti-Ebola virus activity was overlooked, type I and type II IFNs (α-2a, α-2b, -β, -γ, and -universal) were tested in a variety of cell types (Vero E6, Huh 7 cells, and human macrophages).IFNs are weak inhibitors of Ebola virus Makona in these cell lines.

Vero cell

Ebolavirus

10.1093/infdis/jix134

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Citations (9)

SARS-CoV-2 inactivation by ultraviolet radiation and visible light is dependent on wavelength and sample matrix

Journal of Photochemistry and Photobiology B Biology (2022)

Michael Schuit Thomas C. Larason M Krause Brian M. Green Brian Holland

Numerous studies have demonstrated that SARS-CoV-2 can be inactivated by ultraviolet (UV) radiation. However, there are few data available on the relative efficacy of different wavelengths of UV radiation and visible light, which complicates assessments of UV decontamination interventions. The present study evaluated the effects of monochromatic radiation at 16 wavelengths from 222 nm through 488 nm on SARS-CoV-2 in liquid aliquots and dried droplets of water and simulated saliva. The data were used to generate a set of action spectra which quantify the susceptibility of SARS-CoV-2 to genome damage and inactivation across the tested wavelengths. UVC wavelengths (≤280 nm) were most effective for inactivating SARS-CoV-2, although inactivation rates were dependent on sample type. Results from this study suggest that UV radiation can effectively inactivate SARS-CoV-2 in liquids and dried droplets, and provide a foundation for understanding the factors which affect the efficacy of different wavelengths in real-world settings.

Ultraviolet

Monochromatic color

Visible spectrum

Action spectrum

10.1016/j.jphotobiol.2022.112503

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Citations (29)