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Kirk NM, Liang Y, Ly H. Pathogenesis and virulence of coronavirus disease: Comparative pathology of animal models for COVID-19. Virulence 2024; 15:2316438. [PMID: 38362881 PMCID: PMC10878030 DOI: 10.1080/21505594.2024.2316438] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2023] [Accepted: 02/04/2024] [Indexed: 02/17/2024] Open
Abstract
Animal models that can replicate clinical and pathologic features of severe human coronavirus infections have been instrumental in the development of novel vaccines and therapeutics. The goal of this review is to summarize our current understanding of the pathogenesis of coronavirus disease 2019 (COVID-19) and the pathologic features that can be observed in several currently available animal models. Knowledge gained from studying these animal models of SARS-CoV-2 infection can help inform appropriate model selection for disease modelling as well as for vaccine and therapeutic developments.
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Affiliation(s)
- Natalie M. Kirk
- Department of Veterinary & Biomedical Sciences, College of Veterinary Medicine, University of Minnesota, Twin Cities, MN, USA
| | - Yuying Liang
- Department of Veterinary & Biomedical Sciences, College of Veterinary Medicine, University of Minnesota, Twin Cities, MN, USA
| | - Hinh Ly
- Department of Veterinary & Biomedical Sciences, College of Veterinary Medicine, University of Minnesota, Twin Cities, MN, USA
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2
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Pulit-Penaloza JA, Brock N, Belser JA, Sun X, Pappas C, Kieran TJ, Basu Thakur P, Zeng H, Cui D, Frederick J, Fasce R, Tumpey TM, Maines TR. Highly pathogenic avian influenza A(H5N1) virus of clade 2.3.4.4b isolated from a human case in Chile causes fatal disease and transmits between co-housed ferrets. Emerg Microbes Infect 2024; 13:2332667. [PMID: 38494746 PMCID: PMC11177717 DOI: 10.1080/22221751.2024.2332667] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2024] [Accepted: 03/15/2024] [Indexed: 03/19/2024]
Abstract
Clade 2.3.4.4b highly pathogenic avian influenza A(H5N1) viruses have caused large outbreaks within avian populations on five continents, with concurrent spillover into a variety of mammalian species. Mutations associated with mammalian adaptation have been sporadically identified in avian isolates, and more frequently among mammalian isolates following infection. Reports of human infection with A(H5N1) viruses following contact with infected wildlife have been reported on multiple continents, highlighting the need for pandemic risk assessment of these viruses. In this study, the pathogenicity and transmissibility of A/Chile/25945/2023 HPAI A(H5N1) virus, a novel reassortant with four gene segments (PB1, PB2, NP, MP) from North American lineage, isolated from a severe human case in Chile, was evaluated in vitro and using the ferret model. This virus possessed a high capacity to cause fatal disease, characterized by high morbidity and extrapulmonary spread in virus-inoculated ferrets. The virus was capable of transmission to naïve contacts in a direct contact setting, with contact animals similarly exhibiting severe disease, but did not exhibit productive transmission in respiratory droplet or fomite transmission models. Our results indicate that the virus would need to acquire an airborne transmissible phenotype in mammals to potentially cause a pandemic. Nonetheless, this work warrants continuous monitoring of mammalian adaptations in avian viruses, especially in strains isolated from humans, to aid pandemic preparedness efforts.
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Affiliation(s)
| | - Nicole Brock
- Influenza Division, NCIRD, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - Jessica A. Belser
- Influenza Division, NCIRD, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - Xiangjie Sun
- Influenza Division, NCIRD, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - Claudia Pappas
- Influenza Division, NCIRD, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - Troy J. Kieran
- Influenza Division, NCIRD, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - Poulami Basu Thakur
- Influenza Division, NCIRD, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - Hui Zeng
- Influenza Division, NCIRD, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - Dan Cui
- Influenza Division, NCIRD, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - Julia Frederick
- Influenza Division, NCIRD, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - Rodrigo Fasce
- Viral Diseases Sub Department, Public Health Institute, ISP, Santiago, Chile
| | - Terrence M. Tumpey
- Influenza Division, NCIRD, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - Taronna R. Maines
- Influenza Division, NCIRD, Centers for Disease Control and Prevention, Atlanta, GA, USA
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3
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Zumbrun EE, Zak SE, Lee ED, Bowling PA, Ruiz SI, Zeng X, Koehler JW, Delp KL, Bakken RR, Hentschel SS, Bloomfield HA, Ricks KM, Clements TL, Babka AM, Dye JM, Herbert AS. SARS-CoV-2 Aerosol and Intranasal Exposure Models in Ferrets. Viruses 2023; 15:2341. [PMID: 38140582 PMCID: PMC10747480 DOI: 10.3390/v15122341] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2023] [Revised: 11/21/2023] [Accepted: 11/23/2023] [Indexed: 12/24/2023] Open
Abstract
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the causative agent of the worldwide COVID-19 pandemic. Animal models are extremely helpful for testing vaccines and therapeutics and for dissecting the viral and host factors that contribute to disease severity and transmissibility. Here, we report the assessment and comparison of intranasal and small particle (~3 µm) aerosol SARS-CoV-2 exposure in ferrets. The primary endpoints for analysis were clinical signs of disease, recovery of the virus in the upper respiratory tract, and the severity of damage within the respiratory tract. This work demonstrated that ferrets were productively infected with SARS-CoV-2 following either intranasal or small particle aerosol exposure. SARS-CoV-2 infection of ferrets resulted in an asymptomatic disease course following either intranasal or small particle aerosol exposure, with no clinical signs, significant weight loss, or fever. In both aerosol and intranasal ferret models, SARS-CoV-2 replication, viral genomes, and viral antigens were detected within the upper respiratory tract, with little to no viral material detected in the lungs. The ferrets exhibited a specific IgG immune response to the SARS-CoV-2 full spike protein. Mild pathological findings included inflammation, necrosis, and edema within nasal turbinates, which correlated to positive immunohistochemical staining for the SARS-CoV-2 virus. Environmental sampling was performed following intranasal exposure of ferrets, and SARS-CoV-2 genomic material was detected on the feeders and nesting areas from days 2-10 post-exposure. We conclude that both intranasal and small particle aerosol ferret models displayed measurable parameters that could be utilized for future studies, including transmission studies and testing SARS-CoV-2 vaccines and therapeutics.
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Affiliation(s)
- Elizabeth E. Zumbrun
- Division of Virology, United States Army Medical Research Institute of Infectious Disease, Frederick, MD 21702, USA; (S.E.Z.); (R.R.B.); (S.S.H.); (J.M.D.); (A.S.H.)
| | - Samantha E. Zak
- Division of Virology, United States Army Medical Research Institute of Infectious Disease, Frederick, MD 21702, USA; (S.E.Z.); (R.R.B.); (S.S.H.); (J.M.D.); (A.S.H.)
| | - Eric D. Lee
- Division of Pathology, United States Army Medical Research Institute of Infectious Disease, Frederick, MD 21702, USA; (E.D.L.); (X.Z.); (H.A.B.); (A.M.B.)
| | - Philip A. Bowling
- Division of Veterinary Medicine, United States Army Medical Research Institute of Infectious Disease, Frederick, MD 21702, USA;
| | - Sara I. Ruiz
- Division of Bacteriology, United States Army Medical Research Institute of Infectious Disease, Frederick, MD 21702, USA;
| | - Xiankun Zeng
- Division of Pathology, United States Army Medical Research Institute of Infectious Disease, Frederick, MD 21702, USA; (E.D.L.); (X.Z.); (H.A.B.); (A.M.B.)
| | - Jeffrey W. Koehler
- Diagnostic Systems Division, United States Army Medical Research Institute of Infectious Disease, Frederick, MD 21702, USA; (J.W.K.); (K.L.D.); (K.M.R.); (T.L.C.)
| | - Korey L. Delp
- Diagnostic Systems Division, United States Army Medical Research Institute of Infectious Disease, Frederick, MD 21702, USA; (J.W.K.); (K.L.D.); (K.M.R.); (T.L.C.)
| | - Russel R. Bakken
- Division of Virology, United States Army Medical Research Institute of Infectious Disease, Frederick, MD 21702, USA; (S.E.Z.); (R.R.B.); (S.S.H.); (J.M.D.); (A.S.H.)
| | - Shannon S. Hentschel
- Division of Virology, United States Army Medical Research Institute of Infectious Disease, Frederick, MD 21702, USA; (S.E.Z.); (R.R.B.); (S.S.H.); (J.M.D.); (A.S.H.)
| | - Holly A. Bloomfield
- Division of Pathology, United States Army Medical Research Institute of Infectious Disease, Frederick, MD 21702, USA; (E.D.L.); (X.Z.); (H.A.B.); (A.M.B.)
| | - Keersten M. Ricks
- Diagnostic Systems Division, United States Army Medical Research Institute of Infectious Disease, Frederick, MD 21702, USA; (J.W.K.); (K.L.D.); (K.M.R.); (T.L.C.)
| | - Tamara L. Clements
- Diagnostic Systems Division, United States Army Medical Research Institute of Infectious Disease, Frederick, MD 21702, USA; (J.W.K.); (K.L.D.); (K.M.R.); (T.L.C.)
| | - April M. Babka
- Division of Pathology, United States Army Medical Research Institute of Infectious Disease, Frederick, MD 21702, USA; (E.D.L.); (X.Z.); (H.A.B.); (A.M.B.)
| | - John M. Dye
- Division of Virology, United States Army Medical Research Institute of Infectious Disease, Frederick, MD 21702, USA; (S.E.Z.); (R.R.B.); (S.S.H.); (J.M.D.); (A.S.H.)
| | - Andrew S. Herbert
- Division of Virology, United States Army Medical Research Institute of Infectious Disease, Frederick, MD 21702, USA; (S.E.Z.); (R.R.B.); (S.S.H.); (J.M.D.); (A.S.H.)
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4
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Anderson-Mondella CJJ, Maines TR, Tansey CM, Belser JA. Meeting Ferret Enrichment Needs in Infectious Disease Laboratory Settings. JOURNAL OF THE AMERICAN ASSOCIATION FOR LABORATORY ANIMAL SCIENCE : JAALAS 2023; 62:518-524. [PMID: 37857467 PMCID: PMC10772907 DOI: 10.30802/aalas-jaalas-23-000057] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/21/2023] [Revised: 08/07/2023] [Accepted: 09/12/2023] [Indexed: 10/21/2023]
Abstract
Environmental enrichment is a necessary component of all research vivarium settings. However, appropriate enrichment decisions vary greatly depending on the species involved and the research use of the animals. The increasing use of ferrets in research settings-notably for modeling the pathogenicity and transmissibility of viral pathogens that require containment in ABSL-2 to -4 environments-presents a particular challenge for veterinary and research staff to ensure that enrichment needs for these animals are met consistently. Here, we discuss the species-specific enrichment needs of ferrets, enrichment considerations for ferrets housed in research settings, and the challenges and importance of providing appropriate enrichment during experimentation, including when ferrets are housed in high-containment facilities. This article is organized to support the easy availability of information that will facilitate the design and implementation of optimal environmental enrichment for ferrets used in diverse research efforts in vivarium settings.
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Affiliation(s)
- Challie JJ Anderson-Mondella
- Comparative Medicine Branch, Division of Scientific Resources, Centers for Disease Control and Prevention, Atlanta, Georgia
- Georgia Gwinnett College, Lawrenceville, Georgia; and
| | - Taronna R Maines
- Immunology and Pathogenesis Branch, Influenza Division, Centers for Disease Control and Prevention, Atlanta, Georgia
| | - Cassandra M Tansey
- Comparative Medicine Branch, Division of Scientific Resources, Centers for Disease Control and Prevention, Atlanta, Georgia
| | - Jessica A Belser
- Immunology and Pathogenesis Branch, Influenza Division, Centers for Disease Control and Prevention, Atlanta, Georgia
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5
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Wallukat G, Wernike K, Bachamanda Somesh D, Mettenleiter TC, Müller J. Animals Experimentally Infected with SARS-CoV-2 Generate Functional Autoantibodies against G-Protein-Coupled Receptors. Biomedicines 2023; 11:2668. [PMID: 37893042 PMCID: PMC10604621 DOI: 10.3390/biomedicines11102668] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2023] [Revised: 09/20/2023] [Accepted: 09/26/2023] [Indexed: 10/29/2023] Open
Abstract
(1) Background: SARS-CoV-2 infection has been linked to diverse clinical manifestations in humans, including cardiovascular complications. Functional autoantibodies targeting G-protein-coupled receptors have emerged as potential contributors to these effects. This study sought to investigate the production and activity of functional autoantibodies targeting G-protein-coupled receptors after SARS-CoV-2 infection of selected animal species. (2) Methods: The presence of functional autoantibodies such as 2-adrenoceptor, angiotensin II AT1 receptor, muscarinic M2 receptor, and angiotensin 1-7 MAS receptor was assessed in cattle and ferrets experimentally infected with SARS-CoV-2. Bioassays were conducted to evaluate the positive or negative chronotropic responses induced by these autoantibodies. Further experiments identified the extracellular domains to which the functional autoantibodies bind, and receptor antagonists were employed to block the induced responses. (3) Results: Only two out of six cattle that were inoculated with SARS-CoV-2 displayed viral replication and tested positive for functional autoantibodies against G-protein-coupled receptors. These functional autoantibodies specifically recognized β2-adrenoceptor, angiotensin II AT1 receptor, muscarinic M2 receptor, and angiotensin 1-7 MAS receptor and induced distinct positive and negative chronotropic effects in the bioassay. Infected ferrets generated functional autoantibodies against β2-adrenoceptor and muscarinic M2 receptor and presented bioactivity similar to that in cattle. (4) Conclusions: This study uncovers functional autoantibodies targeting G-protein-coupled receptors in cattle and ferrets post-SARS-CoV-2 infection, with implications for cardiovascular function.
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Affiliation(s)
| | - Kerstin Wernike
- Friedrich-Loeffler-Institut, 17493 Greifswald-Insel Riems, Germany
| | | | | | - Johannes Müller
- Berlin Cures GmbH, 13125 Berlin, Germany;
- Berlin Heals, 10719 Berlin, Germany
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6
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Corleis B, Bastian M, Hoffmann D, Beer M, Dorhoi A. Animal models for COVID-19 and tuberculosis. Front Immunol 2023; 14:1223260. [PMID: 37638020 PMCID: PMC10451089 DOI: 10.3389/fimmu.2023.1223260] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2023] [Accepted: 07/21/2023] [Indexed: 08/29/2023] Open
Abstract
Respiratory infections cause tremendous morbidity and mortality worldwide. Amongst these diseases, tuberculosis (TB), a bacterial illness caused by Mycobacterium tuberculosis which often affects the lung, and coronavirus disease 2019 (COVID-19) caused by the Severe Acute Respiratory Syndrome Coronavirus type 2 (SARS-CoV-2), stand out as major drivers of epidemics of global concern. Despite their unrelated etiology and distinct pathology, these infections affect the same vital organ and share immunopathogenesis traits and an imperative demand to model the diseases at their various progression stages and localizations. Due to the clinical spectrum and heterogeneity of both diseases experimental infections were pursued in a variety of animal models. We summarize mammalian models employed in TB and COVID-19 experimental investigations, highlighting the diversity of rodent models and species peculiarities for each infection. We discuss the utility of non-human primates for translational research and emphasize on the benefits of non-conventional experimental models such as livestock. We epitomize advances facilitated by animal models with regard to understanding disease pathophysiology and immune responses. Finally, we highlight research areas necessitating optimized models and advocate that research of pulmonary infectious diseases could benefit from cross-fertilization between studies of apparently unrelated diseases, such as TB and COVID-19.
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Affiliation(s)
- Björn Corleis
- Institute of Immunology, Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Greifswald-Insel Riems, Germany
| | - Max Bastian
- Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Greifswald-Insel Riems, Germany
| | - Donata Hoffmann
- Institute of Diagnostic Virology, Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Greifswald-Insel Riems, Germany
| | - Martin Beer
- Institute of Diagnostic Virology, Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Greifswald-Insel Riems, Germany
| | - Anca Dorhoi
- Institute of Immunology, Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Greifswald-Insel Riems, Germany
- Faculty of Mathematics and Natural Sciences, University of Greifswald, Greifswald, Germany
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7
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Enhanced fitness of SARS-CoV-2 B.1.617.2 Delta variant in ferrets. Virology 2023; 582:57-61. [PMID: 37028126 PMCID: PMC10073010 DOI: 10.1016/j.virol.2023.03.014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2022] [Revised: 03/21/2023] [Accepted: 03/27/2023] [Indexed: 04/08/2023]
Abstract
Competition assays were conducted in vitro and in vivo to examine how the Delta (B.1.617.2) variant displaced the prototype Washington/1/2020 (WA/1) strain. While WA/1 virus exhibited a moderately increased proportion compared to that in the inoculum following co-infection in human respiratory cells, Delta variant possessed a substantial in vivo fitness advantage as this virus becoming predominant in both inoculated and contact animals. This work identifies critical traits of the Delta variant that likely played a role in it becoming a dominant variant and highlights the necessities of employing multiple model systems to assess the fitness of newly emerged SARS-CoV-2 variants.
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Zhao Y, Wang CL, Gao ZY, Qiao HX, Wang WJ, Liu XY, Chuai X. Ferrets: A powerful model of SARS-CoV-2. Zool Res 2023; 44:323-330. [PMID: 36799224 PMCID: PMC10083223 DOI: 10.24272/j.issn.2095-8137.2022.351] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2022] [Accepted: 02/16/2023] [Indexed: 02/18/2023] Open
Abstract
The rapid spread of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in recent years not only caused a global pandemic but resulted in enormous social, economic, and health burdens worldwide. Despite considerable efforts to combat coronavirus disease 2019 (COVID-19), various SARS-CoV-2 variants have emerged, and their underlying mechanisms of pathogenicity remain largely unknown. Furthermore, effective therapeutic drugs are still under development. Thus, an ideal animal model is crucial for studying the pathogenesis of COVID-19 and for the preclinical evaluation of vaccines and antivirals against SARS-CoV-2 and variant infections. Currently, several animal models, including mice, hamsters, ferrets, and non-human primates (NHPs), have been established to study COVID-19. Among them, ferrets are naturally susceptible to SARS-CoV-2 infection and are considered suitable for COVID-19 study. Here, we summarize recent developments and application of SARS-CoV-2 ferret models in studies on pathogenesis, therapeutic agents, and vaccines, and provide a perspective on the role of these models in preventing COVID-19 spread.
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Affiliation(s)
- Yan Zhao
- Department of Pathogenic Biology, Hebei Medical University, Shijiazhuang, Hebei 050017, China
- Institute of Medicine and Healthy of Hebei Medical University, Shijiazhuang, Hebei 050017, China
| | - Chang-Le Wang
- Department of Pathogenic Biology, Hebei Medical University, Shijiazhuang, Hebei 050017, China
| | - Zhi-Yun Gao
- Department of Pathogenic Biology, Hebei Medical University, Shijiazhuang, Hebei 050017, China
- Institute of Medicine and Healthy of Hebei Medical University, Shijiazhuang, Hebei 050017, China
| | - Hong-Xiu Qiao
- Department of Pathogenic Biology, Hebei Medical University, Shijiazhuang, Hebei 050017, China
- Institute of Medicine and Healthy of Hebei Medical University, Shijiazhuang, Hebei 050017, China
| | - Wei-Jie Wang
- Department of Pathogenic Biology, Hebei Medical University, Shijiazhuang, Hebei 050017, China
- Institute of Medicine and Healthy of Hebei Medical University, Shijiazhuang, Hebei 050017, China
| | - Xin-Yan Liu
- Department of Oncology, Hebei Provincial Thoracic Hospital, Shijiazhuang, Hebei 050010, China
| | - Xia Chuai
- Department of Pathogenic Biology, Hebei Medical University, Shijiazhuang, Hebei 050017, China
- Institute of Medicine and Healthy of Hebei Medical University, Shijiazhuang, Hebei 050017, China. E-mail:
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Detection of Airborne Influenza A and SARS-CoV-2 Virus Shedding following Ocular Inoculation of Ferrets. J Virol 2022; 96:e0140322. [PMID: 36448801 PMCID: PMC9769371 DOI: 10.1128/jvi.01403-22] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022] Open
Abstract
Despite reports of confirmed human infection following ocular exposure with both influenza A virus (IAV) and SARS-CoV-2, the dynamics of virus spread throughout oculonasal tissues and the relative capacity of virus transmission following ocular inoculation remain poorly understood. Furthermore, the impact of exposure route on subsequent release of airborne viral particles into the air has not been examined previously. To assess this, ferrets were inoculated by the ocular route with A(H1N1)pdm09 and A(H7N9) IAVs and two SARS-CoV-2 (early pandemic Washington/1 and Delta variant) viruses. Virus replication was assessed in both respiratory and ocular specimens, and transmission was evaluated in direct contact or respiratory droplet settings. Viral RNA in aerosols shed by inoculated ferrets was quantified with a two-stage cyclone aerosol sampler (National Institute for Occupational Safety and Health [NIOSH]). All IAV and SARS-CoV-2 viruses mounted a productive and transmissible infection in ferrets following ocular inoculation, with peak viral titers and release of virus-laden aerosols from ferrets indistinguishable from those from ferrets inoculated by previously characterized intranasal inoculation methods. Viral RNA was detected in ferret conjunctival washes from all viruses examined, though infectious virus in this specimen was recovered only following IAV inoculation. Low-dose ocular-only aerosol exposure or inhalation aerosol exposure of ferrets to IAV similarly led to productive infection of ferrets and shedding of aerosolized virus. Viral evolution during infection was comparable between all inoculation routes examined. These data support that both IAV and SARS-CoV-2 can establish a high-titer mammalian infection following ocular exposure that is associated with rapid detection of virus-laden aerosols shed by inoculated animals. IMPORTANCE Documented human infection with influenza viruses and SARS-CoV-2 has been reported among individuals wearing respiratory protection in the absence of eye protection, highlighting the capacity of these respiratory tract-tropic viruses to exploit nonrespiratory routes of exposure to initiate productive infection. However, comprehensive evaluations of how ocular exposure may modulate virus pathogenicity and transmissibility in mammals relative to respiratory exposure are limited and have not investigated multiple virus families side by side. Using the ferret model, we show that ocular exposure with multiple strains of either coronaviruses or influenza A viruses leads to an infection that results in shedding of detectable aerosolized virus from inoculated animals, contributing toward onward transmission of both viruses to susceptible contacts. Collectively, these studies support that the ocular surface represents a susceptible mucosal surface that, if exposed to a sufficient quantity of either virus, permits establishment of an infection which is similarly transmissible as that following respiratory exposure.
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