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Yamaoka S, Ebihara H. Pathogenicity and Virulence of Ebolaviruses with Species- and Variant-specificity. Virulence 2021; 12:885-901. [PMID: 33734027 PMCID: PMC7993122 DOI: 10.1080/21505594.2021.1898169] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2020] [Revised: 02/10/2021] [Accepted: 02/19/2021] [Indexed: 01/05/2023] Open
Abstract
Ebola virus (EBOV), belonging to the species Zaire ebolavirus in the genus Ebolavirus, causes a severe febrile illness in humans with case fatality rates (CFRs) up to 90%. While there have been six virus species classified, which each have a single type virus in the genus Ebolavirus, CFRs of ebolavirus infections vary among viruses belonging to each distinct species. In this review, we aim to define the ebolavirus species-specific virulence on the basis of currently available laboratory and experimental findings. In addition, this review will also cover the variant-specific virulence of EBOV by referring to the unique biological and pathogenic characteristics of EBOV variant Makona, a new EBOV variant isolated from the 2013-2016 EBOV disease outbreak in West Africa. A better definition of species-specific and variant-specific virulence of ebolaviruses will facilitate our comprehensive knowledge on genus Ebolavirus biology, leading to the development of therapeutics against well-focused pathogenic mechanisms of each Ebola disease.
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Affiliation(s)
- Satoko Yamaoka
- Department of Molecular Medicine, Mayo Clinic, Rochester, USA
| | - Hideki Ebihara
- Department of Molecular Medicine, Mayo Clinic, Rochester, USA
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2
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Escaffre O, Juelich TL, Neef N, Massey S, Smith J, Brasel T, Smith JK, Kalveram B, Zhang L, Perez D, Ikegami T, Freiberg AN, Comer JE. STAT-1 Knockout Mice as a Model for Wild-Type Sudan Virus (SUDV). Viruses 2021; 13:v13071388. [PMID: 34372594 PMCID: PMC8310124 DOI: 10.3390/v13071388] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2021] [Revised: 07/14/2021] [Accepted: 07/16/2021] [Indexed: 12/03/2022] Open
Abstract
Currently there is no FDA-licensed vaccine or therapeutic against Sudan ebolavirus (SUDV) infections. The largest ever reported 2014–2016 West Africa outbreak, as well as the 2021 outbreak in the Democratic Republic of Congo, highlight the critical need for countermeasures against filovirus infections. A well-characterized small animal model that is susceptible to wild-type filoviruses would greatly add to the screening of antivirals and vaccines. Here, we infected signal transducer and activator of transcription-1 knock out (STAT-1 KO) mice with five different wildtype filoviruses to determine susceptibility. SUDV and Marburg virus (MARV) were the most virulent, and caused 100% or 80% lethality, respectively. Zaire ebolavirus (EBOV), Bundibugyo ebolavirus (BDBV), and Taï Forest ebolavirus (TAFV) caused 40%, 20%, and no mortality, respectively. Further characterization of SUDV in STAT-1 KO mice demonstrated lethality down to 3.1 × 101 pfu. Viral genomic material was detectable in serum as early as 1 to 2 days post-challenge. The onset of viremia was closely followed by significant changes in total white blood cells and proportion of neutrophils and lymphocytes, as well as by an influx of neutrophils in the liver and spleen. Concomitant significant fluctuations in blood glucose, albumin, globulin, and alanine aminotransferase were also noted, altogether consistent with other models of filovirus infection. Finally, favipiravir treatment fully protected STAT-1 KO mice from lethal SUDV challenge, suggesting that this may be an appropriate small animal model to screen anti-SUDV countermeasures.
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Affiliation(s)
- Olivier Escaffre
- Department of Pathology, University of Texas Medical Branch at Galveston, Galveston, TX 77555, USA; (O.E.); (T.L.J.); (J.K.S.); (B.K.); (L.Z.); (T.I.)
| | - Terry L. Juelich
- Department of Pathology, University of Texas Medical Branch at Galveston, Galveston, TX 77555, USA; (O.E.); (T.L.J.); (J.K.S.); (B.K.); (L.Z.); (T.I.)
| | - Natasha Neef
- XTR Toxicologic Pathology Services LLC, Sterling, VA 20165, USA;
| | - Shane Massey
- Office of Regulated Nonclinical Studies, University of Texas Medical Branch at Galveston, Galveston, TX 77555, USA; (S.M.); (J.S.); (T.B.)
| | - Jeanon Smith
- Office of Regulated Nonclinical Studies, University of Texas Medical Branch at Galveston, Galveston, TX 77555, USA; (S.M.); (J.S.); (T.B.)
| | - Trevor Brasel
- Office of Regulated Nonclinical Studies, University of Texas Medical Branch at Galveston, Galveston, TX 77555, USA; (S.M.); (J.S.); (T.B.)
- Department of Microbiology and Immunology, University of Texas Medical Branch at Galveston, Galveston, TX 77555, USA
- The Center for Biodefense and Emerging Infectious Diseases, University of Texas Medical Branch at Galveston, Galveston, TX 77555, USA
| | - Jennifer K. Smith
- Department of Pathology, University of Texas Medical Branch at Galveston, Galveston, TX 77555, USA; (O.E.); (T.L.J.); (J.K.S.); (B.K.); (L.Z.); (T.I.)
| | - Birte Kalveram
- Department of Pathology, University of Texas Medical Branch at Galveston, Galveston, TX 77555, USA; (O.E.); (T.L.J.); (J.K.S.); (B.K.); (L.Z.); (T.I.)
| | - Lihong Zhang
- Department of Pathology, University of Texas Medical Branch at Galveston, Galveston, TX 77555, USA; (O.E.); (T.L.J.); (J.K.S.); (B.K.); (L.Z.); (T.I.)
| | - David Perez
- Texas A&M University Division of Research, Texas A&M University, College Station, TX 77843, USA;
| | - Tetsuro Ikegami
- Department of Pathology, University of Texas Medical Branch at Galveston, Galveston, TX 77555, USA; (O.E.); (T.L.J.); (J.K.S.); (B.K.); (L.Z.); (T.I.)
- The Center for Biodefense and Emerging Infectious Diseases, University of Texas Medical Branch at Galveston, Galveston, TX 77555, USA
- Sealy Institute for Vaccine Sciences, University of Texas Medical Branch at Galveston, Galveston, TX 77555, USA
- Institute for Human Infections and Immunity, University of Texas Medical Branch at Galveston, Galveston, TX 77555, USA
| | - Alexander N. Freiberg
- Department of Pathology, University of Texas Medical Branch at Galveston, Galveston, TX 77555, USA; (O.E.); (T.L.J.); (J.K.S.); (B.K.); (L.Z.); (T.I.)
- The Center for Biodefense and Emerging Infectious Diseases, University of Texas Medical Branch at Galveston, Galveston, TX 77555, USA
- Sealy Institute for Vaccine Sciences, University of Texas Medical Branch at Galveston, Galveston, TX 77555, USA
- Institute for Human Infections and Immunity, University of Texas Medical Branch at Galveston, Galveston, TX 77555, USA
- Correspondence: (A.N.F.); (J.E.C.)
| | - Jason E. Comer
- Office of Regulated Nonclinical Studies, University of Texas Medical Branch at Galveston, Galveston, TX 77555, USA; (S.M.); (J.S.); (T.B.)
- Department of Microbiology and Immunology, University of Texas Medical Branch at Galveston, Galveston, TX 77555, USA
- The Center for Biodefense and Emerging Infectious Diseases, University of Texas Medical Branch at Galveston, Galveston, TX 77555, USA
- Institute of Translational Sciences, University of Texas Medical Branch at Galveston, Galveston, TX 77555, USA
- Correspondence: (A.N.F.); (J.E.C.)
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Abstract
Since its discovery in 1976, Ebola virus (EBOV) has caused numerous outbreaks of fatal hemorrhagic disease in Africa. The biggest outbreak on record is the 2013-2016 epidemic in west Africa with almost 30,000 cases and over 11,000 fatalities, devastatingly affecting Guinea, Liberia, and Sierra Leone. The epidemic highlighted the need for licensed drugs or vaccines to quickly combat the disease. While at the beginning of the epidemic no licensed countermeasures were available, several experimental drugs with preclinical efficacy were accelerated into human clinical trials and used to treat patients with Ebola virus disease (EVD) toward the end of the epidemic. In the same manner, vaccines with preclinical efficacy were administered primarily to known contacts of EVD patients on clinical trial protocols using a ring-vaccination strategy. In this review, we describe the pathogenesis of EBOV and summarize the current status of EBOV vaccine development and treatment of EVD.
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Affiliation(s)
- Wakako Furuyama
- Laboratory of Virology, Division of Intramural Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana 59840, USA;
| | - Andrea Marzi
- Laboratory of Virology, Division of Intramural Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana 59840, USA;
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Abstract
Filovirus small animal disease models have so far been developed in laboratory mice, guinea pigs, and hamsters. Since immunocompetent rodents do not exhibit overt signs of disease following infection with wild-type filoviruses isolated from humans, rodent models have been established using adapted viruses produced through sequential passage in rodents. Rodent-adapted viruses target the same cells/tissues as the wild-type viruses, making rodents invaluable basic research tools for studying filovirus pathogenesis. Moreover, comparative analyses using wild-type and rodent-adapted viruses have provided beneficial insights into the molecular mechanisms of pathogenicity and acquisition of species-specific virulence. Additionally, wild-type filovirus infections in immunodeficient rodents have provided a better understanding of the host factors required for resistance to filovirus infection and of the immune response against the infection. This chapter provides comprehensive information on the filovirus rodent models and rodent-adapted filoviruses. Specifically, we summarize the clinical and pathological features of filovirus infections in all rodent models described to date, including the recently developed humanized and collaborative cross (CC) resource recombinant inbred (RI) intercrossed (CC-RIX) mouse models. We also cover the molecular determinants responsible for adaptation and virulence acquisition in a number of rodent-adapted filoviruses. This chapter clearly defines the characteristic and advantages/disadvantages of rodent models, helping to evaluate the practical use of rodent models in future filovirus studies.
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Comer JE, Escaffre O, Neef N, Brasel T, Juelich TL, Smith JK, Smith J, Kalveram B, Perez DD, Massey S, Zhang L, Freiberg AN. Filovirus Virulence in Interferon α/β and γ Double Knockout Mice, and Treatment with Favipiravir. Viruses 2019; 11:v11020137. [PMID: 30717492 PMCID: PMC6410141 DOI: 10.3390/v11020137] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2019] [Revised: 01/25/2019] [Accepted: 01/30/2019] [Indexed: 02/07/2023] Open
Abstract
The 2014 Ebolavirus outbreak in West Africa highlighted the need for vaccines and therapeutics to prevent and treat filovirus infections. A well-characterized small animal model that is susceptible to wild-type filoviruses would facilitate the screening of anti-filovirus agents. To that end, we characterized knockout mice lacking α/β and γ interferon receptors (IFNAGR KO) as a model for wild-type filovirus infection. Intraperitoneal challenge of IFNAGR KO mice with several known human pathogenic species from the genus Ebolavirus and Marburgvirus, except Bundibugyo ebolavirus and Taï Forest ebolavirus, caused variable mortality rate. Further characterization of the prototype Ebola virus Kikwit isolate infection in this KO mouse model showed 100% lethality down to a dilution equivalent to 1.0 × 10−1 pfu with all deaths occurring between 7 and 9 days post-challenge. Viral RNA was detectable in serum after challenge with 1.0 × 102 pfu as early as one day after infection. Changes in hematology and serum chemistry became pronounced as the disease progressed and mirrored the histological changes in the spleen and liver that were also consistent with those described for patients with Ebola virus disease. In a proof-of-principle study, treatment of Ebola virus infected IFNAGR KO mice with favipiravir resulted in 83% protection. Taken together, the data suggest that IFNAGR KO mice may be a useful model for early screening of anti-filovirus medical countermeasures.
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Affiliation(s)
- Jason E Comer
- Department of Microbiology and Immunology, University of Texas Medical Branch at Galveston, Galveston, TX 77555, USA.
- Office of Regulated Nonclinical Studies, University of Texas Medical Branch at Galveston, Galveston, TX 77555, USA.
- Sealy Institute for Vaccine Science, University of Texas Medical Branch at Galveston, Galveston, TX 77555, USA.
- The Center for Biodefense and Emerging Infectious Diseases, University of Texas Medical Branch at Galveston, Galveston, TX 77555, USA.
| | - Olivier Escaffre
- Department of Pathology, University of Texas Medical Branch at Galveston, Galveston, TX 77555, USA.
| | - Natasha Neef
- Experimental Pathology Laboratories, Inc., Sterling, VA 20167, USA.
| | - Trevor Brasel
- Department of Microbiology and Immunology, University of Texas Medical Branch at Galveston, Galveston, TX 77555, USA.
- Office of Regulated Nonclinical Studies, University of Texas Medical Branch at Galveston, Galveston, TX 77555, USA.
- Sealy Institute for Vaccine Science, University of Texas Medical Branch at Galveston, Galveston, TX 77555, USA.
| | - Terry L Juelich
- Department of Pathology, University of Texas Medical Branch at Galveston, Galveston, TX 77555, USA.
| | - Jennifer K Smith
- Department of Pathology, University of Texas Medical Branch at Galveston, Galveston, TX 77555, USA.
| | - Jeanon Smith
- Office of Regulated Nonclinical Studies, University of Texas Medical Branch at Galveston, Galveston, TX 77555, USA.
| | - Birte Kalveram
- Department of Pathology, University of Texas Medical Branch at Galveston, Galveston, TX 77555, USA.
| | - David D Perez
- Department of Pathology, University of Texas Medical Branch at Galveston, Galveston, TX 77555, USA.
| | - Shane Massey
- Office of Regulated Nonclinical Studies, University of Texas Medical Branch at Galveston, Galveston, TX 77555, USA.
| | - Lihong Zhang
- Department of Pathology, University of Texas Medical Branch at Galveston, Galveston, TX 77555, USA.
| | - Alexander N Freiberg
- Sealy Institute for Vaccine Science, University of Texas Medical Branch at Galveston, Galveston, TX 77555, USA.
- The Center for Biodefense and Emerging Infectious Diseases, University of Texas Medical Branch at Galveston, Galveston, TX 77555, USA.
- Department of Pathology, University of Texas Medical Branch at Galveston, Galveston, TX 77555, USA.
- Institute for Human Infections and Immunity, University of Texas Medical Branch at Galveston, Galveston, TX 77555, USA.
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Cooper TK, Huzella L, Johnson JC, Rojas O, Yellayi S, Sun MG, Bavari S, Bonilla A, Hart R, Jahrling PB, Kuhn JH, Zeng X. Histology, immunohistochemistry, and in situ hybridization reveal overlooked Ebola virus target tissues in the Ebola virus disease guinea pig model. Sci Rep 2018; 8:1250. [PMID: 29352230 PMCID: PMC5775334 DOI: 10.1038/s41598-018-19638-x] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2017] [Accepted: 01/02/2018] [Indexed: 12/20/2022] Open
Abstract
Survivors of Ebola virus infection may become subclinically infected, but whether animal models recapitulate this complication is unclear. Using histology in combination with immunohistochemistry and in situ hybridization in a retrospective review of a guinea pig confirmation-of-virulence study, we demonstrate for the first time Ebola virus infection in hepatic oval cells, the endocardium and stroma of the atrioventricular valves and chordae tendinae, satellite cells of peripheral ganglia, neurofibroblasts and Schwann cells of peripheral nerves and ganglia, smooth muscle cells of the uterine myometrium and vaginal wall, acini of the parotid salivary glands, thyroid follicular cells, adrenal medullary cells, pancreatic islet cells, endometrial glandular and surface epithelium, and the epithelium of the vagina, penis and, prepuce. These findings indicate that standard animal models for Ebola virus disease are not as well-described as previously thought and may serve as a stepping stone for future identification of potential sites of virus persistence.
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Affiliation(s)
- Timothy K Cooper
- Integrated Research Facility at Fort Detrick, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Fort Detrick, Frederick, Maryland, USA.
| | - Louis Huzella
- Integrated Research Facility at Fort Detrick, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Fort Detrick, Frederick, Maryland, USA
| | - Joshua C Johnson
- Integrated Research Facility at Fort Detrick, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Fort Detrick, Frederick, Maryland, USA
| | - Oscar Rojas
- Integrated Research Facility at Fort Detrick, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Fort Detrick, Frederick, Maryland, USA
| | - Sri Yellayi
- Integrated Research Facility at Fort Detrick, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Fort Detrick, Frederick, Maryland, USA
- Path-2-Gene, LLC, Harrisburg, PA, USA
| | - Mei G Sun
- United States Army Medical Research Institute of Infectious Diseases, Fort Detrick, Frederick, Maryland, USA
| | - Sina Bavari
- United States Army Medical Research Institute of Infectious Diseases, Fort Detrick, Frederick, Maryland, USA
| | - Amanda Bonilla
- Integrated Research Facility at Fort Detrick, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Fort Detrick, Frederick, Maryland, USA
| | - Randy Hart
- Integrated Research Facility at Fort Detrick, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Fort Detrick, Frederick, Maryland, USA
| | - Peter B Jahrling
- Integrated Research Facility at Fort Detrick, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Fort Detrick, Frederick, Maryland, USA
| | - Jens H Kuhn
- Integrated Research Facility at Fort Detrick, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Fort Detrick, Frederick, Maryland, USA
| | - Xiankun Zeng
- United States Army Medical Research Institute of Infectious Diseases, Fort Detrick, Frederick, Maryland, USA.
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More S, Bøtner A, Butterworth A, Calistri P, Depner K, Edwards S, Garin‐Bastuji B, Good M, Gortázar Schmidt C, Michel V, Miranda MA, Nielsen SS, Raj M, Sihvonen L, Spoolder H, Stegeman JA, Thulke H, Velarde A, Willeberg P, Winckler C, Baldinelli F, Broglia A, Beltrán Beck B, Kohnle L, Morgado J, Bicout D. Assessment of listing and categorisation of animal diseases within the framework of the Animal Health Law (Regulation (EU) No 2016/429): Ebola virus disease. EFSA J 2017; 15:e04890. [PMID: 32625555 PMCID: PMC7009972 DOI: 10.2903/j.efsa.2017.4890] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Ebola virus disease has been assessed according to the criteria of the Animal Health Law (AHL), in particular criteria of Article 7 on disease profile and impacts, Article 5 on the eligibility of Ebola virus disease to be listed, Article 9 for the categorisation of Ebola virus disease according to disease prevention and control rules as in Annex IV and Article 8 on the list of animal species related to Ebola virus disease. The assessment has been performed following a methodology composed of information collection and compilation, expert judgement on each criterion at individual and, if no consensus was reached before, also at collective level. The output is composed of the categorical answer, and for the questions where no consensus was reached, the different supporting views are reported. Details on the methodology used for this assessment are explained in a separate opinion. According to the assessment performed, Ebola virus disease can be considered eligible to be listed for Union intervention as laid down in Article 5(3) of the AHL. The disease would comply with the criteria as in Sections 4 and 5 of Annex IV of the AHL, for the application of the disease prevention and control rules referred to in points (d) and (e) of Article 9(1). The animal species to be listed for Ebola virus disease according to Article 8(3) criteria are some species of non‐human primates, pigs and rodents as susceptible species and some species of fruit bats as reservoir, as indicated in the present opinion.
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St Claire MC, Ragland DR, Bollinger L, Jahrling PB. Animal Models of Ebolavirus Infection. Comp Med 2017; 67:253-262. [PMID: 28662754 PMCID: PMC5482517] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2016] [Revised: 11/29/2016] [Accepted: 01/26/2017] [Indexed: 06/07/2023]
Abstract
Ebola virus is a highly pathogenic member of the family Filoviridae that causes a severe hemorrhagic disease in humans and NHP. The 2013-2016 West African outbreak has increased interest in the development and refinement of animal models of Ebola virus disease. These models are used to test countermeasures and vaccines, gain scientific insights into the mechanisms of disease progression and transmission, and study key correlates of immunology. Ebola virus is classified as a BSL4 pathogen and Category A agent, for which the United States government requires preparedness in case of bioterrorism. Rodents, such as Syrian golden hamsters (Mesocricetus auratus), mice (Mus musculus), and guinea pigs (Cavia porcellus), are the most common research species. However, NHP, especially macaques, are favored for Ebola virus disease research due to similarities with humans regarding the pathogenesis, clinical presentation, laboratory findings, and causes of fatality. To satisfy the regulatory requirements for approval of countermeasures against high-consequence pathogens, the FDA instituted the Animal Rule, which permits efficacy studies in animal models in place of human clinical data when such studies are not feasible or ethical. This review provides a comprehensive summary of various animal models and their use in Ebola virus disease research.
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Affiliation(s)
- Marisa C St Claire
- Integrated Research Facility, Division of Clinical Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Frederick, Maryland;,
| | - Dan R Ragland
- Integrated Research Facility, Division of Clinical Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Frederick, Maryland
| | - Laura Bollinger
- Integrated Research Facility, Division of Clinical Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Frederick, Maryland
| | - Peter B Jahrling
- Integrated Research Facility, Division of Clinical Research, Emerging Viral Pathogens Section, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Frederick, Maryland
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Banadyga L, Dolan MA, Ebihara H. Rodent-Adapted Filoviruses and the Molecular Basis of Pathogenesis. J Mol Biol 2016; 428:3449-66. [PMID: 27189922 PMCID: PMC5010511 DOI: 10.1016/j.jmb.2016.05.008] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2016] [Revised: 05/04/2016] [Accepted: 05/06/2016] [Indexed: 11/29/2022]
Abstract
Ebola, Marburg, and Ravn viruses, all filoviruses, are the causative agents of severe hemorrhagic fever. Much of what we understand about the pathogenesis of filovirus disease is derived from work with animal models, including nonhuman primates, which are considered the "gold standard" filovirus model since they faithfully recapitulate the clinical hallmarks of filovirus disease. However, rodent models, including the mouse, guinea pig, and hamster, also exist for Ebola, Marburg, and Ravn viruses, and although they may not reproduce all the clinical signs of filovirus disease, thanks to their relative ease of use and low cost, they are often the first choice for initial descriptions of virus pathogenesis and evaluation of antiviral prophylactics and therapeutics. Since filoviruses do not cause significant disease in adult, immunocompetent rodents, these models rely on "rodent-adapted" viruses that have been passaged several times through their host until virulence and lethality are achieved. In the process of adaptation, the viruses acquire numerous nucleotide/amino acid mutations that contribute to virulence in their rodent host. Interestingly, virus protein 24 (VP24) and nucleoprotein (NP) appear to be major virulence factors for ebolaviruses in rodents, whereas VP40 appears to be the major virulence factor for marburgviruses. By characterizing these mutations and understanding the molecular mechanisms that lead to the acquisition of virulence, we can gain better insight into the pathogenic processes that underlie filovirus disease in humans. These processes, and the viral and/or cellular proteins that contribute to them, will make attractive targets for the development of novel therapeutics and counter-measures.
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Affiliation(s)
- Logan Banadyga
- Laboratory of Virology, Division of Intramural Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT 59840, USA
| | - Michael A Dolan
- Bioinformatics and Computational Biosciences Branch, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Hideki Ebihara
- Laboratory of Virology, Division of Intramural Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT 59840, USA.
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