Publications by authors named "Heinz Feldmann"

416 Publications

Recovery from Acute SARS-CoV-2 Infection and Development of Anamnestic Immune Responses in T Cell-Depleted Rhesus Macaques.

mBio 2021 Jul 27:e0150321. Epub 2021 Jul 27.

Laboratory of Virology, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseasesgrid.419681.3, National Institutes of Health, Hamilton, Montana, USA.

Severe coronavirus disease 2019 (COVID-19) has been associated with T cell lymphopenia, but no causal effect of T cell deficiency on disease severity has been established. To investigate the specific role of T cells in recovery from severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections, we studied rhesus macaques that were depleted of either CD4, CD8, or both T cell subsets prior to infection. Peak virus loads were similar in all groups, but the resolution of virus in the T cell-depleted animals was slightly delayed compared to that in controls. The T cell-depleted groups developed virus-neutralizing antibody responses and class switched to IgG. When reinfected 6 weeks later, the T cell-depleted animals showed anamnestic immune responses characterized by rapid induction of high-titer virus-neutralizing antibodies, faster control of virus loads, and reduced clinical signs. These results indicate that while T cells play a role in the recovery of rhesus macaques from acute SARS-CoV-2 infections, their depletion does not induce severe disease, and T cells do not account for the natural resistance of rhesus macaques to severe COVID-19. Neither primed CD4 nor CD8 T cells appeared critical for immunoglobulin class switching, the development of immunological memory, or protection from a second infection. Patients with severe COVID-19 often have decreased numbers of T cells, a cell type important in fighting most viral infections. However, it is not known whether the loss of T cells contributes to severe COVID-19 or is a consequence of it. We studied rhesus macaques, which develop only mild COVID-19, similar to most humans. Experimental depletion of T cells slightly prolonged their clearance of virus, but there was no increase in disease severity. Furthermore, they were able to develop protection from a second infection and produced antibodies capable of neutralizing the virus. They also developed immunological memory, which allows a much stronger and more rapid response upon a second infection. These results suggest that T cells are not critical for recovery from acute SARS-CoV-2 infections in this model and point toward B cell responses and antibodies as the essential mediators of protection from re-exposure.
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http://dx.doi.org/10.1128/mBio.01503-21DOI Listing
July 2021

Ebola Virus Glycoprotein Domains Associated with Protective Efficacy.

Vaccines (Basel) 2021 Jun 10;9(6). Epub 2021 Jun 10.

Laboratory of Virology, Division of Intramural Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT 59840, USA.

Ebola virus (EBOV) is the cause of sporadic outbreaks of human hemorrhagic disease in Africa, and the best-characterized virus in the filovirus family. The West African epidemic accelerated the clinical development of vaccines and therapeutics, leading to licensure of vaccines and antibody-based therapeutics for human use in recent years. The most widely used vaccine is based on vesicular stomatitis virus (VSV) expressing the EBOV glycoprotein (GP) (VSV-EBOV). Due to its favorable immune cell targeting, this vaccine has also been used as a base vector for the development of second generation VSV-based vaccines against Influenza, Nipah, and Zika viruses. However, in these situations, it may be beneficial if the immunogenicity against EBOV GP is minimized to induce a better protective immune response against the other foreign immunogen. Here, we analyzed if EBOV GP can be truncated to be less immunogenic, yet still able to drive replication of the vaccine vector. We found that the EBOV GP glycan cap and the mucin-like domain are both dispensable for VSV-EBOV replication. The glycan cap, however, appears critical for mediating a protective immune response against lethal EBOV challenge in mice.
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http://dx.doi.org/10.3390/vaccines9060630DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8229685PMC
June 2021

Favipiravir (T-705) Protects IFNAR Mice against Lethal Zika Virus Infection in a Sex-Dependent Manner.

Microorganisms 2021 May 29;9(6). Epub 2021 May 29.

Laboratory of Virology, Division of Intramural Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT 59840, USA.

Zika virus (ZIKV), a member of the family, is an important human pathogen that has caused epidemics in Africa, Southeast Asia, and the Americas. No licensed treatments for ZIKV disease are currently available. Favipiravir (T-705; 6-fluoro-3-hydroxy-2-pyrazinecarboxamide) and ribavirin (1-(β-D-Ribofuranosyl)-1-1,2,4-triazole-3-carboxamide) are nucleoside analogs that have exhibited antiviral activity against a broad spectrum of RNA viruses, including some flaviviruses. In this study, we strengthened evidence for favipiravir and ribavirin inhibition of ZIKV replication in vitro. Testing in IFNAR mice revealed that daily treatments of favipiravir were sufficient to provide protection against lethal ZIKV challenge in a dose-dependent manner but did not completely abrogate disease. Ribavirin, on the other hand, had no beneficial effect against ZIKV infection in this model and under the conditions examined. Combined treatment of ribavirin and favipiravir did not show improved outcomes over ribavirin alone. Surprisingly, outcome of favipiravir treatment was sex-dependent, with 87% of female but only 25% of male mice surviving lethal ZIKV infection. Since virus mutations were not associated with outcome, a sex-specific host response likely explains the observed sex difference.
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http://dx.doi.org/10.3390/microorganisms9061178DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8227069PMC
May 2021

Continuing Orthohantavirus Circulation in Deer Mice in Western Montana.

Viruses 2021 May 27;13(6). Epub 2021 May 27.

Laboratory of Virology, Division of Intramural Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT 59840, USA.

Hantavirus pulmonary syndrome (HPS) is an often-fatal disease caused by New World hantaviruses, such as (SNV). In the US, >800 cases of HPS have been confirmed since it was first discovered in 1993, of which 43 were reported from the state of Montana. The primary cause of HPS in the US is SNV, which is primarily found in the reservoir host (deer mouse). The reservoir host covers most of the US, including Montana, where multiple studies found SNV in local deer mouse populations. This study aimed to check the prevalence of SNV in the deer mice at popular recreation sites throughout the Bitterroot Valley in Western Montana as compared to previous studies in western Montana. We found high prevalence (up to 20%) of deer mice positive for SNV RNA in the lungs. We were unable to obtain a SNV tissue culture isolate from the lungs but could passage SNV from lung tissue into naïve deer mice. Our findings demonstrate continuing circulation of SNV in western Montana.
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http://dx.doi.org/10.3390/v13061006DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8226622PMC
May 2021

Nipah Virus Efficiently Replicates in Human Smooth Muscle Cells without Cytopathic Effect.

Cells 2021 May 25;10(6). Epub 2021 May 25.

Laboratory of Virology, Division of Intramural Research, NIAID, NIH, Hamilton, MT 59840, USA.

Nipah virus (NiV) is a highly pathogenic zoonotic virus with a broad species tropism, originating in pteropid bats. Human outbreaks of NiV disease occur almost annually, often with high case-fatality rates. The specific events that lead to pathogenesis are not well defined, but the disease has both respiratory and encephalitic components, with relapsing encephalitis occurring in some cases more than a year after initial infection. Several cell types are targets of NiV, dictated by the expression of the ephrin-B2/3 ligand on the cell's outer membrane, which interact with the NiV surface proteins. Vascular endothelial cells (ECs) are major targets of infection. Cytopathic effects (CPE), characterized by syncytia formation and cell death, and an ensuing vasculitis, are a major feature of the disease. Smooth muscle cells (SMCs) of the tunica media that line small blood vessels are infected in humans and animal models of NiV disease, although pathology or histologic changes associated with antigen-positive SMCs have not been reported. To gain an understanding of the possible contributions that SMCs might have in the development of NiV disease, we investigated the susceptibility and potential cytopathogenic changes of human SMCs to NiV infection in vitro. SMCs were permissive for NiV infection and resulted in high titers and prolonged NiV production, despite a lack of cytopathogenicity, and in the absence of detectable ephrin-B2/3. These results indicate that SMC might be important contributors to disease by producing progeny NiV during an infection, without suffering cytopathogenic consequences.
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http://dx.doi.org/10.3390/cells10061319DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8228331PMC
May 2021

An Intramuscular DNA Vaccine for SARS-CoV-2 Decreases Viral Lung Load but Not Lung Pathology in Syrian Hamsters.

Microorganisms 2021 May 12;9(5). Epub 2021 May 12.

Laboratory of Virology, Division of Intramural Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rocky Mountain Laboratories, Hamilton, MT 59840, USA.

The 2019 novel coronavirus, SARS-CoV-2, first reported in December 2019, has infected over 102 million people around the world as of February 2021 and thus calls for rapid development of safe and effective interventions, namely vaccines. In our study, we evaluated a DNA vaccine against SARS-CoV-2 in the Syrian hamster model. Hamsters were vaccinated with a DNA-plasmid encoding the SARS-CoV-2 full length spike open reading frame (ORF) to induce host cells to produce spike protein and protective immune responses before exposure to infectious virus. We tested this vaccine candidate by both intranasal (IN) and intramuscular (IM) routes of administration and complexing with and without an in vivo delivery reagent. Hamsters receiving prime-boost-boost IM-only vaccinations recovered body weight quicker, had decreased lung viral loads, and increased SARS-CoV-2-specific antibody titers compared to control vaccinated animals but, surprisingly, lung pathology was as severe as sham vaccinated controls. The IM/IN combination group showed no efficacy in reducing lung virus titers or pathology. With increasing public health need for rapid and effective interventions, our data demonstrate that in some vaccine contexts, significant antibody responses and decreased viral loads may not be sufficient to prevent lung pathology.
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http://dx.doi.org/10.3390/microorganisms9051040DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8151856PMC
May 2021

Ebola Virus IgG Seroprevalence in Southern Mali.

Emerg Infect Dis 2021 06;27(6):1681-1684

Mali had 2 reported introductions of Ebola virus (EBOV) during the 2013-2016 West Africa epidemic. Previously, no evidence for EBOV circulation was reported in Mali. We performed an EBOV serosurvey study in southern Mali. We found low seroprevalence in the population, indicating local exposure to EBOV or closely related ebola viruses.
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http://dx.doi.org/10.3201/eid2706.203510DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8153881PMC
June 2021

Alkhurma haemorrhagic fever virus causes lethal disease in IFNAR mice.

Emerg Microbes Infect 2021 Dec;10(1):1077-1087

Laboratory of Virology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rocky Mountain Laboratories, Hamilton, MT, USA.

Alkhurma haemorrhagic fever virus (AHFV), a tick-borne flavivirus closely related to Kyasanur Forest disease virus, is the causative agent of a severe, sometimes fatal haemorrhagic/encephalitic disease in humans. To date, there are no specific treatments or vaccines available to combat AHFV infections. A challenge for the development of countermeasures is the absence of a reliable AHFV animal disease model for efficacy testing. Here, we used mice lacking the type I interferon (IFN) receptor (IFNAR). AHFV strains Zaki-2 and 2003 both caused uniform lethality in these mice after intraperitoneal injection, but strain 2003 seemed more virulent with a median lethal dose of 0.4 median tissue culture infectious doses (TCID). Disease manifestation in this animal model was similar to case reports of severe human AHFV infections with early generalized signs leading to haemorrhagic and neurologic complications. AHFV infection resulted in early high viremia followed by high viral loads (<10 TCID/g tissue) in all analyzed organs. Despite systemic viral replication, virus-induced pathology was mainly found in the spleen, lymph nodes, liver and heart. This uniformly lethal AHFV disease model will be instrumental for pathogenesis studies and countermeasure development against this neglected zoonotic pathogen.
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http://dx.doi.org/10.1080/22221751.2021.1932609DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8183530PMC
December 2021

Has a Cellular Immune Response Profile Distinct from Laboratory Mice.

Viruses 2021 04 22;13(5). Epub 2021 Apr 22.

Laboratory of Virology, Division of Intramural Research, National Institute of Allergy and Infectious Diseases, Rocky Mountain Laboratories, National Institute of Health, Hamilton, MT 59840, USA.

The multimammate mouse () has been identified as a major reservoir for multiple human pathogens including Lassa virus (LASV), spp., spp., and spp. Although are related to well-characterized mouse and rat species commonly used in laboratory models, there is an absence of established assays and reagents to study the host immune responses of . As a result, there are major limitations to our understanding of immunopathology and mechanisms of immunological pathogen control in this increasingly important rodent species. In the current study, a large panel of commercially available rodent reagents were screened to identify their cross-reactivity with Using these reagents, ex vivo assays were established and optimized to evaluate lymphocyte proliferation and cytokine production by lymphocytes. In contrast to C57BL/6J mice, lymphocytes from were relatively non-responsive to common stimuli such as phytohaemagglutinin P and lipopolysaccharide. However, they readily responded to concanavalin A stimulation as indicated by proliferation and cytokine production. In summary, we describe lymphoproliferative and cytokine assays demonstrating that the cellular immune responses in to commonly used mitogens differ from a laboratory-bred mouse strain.
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http://dx.doi.org/10.3390/v13050729DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8145423PMC
April 2021

Lassa Virus Treatment Options.

Microorganisms 2021 Apr 7;9(4). Epub 2021 Apr 7.

Laboratory of Virology, Division of Intramural Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT 59840, USA.

Lassa fever causes an approximate 5000 to 10,000 deaths annually in West Africa and cases have been imported into Europe and the Americas, challenging public health. Although Lassa virus was first described over 5 decades ago in 1969, no treatments or vaccines have been approved to treat or prevent infection. In this review, we discuss current therapeutics in the development pipeline for the treatment of Lassa fever, focusing on those that have been evaluated in humans or animal models. Several treatments, including the antiviral favipiravir and a human monoclonal antibody cocktail, have shown efficacy in preclinical rodent and non-human primate animal models and have potential for use in clinical settings. Movement of the promising preclinical treatment options for Lassa fever into clinical trials is critical to continue addressing this neglected tropical disease.
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http://dx.doi.org/10.3390/microorganisms9040772DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8067676PMC
April 2021

Intradermal delivery of a synthetic DNA vaccine protects macaques from Middle East respiratory syndrome coronavirus.

JCI Insight 2021 05 24;6(10). Epub 2021 May 24.

Vaccine & Immunotherapy Center, The Wistar Institute, Philadelphia, Pennsylvania, USA.

Emerging coronaviruses from zoonotic reservoirs, including severe acute respiratory syndrome coronavirus (SARS-CoV), Middle East respiratory syndrome coronavirus (MERS-CoV), and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), have been associated with human-to-human transmission and significant morbidity and mortality. Here, we study both intradermal and intramuscular 2-dose delivery regimens of an advanced synthetic DNA vaccine candidate encoding a full-length MERS-CoV spike (S) protein, which induced potent binding and neutralizing antibodies as well as cellular immune responses in rhesus macaques. In a MERS-CoV challenge, all immunized rhesus macaques exhibited reduced clinical symptoms, lowered viral lung load, and decreased severity of pathological signs of disease compared with controls. Intradermal vaccination was dose sparing and more effective in this model at protecting animals from disease. The data support the further study of this vaccine for preventing MERS-CoV infection and transmission, including investigation of such vaccines and simplified delivery routes against emerging coronaviruses.
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http://dx.doi.org/10.1172/jci.insight.146082DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8262283PMC
May 2021

Inactivation of SARS-CoV-2 Laboratory Specimens.

Am J Trop Med Hyg 2021 Apr 20. Epub 2021 Apr 20.

1Laboratory of Virology, Division of Intramural Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana.

The burden on diagnostic and research laboratories to provide reliable inactivation for biological specimens to allow for safe downstream processing is high during the coronavirus disease 2019 (COVID-19) pandemic. We provide safety data regarding commonly used chemical and physical inactivation procedures that verify their effectiveness against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2).
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http://dx.doi.org/10.4269/ajtmh.21-0229DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8176508PMC
April 2021

Orally delivered MK-4482 inhibits SARS-CoV-2 replication in the Syrian hamster model.

Nat Commun 2021 04 16;12(1):2295. Epub 2021 Apr 16.

Laboratory of Virology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT, USA.

The COVID-19 pandemic progresses unabated in many regions of the world. An effective antiviral against SARS-CoV-2 that could be administered orally for use following high-risk exposure would be of substantial benefit in controlling the COVID-19 pandemic. Herein, we show that MK-4482, an orally administered nucleoside analog, inhibits SARS-CoV-2 replication in the Syrian hamster model. The inhibitory effect of MK-4482 on SARS-CoV-2 replication is observed in animals when the drug is administered either beginning 12 h before or 12 h following infection in a high-risk exposure model. These data support the potential utility of MK-4482 to control SARS-CoV-2 infection in humans following high-risk exposure as well as for treatment of COVID-19 patients.
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http://dx.doi.org/10.1038/s41467-021-22580-8DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8052374PMC
April 2021

Recovery from acute SARS-CoV-2 infection and development of anamnestic immune responses in T cell-depleted rhesus macaques.

bioRxiv 2021 Apr 4. Epub 2021 Apr 4.

Severe COVID-19 has been associated with T cell lymphopenia 1,2, but no causal effect of T cell deficiency on disease severity has been established. To investigate the specific role of T cells in recovery from SARS-CoV-2 infections we studied rhesus macaques that were depleted of either CD4+, CD8+ or both T cell subsets prior to infection. Peak virus loads were similar in all groups, but the resolution of virus in the T cell-depleted animals was slightly delayed compared to controls. The T cell-depleted groups developed virus-neutralizing antibody responses and also class-switched to IgG. When re-infected six weeks later, the T cell-depleted animals showed anamnestic immune responses characterized by rapid induction of high-titer virus-neutralizing antibodies, faster control of virus loads and reduced clinical signs. These results indicate that while T cells play a role in the recovery of rhesus macaques from acute SARS-CoV-2 infections, their depletion does not induce severe disease, and T cells do not account for the natural resistance of rhesus macaques to severe COVID-19. Neither primed CD4+ or CD8+ T cells appeared critical for immunoglobulin class switching, the development of immunological memory or protection from a second infection.
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http://dx.doi.org/10.1101/2021.04.02.438262DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8020972PMC
April 2021

Establishment of a Genetically Confirmed Breeding Colony of from Wild-Caught Founders from West Africa.

Viruses 2021 03 31;13(4). Epub 2021 Mar 31.

Laboratory of Virology, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT 59840, USA.

are a ubiquitous and often dominant rodent across sub-Saharan Africa. Importantly, they are a natural reservoir for microbial pathogens including Lassa virus (LASV), the etiological agent of Lassa fever in humans. Lassa-infected rodents have been documented across West Africa and coincide with regions where annual outbreaks occur. Zoonotic transmission to humans most often occurs directly from infected rodents. Little is known about LASV infection kinetics and transmissibility in , primarily due to available animals. Here, we describe the establishment of a laboratory breeding colony of genetically confirmed from wild-captured rodents. This colony will provide a convenient source of animals to study LASV and other emerging pathogens that utilize in their enzootic lifecycles.
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http://dx.doi.org/10.3390/v13040590DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8065687PMC
March 2021

A single intranasal dose of chimpanzee adenovirus-vectored vaccine protects against SARS-CoV-2 infection in rhesus macaques.

Cell Rep Med 2021 Apr 18;2(4):100230. Epub 2021 Mar 18.

Department of Medicine, Washington University School of Medicine, St. Louis, MO 63110, USA.

The deployment of a vaccine that limits transmission and disease likely will be required to end the coronavirus disease 2019 (COVID-19) pandemic. We recently described the protective activity of an intranasally administered chimpanzee adenovirus-vectored vaccine encoding a pre-fusion stabilized spike (S) protein (ChAd-SARS-CoV-2-S [chimpanzee adenovirus-severe acute respiratory syndrome-coronavirus-2-S]) in the upper and lower respiratory tracts of mice expressing the human angiotensin-converting enzyme 2 (ACE2) receptor. Here, we show the immunogenicity and protective efficacy of this vaccine in non-human primates. Rhesus macaques were immunized with ChAd-Control or ChAd-SARS-CoV-2-S and challenged 1 month later by combined intranasal and intrabronchial routes with SARS-CoV-2. A single intranasal dose of ChAd-SARS-CoV-2-S induces neutralizing antibodies and T cell responses and limits or prevents infection in the upper and lower respiratory tracts after SARS-CoV-2 challenge. As ChAd-SARS-CoV-2-S confers protection in non-human primates, it is a promising candidate for limiting SARS-CoV-2 infection and transmission in humans.
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http://dx.doi.org/10.1016/j.xcrm.2021.100230DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7969912PMC
April 2021

High dose of vesicular stomatitis virus-vectored Ebola virus vaccine causes vesicular disease in swine without horizontal transmission.

Emerg Microbes Infect 2021 Dec;10(1):651-663

Department of Diagnostic Medicine/Pathobiology, Center of Excellence for Emerging and Zoonotic Animal Diseases (CEEZAD), College of Veterinary Medicine, Kansas State University, Manhattan, KS, USA.

The recent impact of Ebola virus disease (EVD) on public health in Africa clearly demonstrates the need for a safe and efficacious vaccine to control outbreaks and mitigate its threat to global health. ERVEBO® is an effective recombinant Vesicular Stomatitis Virus (VSV)-vectored Ebola virus vaccine (VSV-EBOV) that was approved by the FDA and EMA in late 2019 for use in prevention of EVD. Since the parental virus VSV, which was used to construct VSV-EBOV, is pathogenic for livestock and the vaccine virus may be shed at low levels by vaccinated humans, widespread deployment of the vaccine requires investigation into its infectivity and transmissibility in VSV-susceptible livestock species. We therefore performed a comprehensive clinical analysis of the VSV-EBOV vaccine virus in swine to determine its infectivity and potential for transmission. A high dose of VSV-EBOV resulted in VSV-like clinical signs in swine, with a proportion of pigs developing ulcerative vesicular lesions at the nasal injection site and feet. Uninoculated contact control pigs co-mingled with VSV-EBOV-inoculated pigs did not become infected or display any clinical signs of disease, indicating the vaccine is not readily transmissible to naïve pigs during prolonged close contact. In contrast, virulent wild-type VSV Indiana had a shorter incubation period and was transmitted to contact control pigs. These results indicate that the VSV-EBOV vaccine causes vesicular illness in swine when administered at a high dose. Moreover, the study demonstrates the VSV-EBOV vaccine is not readily transmitted to uninfected pigs, encouraging its safe use as an effective human vaccine.
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http://dx.doi.org/10.1080/22221751.2021.1903343DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8023602PMC
December 2021

A Look into Genomes: Functions of Non-Structural (NS) Proteins.

Viruses 2021 02 18;13(2). Epub 2021 Feb 18.

Laboratory of Virology, Rocky Mountain Laboratories, Division of Intramural Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT 59840, USA.

In 2016, the order was established by the International Committee on Taxonomy of Viruses (ICTV) to incorporate the increasing number of related viruses across 13 viral families. While diverse, four of the families () contain known human pathogens and share a similar tri-segmented, negative-sense RNA genomic organization. In addition to the nucleoprotein and envelope glycoproteins encoded by the small and medium segments, respectively, many of the viruses in these families also encode for non-structural (NS) NSs and NSm proteins. The NSs of is the most extensively studied as a host interferon antagonist, functioning through a variety of mechanisms seen throughout the other three families. In addition, functions impacting cellular apoptosis, chromatin organization, and transcriptional activities, to name a few, are possessed by NSs across the families. , , and also encode an NSm, although less extensively studied than NSs, that has roles in antagonizing immune responses, promoting viral assembly and infectivity, and even maintenance of infection in host mosquito vectors. Overall, the similar and divergent roles of NS proteins of these human pathogenic are of particular interest in understanding disease progression, viral pathogenesis, and developing strategies for interventions and treatments.
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http://dx.doi.org/10.3390/v13020314DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7922539PMC
February 2021

Characterization of Ebola Virus Risk to Bedside Providers in an Intensive Care Environment.

Microorganisms 2021 Feb 26;9(3). Epub 2021 Feb 26.

Department of Paediatrics & Child Health, College of Medicine, Faculty of Health Sciences, University of Manitoba, Winnipeg, MB R3A 1S1, Canada.

Background: The 2014-2016 Ebola outbreak in West Africa recapitulated that nosocomial spread of Ebola virus could occur and that health care workers were at particular risk including notable cases in Europe and North America. These instances highlighted the need for centers to better prepare for potential Ebola virus cases; including understanding how the virus spreads and which interventions pose the greatest risk.

Methods: We created a fully equipped intensive care unit (ICU), within a Biosafety Level 4 (BSL4) laboratory, and infected multiple sedated non-human primates (NHPs) with Ebola virus. While providing bedside care, we sampled blood, urine, and gastric residuals; as well as buccal, ocular, nasal, rectal, and skin swabs, to assess the risks associated with routine care. We also assessed the physical environment at end-point.

Results: Although viral RNA was detectable in blood as early as three days post-infection, it was not detectable in the urine, gastric fluid, or swabs until late-stage disease. While droplet spread and fomite contamination were present on a few of the surfaces that were routinely touched while providing care in the ICU for the infected animal, these may have been abrogated through good routine hygiene practices.

Conclusions: Overall this study has helped further our understanding of which procedures may pose the highest risk to healthcare providers and provides temporal evidence of this over the clinical course of disease.
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http://dx.doi.org/10.3390/microorganisms9030498DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7996731PMC
February 2021

Targeting Ebola virus replication through pharmaceutical intervention.

Expert Opin Investig Drugs 2021 Mar;30(3):201-226

Laboratory of Virology, Division of Intramural Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT, USA.

. The consistent emergence/reemergence of filoviruses into a world that previously lacked an approved pharmaceutical intervention parallels an experience repeatedly played-out for most other emerging pathogenic zoonotic viruses. Investment to preemptively develop effective and low-cost prophylactic and therapeutic interventions against viruses that have high potential for emergence and societal impact should be a priority.. Candidate drugs can be characterized into those that interfere with cellular processes required for Ebola virus (EBOV) replication (host-directed), and those that directly target virally encoded functions (direct-acting). We discuss strategies to identify pharmaceutical interventions for EBOV infections. PubMed/Web of Science databases were searched to establish a detailed catalog of these interventions. Many drug candidates show promising inhibitory activity, but experience with EBOV shows the general lack of translation to efficacy for host-directed repurposed drugs. Better translation is seen for direct-acting antivirals, in particular monoclonal antibodies. The FDA-approved monoclonal antibody treatment, Inmazeb™ is a success story that could be improved in terms of impact on EBOV-associated disease and mortality, possibly by combination with other direct-acting agents targeting distinct aspects of the viral replication cycle. Costs need to be addressed given EBOV emergence primarily in under-resourced countries.
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http://dx.doi.org/10.1080/13543784.2021.1881061DOI Listing
March 2021

T-Cells and Interferon Gamma Are Necessary for Survival Following Crimean-Congo Hemorrhagic Fever Virus Infection in Mice.

Microorganisms 2021 Jan 29;9(2). Epub 2021 Jan 29.

Laboratory of Virology, NIAID/NIH, Hamilton, MT 59840, USA.

Crimean-Congo hemorrhagic fever (CCHF) is a severe tick-borne febrile illness with wide geographic distribution. In humans, the disease follows infection by the Crimean-Congo hemorrhagic fever virus (CCHFV) and begins as flu-like symptoms that can rapidly progress to hemorrhaging and death. Case fatality rates can be as high as 30%. An important gap in our understanding of CCHF are the host immune responses necessary to control the infection. A better understanding of these responses is needed to direct therapeutic strategies to limit the often-severe morbidity and mortality seen in humans. In this report, we have utilized a mouse model in which mice develop severe disease but ultimately recover. T-cells were robustly activated, differentiated to produce antiviral cytokines, and were critical for survival following CCHFV infection. We further identified a key role for interferon gamma (IFNγ) in survival following CCHFV infection. These results significantly improve our understanding of the host adaptive immune response to severe CCHFV infection.
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http://dx.doi.org/10.3390/microorganisms9020279DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7912317PMC
January 2021

A single intranasal dose of chimpanzee adenovirus-vectored vaccine protects against SARS-CoV-2 infection in rhesus macaques.

bioRxiv 2021 Jan 26. Epub 2021 Jan 26.

The deployment of a vaccine that limits transmission and disease likely will be required to end the Coronavirus Disease 2019 (COVID-19) pandemic. We recently described the protective activity of an intranasally-administered chimpanzee adenovirus-vectored vaccine encoding a pre-fusion stabilized spike (S) protein (ChAd-SARS-CoV-2-S) in the upper and lower respiratory tract of mice expressing the human angiotensin-converting enzyme 2 (ACE2) receptor. Here, we show the immunogenicity and protective efficacy of this vaccine in non-human primates. Rhesus macaques were immunized with ChAd-Control or ChAd-SARS-CoV-2-S and challenged one month later by combined intranasal and intrabronchial routes with SARS-CoV-2. A single intranasal dose of ChAd-SARS-CoV-2-S induced neutralizing antibodies and T cell responses and limited or prevented infection in the upper and lower respiratory tract after SARS-CoV-2 challenge. As this single intranasal dose vaccine confers protection against SARS-CoV-2 in non-human primates, it is a promising candidate for limiting SARS-CoV-2 infection and transmission in humans.
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http://dx.doi.org/10.1101/2021.01.26.428251DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7852261PMC
January 2021

Purification of Crimean-Congo hemorrhagic fever virus nucleoprotein and its utility for serological diagnosis.

Sci Rep 2021 Jan 27;11(1):2324. Epub 2021 Jan 27.

Division of Global Epidemiology, Hokkaido University Research Center for Zoonosis Control, Sapporo, Japan.

Crimean-Congo hemorrhagic fever virus (CCHFV) causes a zoonotic disease, Crimean-Congo hemorrhagic fever (CCHF) endemic in Africa, Asia, the Middle East, and Southeastern Europe. However, the prevalence of CCHF is not monitored in most of the endemic countries due to limited availability of diagnostic assays and biosafety regulations required for handling infectious CCHFV. In this study, we established a protocol to purify the recombinant CCHFV nucleoprotein (NP), which is antigenically highly conserved among multiple lineages/clades of CCHFVs and investigated its utility in an enzyme-linked immunosorbent assay (ELISA) to detect CCHFV-specific antibodies. The NP gene was cloned into the pCAGGS mammalian expression plasmid and human embryonic kidney 293 T cells were transfected with the plasmid. The expressed NP molecule was purified from the cell lysate using cesium-chloride gradient centrifugation. Purified NP was used as the antigen for the ELISA to detect anti-CCHFV IgG. Using the CCHFV NP-based ELISA, we efficiently detected CCHFV-specific IgG in anti-NP rabbit antiserum and CCHFV-infected monkey serum. When compared to the commercially available Blackbox CCHFV IgG ELISA kit, our assay showed equivalent performance in detecting CCHFV-specific IgG in human sera. These results demonstrate the usefulness of our CCHFV NP-based ELISA for seroepidemiological studies.
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http://dx.doi.org/10.1038/s41598-021-81752-0DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7840982PMC
January 2021

Reston virus causes severe respiratory disease in young domestic pigs.

Proc Natl Acad Sci U S A 2021 01 21;118(2). Epub 2020 Dec 21.

Laboratory of Virology, Division of Intramural Research, National Institute of Allergy and Infectious Diseases, NIH, Hamilton, MT 59840;

Reston virus (RESTV), an ebolavirus, causes clinical disease in macaques but has yet only been associated with rare asymptomatic infections in humans. Its 2008 emergence in pigs in the Philippines raised concerns about food safety, pathogenicity, and zoonotic potential, questions that are still unanswered. Until today, the virulence of RESTV for pigs has remained elusive, with unclear pathogenicity in naturally infected animals and only one experimental study demonstrating susceptibility and evidence for shedding but no disease. Here we show that combined oropharyngeal and nasal infection of young (3- to 7-wk-old) Yorkshire cross pigs with RESTV resulted in severe respiratory disease, with most animals reaching humane endpoint within a week. RESTV-infected pigs developed severe cyanosis, tachypnea, and acute interstitial pneumonia, with RESTV shedding from oronasal mucosal membranes. Our studies indicate that RESTV should be considered a livestock pathogen with zoonotic potential.
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http://dx.doi.org/10.1073/pnas.2015657118DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7812766PMC
January 2021

Single-cell RNA sequencing reveals SARS-CoV-2 infection dynamics in lungs of African green monkeys.

Sci Transl Med 2021 01 11;13(578). Epub 2021 Jan 11.

Laboratory of Virology, Division of Intramural Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT 59840, USA.

Detailed knowledge about the dynamics of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection is important for uncovering the viral and host factors that contribute to coronavirus disease 2019 (COVID-19) pathogenesis. Old-World nonhuman primates recapitulate mild to moderate cases of COVID-19, thereby serving as important pathogenesis models. We compared African green monkeys inoculated with infectious SARS-CoV-2 or irradiated, inactivated virus to study the dynamics of virus replication throughout the respiratory tract. Genomic RNA from the animals inoculated with the irradiated virus was found to be highly stable, whereas subgenomic RNA, an indicator of viral replication, was found to degrade quickly. We combined this information with single-cell RNA sequencing of cells isolated from the lung and lung-draining mediastinal lymph nodes and developed new analysis methods for unbiased targeting of important cells in the host response to SARS-CoV-2 infection. Through detection of reads to the viral genome, we were able to determine that replication of the virus in the lungs appeared to occur mainly in pneumocytes, whereas macrophages drove the inflammatory response. Monocyte-derived macrophages recruited to the lungs, rather than tissue-resident alveolar macrophages, were most likely to be responsible for phagocytosis of infected cells and cellular debris early in infection, with their roles switching during clearance of infection. Together, our dataset provides a detailed view of the dynamics of virus replication and host responses over the course of mild COVID-19 and serves as a valuable resource to identify therapeutic targets.
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http://dx.doi.org/10.1126/scitranslmed.abe8146DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7875333PMC
January 2021

A single dose of a vesicular stomatitis virus-based influenza vaccine confers rapid protection against H5 viruses from different clades.

NPJ Vaccines 2020 Jan 10;5(1). Epub 2020 Jan 10.

Laboratory of Virology, Division of Intramural Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT, USA.

The avian influenza virus outbreak in 1997 highlighted the potential of the highly pathogenic H5N1 virus to cause severe disease in humans. Therefore, effective vaccines against H5N1 viruses are needed to counter the potential threat of a global pandemic. We have previously developed a fast-acting and efficacious vaccine against Ebola virus (EBOV) using the vesicular stomatitis virus (VSV) platform. In this study, we generated recombinant VSV-based H5N1 influenza virus vectors to demonstrate the feasibility of this platform for a fast-acting pan-H5 influenza virus vaccine. We chose multiple approaches regarding antigen design and genome location to define a more optimized vaccine approach. After the VSV-based H5N1 influenza virus constructs were recovered and characterized in vitro, mice were vaccinated by a single dose or prime/boost regimen followed by challenge with a lethal dose of the homologous H5 clade 1 virus. We found that a single dose of VSV vectors expressing full-length hemagglutinin (HAfl) were sufficient to provide 100% protection. The vaccine vectors were fast-acting as demonstrated by uniform protection when administered 3 days prior to lethal challenge. Moreover, single vaccination induced cross-protective H5-specific antibodies and protected mice against lethal challenge with various H5 clade 2 viruses, highlighting the potential of the VSV-based HAfl as a pan-H5 influenza virus emergency vaccine.
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http://dx.doi.org/10.1038/s41541-019-0155-zDOI Listing
January 2020

Immunocompetent mouse model for Crimean-Congo hemorrhagic fever virus.

Elife 2021 Jan 8;10. Epub 2021 Jan 8.

Laboratory of Virology, Division of Intramural Research, NIAID, NIH, Hamilton, United States.

Crimean-Congo hemorrhagic fever (CCHF) is a severe tick-borne febrile illness with wide geographic distribution. CCHF is caused by infection with the Crimean-Congo hemorrhagic fever virus (CCHFV) and case fatality rates can be as high as 30%. Despite causing severe disease in humans, our understanding of the host and viral determinants of CCHFV pathogenesis are limited. A major limitation in the investigation of CCHF has been the lack of suitable small animal models. Wild-type mice are resistant to clinical isolates of CCHFV and consequently, mice must be deficient in type I interferon responses to study the more severe aspects of CCHFV. We report here a mouse-adapted variant of CCHFV that recapitulates in adult, immunocompetent mice the severe CCHF observed in humans. This mouse-adapted variant of CCHFV significantly improves our ability to study host and viral determinants of CCHFV-induced disease in a highly tractable mouse model.
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http://dx.doi.org/10.7554/eLife.63906DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7811403PMC
January 2021

A DNA-based vaccine protects against Crimean-Congo haemorrhagic fever virus disease in a Cynomolgus macaque model.

Nat Microbiol 2021 02 30;6(2):187-195. Epub 2020 Nov 30.

Division of Clinical Microbiology, Department of Laboratory Medicine, Karolinska Institutet at Karolinska University Hospital Huddinge, Stockholm, Sweden.

There is currently no specific prophylaxis or vaccine against Crimean-Congo haemorrhagic fever virus (CCHFV). Crimean-Congo haemorrhagic fever (CCHF) is a severe febrile illness transmitted by Hyalomma ticks in endemic areas, handling of infected livestock or care of infected patients. We report here the successful protection against CCHFV-mediated disease in a non-human primate disease model. Cynomolgus macaques were vaccinated with a DNA-based vaccine using in vivo electroporation-assisted delivery. The vaccine contained two plasmids encoding the glycoprotein precursor (GPC) and the nucleoprotein (NP) of CCHFV. Animals received three vaccinations and we recorded potent antibody and T cell responses after vaccination. While all sham-vaccinated animals developed viraemia, high tissue viral loads and CCHF-induced disease, the NP + GPC vaccinated animals were significantly protected. In conclusion, this is evidence of a vaccine that can protect against CCHFV-induced disease in a non-human primate model. This supports clinical development of the vaccine to protect groups at risk for contracting the infection.
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http://dx.doi.org/10.1038/s41564-020-00815-6DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7854975PMC
February 2021

Defining the Syrian hamster as a highly susceptible preclinical model for SARS-CoV-2 infection.

Emerg Microbes Infect 2020 Dec;9(1):2673-2684

Laboratory of Virology, Division of Intramural Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT, USA.

Following emergence in late 2019, SARS-CoV-2 rapidly became pandemic and is presently responsible for millions of infections and hundreds of thousands of deaths worldwide. There is currently no approved vaccine to halt the spread of SARS-CoV-2 and only very few treatment options are available to manage COVID-19 patients. For development of preclinical countermeasures, reliable and well-characterized small animal disease models will be of paramount importance. Here we show that intranasal inoculation of SARS-CoV-2 into Syrian hamsters consistently caused moderate broncho-interstitial pneumonia, with high viral lung loads and extensive virus shedding, but animals only displayed transient mild disease. We determined the infectious dose 50 to be only five infectious particles, making the Syrian hamster a highly susceptible model for SARS-CoV-2 infection. Neither hamster age nor sex had any impact on the severity of disease or course of infection. Finally, prolonged viral persistence in interleukin 2 receptor gamma chain knockout hamsters revealed susceptibility of SARS-CoV-2 to adaptive immune control. In conclusion, the Syrian hamster is highly susceptible to SARS-CoV-2 making it a very suitable infection model for COVID-19 countermeasure development.
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http://dx.doi.org/10.1080/22221751.2020.1858177DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7782266PMC
December 2020

Hantavirus Cardiopulmonary Syndrome in Canada.

Emerg Infect Dis 2020 12;26(12):3020-3024

Hantavirus cardiopulmonary syndrome (HCPS) is a severe respiratory disease caused by Sin Nombre virus in North America (SNV). As of January 1, 2020, SNV has caused 143 laboratory-confirmed cases of HCPS in Canada. We review critical aspects of SNV virus epidemiology and the ecology, biology, and genetics of HCPS in Canada.
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http://dx.doi.org/10.3201/eid2612.202808DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7706972PMC
December 2020
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