Investigating the Cellular #Transcriptomic Response Induced by the #Makona Variant of #Ebola Virus in Differentiated THP-1 Cells (Viruses, abstract)

[Source: US National Library of Medicine, full page: (LINK). Abstract, edited.]

Viruses. 2019 Nov 4;11(11). pii: E1023. doi: 10.3390/v11111023.

Investigating the Cellular Transcriptomic Response Induced by the Makona Variant of Ebola Virus in Differentiated THP-1 Cells.

Bosworth A1,2,3, Dowall SD4, Armstrong S5,6, Liu X7,8, Dong X9, Bruce CB10, F P Ng L11,12,13, Carroll MW14,15, Hewson R16,17, Hiscox JA18,19,20.

Author information: 1 Public Health England, Manor Farm Road, Porton Down, Salisbury SP4 OJG, UK. Andrew.Bosworth@phe.gov.uk. 2 Health Protection Research Unit in Emerging and Zoonotic Infections, National Institute for Health Research, Liverpool L3 5RF, UK. Andrew.Bosworth@phe.gov.uk. 3 Clinical Virology, Regional Public Health Laboratory, Public Health England, Bordeseley Green East, Birmingham B9 5SS, UK. Andrew.Bosworth@phe.gov.uk. 4 Public Health England, Manor Farm Road, Porton Down, Salisbury SP4 OJG, UK. Stuart.dowall@phe.gov.uk. 5 Health Protection Research Unit in Emerging and Zoonotic Infections, National Institute for Health Research, Liverpool L3 5RF, UK. Stuart.Armstrong@liverpool.ac.uk. 6 Institute of Infection and Global Health, University of Liverpool, Liverpool L3 5RF, UK. Stuart.Armstrong@liverpool.ac.uk. 7 Health Protection Research Unit in Emerging and Zoonotic Infections, National Institute for Health Research, Liverpool L3 5RF, UK. Xuan.Liu@Liverpool.ac.uk. 8 Centre for Genomics Research, University of Liverpool, Liverpool L3 5RF, UK. Xuan.Liu@Liverpool.ac.uk. 9 Institute of Infection and Global Health, University of Liverpool, Liverpool L3 5RF, UK. Xiaofeng.Dong@liverpool.ac.uk. 10 Public Health England, Manor Farm Road, Porton Down, Salisbury SP4 OJG, UK. Christine.bruce@phe.gov.uk. 11 Health Protection Research Unit in Emerging and Zoonotic Infections, National Institute for Health Research, Liverpool L3 5RF, UK. Lisa.Ng@liverpool.ac.uk. 12 Institute of Infection and Global Health, University of Liverpool, Liverpool L3 5RF, UK. Lisa.Ng@liverpool.ac.uk. 13 Singapore Immunology Network, A*Star, Biopolis, Singapore 138648, Singapore. Lisa.Ng@liverpool.ac.uk. 14 Public Health England, Manor Farm Road, Porton Down, Salisbury SP4 OJG, UK. Miles.carroll@phe.gov.uk. 15 Health Protection Research Unit in Emerging and Zoonotic Infections, National Institute for Health Research, Liverpool L3 5RF, UK. Miles.carroll@phe.gov.uk. 16 Public Health England, Manor Farm Road, Porton Down, Salisbury SP4 OJG, UK. roger.hewson@phe.gov.uk. 17 Health Protection Research Unit in Emerging and Zoonotic Infections, National Institute for Health Research, Liverpool L3 5RF, UK. roger.hewson@phe.gov.uk. 18 Health Protection Research Unit in Emerging and Zoonotic Infections, National Institute for Health Research, Liverpool L3 5RF, UK. julian.hiscox@liverpool.ac.uk. 19 Institute of Infection and Global Health, University of Liverpool, Liverpool L3 5RF, UK. julian.hiscox@liverpool.ac.uk. 20 Singapore Immunology Network, A*Star, Biopolis, Singapore 138648, Singapore. julian.hiscox@liverpool.ac.uk.

 

Abstract

Recent studies have shown that transcriptomic analysis of blood samples taken from patients with acute Ebola virus disease (EVD) during the 2013-2016 West African outbreak was suggestive that a severe inflammatory response took place in acutely ill patients. The significant knowledge gained from studying the Makona variant, a cause of the largest known EVD outbreak, may be applicable to other species of ebolavirus, and other variants of the Ebola virus (EBOV) species. To investigate the ability of Makona to initiate an inflammatory response in human macrophages and characterise the host response in a similar manner to previously characterised EBOV variants, the human monocytic cell line THP-1 was differentiated into macrophage-like cells and infected with Makona. RNA-Seq and quantitative proteomics were used to identify and quantify host mRNA and protein abundance during infection. Data from infection with Reston virus (RESTV) were used as comparators to investigate changes that may be specific to, or enhanced in, Makona infection in relation to a less pathogenic species of ebolavirus.. This study found demonstrable induction of the inflammatory response, and increase in the activation state of THP-1 macrophages infected with Makona. NFκB and inflammation-associated transcripts displayed significant changes in abundance, reflective of what was observed in human patients during the 2013-2016 EBOV outbreak in West Africa, and demonstrated that transcriptomic changes found in Makona-infected cells were similar to that observed in Reston virus infection and that have been described in previous studies of other variants of EBOV.

KEYWORDS: Ebola virus; Makona; West Africa; proteomics; transcriptomics

PMID: 31689981 DOI: 10.3390/v11111023

Keywords: Ebola; Ebola-Makona; Ebola-Reston; Viral pathogenesis.

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Single low-dose VSV-EBOV #vaccination protects cynomolgus #macaques from lethal #Ebola challenge (EBioMedicine, abstract)

[Source: US National Library of Medicine, full page: (LINK). Abstract, edited.]

EBioMedicine. 2019 Oct 16. pii: S2352-3964(19)30651-6. doi: 10.1016/j.ebiom.2019.09.055. [Epub ahead of print]

Single low-dose VSV-EBOV vaccination protects cynomolgus macaques from lethal Ebola challenge.

Marzi A1, Reynolds P2, Mercado-Hernandez R2, Callison J2, Feldmann F3, Rosenke R3, Thomas T2, Scott DP3, Hanley PW3, Haddock E2, Feldmann H4.

Author information: 1 Laboratory of Virology, Division of Intramural Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT, USA. Electronic address: marzia@niaid.nih.gov. 2 Laboratory of Virology, Division of Intramural Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT, USA. 3 Rocky Mountain Veterinary Branch, Division of Intramural Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT, USA. 4 Laboratory of Virology, Division of Intramural Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT, USA. Electronic address: feldmannh@niaid.nih.gov.

 

Abstract

BACKGROUND:

Ebola virus (EBOV), variant Makona, was the causative agent of the 2013-2016 West African epidemic responsible for almost 30,000 human infections and over 11,000 fatalities. During the epidemic, the development of several experimental vaccines was accelerated through human clinical trials. One of them, the vesicular stomatitis virus (VSV)-based vaccine VSV-EBOV, showed promising efficacy in a phase 3 clinical trial in Guinea and is currently used in the ongoing EBOV outbreak in the northeastern part of the Democratic Republic of the Congo (DRC). This vaccine expresses the EBOV-Kikwit glycoprotein from the 1995 outbreak as the immunogen.

METHODS:

Here we generated a VSV-based vaccine expressing the contemporary EBOV-Makona glycoprotein. We characterized the vaccine in tissue culture and analyzed vaccine efficacy in the cynomolgus macaque model. Subsequently, we determined the dose-dependent protective efficacy in nonhuman primates against lethal EBOV challenge.

FINDINGS:

We observed complete protection from disease with VSV-EBOV doses ranging from 1 × 107 to 1 × 101 plaque-forming units. Some protected animals receiving lower vaccine doses developed temporary low-level EBOV viremia. Control animals developed classical EBOV disease and reached euthanasia criteria within a week after challenge. This study demonstrates that very low doses of VSV-EBOV uniformly protect macaques against lethal EBOV challenge.

INTERPRETATION:

Our study provides missing pre-clinical data supporting the use of reduced VSV-EBOV vaccine doses without decreasing protective efficacy and at the same time increase vaccine safety and availability – two critical concerns in public health response.

FUNDING:

Division of Intramural Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health.

Published by Elsevier B.V.

KEYWORDS: EBOV-Makona; Ebola virus; Low-dose vaccination; Macaque model; VSV-EBOV

PMID: 31631035 DOI: 10.1016/j.ebiom.2019.09.055

Keywords: Ebola; Ebola-Makona; Vaccines; Animal models.

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Impact of #intensive #care unit supportive care on the #physiology of #Ebola virus disease in a universally lethal #NHP #model (Intensive Care Med Exp., abstract)

[Source: US National Library of Medicine, full page: (LINK). Abstract, edited.]

Intensive Care Med Exp. 2019 Sep 13;7(1):54. doi: 10.1186/s40635-019-0268-8.

Impact of intensive care unit supportive care on the physiology of Ebola virus disease in a universally lethal non-human primate model.

Poliquin G1,2,3, Funk D4, Jones S1, Tran K1, Ranadheera C1, Hagan M1,3, Tierney K1, Grolla A1, Dhaliwal A5, Bello A1, Leung A1, Nakamura C6, Kobasa D1,3, Falzarano D7, Garnett L1, Bovendo HF8, Feldmann H9, Kesselman M2, Hansen G10, Gren J1, Risi G11, Biondi M12,13, Mortimer T13, Racine T3,8, Deschambault Y1, Aminian S1, Edmonds J1, Sourette R1, Allan M1, Rondeau L1, Hadder S1, Press C1, DeGraff C1, Kucas S1, Cook BWM14, Hancock BJ2,15, Kumar A3, Soni R2, Schantz D2, McKitrick J16, Warner B1, Griffin BD1, Qiu X1,3, Kobinger GP3,8, Safronetz D1, Stein D1,3, Cutts T1, Kenny J1, Soule G1, Kozak R17, Theriault S14, Menec L1, Vendramelli R1, Higgins S1, Liu G1, Rahim NM1, Kasloff S1, Sloan A1, He S1, Tailor N1, Gray M1, Strong JE18,19,20.

Author information: 1 National Microbiology Laboratory, Public Health Agency of Canada, 1015 rue Arlington Street, Winnipeg, Manitoba, R3E 3R2, Canada. 2 Department of Pediatrics & Child Health, College of Medicine, Faculty of Health Sciences, University of Manitoba, Winnipeg, Manitoba, Canada. 3 Department of Infectious Diseases and Medical Microbiology, College of Medicine, Faculty of Health Sciences, University of Manitoba, Winnipeg, Manitoba, Canada. 4 Department of Anaesthesia and Medicine, College of Medicine, Faculty of Health Sciences, University of Manitoba, Winnipeg, Manitoba, Canada. 5 Medtronic Canada, Winnipeg, Manitoba, Canada. 6 National Centre for Foreign Animal Disease, Canadian Food Inspection Agency, Winnipeg, Manitoba, Canada. 7 Vaccine and Infectious Disease Organization-International Vaccine Centre, University of Saskatchewan, Saskatoon, Canada. 8 Centre de Recherche en Infectiologie, Centre Hospitalier Universitaire de Québec, Université Laval, Québec, Canada. 9 Laboratory of Virology, Division of Intramural Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, USA. 10 Faculty of Critical Care, Royal University Hospital, Saskatoon, Saskatchewan, Canada. 11 Infectious Disease Specialists, P.C., Missoula, MT, USA. 12 Arthur Labatt Family School of Nursing, Western University, London, Ontario, Canada. 13 Child & Women’s Health Programme, Winnipeg Regional Health Authority, Winnipeg, Manitoba, Canada. 14 Cytophage Technologies, Inc., St. Boniface Hospital, Albrechtsen Research Centre, Winnipeg, Manitoba, Canada. 15 Department of Surgery, Division of Pediatric Surgery, College of Medicine, Faculty of Health Sciences, University of Manitoba, Winnipeg, Manitoba, Canada. 16 Regional Pharmacy, Winnipeg Regional Health Authority, Winnipeg, Manitoba, Canada. 17 Department of Laboratory Medicine & Pathobiology, University of Toronto, Toronto, Ontario, Canada. 18 National Microbiology Laboratory, Public Health Agency of Canada, 1015 rue Arlington Street, Winnipeg, Manitoba, R3E 3R2, Canada. jim.strong@canada.ca. 19 Department of Pediatrics & Child Health, College of Medicine, Faculty of Health Sciences, University of Manitoba, Winnipeg, Manitoba, Canada. jim.strong@canada.ca. 20 Department of Infectious Diseases and Medical Microbiology, College of Medicine, Faculty of Health Sciences, University of Manitoba, Winnipeg, Manitoba, Canada. jim.strong@canada.ca.

 

Abstract

BACKGROUND:

There are currently limited data for the use of specific antiviral therapies for the treatment of Ebola virus disease (EVD). While there is anecdotal evidence that supportive care may be effective, there is a paucity of direct experimental data to demonstrate a role for supportive care in EVD. We studied the impact of ICU-level supportive care interventions including fluid resuscitation, vasoactive medications, blood transfusion, hydrocortisone, and ventilator support on the pathophysiology of EVD in rhesus macaques infected with a universally lethal dose of Ebola virus strain Makona C07.

METHODS:

Four NHPs were infected with a universally lethal dose Ebola virus strain Makona, in accordance with the gold standard lethal Ebola NHP challenge model. Following infection, the following therapeutic interventions were employed: continuous bedside supportive care, ventilator support, judicious fluid resuscitation, vasoactive medications, blood transfusion, and hydrocortisone as needed to treat cardiovascular compromise. A range of physiological parameters were continuously monitored to gage any response to the interventions.

RESULTS:

All four NHPs developed EVD and demonstrated a similar clinical course. All animals reached a terminal endpoint, which occurred at an average time of 166.5 ± 14.8 h post-infection. Fluid administration may have temporarily blunted a rise in lactate, but the effect was short lived. Vasoactive medications resulted in short-lived improvements in mean arterial pressure. Blood transfusion and hydrocortisone did not appear to have a significant positive impact on the course of the disease.

CONCLUSIONS:

The model employed for this study is reflective of an intramuscular infection in humans (e.g., needle stick) and is highly lethal to NHPs. Using this model, we found that the animals developed progressive severe organ dysfunction and profound shock preceding death. While the overall impact of supportive care on the observed pathophysiology was limited, we did observe some time-dependent positive responses. Since this model is highly lethal, it does not reflect the full spectrum of human EVD. Our findings support the need for continued development of animal models that replicate the spectrum of human disease as well as ongoing development of anti-Ebola therapies to complement supportive care.

KEYWORDS: Ebola; Fluid; Hydrocortisone; NHP; Pathophysiology; Supportive care; Vasoactives; Ventilatory support

PMID: 31520194 DOI: 10.1186/s40635-019-0268-8

Keywords: Ebola; Ebola-Makona; Intensive care; Animal models.

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Subsequent #mortality in #survivors of #Ebola virus disease in #Guinea: a nationwide retrospective cohort study (Lancet Infect Dis., abstract)

[Source: The Lancet Infectious Diseases, full page: (LINK). Abstract, edited.]

Subsequent mortality in survivors of Ebola virus disease in Guinea: a nationwide retrospective cohort study

Mory Keita, MD, Boubacar Diallo, MD, Samuel Mesfin, BSc, Abdourahmane Marega, PharmD, Koumpingnin Yacouba Nebie, MD, N’Faly Magassouba, PhD, Ahmadou Barry, MD, Seydou Coulibaly, MD, Boubacar Barry, BSc, Mamadou Oury Baldé, MD, Raymond Pallawo, MD, Sadou Sow, MPH, Prof Alpha Oumar Bah, MD, Mamadou Saliou Balde, MD, Steven Van Gucht, PhD, Prof Mandy Kader Kondé, PhD, Amadou Bailo Diallo, MD, Mamoudou Harouna Djingarey, MD, Ibrahima Socé Fall, PhD, Pierre Formenty, DVM, Prof Judith R Glynn, PhD, Lorenzo Subissi, PhD

Published: September 04, 2019 / DOI: https://doi.org/10.1016/S1473-3099(19)30313-5

 

Summary

Background

A record number of people survived Ebola virus infection in the 2013–16 outbreak in west Africa, and the number of survivors has increased after subsequent outbreaks. A range of post-Ebola sequelae have been reported in survivors, but little is known about subsequent mortality. We aimed to investigate subsequent mortality among people discharged from Ebola treatment units.

Methods

From Dec 8, 2015, Surveillance Active en ceinture, the Guinean national survivors’ monitoring programme, attempted to contact and follow-up all survivors of Ebola virus disease who were discharged from Ebola treatment units. Survivors were followed up until Sept 30, 2016, and deaths up to this timepoint were recorded. Verbal autopsies were done to gain information about survivors of Ebola virus disease who subsequently died from their closest family members. We calculated the age-standardised mortality ratio compared with the general Guinean population, and assessed risk factors for mortality using survival analysis and a Cox proportional hazards regression model.

Findings

Of the 1270 survivors of Ebola virus disease who were discharged from Ebola treatment units in Guinea, information was retrieved for 1130 (89%). Compared with the general Guinean population, survivors of Ebola virus disease had a more than five-times increased risk of mortality up to Dec 31, 2015 (age-standardised mortality ratio 5·2 [95% CI 4·0–6·8]), a mean of 1 year of follow-up after discharge. Thereafter (ie, from Jan 1–Sept 30, 2016), mortality did not differ between survivors of Ebola virus disease and the general population. (0·6 [95% CI 0·2–1·4]). Overall, 59 deaths were reported, and the cause of death was tentatively attributed to renal failure in 37 cases, mostly on the basis of reported anuria. Longer stays (ie, equal to or longer than the median stay) in Ebola treatment units were associated with an increased risk of late death compared with shorter stays (adjusted hazard ratio 2·62 [95% CI 1·43–4·79]).

Interpretation

Mortality was high in people who recovered from Ebola virus disease and were discharged from Ebola treatment units in Guinea. The finding that survivors who were hospitalised for longer during primary infection had an increased risk of death, could help to guide current and future survivors’ programmes and in the prioritisation of funds in resource-constrained settings. The role of renal failure in late deaths after recovery from Ebola virus disease should be investigated.

Funding

WHO, International Medical Corps, and the Guinean Red Cross.

Keywords: Ebola; Ebola-Makona; Post Ebola Virus Disease Syndrome; Guinea.

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Increased #mortality in #survivors of #Ebola virus disease (Lancet Infect Dis., summary)

[Source: The Lancet Infectious Diseases, full page: (LINK). Summary, edited.]

Increased mortality in survivors of Ebola virus disease

Hugues Fausther-Bovendo, Gary Kobinger

Published: September 04, 2019 / DOI: https://doi.org/10.1016/S1473-3099(19)30429-3

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Long-term sequelae of Ebola virus disease—including myalgia, arthralgia, ocular diseases, and mental confusion—have come to light in survivors of the 2014–16 Ebola outbreak in west Africa. The frequency and duration of these sequelae, which are collectively referred to as post-Ebola virus disease syndrome, have since been reported. 1 However, information about subsequent mortality in survivors of Ebola is scarce. Anecdotal reports and one previous study 2  have documented the unexpected death of survivors of Ebola virus disease after viral clearance and discharge from Ebola treatment units, suggesting that the acute phase of the disease can lead to protracted death in some survivors, but no systematic investigations of increased mortality in survivors have previously been published.

(…)

Keywords: Ebola; West Africa; Ebola-Makona.

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#Serological #analysis of #Ebola virus #survivors and close #contacts in #SierraLeone: A cross-sectional study (PLoS Negl Trop Dis., abstract)

[Source: PLoS Neglected Tropical Diseases, full page: (LINK). Abstract, edited.]

OPEN ACCESS /  PEER-REVIEWED / RESEARCH ARTICLE

Serological analysis of Ebola virus survivors and close contacts in Sierra Leone: A cross-sectional study

Peter J. Halfmann , Amie J. Eisfeld, Tokiko Watanabe, Tadashi Maemura, Makoto Yamashita, Satoshi Fukuyama, Tammy Armbrust, Isaiah Rozich, Alhaj N’jai, Gabriele Neumann, Yoshihiro Kawaoka , Foday Sahr

Published: August 1, 2019 / DOI: https://doi.org/10.1371/journal.pntd.0007654 / This is an uncorrected proof.

 

Abstract

The 2013–2016 Ebola virus outbreak in West Africa was the largest and deadliest outbreak to date. Here we conducted a serological study to examine the antibody levels in survivors and the seroconversion in close contacts who took care of Ebola-infected individuals, but did not develop symptoms of Ebola virus disease. In March 2017, we collected blood samples from 481 individuals in Makeni, Sierra Leone: 214 survivors and 267 close contacts. Using commercial, quantitative ELISAs, we tested the plasma for IgG-specific antibodies against three major viral antigens: GP, the only viral glycoprotein expressed on the virus surface; NP, the most abundant viral protein; and VP40, a major structural protein of Zaire ebolavirus. We also determined neutralizing antibody titers. In the cohort of Ebola survivors, 97.7% of samples (209/214) had measurable antibody levels against GP, NP, and/or VP40. Of these positive samples, all but one had measurable neutralizing antibody titers against Ebola virus. For the close contacts, up to 12.7% (34/267) may have experienced a subclinical virus infection as indicated by detectable antibodies against GP. Further investigation is warranted to determine whether these close contacts truly experienced subclinical infections and whether these asymptomatic infections played a role in the dynamics of transmission.

 

Author summary

As the causative agent of an often lethal hemorrhagic fever disease in humans and nonhuman primates, Zaire ebolavirus typically causes high fever, severe diarrhea, and vomiting which results in case fatality rates as high as 90%. The 2013–2016 outbreak in West Africa was the largest and most devastating Ebola outbreak to date resulting in over 28,600 identified human cases and 11,300 deaths. Though our knowledge of virus transmission is incomplete, we do know that transmission occurs through direct contact with virus-contaminated body fluids (blood, secretions, or other body fluids), materials such as bedding contaminated with these fluids, and through the handling and preparation of contaminated food. Asymptomatic Ebola virus infections that result in seroconversion in the absence of disease symptoms have been observed both in humans and experimentally in animal models. In the present serology study, we determined a majority of Ebola survivors in our cohort had measurable antibody levels against at least one viral antigen, as expected. In our cohort of close contacts, relatives and health care workers who took care of Ebola-infected individuals during the outbreak, we observed a rate of seroprevalence of 12.7% as indicated by detectable GP antibody levels. Given that Ebola virus is typically associated with a highly lethal disease in humans, it is of great interest to determine the host-virus interactions and transmission dynamics associated with asymptomatic cases.

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Citation: Halfmann PJ, Eisfeld AJ, Watanabe T, Maemura T, Yamashita M, Fukuyama S, et al. (2019) Serological analysis of Ebola virus survivors and close contacts in Sierra Leone: A cross-sectional study. PLoS Negl Trop Dis 13(8): e0007654. https://doi.org/10.1371/journal.pntd.0007654

Editor: Benjamin Althouse, Institute for Disease Modeling, UNITED STATES

Received: January 23, 2019; Accepted: July 23, 2019; Published: August 1, 2019

Copyright: © 2019 Halfmann et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

Data Availability: All relevant data are within the manuscript.

Funding: YK was was supported for this work by the Japanese agencies of J-PRIDE for Global Epidemic from AMED (JP17fm0208101j0001), by RPERID from AMED (JP17fk018029h002) and by a Grant-in-Aid for Scientific Research on Innovative Areas from MEXT (no. 16H06429, 16K21723 and 16H06434). The funders had no role in the study design data collection and analysis, decision to publish, or preparation of the manuscript.

Competing interests: The authors have declared that no competing interests exist.

Keywords: Ebola; Ebola-Makona; Serology; Seroprevalence; Sierra Leone.

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Characterisation of #infectious #Ebola virus from the ongoing #outbreak to guide #response activities in the #DRC: a #phylogenetic and in vitro analysis (Lancet Infect Dis., abstract)

[Source: The Lancet Infectious Diseases, full page: (LINK). Abstract, edited.]

Characterisation of infectious Ebola virus from the ongoing outbreak to guide response activities in the Democratic Republic of the Congo: a phylogenetic and in vitro analysis

Laura K McMullan, PhD, Mike Flint, PhD, Ayan Chakrabarti, MS, Lisa Guerrero, MPH, Michael K Lo, PhD, Danielle Porter, PhD, Stuart T Nichol, PhD, Christina F Spiropoulou, PhD, César Albariño, PhD

Published: July 09, 2019 / DOI: https://doi.org/10.1016/S1473-3099(19)30291-9

 

Summary

Background

The ongoing Ebola virus outbreak in the Ituri and North Kivu Provinces of the Democratic Republic of the Congo, which began in July, 2018, is the second largest ever recorded. Despite civil unrest, outbreak control measures and the administration of experimental therapies and a vaccine have been initiated. The aim of this study was to test the efficacy of candidate therapies and diagnostic tests with the outbreak strain Ituri Ebola virus. Lacking a virus isolate from this outbreak, a recombinant Ituri Ebola virus was compared with a similarly engineered Makona virus from the 2013–16 outbreak.

Methods

Using Ebola virus sequences provided by organisations in DR Congo and a reverse genetics system, we generated an authentic Ebola virus from the ongoing outbreak in Ituri and North Kivu provinces. To relate this virus to other Ebola viruses in DR Congo, we did a phylogenetic analysis of representative complete Ebola virus genome sequences from previous outbreaks. We evaluated experimental therapies being tested in clinical trials in DR Congo, including remdesivir and ZMapp monoclonal antibodies, for their ability to inhibit the growth of infectious Ituri Ebola virus in cell culture. We also tested diagnostic assays for detection of the Ituri Ebola virus sequence.

Findings

The phylogenetic analysis of whole-genome sequences from each Ebola virus outbreak suggests there are at least two Ebola virus strains in DR Congo, which have independently crossed into the human population. The Ituri Ebola strain initially grew slower than the Makona strain, yet reached similar mean yields of 3 × 10 7 50% tissue culture infectious dose by 72 h infection in Huh-7 cells. Ituri Ebola virus was similar to Makona in its susceptibility to inhibition by remdesivir and to neutralisation by monoclonal antibodies from ZMapp and other monoclonal antibodies. Remdesivir inhibited Ituri Ebola virus at a 50% effective concentration (EC 50) of 12nM (with a selectivity index of 303) and Makona Ebola virus at 13nM (with a selectivity index of 279). The Zmapp monoclonal antibodies 2G4 and 4G7 neutralised Ituri Ebola virus with a mean EC 50 of 0·24 μg/mL and 0·48 μg/mL, and Makona Ebola virus with a mean EC 50 of 0·45 μg/mL and 0·2 μg/mL. The Xpert Ebola and US Centers for Disease Control and Prevention real-time RT-qPCR diagnostic assays detected Ituri and Makona Ebola virus sequences with similar sensitivities and efficiencies, despite primer site binding mismatches in the Ituri Ebola virus.

Interpretation

Our findings provide a rationale for the continued testing of investigational therapies, confirm the effectiveness of the diagnostic assays used in the region, and establish a paradigm for the use of reverse genetics to inform response activities in an outbreak.

Funding

US Centers for Disease Control and Prevention.

Keywords: Ebola; Ebola-Makona; Ebola-Ituri; Antivirals; Monoclonal Antibodies; Zmapp; Remdesivir; DRC.

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