Subject(s)
Clinical Trials as Topic , Disease Outbreaks , Marburg Virus Disease , Marburgvirus , Viral Vaccines , Humans , Disease Outbreaks/prevention & control , Disease Outbreaks/statistics & numerical data , Marburg Virus Disease/epidemiology , Marburg Virus Disease/prevention & control , Marburg Virus Disease/virology , Time FactorsABSTRACT
Marburg virus disease (MVD) is a dreadful but exceptional disease. Formerly mainly identified in Uganda, Angola and the Democratic Republic of Congo, it has recently appeared in the Republic of Guinea, Ghana, Equatorial Guinea and Tanzania, adding West Africa to the affected regions. Humans become infected through exposure to bats Roussettus aegyptiacus or during unprotected care of infected people. Five cases are linked to travellers, the last one dates to 2008 and involved a visit to caves colonized by bats. At present, there is no specific treatment or vaccine. Despite its rarity, adventurous travelers should be aware of the risks of exposure and avoid entering places inhabited by bats.
La maladie à virus Marburg est une maladie redoutable mais exceptionnelle. Autrefois identifiée en Ouganda, Angola et République démocratique du Congo, elle a récemment fait son apparition en République de Guinée, au Ghana, en Guinée équatoriale et en Tanzanie, ajoutant l'Afrique de l'Ouest aux régions touchées. Les humains s'infectent lors d'une exposition avec les chauves-souris roussettes d'Égypte ou lors de la prise en charge sans protection de personnes infectées. Cinq cas sont liés à des voyageurs, le dernier remonte à 2008 et était associé à la visite de grottes colonisées par des roussettes d'Égypte. Actuellement, il n'existe aucun traitement spécifique ni vaccin. Malgré sa rareté, les voyageurs aventureux doivent être informés des risques d'exposition et éviter de pénétrer dans des lieux habités par des chauves-souris.
Subject(s)
Marburgvirus , Travel , Female , Humans , Male , Marburg Virus Disease/epidemiology , Marburg Virus Disease/transmission , Marburg Virus Disease/virology , Marburgvirus/isolation & purification , Viral Zoonoses/epidemiology , Viral Zoonoses/transmission , Viral Zoonoses/virology , Chiroptera/virologyABSTRACT
Marburg virus (MARV) disease is lethal, with fatality rates up to 90%. Neutralizing antibodies (Abs) are promising drug candidates to prevent or treat the disease. Current efforts are focused in part on vaccine development to induce such MARV-neutralizing Abs. We analyzed the antibody repertoire from healthy unexposed and previously MARV-infected individuals to assess if naïve repertoires contain suitable precursor antibodies that could become neutralizing with a limited set of somatic mutations. We computationally searched the human Ab variable gene repertoire for predicted structural homologs of the neutralizing Ab MR78 that is specific to the receptor binding site (RBS) of MARV glycoprotein (GP). Eight Ab heavy-chain complementarity determining region 3 (HCDR3) loops from MARV-naïve individuals and one from a previously MARV-infected individual were selected for testing as HCDR3 loop chimeras on the MR78 Ab framework. Three of these chimerized antibodies bound to MARV GP. We then tested a full-length native Ab heavy chain encoding the same 17-residue-long HCDR3 loop that bound to the MARV GP the best among the chimeric Abs tested. Despite only 57% amino acid sequence identity, the Ab from a MARV-naïve donor recognized MARV GP and possessed neutralizing activity against the virus. Crystallization of both chimeric and full-length native heavy chain-containing Abs provided structural insights into the mechanism of binding for these types of Abs. Our work suggests that the MARV GP RBS is a promising candidate for epitope-focused vaccine design to induce neutralizing Abs against MARV.
Subject(s)
Antibodies, Viral/genetics , Complementarity Determining Regions/genetics , Marburg Virus Disease/immunology , Marburgvirus/immunology , Animals , Antibodies, Neutralizing/genetics , Antibodies, Neutralizing/immunology , Antibodies, Viral/immunology , Complementarity Determining Regions/immunology , Epitopes/genetics , Epitopes/immunology , Glycoproteins/genetics , Glycoproteins/immunology , Humans , Immunoglobulin Heavy Chains/genetics , Immunoglobulin Heavy Chains/immunology , Marburg Virus Disease/drug therapy , Marburg Virus Disease/genetics , Marburg Virus Disease/virology , Marburgvirus/pathogenicity , Mutation/genetics , Mutation/immunology , Viral Envelope Proteins , Viral Vaccines/genetics , Viral Vaccines/immunologyABSTRACT
Marburg virus (MARV) is a lipid-enveloped virus harboring a negative-sense RNA genome, which has caused sporadic outbreaks of viral hemorrhagic fever in sub-Saharan Africa. MARV assembles and buds from the host cell plasma membrane where MARV matrix protein (mVP40) dimers associate with anionic lipids at the plasma membrane inner leaflet and undergo a dynamic and extensive self-oligomerization into the structural matrix layer. The MARV matrix layer confers the virion filamentous shape and stability but how host lipids modulate mVP40 oligomerization is mostly unknown. Using in vitro and cellular techniques, we present a mVP40 assembly model highlighting two distinct oligomerization interfaces: the (N-terminal domain [NTD] and C-terminal domain [CTD]) in mVP40. Cellular studies of NTD and CTD oligomerization interface mutants demonstrate the importance of each interface in matrix assembly. The assembly steps include protein trafficking to the plasma membrane, homo-multimerization that induced protein enrichment, plasma membrane fluidity changes, and elongations at the plasma membrane. An ascorbate peroxidase derivative (APEX)-transmission electron microscopy method was employed to closely assess the ultrastructural localization and formation of viral particles for wildtype mVP40 and NTD and CTD oligomerization interface mutants. Taken together, these studies present a mechanistic model of mVP40 oligomerization and assembly at the plasma membrane during virion assembly that requires interactions with phosphatidylserine for NTD-NTD interactions and phosphatidylinositol-4,5-bisphosphate for proper CTD-CTD interactions. These findings have broader implications in understanding budding of lipid-enveloped viruses from the host cell plasma membrane and potential strategies to target protein-protein or lipid-protein interactions to inhibit virus budding.
Subject(s)
Marburg Virus Disease/virology , Marburgvirus/physiology , Membrane Lipids/metabolism , Viral Matrix Proteins/metabolism , Virion/metabolism , Animals , COS Cells , Cell Membrane/chemistry , Cell Membrane/metabolism , Chlorocebus aethiops , HEK293 Cells , Humans , Lipid Bilayers/chemistry , Lipid Bilayers/metabolism , Marburg Virus Disease/metabolism , Marburgvirus/chemistry , Membrane Lipids/chemistry , Models, Molecular , Protein Multimerization , Viral Matrix Proteins/chemistry , Virion/chemistry , Virus AssemblyABSTRACT
BACKGROUND: Marburg virus (MARV) and Ebola virus (EBOV) are acute infections with high case fatality rates. It is of great significance for epidemic monitoring and prevention and control of infectious diseases by the development of a rapid, specific, and sensitive quantitative PCR method to detect two pathogens simultaneously. METHODS: Primers and TaqMan probes were designed according to highly conserved sequences of these viruses. Sensitivity, specificity, linear range, limit of detection, and the effects of hemolysis and lipid on real-time qPCR were evaluated. RESULTS: The linearity of the curve allowed quantification of nucleic acid concentrations in range from 103 to 109 copies/ml per reaction (MARV and EBOV). The limit of detection of EBOV was 40 copies/ml, and MARV was 100 copies/ml. It has no cross-reaction with other pathogens such as hepatitis b virus (HBV), hepatitis c virus (HCV), human papillomavirus (HPV), Epstein-Barr virus (EBV), herpes simplex virus (HSV), cytomegalovirus (CMV), and human immunodeficiency virus (HIV). Repeatability analysis of the two viruses showed that their coefficient of variation (CV) was less than 5.0%. The above results indicated that fluorescence quantitative PCR could detect EBOV and MARV sensitively and specifically. CONCLUSIONS: The TaqMan probe-based multiplex fluorescence quantitative PCR assays could detect EBOV and MARV sensitively specifically and simultaneously.
Subject(s)
Ebolavirus/genetics , Hemorrhagic Fever, Ebola/diagnosis , Marburg Virus Disease/diagnosis , Marburgvirus/genetics , Multiplex Polymerase Chain Reaction/methods , Real-Time Polymerase Chain Reaction/methods , Animals , Hemorrhagic Fever, Ebola/virology , Humans , Marburg Virus Disease/virology , ROC CurveABSTRACT
Marburg virus (MARV) is a filovirus with documented human case-fatality rates of up to 90%. Here, we evaluated the therapeutic efficacy of remdesivir (GS-5734) in nonhuman primates experimentally infected with MARV. Beginning 4 or 5 days post inoculation, cynomolgus macaques were treated once daily for 12 days with vehicle, 5 mg/kg remdesivir, or a 10-mg/kg loading dose followed by 5 mg/kg remdesivir. All vehicle-control animals died, whereas 83% of animals receiving a 10-mg/kg loading dose of remdesivir survived, as did 50% of animals receiving a 5-mg/kg remdesivir regimen. Remdesivir-treated animals exhibited improved clinical scores, lower plasma viral RNA, and improved markers of kidney function, liver function, and coagulopathy versus vehicle-control animals. The small molecule remdesivir showed therapeutic efficacy in this Marburg virus disease model with treatment initiation 5 days post inoculation, supporting further assessment of remdesivir for the treatment of Marburg virus disease in humans.
Subject(s)
Antimetabolites/therapeutic use , Antiviral Agents/therapeutic use , Marburg Virus Disease/drug therapy , Marburgvirus/drug effects , Monkey Diseases/drug therapy , Adenosine Monophosphate/analogs & derivatives , Alanine/analogs & derivatives , Animals , Disease Models, Animal , Female , Kaplan-Meier Estimate , Macaca fascicularis , Male , Marburg Virus Disease/mortality , Marburg Virus Disease/pathology , Marburg Virus Disease/virology , Monkey Diseases/mortality , Monkey Diseases/pathology , Monkey Diseases/virology , RNA, ViralABSTRACT
Filoviruses are emerging pathogens and causative agents of viral haemorrhagic fever. Case fatality rates of filovirus disease outbreaks are among the highest reported for any human pathogen, exceeding 90% (ref. 1). Licensed therapeutic or vaccine products are not available to treat filovirus diseases. Candidate therapeutics previously shown to be efficacious in non-human primate disease models are based on virus-specific designs and have limited broad-spectrum antiviral potential. Here we show that BCX4430, a novel synthetic adenosine analogue, inhibits infection of distinct filoviruses in human cells. Biochemical, reporter-based and primer-extension assays indicate that BCX4430 inhibits viral RNA polymerase function, acting as a non-obligate RNA chain terminator. Post-exposure intramuscular administration of BCX4430 protects against Ebola virus and Marburg virus disease in rodent models. Most importantly, BCX4430 completely protects cynomolgus macaques from Marburg virus infection when administered as late as 48 hours after infection. In addition, BCX4430 exhibits broad-spectrum antiviral activity against numerous viruses, including bunyaviruses, arenaviruses, paramyxoviruses, coronaviruses and flaviviruses. This is the first report, to our knowledge, of non-human primate protection from filovirus disease by a synthetic drug-like small molecule. We provide additional pharmacological characterizations supporting the potential development of BCX4430 as a countermeasure against human filovirus diseases and other viral diseases representing major public health threats.
Subject(s)
Adenosine/analogs & derivatives , Antiviral Agents/pharmacology , Filoviridae Infections/prevention & control , Filoviridae Infections/virology , Filoviridae/drug effects , Purine Nucleosides/pharmacology , Adenine/analogs & derivatives , Administration, Oral , Animals , Antiviral Agents/administration & dosage , Antiviral Agents/chemistry , Antiviral Agents/pharmacokinetics , DNA-Directed RNA Polymerases/antagonists & inhibitors , DNA-Directed RNA Polymerases/metabolism , Disease Models, Animal , Ebolavirus/drug effects , Filoviridae/enzymology , Hemorrhagic Fever, Ebola/prevention & control , Hemorrhagic Fever, Ebola/virology , Humans , Injections, Intramuscular , Macaca fascicularis/virology , Marburg Virus Disease/prevention & control , Marburg Virus Disease/virology , Marburgvirus/drug effects , Purine Nucleosides/administration & dosage , Purine Nucleosides/chemistry , Purine Nucleosides/pharmacokinetics , Pyrrolidines , RNA/biosynthesis , Time FactorsABSTRACT
Although bats are increasingly being recognized as natural reservoir hosts of emerging zoonotic viruses, little is known about how they control and clear virus infection in the absence of clinical disease. Here, we test >50 convalescent sera from Egyptian rousette bats (ERBs) experimentally primed or prime-boosted with Marburg virus, Ebola virus, or Sosuga virus for the presence of virus-specific neutralizing antibodies, using infectious reporter viruses. After serum neutralization testing, we conclude that antibody-mediated virus neutralization does not contribute significantly to the control and clearance of Marburg virus, Ebola virus, or Sosuga virus infection in ERBs.
Subject(s)
Chiroptera/virology , Ebolavirus/immunology , Hemorrhagic Fever, Ebola/immunology , Marburg Virus Disease/immunology , Marburgvirus/immunology , Paramyxoviridae/immunology , Animals , Antibodies, Viral/immunology , Convalescence , Disease Reservoirs/virology , Egypt/epidemiology , Hemorrhagic Fever, Ebola/virology , Humans , Immunity, Humoral , Marburg Virus Disease/virology , Neutralization TestsABSTRACT
We detected Marburg virus genome in Egyptian fruit bats (Rousettus aegyptiacus) captured in Zambia in September 2018. The virus was closely related phylogenetically to the viruses that previously caused Marburg outbreaks in the Democratic Republic of the Congo. This finding demonstrates that Zambia is at risk for Marburg virus disease.
Subject(s)
Chiroptera/virology , Marburg Virus Disease/virology , Marburgvirus , Animals , Genes, Viral , Humans , Marburg Virus Disease/diagnosis , Marburg Virus Disease/epidemiology , Marburgvirus/classification , Marburgvirus/genetics , Marburgvirus/isolation & purification , Phylogeny , Prevalence , Public Health Surveillance , RNA, Viral , Zambia/epidemiologyABSTRACT
Ebola (EBOV) and Marburg (MARV) viruses are members of the Filoviridae family which cause outbreaks of hemorrhagic fever. The filovirus VP40 matrix protein is essential for virus assembly and budding, and its PPxY L-domain motif interacts with WW-domains of specific host proteins, such as Nedd4 and ITCH, to facilitate the late stage of virus-cell separation. To identify additional WW-domain-bearing host proteins that interact with VP40, we used an EBOV PPxY-containing peptide to screen an array of 115 mammalian WW-domain-bearing proteins. Using this unbiased approach, we identified BCL2 Associated Athanogene 3 (BAG3), a member of the BAG family of molecular chaperone proteins, as a specific VP40 PPxY interactor. Here, we demonstrate that the WW-domain of BAG3 interacts with the PPxY motif of both EBOV and MARV VP40 and, unexpectedly, inhibits budding of both eVP40 and mVP40 virus-like particles (VLPs), as well as infectious VSV-EBOV recombinants. BAG3 is a stress induced protein that regulates cellular protein homeostasis and cell survival through chaperone-mediated autophagy (CMA). Interestingly, our results show that BAG3 alters the intracellular localization of VP40 by sequestering VP40 away from the plasma membrane. As BAG3 is the first WW-domain interactor identified that negatively regulates budding of VP40 VLPs and infectious virus, we propose that the chaperone-mediated autophagy function of BAG3 represents a specific host defense strategy to counteract the function of VP40 in promoting efficient egress and spread of virus particles.
Subject(s)
Adaptor Proteins, Signal Transducing/genetics , Apoptosis Regulatory Proteins/genetics , Autophagy/physiology , Ebolavirus/metabolism , Hemorrhagic Fever, Ebola/transmission , Marburg Virus Disease/transmission , Marburgvirus/metabolism , Viral Matrix Proteins/metabolism , Virus Release/genetics , Animals , Autophagy/genetics , Cell Line, Tumor , Cell Survival/genetics , Cricetinae , Ebolavirus/genetics , Endosomal Sorting Complexes Required for Transport , HEK293 Cells , HeLa Cells , Hemorrhagic Fever, Ebola/pathology , Hemorrhagic Fever, Ebola/virology , Humans , Marburg Virus Disease/pathology , Marburg Virus Disease/virology , Marburgvirus/genetics , Nedd4 Ubiquitin Protein Ligases , Proline/analogs & derivatives , Proline/metabolism , Protein Structure, Tertiary , Protein Transport/physiology , RNA Interference , RNA, Small Interfering/genetics , Repressor Proteins/metabolism , Ubiquitin-Protein Ligases/metabolismABSTRACT
Ebola virus (EBOV) and Marburg virus (MARV) outbreaks are highly lethal, and infection results in a hemorrhagic fever with complex etiology. These zoonotic viruses dysregulate the immune system to cause disease, in part by replicating within myeloid cells that would normally innately control viral infection and shape the adaptive immune response. We used triple knockout (TKO)-bone marrow, liver, thymus (BLT) humanized mice to recapitulate the early in vivo human immune response to filovirus infection. Disease severity in TKO-BLT mice was dissimilar between EBOV and MARV with greater severity observed during EBOV infection. Disease severity was related to increased Kupffer cell infection in the liver, higher levels of myeloid dysfunction, and skewing of macrophage subtypes in EBOV compared with MARV-infected mice. Overall, the TKO-BLT model provided a practical in vivo platform to study the human immune response to filovirus infection and generated a better understanding of how these viruses modulate specific components of the immune system.
Subject(s)
Bone Marrow/virology , Ebolavirus/pathogenicity , Marburgvirus/pathogenicity , Myeloid Cells/virology , Thymus Gland/virology , Animals , Bone Marrow/immunology , Ebolavirus/immunology , Hemorrhagic Fever, Ebola/immunology , Hemorrhagic Fever, Ebola/virology , Immunity/immunology , Liver/immunology , Liver/virology , Macrophages/immunology , Macrophages/virology , Marburg Virus Disease/immunology , Marburg Virus Disease/virology , Marburgvirus/immunology , Mice , Mice, Inbred C57BL , Mice, Knockout , Myeloid Cells/immunology , Thymus Gland/immunology , Virulence/immunologyABSTRACT
We detected a high seroprevalence of Marburg virus (MARV) antibodies in fruit bats in South Africa; 19.1% of recaptured bats seroconverted. The MARV RNA isolated closely resembled the 1975 Ozolin strain. These findings indicate endemic MARV circulation in bats in South Africa and should inform policies on MARV disease risk reduction.
Subject(s)
Chiroptera/virology , Disease Reservoirs/virology , Marburg Virus Disease/epidemiology , Marburg Virus Disease/virology , Marburgvirus , Animals , Genes, Viral , History, 21st Century , Marburg Virus Disease/history , Marburg Virus Disease/transmission , Marburgvirus/classification , Marburgvirus/genetics , Phylogeny , Public Health Surveillance , Seroepidemiologic Studies , South Africa/epidemiologyABSTRACT
BACKGROUND: Ebolavirus and Marburgvirus are genera of the virus family Filoviridae. Filoviruses cause rare but fatal viral hemorrhagic fevers (VHFs) in remote villages of equatorial Africa with potential for regional and international spread. Point-of-care (POC) rapid diagnostic tests (RDTs) are critical for early epidemic detection, reponse and control. There are 2 RDTs for Zaire ebolavirus (EBOV), but not other Ebolavirus spp. or Marburg marburgvirus (MARV). We validate 3 conserved B cell epitopes of filovirus glycoprotein (GP) using ebola virus diseases (EVD) survivor samples, towards devising pan-filovirus RDTs. METHODS: In-silico Immuno-informatics:- (a) multiple and basic local alignments of amino-acid sequences of filovirus (4 Ebolavirus spp. & MARV) Gp1, 2 and epitope prediction and conservation analyses within context of ClusterW, BLAST-P and the immune epitope database analysis resource (IEDB-AR); alongside (b) in-vitro enzyme immuno-assays (EIAs) for SUDV Gp1, 2 antigen and host-specific antibodies (IgM and IgG) among 94 gamma irradiated EVD survivor serum and 9 negative controls. RESULTS: Linear B cell epitopes were present across the entire length of all Gp1, 2, most lying in the region between amino acids positioned 350 and 500. Three seperate epitopes 97/80_GAFFLYDRLAST, 39_YEAGEWAENCY and 500_CGLRQLANETTQALQLFLRATTELR (designated UG-Filo-Peptide- 1, 2 and 3 respectively) were conserved within all studied filovirus species Gp1, 2. Gp1, 2 host specific IgM levels were comparably low (av. ODs < 0.04 [95% CI: 0.02837 to 0.04033]) among the 9 negative controls and 57 survivor samples analyzed. Host specific IgG levels, on the other hand, were elevated (av. ODs > 1.7525 [95% CI: 0.3010 to 3.1352]) among the 92 survivor samples relative to the 9 negative controls (av. ODs < 0.2.321 [95% CI: -0.7596 to 0.5372]). Filovirus Gp1, 2 antigen was not detected [av. ODs < 0.20] within EVD survivor serum relative to recombinant protein positive controls [av. ODs = 0.50]. CONCLUSIONS: These conserved B cell epitopes of filovirus Gp1, 2 and their derivative antibodies are promising for research and development of RDTs for EVD, with potential for extension to detect MVD.
Subject(s)
Ebolavirus/immunology , Epitopes, B-Lymphocyte/immunology , Glycoproteins/immunology , Amino Acid Sequence , Animals , Antibodies, Viral/immunology , Conserved Sequence , Hemorrhagic Fever, Ebola/diagnosis , Hemorrhagic Fever, Ebola/virology , Humans , Immunoglobulin G , Immunoglobulin M , Marburg Virus Disease/diagnosis , Marburg Virus Disease/virology , Marburgvirus/immunology , Reagent Kits, Diagnostic , Viral Proteins/genetics , Viral Proteins/immunologyABSTRACT
Marburg virus (MARV), which is one of the most virulent agents in the world, causes lethal haemorrhagic fever in humans and nonhuman primates (NHPs) with a mortality rate of up to 90%. Currently, there is no effective treatment or approved vaccine for MARV for human use to control disease outbreak and spread. Virus-like particles (VLPs), which are morphologically identical to the native infectious virus particle, are efficacious as vaccines against many viruses, including human papilloma virus (HPV), porcine circovirus (PCV) type 2 and hepatitis B virus (HBV). In this study, we generated MARV virus-like particles (VLPs) by co-expressing a glycoprotein (GP) and matrix protein (VP40) using the baculovirus expression system. Rhesus macaques vaccinated with MARV VLPs mixed with adjuvant Poria cocos polysaccharides (PCP-II) produced a GP-specific IgG titer of up to 1:1280 and virus-neutralizing antibody titers that reached 1:320. MARV VLPs also elicited interferon-γ (IFN-γ) and interleukin-4 (IL-4) secretion associated with T-helper 1 cell (Th1)- and T-helper 2 cell (Th2)-mediated immunity, as detected using enzyme-linked immunospot (ELISpot) assays. These data indicate that MARV VLPs mixed with adjuvant PCP-II have excellent immunogenicity in rhesus macaques and may be a promising candidate vaccine against MARV.
Subject(s)
Antibodies, Neutralizing/immunology , Antibodies, Viral/immunology , Marburgvirus/immunology , Vaccines, Virus-Like Particle/immunology , Viral Vaccines/immunology , Animals , Antibodies, Neutralizing/biosynthesis , Antibodies, Viral/biosynthesis , Enzyme-Linked Immunospot Assay , Humans , Interferon-gamma/metabolism , Interleukin-4/metabolism , Macaca mulatta , Marburg Virus Disease/immunology , Marburg Virus Disease/virology , Marburgvirus/genetics , Marburgvirus/isolation & purification , Membrane Glycoproteins/genetics , Membrane Glycoproteins/immunology , Sf9 Cells , Vaccines, Virus-Like Particle/biosynthesis , Viral Matrix Proteins/genetics , Viral Matrix Proteins/immunologyABSTRACT
The filoviruses, Ebola virus (EBOV), and Marburg virus (MARV), are among the most pathogenic viruses known to man and the causative agents of viral hemorrhagic fever outbreaks in Africa with case fatality rates of up to 90%. Nearly 30,000 infections were observed in the latest EBOV epidemic in West Africa; previous outbreaks were much smaller, typically only affecting less than a few hundred people. Compared to other diseases such as AIDS or Malaria with millions of cases annually, filovirus hemorrhagic fever (FHF) is one of the neglected infectious diseases. There are no licensed vaccines or therapeutics available to treat EBOV and MARV infections; therefore, these pathogens can only be handled in maximum containment laboratories and are classified as select agents. Under these limitations, a very few laboratories worldwide conducted basic research and countermeasure development for EBOV and MARV since their respective discoveries in 1967 (MARV) and 1976 (EBOV). In this review, we discuss several vaccine platforms against EBOV and MARV, which have been assessed for their protective efficacy in animal models of FHF. The focus is on the most promising approaches, which were accelerated in clinical development (phase I-III trials) during the EBOV epidemic in West Africa.
Subject(s)
Ebolavirus/immunology , Hemorrhagic Fever, Ebola/prevention & control , Marburg Virus Disease/prevention & control , Marburgvirus/immunology , Viral Vaccines/immunology , Animals , Antibodies, Viral/immunology , Ebolavirus/genetics , Hemorrhagic Fever, Ebola/immunology , Hemorrhagic Fever, Ebola/virology , Humans , Marburg Virus Disease/immunology , Marburg Virus Disease/virology , Marburgvirus/genetics , Viral Vaccines/administration & dosage , Viral Vaccines/geneticsABSTRACT
Filoviruses are strongly associated with several species of bats as their natural reservoirs. In this study, we determined the replication potential of all filovirus species: Marburg marburgvirus, Taï Forest ebolavirus, Reston ebolavirus, Sudan ebolavirus, Zaire ebolavirus, and Bundibugyo ebolavirus. Filovirus replication was supported by all cell lines derived from 6 Old and New World bat species: the hammer-headed fruit bat, Buettikofer's epauletted fruit bat, the Egyptian fruit bat, the Jamaican fruit bat, the Mexican free-tailed bat and the big brown bat. In addition, we showed that Marburg virus Angola and Ebola virus Makona-WPGC07 efficiently replicated at 37°C, 37°-41°C, or 41°C, contrary to the hypothesis that temporal elevation in temperature due to flight affects filovirus replication in bats.
Subject(s)
Chiroptera/virology , Disease Reservoirs/virology , Filoviridae Infections/virology , Filoviridae/isolation & purification , Hemorrhagic Fever, Ebola/virology , Marburg Virus Disease/virology , Animals , Cell Line , Ebolavirus/immunology , Ebolavirus/isolation & purification , Ebolavirus/physiology , Filoviridae/physiology , Humans , Marburgvirus/immunology , Marburgvirus/isolation & purification , Marburgvirus/physiology , Temperature , Virus ReplicationABSTRACT
Marburg virus (MARV) causes severe, often fatal, disease in humans and transient illness in rodents. Sequential passaging of MARV in guinea pigs resulted in selection of a lethal virus containing 4 aa changes. A D184N mutation in VP40 (VP40D184N), which leads to a species-specific gain of viral fitness, and three mutations in the active site of viral RNA-dependent RNA polymerase L, which were investigated in the present study for functional significance in human and guinea pig cells. The transcription/replication activity of L mutants was strongly enhanced by a substitution at position 741 (S741C), and inhibited by other substitutions (D758A and A759D) in both species. The polymerase activity of L carrying the S741C substitution was eightfold higher in guinea pig cells than in human cells upon co-expression with VP40D184N, suggesting that the additive effect of the two mutations provides MARV a replicative advantage in the new host.
Subject(s)
DNA-Directed RNA Polymerases/genetics , DNA-Directed RNA Polymerases/metabolism , Guinea Pigs/virology , Marburg Virus Disease/virology , Marburgvirus/enzymology , Rodent Diseases/virology , Viral Proteins/genetics , Viral Proteins/metabolism , Animals , Catalytic Domain , DNA-Directed RNA Polymerases/chemistry , Marburg Virus Disease/mortality , Marburgvirus/classification , Marburgvirus/genetics , Marburgvirus/isolation & purification , Mutation, Missense , Rodent Diseases/mortality , Viral Proteins/chemistryABSTRACT
Ebola viruses and Marburg viruses include some of the most virulent and fatal pathogens known to humans. These viruses cause severe haemorrhagic fevers, with case fatality rates in the range 25-90%. The diagnosis of filovirus using formalin-fixed tissues from fatal cases poses a significant challenge. The most characteristic histopathological findings are seen in the liver; however, the findings overlap with many other viral and non-viral haemorrhagic diseases. The need to distinguish filovirus infections from other haemorrhagic fevers, particularly in areas with multiple endemic viral haemorrhagic agents, is of paramount importance. In this review we discuss the current state of knowledge of filovirus infections and their pathogenesis, including histopathological findings, epidemiology, modes of transmission and filovirus entry and spread within host organisms. The pathogenesis of filovirus infections is complex and involves activation of the mononuclear phagocytic system, with release of pro-inflammatory cytokines, chemokines and growth factors, endothelial dysfunction, alterations of the innate and adaptive immune systems, direct organ and endothelial damage from unrestricted viral replication late in infection, and coagulopathy. Although our understanding of the pathogenesis of filovirus infections has rapidly increased in the past few years, many questions remain unanswered.
Subject(s)
Ebolavirus/pathogenicity , Hemorrhagic Fever, Ebola/pathology , Hemorrhagic Fever, Ebola/virology , Marburg Virus Disease/pathology , Marburg Virus Disease/virology , Marburgvirus/pathogenicity , Viral Tropism , Animals , Biopsy , Ebolavirus/genetics , Ebolavirus/immunology , Ebolavirus/isolation & purification , Hemorrhagic Fever, Ebola/diagnosis , Hemorrhagic Fever, Ebola/epidemiology , Hemorrhagic Fever, Ebola/immunology , Hemorrhagic Fever, Ebola/transmission , Host-Pathogen Interactions , Humans , Marburg Virus Disease/diagnosis , Marburg Virus Disease/epidemiology , Marburg Virus Disease/immunology , Marburg Virus Disease/transmission , Marburgvirus/genetics , Marburgvirus/immunology , Marburgvirus/isolation & purification , Pathology, Molecular/methods , Predictive Value of Tests , Prognosis , Risk Factors , Virology/methods , Virulence , Virus InternalizationABSTRACT
In October 2012, a cluster of illnesses and deaths was reported in Uganda and was confirmed to be an outbreak of Marburg virus disease (MVD). Patients meeting the case criteria were interviewed using a standard investigation form, and blood specimens were tested for evidence of acute or recent Marburg virus infection by reverse transcription-polymerase chain reaction (RT-PCR) and antibody enzyme-linked immunosorbent assay. The total count of confirmed and probable MVD cases was 26, of which 15 (58%) were fatal. Four of 15 laboratory-confirmed cases (27%) were fatal. Case patients were located in 4 different districts in Uganda, although all chains of transmission originated in Ibanda District, and the earliest case detected had an onset in July 2012. No zoonotic exposures were identified. Symptoms significantly associated with being a MVD case included hiccups, anorexia, fatigue, vomiting, sore throat, and difficulty swallowing. Contact with a case patient and attending a funeral were also significantly associated with being a case. Average RT-PCR cycle threshold values for fatal cases during the acute phase of illness were significantly lower than those for nonfatal cases. Following the institution of contact tracing, active case surveillance, care of patients with isolation precautions, community mobilization, and rapid diagnostic testing, the outbreak was successfully contained 14 days after its initial detection.
Subject(s)
Marburg Virus Disease/epidemiology , Marburgvirus/isolation & purification , Adolescent , Adult , Animals , Child , Child, Preschool , Disease Outbreaks , Female , Humans , Infant , Infant, Newborn , Male , Marburg Virus Disease/virology , Middle Aged , Uganda/epidemiology , Young AdultABSTRACT
BACKGROUND: Phylogenetic comparisons of known Marburg virus (MARV) strains reveal 2 distinct genetic lineages: Ravn and the Lake Victoria Marburg complex (eg, Musoke, Popp, and Angola strains). Nucleotide variances of >20% between Ravn and other MARV genomes suggest that differing virulence between lineages may accompany this genetic divergence. To date, there exists limited systematic experimental evidence of pathogenic differences between MARV strains. METHODS: Uniformly lethal outbred guinea pig models of MARV-Angola (MARV-Ang) and MARV-Ravn (MARV-Rav) were developed by serial adaptation. Changes in genomic sequence, weight, temperature, histopathologic findings, immunohistochemical findings, hematologic profiles, circulating biochemical enzyme levels, coagulation parameters, viremia levels, cytokine levels, eicanosoid levels, and nitric oxide production were compared between strains. RESULTS: MARV-Rav infection resulted in delayed increases in circulating inflammatory and prothrombotic elements, notably lower viremia levels, less severe histologic alterations, and a delay in mean time to death, compared with MARV-Ang infection. Both strains produced more marked coagulation abnormalities than previously seen in MARV-infected mice or inbred guinea pigs. CONCLUSIONS: Although both strains exhibit great similarity to pathogenic markers of human and nonhuman primate MARV infection, these data highlight several key differences in pathogenicity that may serve to guide the choice of strain and model used for development of vaccines or therapeutics for Marburg hemorrhagic fever.