Vaccine Platform Comparison: Protective Efficacy against Lethal Marburg Virus Challenge in the Hamster Model.

Marburg virus (MARV), a filovirus, was first identified in 1967 in Marburg, Germany, and Belgrade, former Yugoslavia. Since then, MARV has caused sporadic outbreaks of human disease with high case fatality rates in parts of Africa, with the largest outbreak occurring in 2004/05 in Angola. From 2021 to 2023, MARV outbreaks occurred in Guinea, Ghana, New Guinea, and Tanzania, emphasizing the expansion of its endemic area into new geographical regions. There are currently no approved vaccines or therapeutics targeting MARV, but several vaccine candidates have shown promise in preclinical studies. We compared three vaccine platforms simultaneously by vaccinating hamsters with either a single dose of an adenovirus-based (ChAdOx-1 MARV) vaccine, an alphavirus replicon-based RNA (LION-MARV) vaccine, or a recombinant vesicular stomatitis virus-based (VSV-MARV) vaccine, all expressing the MARV glycoprotein as the antigen. Lethal challenge with hamster-adapted MARV 4 weeks after vaccination resulted in uniform protection of the VSV-MARV and LION-MARV groups and 83% of the ChAdOx-1 MARV group. Assessment of the antigen-specific humoral response and its functionality revealed vaccine-platform-dependent differences, particularly in the Fc effector functions.

Design of a novel multi-epitope vaccine against Marburg virus using immunoinformatics studies.

Marburg virus (MARV) is a highly contagious and virulent agent belonging to Filoviridae family. MARV causes severe hemorrhagic fever in humans and non-human primates. Owing to its highly virulent nature, preventive approaches are promising for its control. There is currently no approved drug or vaccine against MARV, and management mainly involves supportive care to treat symptoms and prevent complications. Our aim was to design a novel multi-epitope vaccine (MEV) against MARV using immunoinformatics studies. In this study, various proteins (VP35, VP40 and glycoprotein precursor) were used and potential epitopes were selected. CTL and HTL epitopes covered 79.44% and 70.55% of the global population, respectively. The designed MEV construct was stable and expressed in Escherichia coli (E. coli) host. The physicochemical properties were also acceptable. MARV MEV candidate could predict comprehensive immune responses such as those of humoral and cellular in silico. Additionally, efficient interaction to toll-like receptor 3 (TLR3) and its agonist (ß-defensin) was predicted. There is a need for validation of these results using further in vitro and in vivo studies.

Macaque antibodies targeting Marburg virus glycoprotein induced by multivalent immunization.

Marburg virus infection in humans is associated with case fatality rates that can reach up to 90%, but to date, there are no approved vaccines or monoclonal antibody (mAb) countermeasures. Here, we immunized Rhesus macaques with multivalent combinations of filovirus glycoprotein (GP) antigens belonging to Marburg, Sudan, and Ebola viruses to generate monospecific and cross-reactive antibody responses against them. From the animal that developed the highest titers of Marburg virus GP-specific neutralizing antibodies, we sorted single memory B cells using a heterologous Ravn virus GP probe and cloned and characterized a panel of 34 mAbs belonging to 28 unique lineages. Antibody specificities were assessed by overlapping pepscan and binding competition analyses, revealing that roughly a third of the lineages mapped to the conserved receptor binding region, including potent neutralizing lineages that were confirmed by negative stain electron microscopy to target this region. Additional lineages targeted a protective region on GP2, while others were found to possess cross-filovirus reactivity. Our study advances the understanding of orthomarburgvirus glycoprotein antigenicity and furthers efforts to develop candidate antibody countermeasures against these lethal viruses. IMPORTANCE: Marburg viruses were the first filoviruses characterized to emerge in humans in 1967 and cause severe hemorrhagic fever with average case fatality rates of ~50%. Although mAb countermeasures have been approved for clinical use against the related Ebola viruses, there are currently no approved countermeasures against Marburg viruses. We successfully isolated a panel of orthomarburgvirus GP-specific mAbs from a macaque immunized with a multivalent combination of filovirus antigens. Our analyses revealed that roughly half of the antibodies in the panel mapped to regions on the glycoprotein shown to protect from infection, including the host cell receptor binding domain and a protective region on the membrane-anchoring subunit. Other antibodies in the panel exhibited broad filovirus GP recognition. Our study describes the discovery of a diverse panel of cross-reactive macaque antibodies targeting orthomarburgvirus and other filovirus GPs and provides candidate immunotherapeutics for further study and development.

Potent immunogenicity and protective efficacy of a multi-pathogen vaccination targeting Ebola, Sudan, Marburg and Lassa viruse.

Viral haemorrhagic fevers (VHF) pose a significant threat to human health. In recent years, VHF outbreaks caused by Ebola, Marburg and Lassa viruses have caused substantial morbidity and mortality in West and Central Africa. In 2022, an Ebola disease outbreak in Uganda caused by Sudan virus resulted in 164 cases with 55 deaths. In 2023, a Marburg disease outbreak was confirmed in Equatorial Guinea and Tanzania resulting in over 49 confirmed or suspected cases; 41 of which were fatal. There are no clearly defined correlates of protection against these VHF, impeding targeted vaccine development. Any vaccine developed should therefore induce strong and preferably long-lasting humoral and cellular immunity against these viruses. Ideally this immunity should also cross-protect against viral variants, which are known to circulate in animal reservoirs and cause human disease. We have utilized two viral vectored vaccine platforms, an adenovirus (ChAdOx1) and Modified Vaccinia Ankara (MVA), to develop a multi-pathogen vaccine regime against three filoviruses (Ebola virus, Sudan virus, Marburg virus) and an arenavirus (Lassa virus). These platform technologies have consistently demonstrated the capability to induce robust cellular and humoral antigen-specific immunity in humans, most recently in the rollout of the licensed ChAdOx1-nCoV19/AZD1222. Here, we show that our multi-pathogen vaccines elicit strong cellular and humoral immunity, induce a diverse range of chemokines and cytokines, and most importantly, confers protection after lethal Ebola virus, Sudan virus and Marburg virus challenges in a small animal model.

Infection prevention and control of highly infectious pathogens in resource-limited countries: an experience from Marburg viral disease outbreak in Kagera Region - Tanzania.

Marburg viral disease (MVD) is a highly infectious disease with a case fatality rate of up to 90%, particularly impacting resource-limited countries where implementing Infection Prevention and Control (IPC) measures is challenging. This paper shares the experience of how Tanzania has improved its capacity to prevent and control highly infectious diseases, and how this capacity was utilized during the outbreak of the MVD disease that occurred for the first time in the country in 2023.In 2016 and the subsequent years, Tanzania conducted self and external assessments that revealed limited IPC capacity in responding to highly infectious diseases. To address these gaps, initiatives were undertaken, including the enhancement of IPC readiness through the development and dissemination of guidelines, assessments of healthcare facilities, supportive supervision and mentorship, procurement of supplies, and the renovation or construction of environments to bolster IPC implementation.The official confirmation and declaration of MVD on March 21, 2023, came after five patients had already died of the disease. MVD primarily spreads through contact and presents with severe symptoms, which make patient care and prevention challenging, especially in resource-limited settings. However, with the use of a trained workforce; IPC rapid needs assessment was conducted, identifying specific gaps. Based on the results; mentorship programs were carried out, specific policies and guidelines were developed, security measures were enhanced, all burial activities in the area were supervised, and both patients and staff were monitored across all facilities. By the end of the outbreak response on June 1, 2023, a total of 212 contacts had been identified, with the addition of only three deaths. Invasive procedures like dialysis and Manual Vacuum Aspiration prevented some deaths in infected patients, procedures previously discouraged.In summary, this experience underscores the critical importance of strict adherence to IPC practices in controlling highly infectious diseases. Recommendations for low-income countries include motivating healthcare providers and improving working conditions to enhance commitment in challenging environments. This report offers valuable insights and practical interventions for preparing for and addressing highly infectious disease outbreaks through implementation of IPC measures.

[Marburg virus disease in travellers]. / Maladie à virus Marburg chez les voyageurs.

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.

Development and validation of a French questionnaire that assesses knowledge, attitude, and practices toward Marburg diseases in sub-Saharan African countries.

OBJECTIVES: Marburg virus, previously referred to as Marburg hemorrhagic fever, is a highly severe and frequently fatal illness that affects humans. This study aimed to develop and validate a French questionnaire to assess knowledge, attitude, and practice toward Marburg virus disease (FKAP-MVD). STUDY DESIGN: An anonymous online survey was used, which was distributed through various platforms and emails. Data were collected from Burkina Faso, Guinea, the Democratic Republic of Congo, and Senegal. METHODS: To conduct the study, an anonymous online survey was used, which was distributed through various platforms such as Facebook, Twitter, WhatsApp, and emails. The survey was uploaded onto a Google form to facilitate data collection. Data were collected from Burkina Faso, Guinea, the Democratic Republic of Congo, and Senegal. RESULTS: Of the total sample of 510 participants, 60.0% were male, their mean age was 28.41 ± 6.32 years, 38.0% were married, 86.6% resided in urban areas and 64.1% had a university education. The questionnaire had good internal consistency; Cronbach's alpha was 0.87. The correlation between knowledge and attitude was 0.002, the correlation between knowledge and practice was 0.204, and the correlation between practice and attitude was relatively weak and negative at -0.060. This indicates the divergent validity of the questionnaire. The KMO value of 0.91 indicates a high level of adequacy, suggesting that the data are suitable for factor analysis. The Bartlett test of Sphericity yielded an approximate χ2 value of 4016.890 with 300 degrees of freedom and a P-value of 0.0001. The confirmatory factor analysis revealed 25 questions in three domains. The normed chi-square value is 1.224. The goodness of Fit Index (GFI) is 0.902, the Comparative Fit Index (CFI) is 0.982, the Root Mean Square Error of Approximation (RMSEA) is 0.033, and the Root Mean Square Residual (RMR) is 0.062. These values indicate a good fit of the model to the data. CONCLUSIONS: In general, the developed questionnaire has significant potential to inform public health initiatives and interventions related to MVD.

Coordinated inflammatory responses dictate Marburg virus control by reservoir bats.

Bats are increasingly recognized as reservoirs of emerging zoonotic pathogens. Egyptian rousette bats (ERBs) are the known reservoir of Marburg virus (MARV), a filovirus that causes deadly Marburg virus disease (MVD) in humans. However, ERBs harbor MARV asymptomatically, likely due to a coadapted and specific host immunity-pathogen relationship. Recently, we measured transcriptional responses in MARV-infected ERB whole tissues, showing that these bats possess a disease tolerant strategy that limits pro-inflammatory gene induction, presumably averting MVD-linked immunopathology. However, the host resistant strategy by which ERBs actively limit MARV burden remains elusive, which we hypothesize requires localized inflammatory responses unresolvable at bulk-tissue scale. Here, we use dexamethasone to attenuate ERB pro-inflammatory responses and assess MARV replication, shedding and disease. We show that MARV-infected ERBs naturally mount coordinated pro-inflammatory responses at liver foci of infection, comprised of recruited mononuclear phagocytes and T cells, the latter of which proliferate with likely MARV-specificity. When pro-inflammatory responses are diminished, ERBs display heightened MARV replication, oral/rectal shedding and severe MVD-like liver pathology, demonstrating that ERBs balance immunoprotective tolerance with discreet MARV-resistant pro-inflammatory responses. These data further suggest that natural ERB immunomodulatory stressors like food scarcity and habitat disruption may potentiate viral shedding, transmission and therefore outbreak risk.

Bat-Borne Pathogens and Public Health in Rural African Artisanal Gold Mines.

Marburg virus, the first filovirus discovered and a close cousin to the Ebola virus, is carried by the Egyptian rousette bat, a common cave-dwelling fruit bat endemic to sub-Saharan Africa whose populations can exceed 50 000 individuals. Community outbreaks of Marburg virus can result in high morbidity rates. In eastern Africa, favorite habitats of these bats include rural subterranean gold mines-sometimes worked illegally-that create environments conducive to zoonotic virus transmission. This commentary on a case describes how outbreaks of Marburg virus disease among people exposed to sub-Saharan African caves and mines containing these bats cause tensions among miners, companies, public health officials, and conservationists.

Marburg Virus Outbreak in Equatorial Guinea: Need for Speed.

The co-existence of deadly viral pandemics can be considered a nightmare for public health authorities. The surge of a Marburg virus disease (MVD) outbreak in Africa at a time when the coronavirus-19 (COVID-19) pandemic is partially controlled with its limited resources is an urgent call for concern. Over the past decades, several bouts of MVD outbreaks have occurred in Africa with an alarming case fatality rate. Despite this, little has been done to end its recurrence, and affected countries essentially depend on preventative rather than curative measures of management. The recent outbreak of MVD declared by the health officials of Equatorial Guinea, causing several deaths in the context of the COVID-19 pandemic, signals the need for speed in the establishment and the implementation of appropriate health policies and health system strategies to contain, destroy, and prevent the spread of this deadly virus to other neighboring countries.

Structural and Dynamical Basis of VP35-RBD Inhibition by Marine Fungi Compounds to Combat Marburg Virus Infection.

The Marburg virus (MBV), a deadly pathogen, poses a serious threat to world health due to the lack of effective treatments, calling for an immediate search for targeted and efficient treatments. In this study, we focused on compounds originating from marine fungi in order to identify possible inhibitory compounds against the Marburg virus (MBV) VP35-RNA binding domain (VP35-RBD) using a computational approach. We started with a virtual screening procedure using the Lipinski filter as a guide. Based on their docking scores, 42 potential candidates were found. Four of these compounds-CMNPD17596, CMNPD22144, CMNPD25994, and CMNPD17598-as well as myricetin, the control compound, were chosen for re-docking analysis. Re-docking revealed that these particular compounds had a higher affinity for MBV VP35-RBD in comparison to the control. Analyzing the chemical interactions revealed unique binding properties for every compound, identified by a range of Pi-cation interactions and hydrogen bond types. We were able to learn more about the dynamic behaviors and stability of the protein-ligand complexes through a 200-nanosecond molecular dynamics simulation, as demonstrated by the compounds' consistent RMSD and RMSF values. The multidimensional nature of the data was clarified by the application of principal component analysis, which suggested stable conformations in the complexes with little modification. Further insight into the energy profiles and stability states of these complexes was also obtained by an examination of the free energy landscape. Our findings underscore the effectiveness of computational strategies in identifying and analyzing potential inhibitors for MBV VP35-RBD, offering promising paths for further experimental investigations and possible therapeutic development against the MBV.

Characterization of the Cynomolgus Macaque Model of Marburg Virus Disease and Assessment of Timing for Therapeutic Treatment Testing.

Marburg virus (MARV) causes severe disease and high mortality in humans. The objective of this study was to characterize disease manifestations and pathogenesis in cynomolgus macaques exposed to MARV. The results of this natural history study may be used to identify features of MARV disease useful in defining the ideal treatment initiation time for subsequent evaluations of investigational therapeutics using this model. Twelve cynomolgus macaques were exposed to a target dose of 1000 plaque-forming units MARV by the intramuscular route, and six control animals were mock-exposed. The primary endpoint of this study was survival to Day 28 post-inoculation (PI). Anesthesia events were minimized with the use of central venous catheters for periodic blood collection, and temperature and activity were continuously monitored by telemetry. All mock-exposed animals remained healthy for the duration of the study. All 12 MARV-exposed animals (100%) became infected, developed illness, and succumbed on Days 8-10 PI. On Day 4 PI, 11 of the 12 MARV-exposed animals had statistically significant temperature elevations over baseline. Clinically observable signs of MARV disease first appeared on Day 5 PI, when 6 of the 12 animals exhibited reduced responsiveness. Ultimately, systemic inflammation, coagulopathy, and direct cytopathic effects of MARV all contributed to multiorgan dysfunction, organ failure, and death or euthanasia of all MARV-exposed animals. Manifestations of MARV disease, including fever, systemic viremia, lymphocytolysis, coagulopathy, and hepatocellular damage, could be used as triggers for initiation of treatment in future therapeutic efficacy studies.

Development of an Immunochromatography Assay to Detect Marburg Virus and Ravn Virus.

The recent outbreaks of Marburg virus disease (MVD) in Guinea, Ghana, Equatorial Guinea, and Tanzania, none of which had reported previous outbreaks, imply increasing risks of spillover of the causative viruses, Marburg virus (MARV) and Ravn virus (RAVV), from their natural host animals. These outbreaks have emphasized the need for the development of rapid diagnostic tests for this disease. Using monoclonal antibodies specific to the viral nucleoprotein, we developed an immunochromatography (IC) assay for the rapid diagnosis of MVD. The IC assay was found to be capable of detecting approximately 102-4 50% tissue culture infectious dose (TCID50)/test of MARV and RAVV in the infected culture supernatants. We further confirmed that the IC assay could detect the MARV and RAVV antigens in the serum samples from experimentally infected nonhuman primates. These results indicate that the IC assay to detect MARV can be a useful tool for the rapid point-of-care diagnosis of MVD.

[Ebola and Marburg virus disease]. / Ebola-Virus- und Marburg-Viruserkrankung.

Viral hemorrhagic fevers (VHF) are serious, often fatal diseases that affect humans and non-human primates. The nomenclature of these diseases has changed in that they are now referred to as viral diseases because the previously named symptoms of fever or hemorrhages are not obligatory. In this article, the focus will be on the VHFs Ebola and Marburg viral disease with the potential for human-to-human transmission; these diseases are so-called high-consequence infectious diseases (HCID), some with considerable potential for epidemic spread and the risk of nosocomial transmission.

A mathematical model of Marburg virus disease outbreaks and the potential role of vaccination in control.

BACKGROUND: Marburg virus disease is an acute haemorrhagic fever caused by Marburg virus. Marburg virus is zoonotic, maintained in nature in Egyptian fruit bats, with occasional spillover infections into humans and nonhuman primates. Although rare, sporadic cases and outbreaks occur in Africa, usually associated with exposure to bats in mines or caves, and sometimes with secondary human-to-human transmission. Outbreaks outside of Africa have also occurred due to importation of infected monkeys. Although all previous Marburg virus disease outbreaks have been brought under control without vaccination, there is nevertheless the potential for large outbreaks when implementation of public health measures is not possible or breaks down. Vaccines could thus be an important additional tool, and development of several candidate vaccines is under way. METHODS: We developed a branching process model of Marburg virus transmission and investigated the potential effects of several prophylactic and reactive vaccination strategies in settings driven primarily by multiple spillover events as well as human-to-human transmission. Linelist data from the 15 outbreaks up until 2022, as well as an Approximate Bayesian Computational framework, were used to inform the model parameters. RESULTS: Our results show a low basic reproduction number which varied across outbreaks, from 0.5 [95% CI 0.05-1.8] to 1.2 [95% CI 1.0-1.9] but a high case fatality ratio. Of six vaccination strategies explored, the two prophylactic strategies (mass and targeted vaccination of high-risk groups), as well as a combination of ring and targeted vaccination, were generally most effective, with a probability of potential outbreaks being terminated within 1 year of 0.90 (95% CI 0.90-0.91), 0.89 (95% CI 0.88-0.90), and 0.88 (95% CI 0.87-0.89) compared with 0.68 (0.67-0.69) for no vaccination, especially if the outbreak is driven by zoonotic spillovers and the vaccination campaign initiated as soon as possible after onset of the first case. CONCLUSIONS: Our study shows that various vaccination strategies can be effective in helping to control outbreaks of MVD, with the best approach varying with the particular epidemiologic circumstances of each outbreak.