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Filovirus ebolavirus (ZE; Zaire ebolavirus, Bundibugyo ebolavirus), Neisseria meningitidis (NM), and Trypanosoma brucei (Tb) are serious infectious pathogens, spanning viruses, bacteria and protists and all may target the blood and central nervous system during their life cycle. NM and Tb are extracellular pathogens while ZE is obligatory intracellular, targetting immune privileged sites. By using interactomics and comparative evolutionary analysis we studied whether conserved human proteins are targeted by these pathogens. We examined 2797 unique pathogen-targeted human proteins. The information derived from orthology searches of experimentally validated protein–protein interactions (PPIs) resulted both in unique and shared PPIs for each pathogen. Comparing and analyzing conserved and pathogen-specific infection pathways for NM, TB and ZE, we identified human proteins predicted to be targeted in at least two of the compared host-pathogen networks. However, four proteins were common to all three host-pathogen interactomes: the elongation factor 1-alpha 1 (EEF1A1), the SWI/SNF complex subunit SMARCC2 (matrix-associated actin-dependent regulator of chromatin subfamily C), the dolichyl-diphosphooligosaccharide--protein glycosyltransferase subunit 1 (RPN1), and the tubulin beta-5 chain (TUBB). These four human proteins all are also involved in cytoskeleton and its regulation and are often addressed by various human pathogens. Specifically, we found (i) 56 human pathogenic bacteria and viruses that target these four proteins, (ii) the well researched new pandemic pathogen SARS-CoV-2 targets two of these four human proteins and (iii) nine human pathogenic fungi (yet another evolutionary distant organism group) target three of the conserved proteins by 130 high confidence interactions.

BackgroundThe Ebolavirus is one of the deadliest viral pathogens which was first discovered in the year 1976 during two consecutive outbreaks in the Democratic Republic of Congo and Sudan. Six known strains have been documented. The Bundibugyo Ebolavirus in particular first emerged in the year 2007 in Uganda. This outbreak was constituted with 116 human cases and 39 laboratory confirmed deaths. After 5 years, it re-emerged and caused an epidemic for the first time in the Democratic Republic of Congo in the year 2012 as reported by the WHO. Here, 36 human cases with 13 laboratory confirmed deaths were registered. Despite several research studies conducted in the past, there is still scarcity of knowledge available on the genetic diversity of Bundibugyo Ebolavirus. We undertook a research project to provide insights into the unique variants of Bundibugyo Ebolavirus that circulated in the two epidemics that occurred in Uganda and the Democratic Republic of CongoMaterials and MethodsThe Bioinformatics approaches used were; Quality Control, Reference Mapping, Variant Calling, Annotation, Multiple Sequence Alignment and Phylogenetic analysis to identify genomic variants as well determine the genetic relatedness between the two epidemics. Overall, we used 41 viral sequences that were retrieved from the publicly available sequence database, which is the National Center for Biotechnology and Information Gen-bank database.ResultsOur analysis identified 14,362 unique genomic variants from the two epidemics. The Uganda isolates had 5,740 unique variants, 75 of which had high impacts on the genomes. These were 51 frameshift, 15 stop gained, 5 stop lost, 2 missense, 1 synonymous and 1 stop lost and splice region. Their effects mainly occurred within the L-gene region at reference positions 17705, 11952, 11930 and 11027. For the DRC genomes, 8,622 variant sites were identified. The variants had a modifier effect on the genome occurring at reference positions, 213, 266 and 439. Examples are C213T, A266G and C439T. Phylogenetic reconstruction identified two separate and unique clusters from the two epidemics.ConclusionOur analysis provided further insights into the genetic diversity of Bundibugyo Ebolavirus from the two epidemics. The Bundibugyo Ebolavirus strain was genetically diverse with multiple variants. Phylogenetic reconstruction identified two unique variants. This signified an independent spillover event from a natural reservoir, rather a continuation from the ancestral outbreak that initiated the resurgence in DRC in the year 2012. Therefore, the two epidemics were not genetically related.

Members of the genus Ebolavirus cause lethal disease in humans, with Zaire ebolavirus (EBOV) being the most pathogenic (up to 90% morality) and Bundibugyo ebolavirus (BDBV) the least pathogenic (∼37% mortality). Historically, there has been a lack of research on BDBV, and there is no means to study BDBV outside of a high-containment laboratory. Here, we describe a minigenome replication system to study BDBV transcription and compare the efficacy of small-molecule inhibitors between EBOV and BDBV. Using this system, we examined the ability of the polymerase complex proteins from EBOV and BDBV to interact and form a functional unit as well as the impact of the genomic untranslated ends, known to contain important signals for transcription (3′-untranslated region) and replication (5′-untranslated region). Various levels of compatibility were observed between proteins of the polymerase complex from each ebolavirus, resulting in differences in genome transcription efficiency. Most pronounced was the effect of the nucleoprotein and the 3′-untranslated region. These data suggest that there are intrinsic specificities in the polymerase complex and untranslated signaling regions that could offer insight regarding observed pathogenic differences. Further adding to the differences in the polymerase complexes, posttransfection/infection treatment with the compound remdesivir (GS-5734) showed a greater inhibitory effect against BDBV than EBOV. The delayed growth kinetics of BDBV and the greater susceptibility to polymerase inhibitors indicate that disruption of the polymerase complex is a viable target for therapeutics. IMPORTANCE Ebolavirus disease is a viral infection and is fatal in 25 to 90% of cases, depending on the viral species and the amount of supportive care available. Two species have caused outbreaks in the Democratic Republic of the Congo, Zaire ebolavirus (EBOV) and Bundibugyo ebolavirus (BDBV). Pathogenesis and clinical outcome differ between these two species, but there is still limited information regarding the viral mechanism for these differences. Previous studies suggested that BDBV replicates slower than EBOV, but it is unknown if this is due to differences in the polymerase complex and its role in transcription and replication. This study details the construction of a minigenome replication system that can be used in a biosafety level 2 laboratory. This system will be important for studying the polymerase complex of BDBV and comparing it with other filoviruses and can be used as a tool for screening inhibitors of viral growth.

Ebolaviruses Bundibugyo virus (BDBV) and Ebola virus (EBOV) cause fatal hemorrhagic disease in humans and nonhuman primates. While the host response to EBOV is well characterized, less is known about BDBV infection. Moreover, immune signatures that mediate natural protection against all ebolaviruses remain poorly defined. To explore these knowledge gaps, we transcriptionally profiled BDBV-infected rhesus macaques, a disease model that results in incomplete lethality. This approach enabled us to identify prognostic indicators. As expected, survival (∼60%) correlated with reduced clinical pathology and circulating infectious virus, although peak viral RNA loads were not significantly different between surviving and nonsurviving macaques. Survivors had higher anti-BDBV antibody titers and transcriptionally derived cytotoxic T cell-, memory B cell-, and plasma cell-type quantities, demonstrating activation of adaptive immunity. Conversely, a poor prognosis was associated with lack of an appropriate adaptive response, sustained innate immune signaling, and higher expression of myeloid-derived suppressor cell (MDSC)-related transcripts (S100A8, S100A9, CEBPB, PTGS2, CXCR1, and LILRA3). MDSCs are potent immunosuppressors of cellular and humoral immunity, and therefore, they represent a potential therapeutic target. Circulating plasminogen activator inhibitor 1 (PAI-1) and tissue plasminogen activator (tPA) levels were also elevated in nonsurvivors and in survivors exhibiting severe illness, emphasizing the importance of maintaining coagulation homeostasis to control disease progression. IMPORTANCE Bundibugyo virus (BDBV) and Ebola virus (EBOV) are ebolaviruses endemic to Africa that cause severe, often fatal hemorrhagic disease. BDBV is considered a less pathogenic ebolavirus due to its reduced lethality during human outbreaks, as well as in experimentally infected nonhuman primates. The reduced mortality of BDBV in NHP models, resulting in a pool of survivors, afforded us the unique opportunity of identifying immune correlates that confer protection against ebolaviruses. In this study, we discovered that the survival of BDBV-infected nonhuman primates (NHPs) was dependent on early development of adaptive (memory) immune responses and reduced myeloid-derived suppressor cell (MDSC)-related signaling. MDSCs are a heterogenous group of immune cells implicated in a number of diseases that are powerful immunosuppressors of cellular and humoral immunity. Thus, MDSCs represent a novel therapeutic target to prevent ebolavirus disease. To our knowledge, this is the first study to link increased morbidity with recruitment of these potent immunosuppressive cells.

Currently there is no FDA-licensed vaccine or therapeutic against Sudan ebolavirus (SUDV) infections. The largest ever reported 2014–2016 West Africa outbreak, as well as the 2021 outbreak in the Democratic Republic of Congo, highlight the critical need for countermeasures against filovirus infections. A well-characterized small animal model that is susceptible to wild-type filoviruses would greatly add to the screening of antivirals and vaccines. Here, we infected signal transducer and activator of transcription-1 knock out (STAT-1 KO) mice with five different wildtype filoviruses to determine susceptibility. SUDV and Marburg virus (MARV) were the most virulent, and caused 100% or 80% lethality, respectively. Zaire ebolavirus (EBOV), Bundibugyo ebolavirus (BDBV), and Taï Forest ebolavirus (TAFV) caused 40%, 20%, and no mortality, respectively. Further characterization of SUDV in STAT-1 KO mice demonstrated lethality down to 3.1 × 101 pfu. Viral genomic material was detectable in serum as early as 1 to 2 days post-challenge. The onset of viremia was closely followed by significant changes in total white blood cells and proportion of neutrophils and lymphocytes, as well as by an influx of neutrophils in the liver and spleen. Concomitant significant fluctuations in blood glucose, albumin, globulin, and alanine aminotransferase were also noted, altogether consistent with other models of filovirus infection. Finally, favipiravir treatment fully protected STAT-1 KO mice from lethal SUDV challenge, suggesting that this may be an appropriate small animal model to screen anti-SUDV countermeasures.

Prior to the discovery of the Reston ebolavirus (RESTV) in 1989, filoviruses were thought to be present only in Africa. The virus was discovered in a quarantine facility in Reston, Virginia, USA, following the deaths of imported cynomolgus macaques (Macaca fascicularis) from the Philippines displaying severe haemorrhagic disease. It was thought that aerosol and fomite transmission of RESTV occurred between the macaques and humans during this outbreak. In addition to RESTV, the macaques were found to be infected with the Arterivirus, Simian haemorrhagic fever virus, which naturally occurs in African monkeys. An epizootic event involving the cynomolgus macaques occurred again in 1992 in Siena, Italy and in 1996 in Alice, Texas, USA. All of these infections were traced to monkeys exported from a single primate facility located south of metropolitan Manila, on the island of Luzon in the Philippines. This facility was subsequently closed down by the government in 1997 due to non-compliance issues relating to environmental regulations. RESTV has also emerged in pigs in the Philippines in 2008 and China in 2011 where in both cases coinfection with porcine reproductive and respiratory syndrome virus (PRRSV) occurred. It was hypothesized that the source of these outbreaks were from exposure to bats.

The genus Ebolavirus from the family Filoviridae is composed of five species including Sudan ebolavirus, Reston ebolavirus, Bundibugyo ebolavirus, Taï Forest ebolavirus, and Ebola virus (previously known as Zaire ebolavirus). These viruses have a large non-segmented, negative-strand RNA of approximately 19 kb that encodes for glycoproteins (i.e., GP, sGP, ssGP), nucleoproteins, virion proteins (i.e., VP 24, 30,40) and an RNA dependent RNA polymerase. These viruses have become a global health concern because of mortality, their rapid dissemination, new outbreaks in West-Africa, and the emergence of a new condition known as “Post-Ebola virus disease syndrome” that resembles inflammatory and autoimmune conditions such as rheumatoid arthritis, systemic lupus erythematosus and spondyloarthritis with uveitis. However, there are many gaps in the understanding of the mechanisms that may induce the development of such autoimmune-like syndromes. Some of these mechanisms may include a high formation of neutrophil extracellular traps, an uncontrolled “cytokine storm”, and the possible formation of auto-antibodies. The likely appearance of autoimmune phenomena in Ebola survivors suppose a new challenge in the management and control of this disease and opens a new field of research in a special subgroup of patients. Herein, the molecular biology, pathogenesis, clinical manifestations, and treatment of Ebola virus disease are reviewed and some strategies for control of disease are discussed. © 2019 The Authors

Summary Bundibugyo virus (BDBV) is one of four ebolaviruses known to cause disease in humans. Bundibugyo virus disease (BVD) outbreaks occurred in 2007–2008 in Bundibugyo District, Uganda, and in 2012 in Isiro, Province Orientale, Democratic Republic of the Congo. The 2012 BVD outbreak resulted in 38 laboratory-confirmed cases of human infection, 13 of whom died. However, only 4 BDBV specimens from the 2012 outbreak have been sequenced. Here, we provide BDBV sequences from seven additional patients. Analysis of the molecular epidemiology and evolutionary dynamics of the 2012 outbreak with these additional isolates challenges the current hypothesis that the outbreak was the result of a single spillover event. In addition, one patient record indicates that BDBV’s initial emergence in Isiro occurred 50 days earlier than previously accepted. Collectively, this work demonstrates how retrospective sequencing can be used to elucidate outbreak origins and provide epidemiological contexts to a medically relevant pathogen., Graphical abstract, Highlights In 2012, BDBV was circulating earlier than previously appreciated BDBV genomes from seven additional patients are sequenced Molecular analyses indicate that multiple spillover events fueled the BVD outbreak, Elucidation of the epidemiology underlying the 2012 Bundibugyo virus disease outbreak in the Democratic Republic of the Congo has been challenging. Hulseberg et al. acquire additional genomic and phylodynamic data indicating that multiple Bundibugyo virus spillover events, some of which occurred much earlier than previously known, contributed to the outbreak.

Family Filoviridae includes a set of etiological agents of human hemorrhagic fevers distributed in Africa: Zaire ebolavirus (ZEBOV), Sudan ebolavirus (SUDV), Bundibugyo ebolavirus (BDBV), Taï Forest ebolavirus (TAFV), Marburg marburgvirus (MMARV). Historiography and recent taxonomical structure of Filoviridae family are considered in the review. The discussed data of laboratory and ecological-virological field researches demonstrate the presence of a natural reservoir of filoviruses among fruit-bats (Chiroptera, Megachiroptera) which carry filovirus infection without clinical signs but allocate viruses with urine, saliva, excrements, and sperm, as well as contain viruses in blood and internals. The potential hosts of filoviruses are various mammal species including the higher primacies (Anthropoidea) and the humans (Homo sapiens sapiens). A brief comparison of anatomic and morphologic features of fruit bats and bats (Chiroptera, Microchiroptera) belonging to another suborder of chiropterans is presented. The description of the basic characteristics of the four types of epidemic outbreaks linked with Filoviridae-associated fevers — speleological (from Ancient Greek σπήλαιον — cave), forest, rural, and urban are given; their possible transformation directions are considered as well.

We describe two approaches to modeling data from a small to moderate-sized epidemic outbreak. The first approach isВ based on a branching process approximation and direct analysis of the transmission network, whereas the second one is based on a survival model derived from the classical SIR equations with no explicit transmission information. We compare these approaches using data from a 2012 outbreak of Ebola virus disease caused byВ Bundibugyo ebolavirusВ in city of Isiro, Demo- cratic Republic of the Congo. The branching process model allows for a direct comparison of disease transmission across different environments, such as the general community or the Ebola treatment unit. However, the survival model appears to yield parameter estimates with more accuracy and better precision in some circumstances.

We introduce an alignment-free method, the Magnus Representation, to analyze genome sequences. The Magnus Representation captures higher-order information in genome sequences. We combine our approach with the idea ofk-mers to define an effectively computable Mean Magnus Vector. We perform phylogenetic analysis on three datasets: mosquito-borne viruses, filoviruses, and bacterial genomes. Our results on ebolaviruses are consistent with previous phylogenetic analyses, and confirm the modern viewpoint that the 2014 West African Ebola outbreak likely originated from Central Africa. Our analysis also confirms the close relationship betweenBundibugyo ebolavirusandTaï Forest ebolavirus. For bacterial genomes, our method is able to classify relatively well at the family and genus level, as well as at higher levels such as phylum level. The bacterial genomes are also separated well into Gram-positive and Gram-negative subgroups.

The 2014 Ebolavirus outbreak in West Africa highlighted the need for vaccines and therapeutics to prevent and treat filovirus infections. A well-characterized small animal model that is susceptible to wild-type filoviruses would facilitate the screening of anti-filovirus agents. To that end, we characterized knockout mice lacking &alpha, /&beta, and &gamma, interferon receptors (IFNAGR KO) as a model for wild-type filovirus infection. Intraperitoneal challenge of IFNAGR KO mice with several known human pathogenic species from the genus Ebolavirus and Marburgvirus, except Bundibugyo ebolavirus and Ta&iuml, Forest ebolavirus, caused variable mortality rate. Further characterization of the prototype Ebola virus Kikwit isolate infection in this KO mouse model showed 100% lethality down to a dilution equivalent to 1.0 &times, 10&minus, 1 pfu with all deaths occurring between 7 and 9 days post-challenge. Viral RNA was detectable in serum after challenge with 1.0 &times, 102 pfu as early as one day after infection. Changes in hematology and serum chemistry became pronounced as the disease progressed and mirrored the histological changes in the spleen and liver that were also consistent with those described for patients with Ebola virus disease. In a proof-of-principle study, treatment of Ebola virus infected IFNAGR KO mice with favipiravir resulted in 83% protection. Taken together, the data suggest that IFNAGR KO mice may be a useful model for early screening of anti-filovirus medical countermeasures.

Background Ebola and Marburg virus diseases are said to occur at a low prevalence, but are very severe diseases with high lethalities. The fatality rates reported in different outbreaks ranged from 24–100%. In addition, sero-surveys conducted have shown different seropositivity for both Ebola and Marburg viruses. We aimed to use a meta-analysis approach to estimate the case fatality and seroprevalence rates of these filoviruses, providing vital information for epidemic response and preparedness in countries affected by these diseases. Methods Published literature was retrieved through a search of databases. Articles were included if they reported number of deaths, cases, and seropositivity. We further cross-referenced with ministries of health, WHO and CDC databases. The effect size was proportion represented by case fatality rate (CFR) and seroprevalence. Analysis was done using the metaprop command in STATA. Results The weighted average CFR of Ebola virus disease was estimated to be 65.0% [95% CI (54.0–76.0%), I2 = 97.98%] whereas that of Marburg virus disease was 53.8% (26.5–80.0%, I2 = 88.6%). The overall seroprevalence of Ebola virus was 8.0% (5.0%–11.0%, I2 = 98.7%), whereas that for Marburg virus was 1.2% (0.5–2.0%, I2 = 94.8%). The most severe species of ebolavirus was Zaire ebolavirus while Bundibugyo Ebolavirus was the least severe. Conclusions The pooled CFR and seroprevalence for Ebola and Marburg viruses were found to be lower than usually reported, with species differences despite high heterogeneity between studies. Countries with an improved health surveillance and epidemic response have lower CFR, thereby indicating need for improving early detection and epidemic response in filovirus outbreaks.

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, Tai 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.

Differences from other outbreaks could suggest guidance for optimizing clinical management and disease control., During July–November 2014, the Democratic Republic of the Congo underwent its seventh Ebola virus disease (EVD) outbreak. The etiologic agent was Zaire Ebola virus; 66 cases were reported (overall case-fatality rate 74.2%). Through a retrospective observational study of confirmed EVD in 25 patients admitted to either of 2 Ebola treatment centers, we described clinical features and investigated correlates associated with death. Clinical features were mainly generic. At admission, 76% of patients had >1 gastrointestinal symptom and 28% >1 hemorrhagic symptom. The case-fatality rate in this group was 48% and was higher for female patients (67%). Cox regression analysis correlated death with initial low cycle threshold, indicating high viral load. Cycle threshold was a robust predictor of death, as were fever, hiccups, diarrhea, dyspnea, dehydration, disorientation, hematemesis, bloody feces during hospitalization, and anorexia in recent medical history. Differences from other outbreaks could suggest guidance for optimizing clinical management and disease control.

Screening of monoclonal antibodies against ebolaviruses requires small-animal models. Wild-type mice require adaptation of ebolaviruses, whereas immunodeficient mice are still resistant to nonadapted Bundibugyo ebolavirus. Swapping of Ebola virus glycoprotein with that from Bundibugyo virus resulted in a replication-competent chimeric virus, which caused 100% lethal infection in STAT1 knockout mice. Monoclonal antibody BDBV223 isolated from a human survivor of Bundibugyo virus infection protected mice from challenge with the chimeric virus. These data demonstrate the suitability of the approach for in vivo screening of antibodies and suggest the greater contribution of internal Ebola proteins in pathogenesis compared to Bundibugyo virus proteins.

Filovirus including Ebola and Marburg hemorrhagic fever is a zoonotic disease that characterised by immune suppression and systemic inflammatory response causing impairment of the vascular and immune systems. It is leading to multiorgan failures with mortality varies from 50-90% in human and primate. The Ebola virus is currently divided into five species, namely Zaire ebolavirus (ZEBOV), Sudan ebolavirus (SEBOV), Tai Forest ebolavirus , Reston ebolavirus (REBOV) and Bundibugyo ebolavirus . Geographical distribution of Ebola virus in the Afrotropics region is mainly in the rainforests of Central and West Africa, while REBOV was detected in the Philippines. Bats are suspected as reservoir host of the virus. Recently, Ebola cases had been reported in endemic areas in Africa and then distributed to other countries which was not endemic through human travellers. Ebola virus is also potentially used as a biological weapon, so Ebola virus becomes public health concern. This paper describes the characters of Ebola virus, its clinical signs, transmission and threat as an exotic disease in Indonesia. By understanding the disease, the emergence of Ebola virus in Indonesia can be anticipated quickly. Key words: Ebola virus, exotic, pathogen

Ebolaviruses have a surface glycoprotein (GP 1,2 ) that is required for virus attachment and entry into cells. Mutations affecting GP 1,2 functions can alter virus growth properties. We generated a recombinant vesicular stomatitis virus encoding Ebola virus Makona variant GP 1,2 (rVSV-MAK-GP) and observed emergence of a T544I mutation in the Makona GP 1,2 gene during tissue culture passage in certain cell lines. The T544I mutation emerged within two passages when VSV-MAK-GP was grown on Vero E6, Vero, and BS-C-1 cells but not when it was passaged on Huh7 and HepG2 cells. The mutation led to a marked increase in virus growth kinetics and conferred a robust growth advantage over wild-type rVSV-MAK-GP on Vero E6 cells. Analysis of complete viral genomes collected from patients in western Africa indicated that this mutation was not found in Ebola virus clinical samples. However, we observed the emergence of T544I during serial passage of various Ebola Makona isolates on Vero E6 cells. Three independent isolates showed emergence of T544I from undetectable levels in nonpassaged virus or virus passaged once to frequencies of greater than 60% within a single passage, consistent with it being a tissue culture adaptation. Intriguingly, T544I is not found in any Sudan, Bundibugyo, or Tai Forest ebolavirus sequences. Furthermore, T544I did not emerge when we serially passaged recombinant VSV encoding GP 1,2 from these ebolaviruses. This report provides experimental evidence that the spontaneous mutation T544I is a tissue culture adaptation in certain cell lines and that it may be unique for the species Zaire ebolavirus . IMPORTANCE The Ebola virus (Zaire) species is the most lethal species of all ebolaviruses in terms of mortality rate and number of deaths. Understanding how the Ebola virus surface glycoprotein functions to facilitate entry in cells is an area of intense research. Recently, three groups independently identified a polymorphism in the Ebola glycoprotein (I544) that enhanced virus entry, but they did not agree in their conclusions regarding its impact on pathogenesis. Our findings here address the origins of this polymorphism and provide experimental evidence showing that it is the result of a spontaneous mutation (T544I) specific to tissue culture conditions, suggesting that it has no role in pathogenesis. We further show that this mutation may be unique to the species Zaire ebolavirus , as it does not occur in Sudan, Bundibugyo, and Tai Forest ebolaviruses. Understanding the mechanism behind this mutation can provide insight into functional differences that exist in culture conditions and among ebolavirus glycoproteins.

Ebola Virus Disease (EVD) is a disease caused by a virus of the genus Ebolavirus (EBOV), family Filoviridae. Ebola virus is classifed into five types, namely Zaire ebolavirus (ZEBOV), Sudan ebolavirus (SEBOV), Bundibugyo ebolavirus (BEBOV), Tai Forest ebolavirus also known as Cote d’Ivoire ebolavirus (CIEBOV), and Reston ebolavirus (REBOV). Identification of kinship types of Ebola virus can be performed using phylogenetic trees. In this study, the phylogenetic tree constructed by UPGMA method in which there are Multiple Alignment using Progressive Method. The results concluded that the phylogenetic tree formation kinship ebola virus types that kind of Tai Forest ebolavirus close to Bundibugyo ebolavirus but the layout state ebola epidemic spread far apart. The genetic distance for this type of Bundibugyo ebolavirus with Tai Forest ebolavirus is 0.3725. Type Tai Forest ebolavirus similar to Bundibugyo ebolavirus not inuenced by the proximity of the area ebola epidemic spread.

The current ongoing outbreak of Ebola Virus Disease (EVD) in West Africa is unprecedented in many ways. It is certainly one of the largest and deadliest outbreaks in recent times. It began in Guinea in late 2013 and spread to neighboring countries of Liberia and Sierre Leone. A total of 18,464 suspected, probable and confirmed (11,699) cases with 6841 deaths have been reported till 13th December 2014. Limited transmission is reported from United States of America (4 cases, 1 death) and Mali (8 cases, 6 deaths) whereas, Nigeria (20 cases, 8 deaths), Senegal (1 case, 0 deaths) and Spain (1 case, 0 deaths) have been declared free of EVD [1]. The outbreak has mounted exceptional concern, preparedness and response worldwide as it is dreaded as one of the most virulent disease causing high fatality in humans. It has no specific treatment or vaccine despite it being known since 1976 when it first appeared in Democratic Republic of the Congo (DRC) in two simultaneous outbreaks in Nzara, Sudan, and Yambuku, DRC. Until December 2013, a total of 23 outbreaks recorded 2388 human cases and 1590 deaths [2]. Formerly known as Ebola hemorrhagic fever, in the current outbreak EVD involved the health care workers and further weakened the already compromised health care system in the affected countries. Notably, experimental drugs were used in the treatment of humans. UN and other agencies and experts have accelerated the research, clinical trials and resolution of ethical concerns so that drugs and vaccines can be made available for prevention and control of EVD. Ebolavirus is one of three members of the Filoviridae family (filovirus), along with genus Marburgvirus and Cuevavirus. There are five distinct species of Ebolavirus viz. Bundibugyo ebolavirus (BDBV), Zaire ebolavirus (EBOV), Reston ebolavirus (RESTV), Sudan ebolavirus (SUDV) and Tai Forest ebolavirus (TAFV). While BDBV, EBOV, and SUDV have been associated with large EVD outbreaks in Africa, RESTV and TAFV have not yet been implicated in a human outbreak. The RESTV species, found in Philippines and the People’s Republic of China, can infect humans, but no illness or death in humans has been reported [3, 4]. The natural reservoir of Ebola viruses has not yet been proven conclusively. However, fruit batsHypsignathus monstrosus, Epomops franqueti and Myonycteris torquata, may be the natural hosts in Africa. Human beings can get infected and initiate human to human transmission on contact with infected animals or their carcasses. In Africa, infection has been documented through the handling of infected chimpanzees, gorillas, fruit bats, monkeys, forest antelope and porcupines found ill or dead or in the rainforest [3]. The most common mode of human-to-human transmission is direct contact through broken skin or unprotected mucous membranes e.g., the eyes, nose, or mouth, with the blood or body fluids (urine, feces, saliva, semen, and other secretions) of a person who is sick or has died of EVD. However, infection cannot be transmitted before the appearance of symptoms. Transmissionmay also occur with contaminated needles or infected animals. Ebola does not spread through the air or by water. In Africa, it can spread by handling infected bush meat. There is no evidence that mosquitoes and other insects can transmit the virus [3]. V. Mittal (*) :M. Chhabra Zoonosis Division, National Centre for Disease Control, Dte.GHS, 22-Sham Nath Marg, Delhi 110054, India e-mail: veena_m12@yahoo.com

Ebola virus disease (EVD), a highly virulent infectious disease caused by ebolaviruses, has a fatality rate of 25-90%. Without a licensed chemotherapeutic agent or vaccine for the treatment and prevention of EVD, control of outbreaks requires accurate and rapid diagnosis of cases. In this study, five sets of six oligonucleotide primers targeting the nucleoprotein gene were designed for specific identification of each of the five ebolavirus species using reverse transcription-loop mediated isothermal amplification (RT-LAMP) assay. The detection limits of the ebolavirus species-specific primer sets were evaluated using in vitro transcribed RNAs. The detection limit of species-specific RT-LAMP assays for Zaire ebolavirus, Sudan ebolavirus, Tai Forest ebolavirus, and Bundibugyo ebolavirus was 256 copies/reaction, while the detection limit for Reston ebolavirus was 64 copies/reaction, and the detection time for each of the RT-LAMP assays was 13.3±3.0, 19.8±4.6, 14.3±0.6, 16.1±4.7, and 19.8±2.4min (mean±SD), respectively. The sensitivity of the species-specific RT-LAMP assays were similar to that of the established RT-PCR and quantitative RT-PCR assays for diagnosis of EVD and are suitable for field or point-of-care diagnosis. The RT-LAMP assays were specific for the detection of the respective species of ebolavirus with no cross reaction with other species of ebolavirus and other viral hemorrhagic fever viruses such as Marburg virus, Lassa fever virus, and Dengue virus. The species-specific RT-LAMP assays developed in this study are rapid, sensitive, and specific and could be useful in case of an EVD outbreak.

Zaire ebolavirus (EBOV), Bundibugyo ebolavirus (BDBV), and Reston ebolavirus (RESTV) belong to the same genus but exhibit different virulence properties. VP24 protein, a structural protein present in all family members, blocks interferon (IFN) signaling and likely contributes to virulence. Inhibition of IFN signaling by EBOV VP24 (eVP24) involves its interaction with the NPI-1 subfamily of karyopherin alpha (KPNA) nuclear transporters. Here, we evaluated eVP24, BDBV VP24 (bVP24), and RESTV VP24 (rVP24) interactions with three NPI-1 subfamily KPNAs (KPNA1, KPNA5, and KPNA6). Using purified proteins, we demonstrated that each VP24 binds to each of the three NPI-1 KPNAs. bVP24, however, exhibited approximately 10-fold-lower KPNA binding affinity than either eVP24 or rVP24. Cell-based assays also indicate that bVP24 exhibits decreased KPNA interaction, decreased suppression of IFN induced gene expression, and a decreased half-life in transfected cells compared to eVP24 or rVP24. Amino acid sequence alignments between bVP24 and eVP24 also identified residues within and surrounding the previously defined eVP24-KPNA5 binding interface that decrease eVP24-KPNA affinity or bVP24-KPNA affinity. VP24 mutations that lead to reduced KPNA binding affinity also decrease IFN inhibition and shorten VP24 half-lives. These data identify novel functional differences in VP24-KPNA interaction and reveal a novel impact of the VP24-KPNA interaction on VP24 stability. IMPORTANCE The interaction of Ebola virus (EBOV) VP24 protein with host karyopherin alpha (KPNA) proteins blocks type I interferon (IFN) signaling, which is a central component of the host innate immune response to viral infection. Here, we quantitatively compared the interactions of VP24 proteins from EBOV and two members of the Ebolavirus genus, Bundibugyo virus (BDBV) and Reston virus (RESTV). The data reveal lower binding affinity of the BDBV VP24 (bVP24) for KPNAs and demonstrate that the interaction with KPNA modulates inhibition of IFN signaling and VP24 stability. The effect of KPNA interaction on VP24 stability is a novel functional consequence of this virus-host interaction, and the differences identified between viral species may contribute to differences in pathogenesis.

The Ebolavirus genus includes five member species, all of which pose a threat to global public health. These viruses cause fatal hemorrhagic fever in humans and nonhuman primates, and are considered category A pathogens due to the risk of their use as a bioweapon. The potential for an outbreak, either as a result of a natural emergence, deliberate release, or imported case underscores the need for protective vaccines. Recent progress in advancing vaccines for use against the strain of Zaire ebolavirus (EBOV) responsible for the West African Ebola outbreak offers reasons for optimism against EBOV, and demonstrates that protection against other Ebolavirus species is achievable.

During the latest outbreak of Ebola virus disease in West Africa, monoclonal antibody therapy (e.g., ZMapp) was utilized to treat patients. However, due to the antigenic differences among the five ebolavirus species, the current therapeutic monoclonal antibodies are only effective against viruses of the species Zaire ebolavirus. Although this particular species has indeed caused the majority of human infections in Central and, recently, West Africa, other ebolavirus species (e.g., Sudan ebolavirus and Bundibugyo ebolavirus) have also repeatedly caused outbreaks in Central Africa and thus should not be neglected in the development of countermeasures against ebolaviruses. Here we report the generation of an ebolavirus glycoprotein-specific monoclonal antibody that effectively inhibits cellular entry of representative isolates of all known ebolavirus species in vitro and show its protective efficacy in mouse models of ebolavirus infections. This novel neutralizing monoclonal antibody targets a highly conserved internal fusion loop in the glycoprotein molecule and prevents membrane fusion of the viral envelope with cellular membranes. The discovery of this highly cross-neutralizing antibody provides a promising option for broad-acting ebolavirus antibody therapy and will accelerate the design of improved vaccines that can selectively elicit cross-neutralizing antibodies against multiple species of ebolaviruses.

Ebola virus disease (EVD), characterized by fatal bleeding and coagulation abnormalities, is caused by infection of Ebola viruses (EBOV) and other members of the family Filoviridae. Ebola viruses have 5 species named after the places of outbreaks: Zaire ebolavirus (ZEBOV), Bundibugyo ebolavirus (BDBV), Reston ebolavirus (RESTV), Sudan ebolavirus (SUDV), and Tai Forest ebolavirus (TAFV). Among them, the Zaire strain is the most lethal. The EBOV genome consists of a linear, non-segmented negative-stranded RNA of 19 kb in length, coding for 7 structural proteins, including nucleoprotein (NP), VP35, VP40, glycoprotein (GP), VP30, VP24, and L protein. Human infection by EBOV is possible through contact with body fluids of virus infected individuals or animals like Primates or fruit bats. There have been over 25 outbreaks since its discovery in 1976. In the most recent largest Ebola outbreak in Western Africa, 28,639 cases and 11,316 deaths were recorded by the World Health Organization (WHO, http://www.who.int/csr/disease/ebola/situationreports/en/). There is no Food and Drug Administration (FDA) approved specific treatment for the EVD. The medical care for patients primarily relies on intensive supportive care. The use of convalescent plasma from patients who have recovered from EVD was among the first specific therapeutic approaches, and later on, human neutralizing antibodies, like ZMappTM, have been tested. However, the source of convalescent plasma is very limited and antibody production is too expensive to meet the demands for large scale applications, especially for those patients in less developed countries most at risk from Ebola outbreaks. Using small interfering RNA (siRNA) targeting Ebola Virus (EBOV) genome is another appealing therapeutic idea. A successful siRNA product, TKM-Ebola, developed by the Tekmira pharmaceuticals corp, has been tried clinically during Ebola crisis. It uses a mixture of three siRNAs to target EBOV VP24 (membrane associated protein), VP35 (polymerase complex protein) and L (RNA dependent RNA polymerase) respectively. It is effective against Ebola virus, however, the TKM-Ebola therapy was discontinued soon after phase I clinical trials due to activation of inflammatory pathways in patients.

For Ebola virus (EBOV), 4 different species are known: Zaire, Sudan, Côte d’Ivoire, and Reston ebolavirus. The newly discovered Bundibugyo ebolavirus has been proposed as a 5th species. So far, no cross-neutralization among EBOV species has been described, aggravating progress toward cross-species protective vaccines. With the use of recombinant vesicular stomatitis virus (rVSV)–based vaccines, guinea pigs could be protected against Zaire ebolavirus (ZEBOV) infection only when immunized with a vector expressing the homologous, but not a heterologous, EBOV glycoprotein (GP). However, infection of guinea pigs with nonadapted wild-type strains of the different species resulted in full protection of all animals against subsequent challenge with guinea pig–adapted ZEBOV, showing that cross-species protection is possible. New vectors were generated that contain EBOV viral protein 40 (VP40) or EBOV nucleoprotein (NP) as a second antigen expressed by the same rVSV vector that encodes the heterologous GP. After applying a 2-dose immunization approach, we observed an improved cross-protection rate, with 5 of 6 guinea pigs surviving the lethal ZEBOV challenge if vaccinated with rVSV-expressing SEBOV-GP and -VP40. Our data demonstrate that cross-protection between the EBOV species can be achieved, although EBOV-GP alone cannot induce the required immune response.

Highlights ► Authors review the current and proposed nomenclature of filoviruses. ► Filovirus genome structure and content are reviewed. ► New filoviruses finds are discussed with regard to the current view of phylogeny. ► Swine as a newly identified host is discussed with regard to phylogenetic diversity. ► Integrations of filovirus-like sequences in host genomes are reviewed., Sporadic fatal outbreaks of disease in humans and non-human primates caused by Ebola or Marburg viruses have driven research into the characterization of these viruses with the hopes of identifying host tropisms and potential reservoirs. Such an understanding of the relatedness of newly discovered filoviruses may help to predict risk factors for outbreaks of hemorrhagic disease in humans and/or non-human primates. Recent discoveries such as three distinct genotypes of Reston ebolavirus, unexpectedly discovered in domestic swine in the Philippines; as well as a new species, Bundibugyo ebolavirus; the recent discovery of Lloviu virus as a potential new genus, Cuevavirus, within Filoviridae; and germline integrations of filovirus-like sequences in some animal species bring new insights into the relatedness of filoviruses, their prevalence and potential for transmission to humans. These new findings reveal that filoviruses are more diverse and may have had a greater influence on the evolution of animals than previously thought. Herein we review these findings with regard to the implications for understanding the host range, prevalence and transmission of Filoviridae.

Bundibugyo ebolavirus is a newly identified Ebolavirus species. The virus was responsible for a recent hemorrhagic fever outbreak in Uganda with an approximate 30% case fatality rate. In this study, we compared the pathogenesis of Bundibugyo with highly lethal Zaire Ebolavirus by using in vitro human PBMCs. We found that PBMCs infected with Bundibugyo ebolaviruses resulted in 1 to 2 log lower virus yields compared to Zaire ebolavirus and produced 2- to 10-fold lower levels of TNF-alpha, MCP-1, IL-1beta, MIP1-alpha and IL-10 than PBMCs infected with Zaire ebolavirus. In addition, flow cytometric studies have shown lower levels and delay of the macrophage cell death in Bundibugyo ebolavirus compared to Zaire ebolavirus infection. The findings of slower Bundibugyo ebolavirus replication, lower production of proinflammatory cytokines and delay in macrophage cell death provide insight into the basis of the lower case fatality observed with Bundibugyo ebolavirus.

Genome-similarity based codes were assigned to individual ebolavirus isolates. Codes were found to be informative of phylogenetic and epidemiological relationships. It is proposed that such codes should be assigned to every genome-sequenced virus to complement current viral taxonomy., Background. Developing a universal standardized microbial typing and nomenclature system that provides phylogenetic and epidemiological information in real time has never been as urgent in public health as it is today. We previously proposed to use genome similarity as the basis for immediate and precise typing and naming of individual organisms or viruses. In this study, we tested the validity of the proposed system and applied it to the epidemiology of infectious diseases using Ebola virus disease (EVD) outbreaks as the example. Methods. One hundred twenty-eight publicly available ebolavirus genomes were compared with each other, and average nucleotide identity (ANI) was calculated. The ANI was then used to assign unique codes, hereafter referred to as Life Identification Numbers (LINs), to every viral isolate, whereby each LIN consisted of a series of positions reflecting increasing genome similarity. Congruence of LINs with phylogenetic and epidemiological relationships was then determined. Results. Assigned LINs correlate with phylogeny at the species and infraspecies level and can even identify some individual transmission chains during the 2014–2015 EVD epidemic in West Africa. Conclusions. Life Identification Numbers can provide a fast, automated, standardized, and scalable approach to precisely identify and name viral isolates upon genome sequence submission, facilitating unambiguous communication during disease epidemics among clinicians, epidemiologists, and governments.

Globalization, accompanied by increasing levels of international travel and trade, climate change, altered human behavior and demographics, is leading to the emergence of manifold viral diseases, many of which are highly pathogenic and hence are considered of great public and animal health importance to the global populace [1]. An excellent, if devastating, example of this is represented by the filovirus family, to which Ebolavirus and Marburgvirus belong. To undertake basic virological research and novel therapeutic development, filoviruses require expert handling and manipulation by highly trained staff within expensive CL-4 facilities not readily available to the virology research community [2]. In order to circumvent the enhanced biosafety requirement, the develop ment of nonpatho genic, replication-defective pseudotyped vectors, developed historically for gene therapy applications, is an effective and established solution to permit the study of many facets of filovirus biology and virus therapeutics in a low containment CL-1/2 laboratory [3]. Ebola virus glycoprotein (GP) pseudotypes constructed with murine leukemia virus cores were first described in 1998 and have been used since then in a broad range of studies [4]. In order to be able to respond in a timely and effective manner to future filovirus outbreaks, a library of pseudotyped vectors bearing the GP of filo viruses of major public and animal health importance should be prioritized. These pseudotype viruses can be readily used for sero-surveillance, mAb/antiviral screening, vaccine immunogenicity studies and for tropism/pathogenicity studies as soon as the nucleotide sequence of the GP is online. Such a collection has been instigated by Edward Wright’s group at the University of Westminster and includes to date, all five Ebolavirus species including the Makona variant (Guinea, 2014) implicated in the current outbreak [5]. These pseudotypes are currently being utilized as surrogate antigens in virus neutralization assays as part of immunogenicity studies of the vaccine ChAd3 EBOZ at the Jenner Institute (University of Oxford, UK) [6]. Pseudotypes of Zaire Ebolavirus (Mayinga), Bundibugyo Ebolavirus (2008 isolate) and Marburg virus (Lake Victoria

Not Reston at All Reston ebolavirus is named, mistakenly perhaps, for Reston, Virginia, where it was discovered in the 1970s in imported macaques. After some alarm it was found not to be virulent in humans, uniquely among the ebola viruses, which are characteristically fatal causing a horrific spectrum of symptoms. Using a panviral detection assay, Reston ebolavirus has been rediscovered by Barrette et al. (p. 204 ) in domesticated pigs in the Philippines in association with other viruses that cause respiratory illness. The strains involved are closely related to the original macaque strain and, given how little variance there is among the viruses, it appears that it is freely circulating between these species possibly, like several other zoonotic viruses, having a reservoir in bats. Serological assays indicated that farm workers have become infected, although no obvious symptoms of human disease have been reported.

Ebola virus (EBOV) causes severe and often fatal hemorrhagic fever in humans and nonhuman primates (NHPs). Currently, there are no licensed vaccines or therapeutics for human use. Recombinant vesicular stomatitis virus (rVSV)-based vaccine vectors, which encode an EBOV glycoprotein in place of the VSV glycoprotein, have shown 100% efficacy against homologous Sudan ebolavirus (SEBOV) or Zaire ebolavirus (ZEBOV) challenge in NHPs. In addition, a single injection of a blend of three rVSV vectors completely protected NHPs against challenge with SEBOV, ZEBOV, the former Côte d'Ivoire ebolavirus, and Marburg virus. However, recent studies suggest that complete protection against the newly discovered Bundibugyo ebolavirus (BEBOV) using several different heterologous filovirus vaccines is more difficult and presents a new challenge. As BEBOV caused nearly 50% mortality in a recent outbreak any filovirus vaccine advanced for human use must be able to protect against this new species. Here, we evaluated several different strategies against BEBOV using rVSV-based vaccines. Groups of cynomolgus macaques were vaccinated with a single injection of a homologous BEBOV vaccine, a single injection of a blended heterologous vaccine (SEBOV/ZEBOV), or a prime-boost using heterologous SEBOV and ZEBOV vectors. Animals were challenged with BEBOV 29–36 days after initial vaccination. Macaques vaccinated with the homologous BEBOV vaccine or the prime-boost showed no overt signs of illness and survived challenge. In contrast, animals vaccinated with the heterologous blended vaccine and unvaccinated control animals developed severe clinical symptoms consistent with BEBOV infection with 2 of 3 animals in each group succumbing. These data show that complete protection against BEBOV will likely require incorporation of BEBOV glycoprotein into the vaccine or employment of a prime-boost regimen. Fortunately, our results demonstrate that heterologous rVSV-based filovirus vaccine vectors employed in the prime-boost approach can provide protection against BEBOV using an abbreviated regimen, which may have utility in outbreak settings., Author Summary Ebola viruses (EBOV), of which there are five species, are categorized as Category A Priority Pathogens and Tier 1 Select Agents by several US Government agencies as a result of their high mortality rates and potential for use as agents of bioterrorism. Currently, there are no vaccines or therapeutics approved for human use. Replication-competent, recombinant vesicular stomatitis virus (rVSV) vectors expressing filovirus glycoproteins (GP), in place of the VSV glycoprotein have shown promise in lethal nonhuman primate (NHP) models of filovirus infection as both single injection preventive vaccines and as post-exposure treatments. The recent outbreak of the fifth recognized EBOV species, Bundibugyo ebolavirus (BEBOV), demonstrates the need for vaccines that can be rapidly deployed to combat an outbreak of a new filovirus species. To date, rVSV-filovirus GP-based vaccines have only been able to protect against challenge with a homologous species of EBOV. Here, we show that the two heterologous rVSV-based filovirus vaccines available at the time of the original BEBOV outbreak can protect NHPs against BEBOV challenge using a short prime-boost vaccination strategy. While the prime-boost strategy was successful, a single injection blended vaccination strategy with the same vaccine vectors failed to provide protection. These data suggest that an abbreviated prime-boost regimen of 36 days may have utility for quickly responding to outbreaks caused by new species of EBOV.

We have isolated a new strain of Ebola virus from a non-fatal human case infected during the autopsy of a wild chimpanzee in the Cote-d'Ivoire. The wild troop to which this animal belonged has been decimated by outbreaks of haemorrhagic syndromes. This is the first time that a human infection has been connected to naturally-infected monkeys in Africa. Data from the long-term survey of this troop of chimpanzees could answer questions about the natural reservoir of the Ebola virus.

A confirmed Ebola haemorrhagic fever (EHF) outbreak in Bundibugyo, Uganda, November 2007-February 2008, was caused by a putative new species (Bundibugyo ebolavirus). It included 93 putative cases, 56 laboratory-confirmed cases, and 37 deaths (CFR = 25%). Study objectives are to describe clinical manifestations and case management for 26 hospitalised laboratory-confirmed EHF patients. Clinical findings are congruous with previously reported EHF infections. The most frequently experienced symptoms were non-bloody diarrhoea (81%), severe headache (81%), and asthenia (77%). Seven patients reported or were observed with haemorrhagic symptoms, six of whom died. Ebola care remains difficult due to the resource-poor setting of outbreaks and the infection-control procedures required. However, quality data collection is essential to evaluate case definitions and therapeutic interventions, and needs improvement in future epidemics. Organizations usually involved in EHF case management have a particular responsibility in this respect.

Ebola haemorrhagic fever (EHF) is a zoonosis affecting both human and non-human primates (NHP). Outbreaks in Africa occur mainly in the Congo and Nile basins. The first outbreaks of EHF occurred nearly simultaneously in 1976 in the Democratic Republic of the Congo (DRC, former Zaire) and Sudan with very high case fatality rates of 88% and 53%, respectively. The two outbreaks were caused by two distinct species of Ebola virus named Zaire ebolavirus (ZEBOV) and Sudan ebolavirus (SEBOV). The source of transmission remains unknown. After a long period of silence (1980–1993), EHF outbreaks in Africa caused by the two species erupted with increased frequency and new species were discovered, namely Côte d’Ivoire ebolavirus (CIEBOV) in 1994 in the Ivory Coast and Bundibugyo ebolavirus (BEBOV) in 2007 in Uganda. The re-emergence of EHF outbreaks in Gabon and Republic of the Congo were concomitant with an increase in mortality amongst gorillas and chimpanzees infected with ZEBOV. The human outbreaks were related to multiple, unrelated index cases who had contact with dead gorillas or chimpanzees. However, in areas where NHP were rare or absent, as in Kikwit (DRC) in 1995, Mweka (DRC) in 2007, Gulu (Uganda) in 2000 and Yambio (Sudan) in 2004, the hunting and eating of fruit bats may have resulted in the primary transmission of Ebola virus to humans. Human-to-human transmission is associated with direct contact with body fluids or tissues from an infected subject or contaminated objects. Despite several, often heroic field studies, the epidemiology and ecology of Ebola virus, including identification of its natural reservoir hosts, remains a formidable challenge for public health and scientific communities.

The recombinant vesicular stomatitis virus (rVSV) vector-based monovalent vaccine platform expressing a filovirus glycoprotein has been demonstrated to provide protection from lethal challenge with Ebola (EBOV) and Marburg (MARV) viruses both prophylactically and after exposure. This platform provides protection between heterologous strains within a species; however, protection from lethal challenge between species has been largely unsuccessful. To determine whether the rVSV-EBOV vaccines have the potential to provide protection against a newly emerging, phylogenetically related species, cynomolgus macaques were vaccinated with an rVSV vaccine expressing either the glycoprotein of Zaire ebolavirus (ZEBOV) or Cote d'Ivoire ebolavirus (CIEBOV) and then challenged with Bundibugyo ebolavirus (BEBOV), which was recently proposed as a new EBOV species following an outbreak in Uganda in 2007. A single vaccination with the ZEBOV-specific vaccine provided cross-protection (75% survival) against subsequent BEBOV challenge, whereas vaccination with the CIEBOV-specific vaccine resulted in an outcome similar to mock-immunized animals (33% and 25% survival, respectively). This demonstrates that monovalent rVSV-based vaccines may be useful against a newly emerging species; however, heterologous protection across species remains challenging and may depend on enhancing the immune responses either through booster immunizations or through the inclusion of multiple immunogens.

The first outbreak of Ebola hemorrhagic fever (EHF) due to Bundibugyo ebolavirus occurred in Uganda from August to December 2007. During outbreak response and assessment, we identified 131 EHF cases (44 suspect, 31 probable, and 56 confirmed). Consistent with previous large filovirus outbreaks, a long temporal lag (approximately 3 months) occurred between initial EHF cases and the subsequent identification of Ebola virus and outbreak response, which allowed for prolonged person-to-person transmission of the virus. Although effective control measures for filovirus outbreaks, such as patient isolation and contact tracing, are well established, our observations from the Bundibugyo EHF outbreak demonstrate the need for improved filovirus surveillance, reporting, and diagnostics, in endemic locations in Africa.

Members of the genus Ebolavirus cause fulminating outbreaks of disease in human and non-human primate populations with a mortality rate up to 90%. To facilitate rapid detection of these pathogens in clinical and environmental samples, robust reagents capable of providing sensitive and specific detection are required. In this work recombinant antibody libraries were generated from murine (single chain variable domain fragment; scFv) and nurse shark, Ginglymostoma cirratum (IgNAR V) hosts immunised with Zaire ebolavirus. This provides the first recorded IgNAR V response against a particulate antigen in the nurse shark. Both murine scFv and shark IgNAR V libraries were panned by phage display technology to identify useful antibodies for the generation of immunological detection reagents. Two murine scFv were shown to have specificity to the Zaire ebolavirus viral matrix protein VP40. Two isolated IgNAR V were shown to bind to the viral nucleoprotein (NP) and to capture viable Zaire ebolavirus with a high degree of sensitivity. Assays developed with IgNAR V cross-reacted to Reston ebolavirus, Sudan ebolavirus and Bundibugyo ebolavirus. Despite this broad reactivity, neither of IgNAR V showed reactivity to Cote d'Ivoire ebolavirus. IgNAR V was substantially more resistant to irreversible thermal denaturation than murine scFv and monoclonal IgG in a comparative test. The demonstrable robustness of the IgNAR V domains may offer enhanced utility as immunological detection reagents in fieldable biosensor applications for use in tropical or subtropical countries where outbreaks of Ebolavirus haemorrhagic fever occur.

On 23 March 2014, the ministry of health of Guineanotified WHO of a rapidly spreading outbreak of Ebolavirus disease (EVD) in south-eastern forested areas, and4 days later, the disease was confirmed to be transmitted toConakry, the Capital of Guinea. The disease also rapidlyspread to Liberia, Nigeria and Sierra Leone. As of 27 July2014, the cumulative number of confirmed (909), probable(276) and suspect (138) EVD cases in the above fourcountries reached 1,323, including 729 deaths (with thedeath rate of 55.1 %) (http://www.who.int/csr/don/2014_07_31_ebola/en/). This is the largest outbreak of EVD untilnow and the first time the disease detected in West Africa.EVD, previously known as Ebola haemorrhagic fever, isa severe, often fatal illness, with very high case fatality rateof up to 90 %. The previous EVD outbreaks in Uganda(epidemic from October of 2000 to February of 2001) andin Gabon and the Republic of the Congo (outbreak fromDecember of 2001 to March of 2002) were also persistedfor several months. The outbreak of EVD in West Africaseemed out of control although WHO has coordinated withdifferent organizations and countries for containing thisdisease [1]. For the last four months, the EVD epidemic hasspread to the nearby countries and new cases and newdeaths were reported almost every day. Until 6 August2014, there were 14 outbreaks of EVD and three singlecase reports in the world, resulting in 4,178 cases ofinfection and 2,564 deaths, with death rate from 41 %–88 %(excluding the single case report, Fig. 1).Ebola was first reported in 1976 when there were out-breaks in Sudan and Democratic Republic of Congo [2, 3].The genus Ebolavirus belongs to the Filoviridae family(filovirus), which also includes genus Marburgvirus andgenus Cuevavirus. There are five distinct species in thegenus Ebolavirus, including Bundibugyo ebolavirus; Zaireebolavirus; Sudan ebolavirus; Reston ebolavirus; and Tai¨Forest ebolavirus. The first three species have been asso-ciated with large EVD outbreaks in Africa, whereas thelatter two have not. Samples taken from patients of thisoutbreak have been confirmed to be caused by a strain ofebolavirus closely related (98 %) to the Zaire one. Theebolavirus should be operated under biosafety level IVlaboratory. Even in this high-level containment laboratory,there were still accidentally laboratory-acquired infectionsreported [4, 5].Fruit bats are believed to be the natural hosts of Ebolavirus [6]. The wild animals (monkeys or apes) could becontracted the virus from contacting with bat saliva orfaeces. Humans could be transmitted from contacting withinfected bats or wild animals. The EVD can be transmittedfrom person to person by direct contact. More and moreevidence showed that pigs might be the host of ebolavirus[7, 8]. From the distribution of fruit bats (http://www.who.int/csr/disease/ebola/en/#), the potential riskregion of EVD not only is limited to Africa but alsoincludes wide range of America, southern Asia and part ofAustralia.Since there is no effective antiviral drugs and specificvaccine for treating and preventing EVD, we all need toprepare for early recognition of EVD and special pre-ventive countermeasures should be taken for the suspectedpatients. Rapid and specific screening assays should bedeveloped for early diagnosis of EVD; however, the clin-ical doctors should pay close attention to the suspectedpatients, especially for those with travel history in theepidemic regions. Hospitals need to prepare to protect

Ebola viruses are the causative agents of a severe form of viral haemorrhagic fever in man, designated Ebola haemorrhagic fever, and are endemic in regions of central Africa. The exception is the species Reston Ebola virus, which has not been associated with human disease and is found in the Philippines. Ebola virus constitutes an important local public health threat in Africa, with a worldwide effect through imported infections and through the fear of misuse for biological terrorism. Ebola virus is thought to also have a detrimental effect on the great ape population in Africa. Case-fatality rates of the African species in man are as high as 90%, with no prophylaxis or treatment available. Ebola virus infections are characterised by immune suppression and a systemic inflammatory response that causes impairment of the vascular, coagulation, and immune systems, leading to multiorgan failure and shock, and thus, in some ways, resembling septic shock.

The taxonomy of the family Filoviridae (marburgviruses and ebolaviruses) has changed several times since the discovery of its members, resulting in a plethora of species and virus names and abbreviations. The current taxonomy has only been partially accepted by most laboratory virologists. Confusion likely arose for several reasons: species names that consist of several words or which (should) contain diacritical marks, the current orthographic identity of species and virus names, and the similar pronunciation of several virus abbreviations in the absence of guidance for the correct use of vernacular names. To rectify this problem, we suggest (1) to retain the current species names Reston ebolavirus, Sudan ebolavirus, and Zaire ebolavirus, but to replace the name Cote d'Ivoire ebolavirus [sic] with Taï Forest ebolavirus and Lake Victoria marburgvirus with Marburg marburgvirus; (2) to revert the virus names of the type marburgviruses and ebolaviruses to those used for decades in the field (Marburg virus instead of Lake Victoria marburgvirus and Ebola virus instead of Zaire ebolavirus); (3) to introduce names for the remaining viruses reminiscent of jargon used by laboratory virologists but nevertheless different from species names (Reston virus, Sudan virus, Taï Forest virus), and (4) to introduce distinct abbreviations for the individual viruses (RESTV for Reston virus, SUDV for Sudan virus, and TAFV for Taï Forest virus), while retaining that for Marburg virus (MARV) and reintroducing that used over decades for Ebola virus (EBOV). Paying tribute to developments in the field, we propose (a) to create a new ebolavirus species (Bundibugyo ebolavirus) for one member virus (Bundibugyo virus, BDBV); (b) to assign a second virus to the species Marburg marburgvirus (Ravn virus, RAVV) for better reflection of now available high-resolution phylogeny; and (c) to create a new tentative genus (Cuevavirus) with one tentative species (Lloviu cuevavirus) for the recently discovered Lloviu virus (LLOV). Furthermore, we explain the etymological derivation of individual names, their pronunciation, and their correct use, and we elaborate on demarcation criteria for each taxon and virus. Sí

Over the past 30 years, Zaire and Sudan ebolaviruses have been responsible for large hemorrhagic fever (HF) outbreaks with case fatalities ranging from 53% to 90%, while a third species, Côte d'Ivoire ebolavirus, caused a single non-fatal HF case. In November 2007, HF cases were reported in Bundibugyo District, Western Uganda. Laboratory investigation of the initial 29 suspect-case blood specimens by classic methods (antigen capture, IgM and IgG ELISA) and a recently developed random-primed pyrosequencing approach quickly identified this to be an Ebola HF outbreak associated with a newly discovered ebolavirus species (Bundibugyo ebolavirus) distantly related to the Côte d'Ivoire ebolavirus found in western Africa. Due to the sequence divergence of this new virus relative to all previously recognized ebolaviruses, these findings have important implications for design of future diagnostic assays to monitor Ebola HF disease in humans and animals, and ongoing efforts to develop effective antivirals and vaccines., Author Summary In this report we describe a newly discovered ebolavirus species which caused a large hemorrhagic fever outbreak in western Uganda. The virus is genetically distinct, differing by more than 30% at the genome level from all other known ebolavirus species. The unique nature of this virus created challenges for traditional filovirus molecular based diagnostic assays and genome sequencing approaches. Instead, we quickly determined over 70% of the virus genome using a recently developed random-primed pyrosequencing approach that allowed the rapid development of a molecular detection assay that was deployed in the disease outbreak response. This draft sequence allowed easy completion of the whole genome sequence using a traditional primer walking approach and prompt confirmation that this virus represented a new ebolavirus species. Current efforts to design effective diagnostics, antivirals and vaccines will need to take into account the distinct nature of this important new member of the filovirus family.

The first recorded human outbreak of Ebola virus was in 1976, but the wild reservoir of this virus is still unknown. Here we test for Ebola in more than a thousand small vertebrates that were collected during Ebola outbreaks in humans and great apes between 2001 and 2003 in Gabon and the Republic of the Congo. We find evidence of asymptomatic infection by Ebola virus in three species of fruit bat, indicating that these animals may be acting as a reservoir for this deadly virus.