RESUMEN
Next generation sequencing has revealed the presence of numerous RNA viruses in animal reservoir hosts, including many closely related to known human pathogens. Despite their zoonotic potential, most of these viruses remain understudied due to not yet being cultured. While reverse genetic systems can facilitate virus rescue, this is often hindered by missing viral genome ends. A prime example is Lloviu virus (LLOV), an uncultured filovirus that is closely related to the highly pathogenic Ebola virus. Using minigenome systems, we complemented the missing LLOV genomic ends and identified cis-acting elements required for LLOV replication that were lacking in the published sequence. We leveraged these data to generate recombinant full-length LLOV clones and rescue infectious virus. Similar to other filoviruses, recombinant LLOV (rLLOV) forms filamentous virions and induces the formation of characteristic inclusions in the cytoplasm of the infected cells, as shown by electron microscopy. Known target cells of Ebola virus, including macrophages and hepatocytes, are permissive to rLLOV infection, suggesting that humans could be potential hosts. However, inflammatory responses in human macrophages, a hallmark of Ebola virus disease, are not induced by rLLOV. Additional tropism testing identified pneumocytes as capable of robust rLLOV and Ebola virus infection. We also used rLLOV to test antivirals targeting multiple facets of the replication cycle. Rescue of uncultured viruses of pathogenic concern represents a valuable tool in our arsenal for pandemic preparedness.
Asunto(s)
Ebolavirus/genética , Infecciones por Filoviridae/virología , Filoviridae/genética , Replicación Viral , Animales , Línea Celular , Chlorocebus aethiops , Prueba de Complementación Genética , Genoma Viral , Fiebre Hemorrágica Ebola/virología , Interacciones Microbiota-Huesped , Humanos , Cuerpos de Inclusión/virología , Células Madre Pluripotentes Inducidas/virología , Macrófagos/virología , ARN Viral , Genética Inversa , Células Vero , Virión/genéticaRESUMEN
The most commonly reported symptom of post-Ebola virus disease syndrome in survivors is arthralgia, yet involvement of the joints in acute or convalescent Ebola virus infection is not well characterized in human patients or animal models. Through immunohistochemistry, we found that the lining synovial intima of the stifle (knee) is a target for acute infection by Ebola virus/Kikwit, Ebola virus/Makona-C05, and Marburg virus/Angola in the rhesus macaque model. Furthermore, histologic analysis, immunohistochemistry, RNAscope in situ hybridization, and transmission electron microscopy showed that synoviocytes of the stifle, shoulder, and hip are a target for mouse-adapted Ebola virus/Yambuku-Mayinga infection during acute disease in rhesus macaques. A time course of infection study with Ebola virus/Kikwit found that the large joint synovium became immunopositive beginning on postinfection day 6. In total, the synovium of 28 of 30 rhesus macaques with terminal filovirus disease had evidence of infection (64 of 96 joints examined). On the basis of immunofluorescence, infected cell types included CD68+ type A (macrophage-like) synoviocytes and CD44+ type B (fibroblast-like) synoviocytes. Cultured primary human fibroblast-like synoviocytes were permissive to infection with Ebola and Marburg viruses in vitro. Because synovial joints include immune privileged sites, these findings are significant for future investigations of filovirus pathogenesis and persistence as well as arthralgias in acute and convalescent filovirus disease.
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Infecciones por Filoviridae/virología , Sinoviocitos/virología , Animales , Células Cultivadas , Filoviridae , Humanos , Macaca mulattaRESUMEN
Bat-borne zoonotic pathogens belonging to the family Paramxyoviridae, including Nipah and Hendra viruses, and the family Filoviridae, including Ebola and Marburg viruses, can cause severe disease and high mortality rates on spillover into human populations. Surveillance efforts for henipaviruses and filoviruses have been largely restricted to the Old World; however, recent studies suggest a potentially broader distribution for henipaviruses and filoviruses than previously recognized. In the current study, we screened for henipaviruses and filoviruses in New World bats collected across 4 locations in Trinidad near the coast of Venezuela. Bat tissue samples were screened using previously established reverse-transcription polymerase chain reaction assays. Serum were screened using a multiplex immunoassay to detect antibodies reactive with the envelope glycoprotein of viruses in the genus Henipavirus and the family Filoviridae. Serum samples were also screened by means of enzyme-linked immunosorbent assay for antibodies reactive with Nipah G and F glycoproteins. Of 84 serum samples, 28 were reactive with ≥1 henipavirus glycoprotein by ≥1 serological method, and 6 serum samples were reactive against ≥1 filovirus glycoproteins. These data provide evidence of potential circulation of viruses related to the henipaviruses and filoviruses in New World bats.
Asunto(s)
Quirópteros/virología , Infecciones por Filoviridae/veterinaria , Filoviridae , Infecciones por Henipavirus/veterinaria , Henipavirus , Animales , Quirópteros/sangre , Quirópteros/clasificación , Infecciones por Filoviridae/epidemiología , Infecciones por Filoviridae/virología , Infecciones por Henipavirus/epidemiología , Infecciones por Henipavirus/virología , Pruebas Serológicas , Trinidad y Tobago/epidemiologíaRESUMEN
The family Filoviridae contains many important human viruses, including Marburg virus (MARV) and Ebola virus (EBOV). Menglà virus (MLAV), a newly discovered filovirus, is considered a potential human pathogen. The VP30 C-terminal domain (CTD) of these filoviruses plays an essential role in virion assembly. In common with other filoviruses, MLAV VP30 CTD mainly exists as a dimer in solution. In this work, we determined the crystal structure of recombinant MLAV VP30 CTD monomer, verifying that C-terminal helix-7 (H7) is critical for the dimerization process. This study provides a preliminary model for investigation of MLAV VP30 CTD as an anti-filovirus drug development target.
Asunto(s)
Infecciones por Filoviridae/virología , Filoviridae/química , Proteínas Virales/química , Animales , Cristalografía por Rayos X , Descubrimiento de Drogas , Modelos Moleculares , Conformación Proteica en Hélice alfa , Dominios Proteicos , Multimerización de ProteínaRESUMEN
Filoviruses are emerging pathogens and causative agents of viral haemorrhagic fever. Case fatality rates of filovirus disease outbreaks are among the highest reported for any human pathogen, exceeding 90% (ref. 1). Licensed therapeutic or vaccine products are not available to treat filovirus diseases. Candidate therapeutics previously shown to be efficacious in non-human primate disease models are based on virus-specific designs and have limited broad-spectrum antiviral potential. Here we show that BCX4430, a novel synthetic adenosine analogue, inhibits infection of distinct filoviruses in human cells. Biochemical, reporter-based and primer-extension assays indicate that BCX4430 inhibits viral RNA polymerase function, acting as a non-obligate RNA chain terminator. Post-exposure intramuscular administration of BCX4430 protects against Ebola virus and Marburg virus disease in rodent models. Most importantly, BCX4430 completely protects cynomolgus macaques from Marburg virus infection when administered as late as 48 hours after infection. In addition, BCX4430 exhibits broad-spectrum antiviral activity against numerous viruses, including bunyaviruses, arenaviruses, paramyxoviruses, coronaviruses and flaviviruses. This is the first report, to our knowledge, of non-human primate protection from filovirus disease by a synthetic drug-like small molecule. We provide additional pharmacological characterizations supporting the potential development of BCX4430 as a countermeasure against human filovirus diseases and other viral diseases representing major public health threats.
Asunto(s)
Adenosina/análogos & derivados , Antivirales/farmacología , Infecciones por Filoviridae/prevención & control , Infecciones por Filoviridae/virología , Filoviridae/efectos de los fármacos , Nucleósidos de Purina/farmacología , Adenina/análogos & derivados , Administración Oral , Animales , Antivirales/administración & dosificación , Antivirales/química , Antivirales/farmacocinética , ARN Polimerasas Dirigidas por ADN/antagonistas & inhibidores , ARN Polimerasas Dirigidas por ADN/metabolismo , Modelos Animales de Enfermedad , Ebolavirus/efectos de los fármacos , Filoviridae/enzimología , Fiebre Hemorrágica Ebola/prevención & control , Fiebre Hemorrágica Ebola/virología , Humanos , Inyecciones Intramusculares , Macaca fascicularis/virología , Enfermedad del Virus de Marburg/prevención & control , Enfermedad del Virus de Marburg/virología , Marburgvirus/efectos de los fármacos , Nucleósidos de Purina/administración & dosificación , Nucleósidos de Purina/química , Nucleósidos de Purina/farmacocinética , Pirrolidinas , ARN/biosíntesis , Factores de TiempoRESUMEN
Filoviruses such as Ebola virus (EBOV), Marburg virus (MARV), and Sudan virus (SUDV) cause deadly viral hemorrhagic fever in humans, with high case-fatality rates; however, no licensed therapeutic agent or vaccine has been clinically approved to treat or prevent infection. T-705 (favipiravir) is a novel antiviral drug that has been approved for the treatment of influenza in Japan. T-705 exhibits broad-spectrum antiviral activity against different viruses, including MARV and EBOV, and here, we are the first to report the in vitro and in vivo antiviral activity of T-705 against SUDV. T-705 treatment reduced SUDV replication in Vero E6 cells. Subcutaneous administration of T-705, beginning 1-4 days after infection and continuing for 7 days, significantly protected SUDV-infected guinea pigs, with a survival rate of 83%-100%. Viral RNA replication and infectious virus production were also significantly reduced in the blood, spleen, liver, lungs, and kidney. Moreover, early administration of low-dose T-705 and late administration (at 5 days after infection) of higher-dose T-705 also showed partial protection. Overall, our study is the first to demonstrate the antiviral activity of T-705 against SUDV, suggesting that T-705 may be a potential drug candidate for use during outbreaks.
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Amidas/uso terapéutico , Antivirales/uso terapéutico , Infecciones por Filoviridae/prevención & control , Pirazinas/uso terapéutico , Animales , Recuento de Células Sanguíneas , Chlorocebus aethiops , Femenino , Infecciones por Filoviridae/sangre , Infecciones por Filoviridae/virología , Cobayas , ARN Viral/análisis , Células Vero , Replicación Viral/efectos de los fármacosRESUMEN
Background: Human and filovirus host interactions remain poorly understood in areas where Ebola hemorrhagic fever outbreaks are likely to occur. In the Bwindi region of Uganda, a hot spot of mammalian biodiversity in Africa, human livelihoods are intimately connected with wildlife, creating potential for exposure to filoviruses. Methods: We tested samples from 331 febrile patients presenting to healthcare facilities near Bwindi Impenetrable Forest, Uganda, by polymerase chain reaction (PCR) analysis and Western blot, using recombinant glycoprotein antigens for Ebola virus (EBOV), Sudan virus (SUDV), Bundibugyo virus (BDBV), and Marburg virus. Behavioral data on contact with wildlife were collected to examine risk factors for filovirus seropositivity. Results: All patients were negative for active filovirus infection, by PCR analysis. However, patients were seroreactive to SUDV (4.7%), EBOV (5.3%), and BDBV (8.9%), indicating previous exposure. Touching duikers was the most significant risk factor associated with EBOV seropositivity, while hunting primates and touching and/or eating cane rats were significant risk factors for SUDV seropositivity. Conclusions: People in southwestern Uganda have suspected previous exposure to filoviruses, particularly those with a history of wildlife contact. Circulation of filoviruses in wild animals and subsequent spillover into humans could be more common than previously reported.
Asunto(s)
Animales Salvajes/virología , Infecciones por Filoviridae/genética , Infecciones por Filoviridae/virología , Filoviridae/patogenicidad , Adolescente , Adulto , Anciano , Animales , Animales Salvajes/inmunología , Antígenos Virales/inmunología , Niño , Preescolar , Femenino , Filoviridae/inmunología , Infecciones por Filoviridae/inmunología , Glicoproteínas/inmunología , Humanos , Lactante , Recién Nacido , Masculino , Persona de Mediana Edad , Uganda , Adulto JovenRESUMEN
Bats are suspected to play important roles in the ecology of filoviruses, including ebolaviruses and marburgviruses. A cave-dwelling fruit bat, Rousettus aegyptiacus, has been shown to be a reservoir of marburgviruses. Using an enzyme-linked immunosorbent assay with the viral glycoprotein antigen, we detected immunoglobulin G antibodies specific to multiple filoviruses in 158 of 290 serum samples of R aegyptiacus bats captured in Zambia during the years 2014-2017. In particular, 43.8% of the bats were seropositive to marburgvirus, supporting the notion that this bat species continuously maintains marburgviruses as a reservoir. Of note, distinct peaks of seropositive rates were repeatedly observed at the beginning of rainy seasons, suggesting seasonality of the presence of newly infected individuals in this bat population. These data highlight the need for continued monitoring of filovirus infection in this bat species even in countries where filovirus diseases have not been reported.
Asunto(s)
Quirópteros/sangre , Quirópteros/inmunología , Infecciones por Filoviridae/sangre , Infecciones por Filoviridae/inmunología , Filoviridae/inmunología , Animales , Anticuerpos Antivirales/sangre , Anticuerpos Antivirales/inmunología , Quirópteros/virología , Reservorios de Enfermedades/virología , Femenino , Infecciones por Filoviridae/virología , Glicoproteínas/sangre , Glicoproteínas/inmunología , Inmunoglobulina G/sangre , Inmunoglobulina G/inmunología , Masculino , Estudios Seroepidemiológicos , ZambiaRESUMEN
Filovirus small animal disease models have so far been developed in laboratory mice, guinea pigs, and hamsters. Since immunocompetent rodents do not exhibit overt signs of disease following infection with wild-type filoviruses isolated from humans, rodent models have been established using adapted viruses produced through sequential passage in rodents. Rodent-adapted viruses target the same cells/tissues as the wild-type viruses, making rodents invaluable basic research tools for studying filovirus pathogenesis. Moreover, comparative analyses using wild-type and rodent-adapted viruses have provided beneficial insights into the molecular mechanisms of pathogenicity and acquisition of species-specific virulence. Additionally, wild-type filovirus infections in immunodeficient rodents have provided a better understanding of the host factors required for resistance to filovirus infection and of the immune response against the infection. This chapter provides comprehensive information on the filovirus rodent models and rodent-adapted filoviruses. Specifically, we summarize the clinical and pathological features of filovirus infections in all rodent models described to date, including the recently developed humanized and collaborative cross (CC) resource recombinant inbred (RI) intercrossed (CC-RIX) mouse models. We also cover the molecular determinants responsible for adaptation and virulence acquisition in a number of rodent-adapted filoviruses. This chapter clearly defines the characteristic and advantages/disadvantages of rodent models, helping to evaluate the practical use of rodent models in future filovirus studies.
Asunto(s)
Modelos Animales de Enfermedad , Infecciones por Filoviridae/virología , Filoviridae/patogenicidad , Roedores/virología , Animales , Fiebre Hemorrágica Ebola/virología , Humanos , VirulenciaRESUMEN
Therapies for filovirus infections are urgently needed. The paradoxical issue facing therapies is the need for rigorous safety and efficacy testing, adhering to the principle tenant of medicine to do no harm, while responding to the extreme for a treatment option during an outbreak. Supportive care remains a primary goal for infected patients. Years of research into filoviruses has provided possible medical interventions ranging from direct antivirals, host-factor supportive approaches, and passive immunity. As more basic research is directed toward understanding these pathogens and their impact on the host, effective approaches to treat patients during infection will be identified. The ability to manage outbreaks with medical interventions beyond supportive care will require clinical trial design that will balance the benefits of the patient and scientific community.
Asunto(s)
Infecciones por Filoviridae/terapia , Antivirales/efectos adversos , Antivirales/uso terapéutico , Ensayos Clínicos como Asunto/métodos , Brotes de Enfermedades , Infecciones por Filoviridae/virología , HumanosRESUMEN
Filoviruses can cause severe and often fatal disease in humans. To date, there have been 47 outbreaks resulting in more than 31,500 cases of human illness and over 13,200 reported deaths. Since their discovery, researchers from many scientific disciplines have worked to better understand the natural history of these deadly viruses. Citing original research wherever possible, this chapter reviews laboratory and field-based studies on filovirus ecology and summarizes efforts to identify where filoviruses persist in nature, how virus is transmitted to other animals and ultimately, what drivers cause spillover to human beings. Furthermore, this chapter discusses concepts on what constitutes a reservoir host and highlights challenges encountered while conducting research on filovirus ecology, particularly field-based investigations.
Asunto(s)
Ecología , Infecciones por Filoviridae/transmisión , Infecciones por Filoviridae/virología , Filoviridae , Animales , Brotes de Enfermedades , Filoviridae/aislamiento & purificación , Filoviridae/patogenicidad , Infecciones por Filoviridae/epidemiología , HumanosRESUMEN
Genetically divergent filoviruses detected in Rousettus and Eonycteris spp. bats in China exhibited 61%-99% nt identity with reported filoviruses, based on partial replicase sequences, and they demonstrated lung tropism. Co-infection with 4 different filoviruses was found in 1 bat. These results demonstrate that fruit bats are key reservoirs of filoviruses.
Asunto(s)
Quirópteros/virología , Infecciones por Filoviridae/veterinaria , Filoviridae/genética , Variación Genética , Animales , China/epidemiología , Filoviridae/aislamiento & purificación , Infecciones por Filoviridae/epidemiología , Infecciones por Filoviridae/virología , HumanosRESUMEN
UNLABELLED: Bundibugyo virus (BDBV) is the etiological agent of a severe hemorrhagic fever in humans with a case-fatality rate ranging from 25 to 36%. Despite having been known to the scientific and medical communities for almost 1 decade, there is a dearth of studies on this pathogen due to the lack of a small animal model. Domestic ferrets are commonly used to study other RNA viruses, including members of the order Mononegavirales To investigate whether ferrets were susceptible to filovirus infections, ferrets were challenged with a clinical isolate of BDBV. Animals became viremic within 4 days and succumbed to infection between 8 and 9 days, and a petechial rash was observed with moribund ferrets. Furthermore, several hallmarks of human filoviral disease were recapitulated in the ferret model, including substantial decreases in lymphocyte and platelet counts and dysregulation of key biochemical markers related to hepatic/renal function, as well as coagulation abnormalities. Virological, histopathological, and immunohistochemical analyses confirmed uncontrolled BDBV replication in the major organs. Ferrets were also infected with Ebola virus (EBOV) to confirm their susceptibility to another filovirus species and to potentially establish a virus transmission model. Similar to what was seen with BDBV, important hallmarks of human filoviral disease were observed in EBOV-infected ferrets. This study demonstrates the potential of this small animal model for studying BDBV and EBOV using wild-type isolates and will accelerate efforts to understand filovirus pathogenesis and transmission as well as the development of specific vaccines and antivirals. IMPORTANCE: The 2013-2016 outbreak of Ebola virus in West Africa has highlighted the threat posed by filoviruses to global public health. Bundibugyo virus (BDBV) is a member of the genus Ebolavirus and has caused outbreaks in the past but is relatively understudied, likely due to the lack of a suitable small animal model. Such a model for BDBV is crucial to evaluating vaccines and therapies and potentially understanding transmission. To address this, we demonstrated that ferrets are susceptible models to BDBV infection as well as to Ebola virus infection and that no virus adaptation is required. Moreover, these animals develop a disease that is similar to that seen in humans and nonhuman primates. We believe that this will improve the ability to study BDBV and provide a platform to test vaccines and therapeutics.
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Ebolavirus/inmunología , Hurones/virología , Infecciones por Filoviridae/microbiología , Filoviridae/inmunología , África Occidental , Animales , Anticuerpos Monoclonales/inmunología , Anticuerpos Antivirales/inmunología , Modelos Animales de Enfermedad , Femenino , Infecciones por Filoviridae/virología , Fiebre Hemorrágica Ebola/inmunología , Fiebre Hemorrágica Ebola/virología , Humanos , Vacunas Virales/inmunologíaRESUMEN
Filoviruses are strongly associated with several species of bats as their natural reservoirs. In this study, we determined the replication potential of all filovirus species: Marburg marburgvirus, Taï Forest ebolavirus, Reston ebolavirus, Sudan ebolavirus, Zaire ebolavirus, and Bundibugyo ebolavirus. Filovirus replication was supported by all cell lines derived from 6 Old and New World bat species: the hammer-headed fruit bat, Buettikofer's epauletted fruit bat, the Egyptian fruit bat, the Jamaican fruit bat, the Mexican free-tailed bat and the big brown bat. In addition, we showed that Marburg virus Angola and Ebola virus Makona-WPGC07 efficiently replicated at 37°C, 37°-41°C, or 41°C, contrary to the hypothesis that temporal elevation in temperature due to flight affects filovirus replication in bats.
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Quirópteros/virología , Reservorios de Enfermedades/virología , Infecciones por Filoviridae/virología , Filoviridae/aislamiento & purificación , Fiebre Hemorrágica Ebola/virología , Enfermedad del Virus de Marburg/virología , Animales , Línea Celular , Ebolavirus/inmunología , Ebolavirus/aislamiento & purificación , Ebolavirus/fisiología , Filoviridae/fisiología , Humanos , Marburgvirus/inmunología , Marburgvirus/aislamiento & purificación , Marburgvirus/fisiología , Temperatura , Replicación ViralRESUMEN
BACKGROUND: Diagnosis of Ebola virus (EBOV) disease (EVD) requires laboratory testing. METHODS: The RealStar Filovirus Screen reverse transcription-polymerase chain reaction (RT-PCR) kit and the derived RealStar Zaire Ebolavirus RT-PCR kit were validated using in vitro transcripts, supernatant of infected cell cultures, and clinical specimens from patients with EVD. RESULTS: The Filovirus Screen kit detected EBOV, Sudan virus, Taï Forest virus, Bundibugyo virus, Reston virus, and Marburg virus and differentiated between the genera Ebolavirus and Marburgvirus The amount of filovirus RNA that could be detected with a probability of 95% ranged from 11 to 67 RNA copies/reaction on a LightCycler 480 II. The Zaire Ebolavirus kit is based on the Filovirus Screen kit but was optimized for detection of EBOV. It has an improved signal-to-noise ratio at low EBOV RNA concentrations and is somewhat more sensitive than the Filovirus kit. Both kits show significantly lower analytical sensitivity on a SmartCycler II. Clinical evaluation revealed that the SmartCycler II, compared with other real-time PCR platforms, decreases the clinical sensitivity of the Filovirus Screen kit to diagnose EVD at an early stage. CONCLUSIONS: The Filovirus Screen kit detects all human-pathogenic filoviruses with good analytical sensitivity if performed on an appropriate real-time PCR platform. High analytical sensitivity is important for early diagnosis of EVD.
Asunto(s)
Ebolavirus/aislamiento & purificación , Infecciones por Filoviridae/diagnóstico , Filoviridae/aislamiento & purificación , Fiebre Hemorrágica Ebola/diagnóstico , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa/métodos , Ebolavirus/genética , Filoviridae/genética , Infecciones por Filoviridae/virología , Fiebre Hemorrágica Ebola/virología , Humanos , Patología Molecular , ARN Viral/análisis , ARN Viral/genética , Juego de Reactivos para Diagnóstico , Sensibilidad y EspecificidadRESUMEN
BACKGROUND: A unit of the European Mobile Laboratory (EMLab) consortium was deployed to the Ebola virus disease (EVD) treatment unit in Guéckédou, Guinea, from March 2014 through March 2015. METHODS: The unit diagnosed EVD and malaria, using the RealStar Filovirus Screen reverse transcription-polymerase chain reaction (RT-PCR) kit and a malaria rapid diagnostic test, respectively. RESULTS: The cleaned EMLab database comprised 4719 samples from 2741 cases of suspected EVD from Guinea. EVD was diagnosed in 1231 of 2178 hospitalized patients (57%) and in 281 of 563 who died in the community (50%). Children aged <15 years had the highest proportion of Ebola virus-malaria parasite coinfections. The case-fatality ratio was high in patients aged <5 years (80%) and those aged >74 years (90%) and low in patients aged 10-19 years (40%). On admission, RT-PCR analysis of blood specimens from patients who died in the hospital yielded a lower median cycle threshold (Ct) than analysis of blood specimens from survivors (18.1 vs 23.2). Individuals who died in the community had a median Ct of 21.5 for throat swabs. Multivariate logistic regression on 1047 data sets revealed that low Ct values, ages of <5 and ≥45 years, and, among children aged 5-14 years, malaria parasite coinfection were independent determinants of a poor EVD outcome. CONCLUSIONS: Virus load, age, and malaria parasite coinfection play a role in the outcome of EVD.
Asunto(s)
Ebolavirus/aislamiento & purificación , Epidemias , Infecciones por Filoviridae/diagnóstico , Fiebre Hemorrágica Ebola/diagnóstico , Malaria/complicaciones , Unidades Móviles de Salud , Adolescente , Adulto , Anciano , Niño , Preescolar , Servicios de Laboratorio Clínico , Ebolavirus/genética , Femenino , Filoviridae , Infecciones por Filoviridae/complicaciones , Infecciones por Filoviridae/virología , Guinea , Fiebre Hemorrágica Ebola/complicaciones , Fiebre Hemorrágica Ebola/virología , Humanos , Lactante , Malaria/parasitología , Masculino , Persona de Mediana Edad , ARN Viral/sangre , Carga Viral , Adulto JovenRESUMEN
UNLABELLED: Filoviruses, including both Ebola virus (EBOV) and Marburg virus (MARV), can infect humans and other animals, causing hemorrhagic fever with a high mortality rate. Entry of these viruses into the host is mediated by a single filoviral glycoprotein (GP). GP is composed of two subunits: GP1, which is responsible for attachment and binding to receptor(s) on susceptible cells, and GP2, which mediates viral and cell membrane fusion. Although numerous host factors have been implicated in the entry process, the initial attachment receptor(s) has not been well defined. In this report, we demonstrate that exostosin 1 (EXT1), which is involved in biosynthesis of heparan sulfate (HS), plays a role in filovirus entry. Expression knockdown of EXT1 by small interfering RNAs (siRNAs) impairs GP-mediated pseudoviral entry and that of infectious EBOV and MARV in tissue cultured cells. Furthermore, HS, heparin, and other related glycosaminoglycans (GAGs), to different extents, can bind to and block GP-mediated viral entry and that of infectious filoviruses. These results strongly suggest that HS and other related GAGs are attachment receptors that are utilized by filoviruses for entry and infection. These GAGs may have therapeutic potential in treating EBOV- and MARV-infected patients. IMPORTANCE: Infection by Ebola virus and Marburg virus can cause severe illness in humans, with a high mortality rate, and currently there is no FDA-approved vaccine or therapeutic treatment available. The ongoing 2014 outbreak in West Africa underscores a lack of our understanding in the infection and pathogenesis of these viruses and the urgency of drug discovery and development. In this study, we provide several pieces of evidence that demonstrate that heparan sulfate and other closely related glycosaminoglycans are the molecules that are used by filoviruses for initial attachment. Furthermore, we demonstrate that these glycosaminoglycans can block entry of and infection by filoviruses. Thus, this work provides mechanistic insights on the early step of filoviral infection and suggests a possible therapeutic option for diseases caused by filovirus infection.
Asunto(s)
Filoviridae/fisiología , Glicosaminoglicanos/fisiología , N-Acetilglucosaminiltransferasas/fisiología , Internalización del Virus , Animales , Línea Celular , Ebolavirus/patogenicidad , Ebolavirus/fisiología , Filoviridae/patogenicidad , Infecciones por Filoviridae/etiología , Infecciones por Filoviridae/virología , Técnicas de Silenciamiento del Gen , Células HEK293 , Heparina/fisiología , Heparitina Sulfato/biosíntesis , Heparitina Sulfato/deficiencia , Interacciones Huésped-Patógeno , Humanos , Marburgvirus/patogenicidad , Marburgvirus/fisiología , Ratones , N-Acetilglucosaminiltransferasas/antagonistas & inhibidores , N-Acetilglucosaminiltransferasas/genética , Receptores Virales/fisiología , Proteínas Virales/fisiología , VirulenciaRESUMEN
The filoviruses, Marburg marburgvirus (MARV), Zaire ebolavirus (ZEBOV), and Sudan ebolavirus (SEBOV), cause severe and often fatal hemorrhagic fever in humans and nonhuman primates (NHPs). Monovalent recombinant vesicular stomatitis virus (rVSV)-based vaccine vectors, which encode a filovirus glycoprotein (GP) in place of the VSV glycoprotein, have shown 100% efficacy against homologous filovirus challenge in rodent and NHP studies. Here, we examined the utility of a single-vector, single-injection trivalent rVSV vector expressing MARV, ZEBOV, and SEBOV GPs to protect against MARV-, ZEBOV-, and SEBOV-induced disease in outbred Hartley guinea pigs where we observed protection from effects of all 3 filoviruses.
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Infecciones por Filoviridae/inmunología , Filoviridae/inmunología , Vectores Genéticos/inmunología , Vacunas Virales/inmunología , Animales , Anticuerpos Antivirales/inmunología , Femenino , Infecciones por Filoviridae/virología , Glicoproteínas/inmunología , Cobayas , Vesiculovirus/inmunologíaRESUMEN
Personal protective equipment (PPE) is an important part of worker protection during filovirus outbreaks. The need to protect against a highly virulent fluid-borne pathogen in the tropical environment imposes a heat stress on the wearer that is itself a safety risk. No evidence supports the choice of PPE employed in recent outbreaks, and standard testing procedures employed by the protective garment industry do not well simulate filovirus exposure. Further research is needed to determine the appropriate PPE for filoviruses and the heat stress that it imposes.
Asunto(s)
Infecciones por Filoviridae/epidemiología , Infecciones por Filoviridae/prevención & control , Filoviridae/patogenicidad , Equipo de Protección Personal/virología , Brotes de Enfermedades , Epidemias , Infecciones por Filoviridae/virología , HumanosRESUMEN
Stat1(-/-) mice lack a response to interferon α, ß, and γ, allowing for replication of nonadapted wild-type (wt) Ebolavirus and Marburgvirus. We sought to establish a mouse model for efficacy testing of live attenuated recombinant vesicular stomatitis virus (rVSV)-based filovirus vaccine vectors using wt Ebolavirus and Marburgvirus challenge strains. While infection of immunocompetent mice with different rVSV-based filovirus vectors did not cause disease, infection of Stat1(-/-) mice with the same vectors resulted in systemic infection and lethal outcome for the majority of tested rVSVs. Despite differences in viral loads, organ tropism was remarkably similar between rVSV filovirus vaccine vectors and rVSVwt, with the exception of the brain. In conclusion, Stat1(-/-) mice are not an appropriate immunocompromised mouse model for efficacy testing of live attenuated, replication-competent rVSV vaccine vectors.