RESUMEN

BACKGROUND: In June 2019, the Bolivian Ministry of Health reported a cluster of cases of hemorrhagic fever that started in the municipality of Caranavi and expanded to La Paz. The cause of these cases was unknown. METHODS: We obtained samples for next-generation sequencing and virus isolation. Human and rodent specimens were tested by means of virus-specific real-time quantitative reverse-transcriptase-polymerase-chain-reaction assays, next-generation sequencing, and virus isolation. RESULTS: Nine cases of hemorrhagic fever were identified; four of the patients with this illness died. The etiologic agent was identified as Mammarenavirus Chapare mammarenavirus, or Chapare virus (CHAPV), which causes Chapare hemorrhagic fever (CHHF). Probable nosocomial transmission among health care workers was identified. Some patients with CHHF had neurologic manifestations, and those who survived had a prolonged recovery period. CHAPV RNA was detected in a variety of human body fluids (including blood; urine; nasopharyngeal, oropharyngeal, and bronchoalveolar-lavage fluid; conjunctiva; and semen) and in specimens obtained from captured small-eared pygmy rice rats (Oligoryzomys microtis). In survivors of CHHF, viral RNA was detected up to 170 days after symptom onset; CHAPV was isolated from a semen sample obtained 86 days after symptom onset. CONCLUSIONS: M. Chapare mammarenavirus was identified as the etiologic agent of CHHF. Both spillover from a zoonotic reservoir and possible person-to-person transmission were identified. This virus was detected in a rodent species, O. microtis. (Funded by the Bolivian Ministry of Health and others.).

Asunto(s)

Arenavirus del Nuevo Mundo , Fiebre Hemorrágica Americana , ARN Viral , Roedores , Animales , Arenavirus del Nuevo Mundo/genética , Arenavirus del Nuevo Mundo/aislamiento & purificación , Bolivia/epidemiología , Infección Hospitalaria/transmisión , Infección Hospitalaria/virología , Transmisión de Enfermedad Infecciosa , Fiebre Hemorrágica Americana/complicaciones , Fiebre Hemorrágica Americana/genética , Fiebre Hemorrágica Americana/transmisión , Fiebre Hemorrágica Americana/virología , Fiebres Hemorrágicas Virales/genética , Fiebres Hemorrágicas Virales/transmisión , Fiebres Hemorrágicas Virales/virología , Secuenciación de Nucleótidos de Alto Rendimiento , Humanos , Reacción en Cadena de la Polimerasa , ARN Viral/genética , ARN Viral/aislamiento & purificación , Ratas/virología , Roedores/virología , Zoonosis Virales/transmisión , Zoonosis Virales/virología

RESUMEN

Several highly pathogenic mammarenaviruses cause severe hemorrhagic and neurologic disease in humans for which vaccines and antivirals are limited or unavailable. New World (NW) mammarenavirus Machupo virus (MACV) infection causes Bolivian hemorrhagic fever in humans. We previously reported that the disruption of specific N-linked glycan sites on the glycoprotein (GPC) partially attenuates MACV in an interferon alpha/beta and gamma (IFN-α/ß and -γ) receptor knockout (R-/-) mouse model. However, some capability to induce neurological pathology still remained. The highly pathogenic Junin virus (JUNV) is another NW arenavirus closely related to MACV. An F427I substitution in the GPC transmembrane domain (TMD) rendered JUNV attenuated in a lethal mouse model after intracranial inoculation. In this study, we rationally designed and rescued a MACV containing mutations at two glycosylation sites and the corresponding F438I substitution in the GPC TMD. The MACV mutant is fully attenuated in IFN-α/ß and -γ R-/- mice and outbred guinea pigs. Furthermore, inoculation with this mutant MACV completely protected guinea pigs from wild-type MACV lethal challenge. Last, we found the GPC TMD F438I substitution greatly impaired MACV growth in neuronal cell lines of mouse and human origins. Our results highlight the critical roles of the glycans and the TMD on the GPC in arenavirus virulence, which provide insight into the rational design of potential vaccine candidates for highly pathogenic arenaviruses. IMPORTANCE For arenaviruses, the only vaccine available is the live attenuated Candid#1 vaccine, a JUNV vaccine approved in Argentina. We and others have found that the glycans on GPC and the F427 residue in the GPC TMD are important for virulence of JUNV. Nevertheless, mutating either of them is not sufficient for full and stable attenuation of JUNV. Using reverse genetics, we disrupted specific glycosylation sites on MACV GPC and also introduced the corresponding F438I substitution in the GPC TMD. This MACV mutant is fully attenuated in two animal models and protects animals from lethal infection. Thus, our studies highlight the feasibility of rational attenuation of highly pathogenic arenaviruses for vaccine development. Another important finding from this study is that the F438I substitution in GPC TMD could substantially affect MACV replication in neurons. Future studies are warranted to elucidate the underlying mechanism and the implication of this mutation in arenavirus neural tropism.

Asunto(s)

Arenavirus del Nuevo Mundo , Fiebre Hemorrágica Americana , Vacunas Virales , Animales , Arenavirus del Nuevo Mundo/genética , Arenavirus del Nuevo Mundo/inmunología , Modelos Animales de Enfermedad , Glicoproteínas/metabolismo , Glicosilación , Cobayas , Fiebre Hemorrágica Americana/inmunología , Fiebre Hemorrágica Americana/virología , Virus Junin/genética , Virus Junin/inmunología , Mutación , Vacunas Atenuadas/inmunología , Vacunas Virales/inmunología

RESUMEN

Pathogenic clade B New World mammarenaviruses (NWM) can cause Argentine, Venezuelan, Brazilian, and Bolivian hemorrhagic fevers. Sequence variability among NWM glycoproteins (GP) poses a challenge to the development of broadly neutralizing therapeutics against the entire clade of viruses. However, blockade of their shared binding site on the apical domain of human transferrin receptor 1 (hTfR1/CD71) presents an opportunity for the development of effective and broadly neutralizing therapeutics. Here, we demonstrate that the murine monoclonal antibody OKT9, which targets the apical domain of hTfR1, can sterically block cellular entry by viral particles presenting clade B NWM glycoproteins (GP1-GP2). OKT9 blockade is also effective against viral particles pseudotyped with glycoproteins of a recently identified pathogenic Sabia-like virus. With nanomolar affinity for hTfR1, the OKT9 antigen binding fragment (OKT9-Fab) sterically blocks clade B NWM-GP1s and reduces infectivity of an attenuated strain of Junin virus. Binding of OKT9 to the hTfR1 ectodomain in its soluble, dimeric state produces stable assemblies that are observable by negative-stain electron microscopy. A model of the OKT9-sTfR1 complex, informed by the known crystallographic structure of sTfR1 and a newly determined structure of the OKT9 antigen binding fragment (Fab), suggests that OKT9 and the Machupo virus GP1 share a binding site on the hTfR1 apical domain. The structural basis for this interaction presents a framework for the design and development of high-affinity, broadly acting agents targeting clade B NWMs. IMPORTANCE Pathogenic clade B NWMs cause grave infectious diseases, the South American hemorrhagic fevers. Their etiological agents are Junin (JUNV), Guanarito (GTOV), Sabiá (SABV), Machupo (MACV), Chapare (CHAV), and a new Sabiá-like (SABV-L) virus recently identified in Brazil. These are priority A pathogens due to their high infectivity and mortality, their potential for person-to-person transmission, and the limited availability of effective therapeutics and vaccines to curb their effects. While low homology between surface glycoproteins of NWMs foils efforts to develop broadly neutralizing therapies targeting NWMs, this work provides structural evidence that OKT9, a monoclonal antibody targeting a single NWM glycoprotein binding site on hTfR1, can efficiently prevent their entry into cells.

Asunto(s)

Anticuerpos Monoclonales/administración & dosificación , Anticuerpos Neutralizantes/administración & dosificación , Anticuerpos Antivirales/administración & dosificación , Arenavirus del Nuevo Mundo/fisiología , Glicoproteínas/inmunología , Fiebre Hemorrágica Americana/prevención & control , Receptores de Transferrina/inmunología , Células A549 , Secuencia de Aminoácidos , Anticuerpos Monoclonales/inmunología , Anticuerpos Neutralizantes/inmunología , Anticuerpos Antivirales/inmunología , Fiebre Hemorrágica Americana/inmunología , Fiebre Hemorrágica Americana/virología , Humanos , Estructura Terciaria de Proteína , Receptores de Transferrina/química , Receptores de Transferrina/genética

RESUMEN

Emerging infectious diseases are a global threat. In countries like Brazil, where biodiversity is high and public health conditions in terms of infrastructure and medical care are often precarious, emerging diseases are particularly worrisome. The lack of monitoring strategies to identify pathogens with the potential to cause outbreaks or epidemics is another problem in Brazil and other developing countries. In this article, we present the history of the Sabiá virus (SABV), a pathogen that was described in the 1990s in Brazil. Several aspects of the biology and ecology of the SABV remain unknown. The SABV has the potential to cause hemorrhagic fever in humans. To date, four cases of human infections have been reported worldwide; two were naturally acquired (both in Brazil), whereas the other two were linked to occupational exposure in the laboratory environment (one in Brazil and one in the USA). In this review, we summarize the basic biological and ecological characteristics of the SABV. This is the first work to gather all available data on the historical aspects involving the cases of SABV infection along with an update on its characteristic features.

Asunto(s)

Accidentes de Trabajo , Arenavirus del Nuevo Mundo , Fiebre Hemorrágica Americana/virología , Adulto , Brasil , Humanos , Personal de Laboratorio , Masculino

RESUMEN

Junin virus (JUNV), a highly pathogenic New World arenavirus, is the causative agent of Argentine hemorrhagic fever (AHF). The live-attenuated Candid #1 (Can) strain currently serves as a vaccine for at-risk populations. We have previously shown that the Can glycoprotein (GPC) gene is the primary gene responsible for attenuation in a guinea pig model of AHF. However, the mechanisms through which the GPC contributes to the attenuation of the Can strain remain unknown. A more complete understanding of the mechanisms underlying the attenuation and immunogenicity of the Can strain will potentially allow for the rational design of additional safe and novel vaccines. Here, we provide a detailed comparison of both RNA and protein expression profiles between both inter- and intra-segment chimeric JUNV recombinant clones expressing combinations of genes from the Can strain and the pathogenic Romero (Rom) strain. The recombinant viruses that express Can GPC, which were shown to be attenuated in guinea pigs, displayed different RNA levels and GPC processing patterns as determined by Northern and Western blot analyses, respectively. Analysis of recombinant viruses containing amino acid substitutions selected at different mouse brain passages during the generation of Can revealed that altered Can GPC processing was primarily due to the T168A substitution within G1, which eliminates an N-linked glycosylation motif. Incorporation of the T168A substitution in the Rom GPC resulted in a Can-like processing pattern of Rom GPC. In addition, JUNV GPCs containing T168A substitution were retained within the endoplasmic reticulum (ER) and displayed significantly lower cell surface expression than wild-type Rom GPC. Interestingly, the reversion A168T in Can GPC significantly increased GPC expression at the cell surface. Our results demonstrate that recombinant JUNV (rJUNV) expressing Can GPC display markedly different protein expression and elevated genomic RNA expression when compared to viruses expressing Rom GPC. Additionally, our findings indicate that the N-linked glycosylation motif at amino acid positions 166-168 is important for trafficking of JUNV GPC to the cell surface, and the elimination of this motif interferes with the GPC release from the ER.

Asunto(s)

Secuencias de Aminoácidos , Arenavirus del Nuevo Mundo/inmunología , Glicoproteínas/genética , Glicoproteínas/metabolismo , Fiebre Hemorrágica Americana , Vacunas Virales , Animales , Arenavirus del Nuevo Mundo/genética , Línea Celular , Células Cultivadas , Cricetinae , Retículo Endoplásmico/metabolismo , Estrés del Retículo Endoplásmico , Expresión Génica , Regulación Viral de la Expresión Génica , Glicoproteínas/química , Glicoproteínas/inmunología , Glicosilación , Fiebre Hemorrágica Americana/inmunología , Fiebre Hemorrágica Americana/metabolismo , Fiebre Hemorrágica Americana/prevención & control , Fiebre Hemorrágica Americana/virología , Humanos , Procesamiento Proteico-Postraduccional , Transporte de Proteínas , Transcripción Genética , Vacunas Virales/genética , Vacunas Virales/inmunología , Virulencia

RESUMEN

Abstract Emerging infectious diseases are a global threat. In countries like Brazil, where biodiversity is high and public health conditions in terms of infrastructure and medical care are often precarious, emerging diseases are particularly worrisome. The lack of monitoring strategies to identify pathogens with the potential to cause outbreaks or epidemics is another problem in Brazil and other developing countries. In this article, we present the history of the Sabiá virus (SABV), a pathogen that was described in the 1990s in Brazil. Several aspects of the biology and ecology of the SABV remain unknown. The SABV has the potential to cause hemorrhagic fever in humans. To date, four cases of human infections have been reported worldwide; two were naturally acquired (both in Brazil), whereas the other two were linked to occupational exposure in the laboratory environment (one in Brazil and one in the USA). In this review, we summarize the basic biological and ecological characteristics of the SABV. This is the first work to gather all available data on the historical aspects involving the cases of SABV infection along with an update on its characteristic features.

Asunto(s)

Humanos , Masculino , Adulto , Accidentes de Trabajo , Arenavirus del Nuevo Mundo , Fiebre Hemorrágica Americana/virología , Brasil , Personal de Laboratorio

RESUMEN

Machupo virus, the cause of Bolivian hemorrhagic fever, is a highly lethal viral hemorrhagic fever with no Food and Drug Administration-approved vaccines or therapeutics. This study evaluated the guinea pig as a model using the Machupo virus-Chicava strain administered via aerosol challenge. Guinea pigs (Cavia porcellus) were serially sampled to evaluate the temporal progression of infection, gross and histologic lesions, and sequential changes in serum chemistry and hematology. The incubation period was 5 to 12 days, and complete blood counts revealed leukopenia with lymphopenia and thrombocytopenia. Gross pathologic findings included congestion and hemorrhage of the gastrointestinal mucosa and serosa, noncollapsing lungs with fluid exudation, enlarged lymph nodes, and progressive pallor and friability of the liver. Histologic lesions consisted of foci of degeneration and cell death in the haired skin, liver, pancreas, adrenal glands, lymph nodes, tongue, esophagus, salivary glands, renal pelvis, small intestine, and large intestine. Lymphohistiocytic interstitial pneumonia was also present. Inflammation within the central nervous system, interpreted as nonsuppurative encephalitis, was histologically apparent approximately 16 days postexposure and was generally progressive. Macrophages in the tracheobronchial lymph node, on day 5 postexposure, were the first cells to demonstrate visible viral antigen. Viral antigen was detected throughout the lymphoid system by day 9 postexposure, followed by prominent spread within epithelial tissues and then brain. This study provides insight into the course of Machupo virus infection and supports the utility of guinea pigs as an additional animal model for vaccine and therapeutic development.

Asunto(s)

Arenavirus del Nuevo Mundo/patogenicidad , Modelos Animales de Enfermedad , Cobayas , Fiebre Hemorrágica Americana/patología , Glándulas Suprarrenales/patología , Aerosoles , Animales , Epitelio/patología , Femenino , Fiebre Hemorrágica Americana/virología , Humanos , Hígado/patología , Pulmón/patología , Ganglios Linfáticos/patología , Masculino , Páncreas/patología

RESUMEN

Clade C, of the New World Arenaviruses, is composed of only the Latino and Oliveros viruses and, besides the geographic range of their rodent reservoirs, the distribution of these viruses has been restricted to Bolivia and Argentina. In this study, the genetic detection and phylogenetic analysis of the complete S segment sequences of sympatric arenaviruses from Brazil revealed a new geographic distribution of clade C arenaviruses, as well as the association of Oliveros virus with a new rodent reservoir.

Asunto(s)

Arenavirus del Nuevo Mundo/genética , Genotipo , Fiebre Hemorrágica Americana/epidemiología , Fiebre Hemorrágica Americana/virología , Animales , Arenavirus del Nuevo Mundo/clasificación , Reservorios de Enfermedades/virología , Fiebre Hemorrágica Americana/transmisión , Interacciones Huésped-Patógeno , Humanos , Datos de Secuencia Molecular , Filogenia , ARN Viral , Roedores , América del Sur/epidemiología , Análisis Espacio-Temporal

RESUMEN

UNLABELLED: The New World arenavirus Junin virus (JUNV) is the causative agent of Argentine hemorrhagic fever (AHF), a potentially deadly disease endemic to central regions of Argentina. The live-attenuated Candid #1 (Can) strain of JUNV is currently used to vaccinate the human population at risk. However, the mechanism of attenuation of this strain is still largely unknown. Therefore, the identification and functional characterization of viral genetic determinants dictating JUNV virulence or attenuation would significantly improve the understanding of the mechanisms underlying AHF and facilitate the development of novel, more effective, and safer vaccines. Here, we utilized a reverse genetics approach to generate recombinant JUNV (rJUNV) strains encoding different gene combinations of the pathogenic Romero (Rom) and attenuated Can strains of JUNV. All strains of rJUNV exhibited in vitro growth kinetics similar to those of their parental counterparts. Analysis of virulence of the rJUNV in a guinea pig model of lethal infection that closely reproduces the features of AHF identified the envelope glycoproteins (GPs) as the major determinants of pathogenesis and attenuation of JUNV. Accordingly, rJUNV strains expressing the full-length GPs of Rom and Can exhibited virulent and attenuated phenotypes, respectively, in guinea pigs. Mutation F427I in the transmembrane region of JUNV envelope glycoprotein GP2 has been shown to attenuate the neurovirulence of JUNV in suckling mice. We document that in the guinea pig model of AHF, mutation F427I in GP2 is also highly attenuating but insufficient to prevent virus dissemination and development of mild clinical and pathological symptoms, indicating that complete attenuation of JUNV requires additional mutations present in Can glycoprotein precursor (GPC). IMPORTANCE: Development of antiviral strategies against viral hemorrhagic fevers, including AHF, is one of the top priorities within the Implementation Plan of the U.S. Department of Health and Human Services Public Health Emergency Medical Countermeasures Enterprise. Live-attenuated Candid #1 strain, derived from the 44th mouse brain passage of the prototype XJ strain of JUNV, has been demonstrated to be safe, immunogenic, and highly protective and is currently licensed for human use in Argentina. However, the bases for the attenuated phenotype of Candid #1 have not been established. Therefore, the identification and functional characterization of viral genetic factors implicated in JUNV pathogenesis and attenuation would significantly improve the understanding of the molecular mechanisms underlying AHF and facilitate the development of novel antiviral strategies.

Asunto(s)

Glicoproteínas/metabolismo , Fiebre Hemorrágica Americana/virología , Virus Junin/fisiología , Proteínas del Envoltorio Viral/metabolismo , Animales , Modelos Animales de Enfermedad , Glicoproteínas/genética , Cobayas , Fiebre Hemorrágica Americana/patología , Virus Junin/genética , Genética Inversa , Proteínas del Envoltorio Viral/genética , Virulencia , Factores de Virulencia

RESUMEN

In previous work, we demonstrated that the arenavirus Junín virus (JUNV) is able to activate Akt by means of the phosphatidylinositol-3-kinase (PI3K) survival pathway during virus entry. This work extends our study, emphasizing the relevance of this pathway in the establishment and maintenance of persistent infection in vitro. During the course of infection, JUNV-infected Vero cells showed a typical cytopathic effect that may be ascribed to apoptotic cell death. Treatment of infected cultures with Ly294002, an inhibitor of the PI3K/Akt pathway, produced an apoptotic response similar to that observed for uninfected cells treated with the drug. This result suggests that virus-induced activation of the PI3K/Akt pathway does not deliver a strong enough anti-apoptotic signal to explain the low proportion of apoptotic cells observed during infection. Also, inhibition of the PI3K/Akt pathway during the acute stage of infection did not prevent the establishment of persistence. Furthermore, treatment of persistently JUNV-infected cells with Ly294002 did not alter viral protein expression. These findings indicate that despite the positive modulation of the PI3/Akt pathway during Junín virus entry, this would not play a critical role in the establishment and maintenance of JUNV persistence in Vero cells.

Asunto(s)

Cromonas/farmacología , Inhibidores Enzimáticos/farmacología , Fiebre Hemorrágica Americana/virología , Virus Junin/efectos de los fármacos , Morfolinas/farmacología , Fosfatidilinositol 3-Quinasas/farmacología , Proteínas Proto-Oncogénicas c-akt/fisiología , Internalización del Virus/efectos de los fármacos , Replicación Viral/efectos de los fármacos , Animales , Apoptosis , Línea Celular , Chlorocebus aethiops , Fiebre Hemorrágica Americana/tratamiento farmacológico , Virus Junin/crecimiento & desarrollo , Inhibidores de las Quinasa Fosfoinosítidos-3 , Proteínas Proto-Oncogénicas c-akt/antagonistas & inhibidores , Células Vero , Proteínas Virales/biosíntesis

RESUMEN

AIM: Study sensitivity of laboratory animals to a causative agent ofArgentine hemorrhagic fever. MATERIALS AND METHODS: Junin virus strain XJ P37 was obtained from the State Collection of Causative Agents of Viral Hemorrhagic Fevers of the Pathogenicity Group I of Scientific Research Center of the 33rd Central Scientific Research Test Institute (SRC of the 33rd CSRTI). Junin virus strain XJ P37 culture with biological activity of 5.2 1g PFU x ml was used in the experiments. Mice (2 - 4 and 7 - 14 days old), guinea pigs (250 - 300 g), 1.8 - 2.5 kg shinshilla breed rabbits, 2.0 - 3.0 kg javanese macaque monkeys were obtained from vivarium of the SRC of the 33rd CSRTI. Vero (B) and GMK-AH-1 (D) cell cultures were obtained from cell culture collection of the SRC of the 33rd CSRTI. Biological activity calculation of Junin virus was carried out by Kerber in I.P. Amsharin modification. RESULTS: Lethality in animals was from 12.5 to 50% after intranasal and intraperitoneal infection of guinea pigs, intramuscular, intraperitoneal and subcutaneous infection of rabbits, intracerebral and intranasal infection of mice at the doses from 0.4 to 1.0 x 10(5) PFU. Death of infected monkeys after intramuscular administration of the virus at 1.0 x 10(4) PFU dose was not observed. In 100% of surviving animals formation of virus-neutralizing antibodies was registered. CONCLUSION: Evaluation of sensitivity of laboratory animals to Junin virus has shown that intracerebrally infected mice may be used to maintain causative agent culture, infected guinea pigs - to prepare virus-containing cultures and modelling infection exacerbation in humans. Intramuscularly infected rabbits may be used to obtain hyper-immune sera.

Asunto(s)

Arenavirus del Nuevo Mundo/patogenicidad , Fiebre Hemorrágica Americana/virología , Virus Junin/patogenicidad , Animales , Anticuerpos Antivirales/aislamiento & purificación , Modelos Animales de Enfermedad , Cobayas , Fiebre Hemorrágica Americana/epidemiología , Fiebre Hemorrágica Americana/patología , Humanos , Ratones , Conejos

RESUMEN

The etiologic agent of Bolivian hemorrhagic fever (BHF), Machupo virus (MACV) is reported to have a mortality rate of 25-35%. First identified in 1959, BHF was the cause of a localized outbreak in San Joaquin until rodent population controls were implemented in 1964. The rodent Calomys collosus was identified as the primary vector and reservoir for the virus. Multiple animal models were considered during the 1970s with the most human-like disease identified in Rhesus macaques but minimal characterization of the pathogenesis has been published since. A reemergence of reported BHF cases has been reported in recent years, which necessitates the further study and development of a vaccine to prevent future outbreaks.

Asunto(s)

Arenavirus del Nuevo Mundo/patogenicidad , Fiebre Hemorrágica Americana/virología , Animales , Arenavirus del Nuevo Mundo/genética , Arenavirus del Nuevo Mundo/fisiología , Modelos Animales de Enfermedad , Fiebre Hemorrágica Americana/epidemiología , Humanos , Macaca mulatta , Virulencia

RESUMEN

Guanarito virus (GTOV) is an emergent and deadly pathogen. We present the crystal structure of the glycosylated GTOV fusion glycoprotein to 4.1-Å resolution in the postfusion conformation. Our structure reveals a classical six-helix bundle and presents direct verification that New World arenaviruses exhibit class I viral membrane fusion machinery. The structure provides visualization of an N-linked glycocalyx coat, and consideration of glycan dynamics reveals extensive coverage of the underlying protein surface, following virus-host membrane fusion.

Asunto(s)

Arenavirus del Nuevo Mundo/metabolismo , Proteínas Virales de Fusión/química , Proteínas Virales de Fusión/metabolismo , Secuencia de Aminoácidos , Arenavirus del Nuevo Mundo/química , Arenavirus del Nuevo Mundo/genética , Línea Celular , Cristalografía por Rayos X , Glicosilación , Fiebre Hemorrágica Americana/virología , Humanos , Modelos Moleculares , Datos de Secuencia Molecular , Estructura Secundaria de Proteína , Alineación de Secuencia , Proteínas Virales de Fusión/genética , Internalización del Virus

RESUMEN

Analysis of data of the available literature on epidemiology of Bolivian hemorrhagic fever, manifestations of human disease, biological properties of the causative agent and development carried out abroad of means and methods of diagnostics, prophylaxis and therapy of this infection that presents a potential threat for the population and economy of the Russian Federation in case of introduction of the causative agent is presented.

Asunto(s)

Arenavirus del Nuevo Mundo/fisiología , Fiebre Hemorrágica Americana/epidemiología , Fiebre Hemorrágica Americana/fisiopatología , Muridae/virología , Virión/fisiología , Animales , Anticuerpos Neutralizantes/sangre , Antivirales/uso terapéutico , Arenavirus del Nuevo Mundo/patogenicidad , Manejo de la Enfermedad , Brotes de Enfermedades , Vectores de Enfermedades , Fiebre Hemorrágica Americana/terapia , Fiebre Hemorrágica Americana/virología , Humanos , Federación de Rusia/epidemiología , América del Sur/epidemiología , Virión/patogenicidad , Replicación Viral

RESUMEN

AIM: Optimization of conditions of quantitative evaluation of Argentine hemorrhagic fever causative agent. MATERIALS AND METHODS: Junin virus (XJ P37 strain) was obtained from National collection of viral hemorrhagic fever causative agents of the 1st pathogenicity group of the 33rd Central Research Testing Institute. Junin virus (XJ P37 strain) culture with biological activity of 5.2 lg PFUxm(-1) was used in the experiments. Vero B, 6619-1(D) and GMK-AH-1(D) were obtained from collection of cell culture of the Research Scientific Centre of the 33rd Central Research Testing Institute. Calculation of biological activity of Junin virus during titration in cell cultures was carried out by Kerber method with modification by I.P. Ashmarin. RESULTS: During incubation for 4 - 7 days after the infection of cell monolayer the determined biological activity was 4.4 - 6.4 lg PFUxml(-1); the size of the formed negative colonies--(1.5 +/- 0.5) mm. CONCLUSION: The conditions of quantitative evaluation of Argentine hemorrhagic fever were optimized by negative colonies method (using 5 - 7 day Vero B cell culture monolayer with staining of monolayer on day 5 of secondary incubation, recording of results at day 7 after the infection).

Asunto(s)

Virus Junin/aislamiento & purificación , Ensayo de Placa Viral/métodos , Animales , Chlorocebus aethiops , Fiebre Hemorrágica Americana/virología , Virus Junin/crecimiento & desarrollo , Células Vero , Replicación Viral

RESUMEN

BACKGROUND: Junín virus (JUNV), the etiologic agent of Argentine hemorrhagic fever (AHF), is classified by the NIAID and CDC as a Category A priority pathogen. Presently, antiviral therapy for AHF is limited to immune plasma, which is readily available only in the endemic regions of Argentina. T-705 (favipiravir) is a broadly active small molecule RNA-dependent RNA polymerase inhibitor presently in clinical evaluation for the treatment of influenza. We have previously reported on the in vitro activity of favipiravir against several strains of JUNV and other pathogenic New World arenaviruses. METHODOLOGY/PRINCIPAL FINDINGS: To evaluate the efficacy of favipiravir in vivo, guinea pigs were challenged with the pathogenic Romero strain of JUNV, and then treated twice daily for two weeks with oral or intraperitoneal (i.p.) favipiravir (300 mg/kg/day) starting 1-2 days post-infection. Although only 20% of animals treated orally with favipiravir survived the lethal challenge dose, those that succumbed survived considerably longer than guinea pigs treated with placebo. Consistent with pharmacokinetic analysis that showed greater plasma levels of favipiravir in animals dosed by i.p. injection, i.p. treatment resulted in a substantially higher level of protection (78% survival). Survival in guinea pigs treated with ribavirin was in the range of 33-40%. Favipiravir treatment resulted in undetectable levels of serum and tissue viral titers and prevented the prominent thrombocytopenia and leucopenia observed in placebo-treated animals during the acute phase of infection. CONCLUSIONS/SIGNIFICANCE: The remarkable protection afforded by i.p. favipiravir intervention beginning 2 days after challenge is the highest ever reported for a small molecule antiviral in the difficult to treat guinea pig JUNV challenge model. These findings support the continued development of favipiravir as a promising antiviral against JUNV and other related arenaviruses.

Asunto(s)

Amidas/uso terapéutico , Antivirales/uso terapéutico , Fiebre Hemorrágica Americana/tratamiento farmacológico , Virus Junin/efectos de los fármacos , Pirazinas/uso terapéutico , Administración Oral , Amidas/farmacocinética , Animales , Antivirales/farmacocinética , Modelos Animales de Enfermedad , Cobayas , Fiebre Hemorrágica Americana/virología , Inyecciones Intraperitoneales , Masculino , Plasma/química , Pirazinas/farmacocinética , Análisis de Supervivencia , Viremia/prevención & control

RESUMEN

Arenavirus RNA was isolated from Mexican deer mice (Peromyscus mexicanus) captured near the site of a 1967 epidemic of hemorrhagic fever in southern Mexico. Analyses of nucleotide and amino acid sequence data indicated that the deer mice were infected with a novel Tacaribe serocomplex virus (proposed name Ocozocoautla de Espinosa virus), which is phylogenetically closely related to Tacaribe serocomplex viruses that cause hemorrhagic fever in humans in South America.

Asunto(s)

Arenavirus del Nuevo Mundo/aislamiento & purificación , Fiebre Hemorrágica Americana/epidemiología , Animales , Arenavirus del Nuevo Mundo/clasificación , Arenavirus del Nuevo Mundo/genética , Fiebre Hemorrágica Americana/diagnóstico , Fiebre Hemorrágica Americana/virología , Humanos , México/epidemiología , Datos de Secuencia Molecular , Proteínas de la Nucleocápside/genética , Peromyscus/virología , Filogenia , Homología de Secuencia

RESUMEN

Argentine haemorrhagic fever (AHF) is a systemic febrile syndrome characterized by several haematological and neurological alterations caused by Junín virus (JUNV), a member of the Arenaviridae family. Newborn mice are highly susceptible to JUNV and the course of infection has been associated with the viral strain used. Galectin-3 (Gal-3) is an animal lectin that has been proposed to play an important role in some central nervous system (CNS) diseases. In this study, we analysed Gal-3 expression at the transcriptional and translational expression levels during JUNV-induced CNS disease. We found that Candid 1 strain induced, with relatively low mortality, a subacute/chronic CNS disease with significant glia activation and upregulation of Gal-3 in microglia cells as well as in reactive astrocytes that correlated with viral levels. Our results suggest an important role for Gal-3 in viral-induced CNS disease.

Asunto(s)

Infecciones por Arenaviridae/metabolismo , Encefalitis Viral/metabolismo , Galectina 3/biosíntesis , Virus Junin/patogenicidad , Neuroglía/metabolismo , Neuroglía/virología , Regulación hacia Arriba/fisiología , Animales , Animales Recién Nacidos , Infecciones por Arenaviridae/patología , Astrocitos/metabolismo , Astrocitos/patología , Astrocitos/virología , Modelos Animales de Enfermedad , Encefalitis Viral/patología , Fiebre Hemorrágica Americana/metabolismo , Fiebre Hemorrágica Americana/patología , Fiebre Hemorrágica Americana/virología , Ratones , Ratones Endogámicos C57BL , Microglía/metabolismo , Microglía/patología , Microglía/virología , Neuroglía/patología

RESUMEN

Junín virus of the Arenaviridae family is the etiological agent of Argentine hemorrhagic fever, a febrile syndrome causing hematological and neurological symptoms. We review historical perspectives of current knowledge on the disease, and update information related to the virion and its potential pathogenic mechanisms.

Asunto(s)

Fiebre Hemorrágica Americana/fisiopatología , Virus Junin/fisiología , Virus Junin/patogenicidad , Animales , Fiebre Hemorrágica Americana/virología , Humanos , Virus Junin/clasificación , Virus Junin/ultraestructura , Modelos Animales , Replicación Viral/fisiología

RESUMEN

Herein, we describe the syntheses of 3,5-disubstituted imidazo[2,1-b]thiazole. The cyclization step was performed in two different conditions by using either thermal or microwave heating. Comparing the results of both methodologies, we found that the microwave assistance is an improved alternative to obtain this family of heterocyclic compound. Compounds were first evaluated for cytotoxicity in Vero cells by MTT method and then, the antiviral activity was assayed by a virus yield inhibition assay in the range of concentrations lower than the corresponding CC(50), using JUNV strain IV4454 as the model system. The most active compounds (3 and 4), showed a level of antiviral activity against JUNV in monkey Vero cells better than the reference substance ribavirin. Then, they are promising lead compound for further analysis and characterization to establish their therapeutic potential against hemorrhagic fever viruses.

Asunto(s)

Antivirales/química , Antivirales/farmacología , Carbohidratos/química , Fiebre Hemorrágica Americana/virología , Virus Junin/efectos de los fármacos , Tiazoles/química , Tiazoles/farmacología , Animales , Antivirales/síntesis química , Antivirales/toxicidad , Chlorocebus aethiops , Concentración 50 Inhibidora , Virus Junin/fisiología , Tiazoles/síntesis química , Tiazoles/toxicidad , Células Vero