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The non-structural protein 5(NS5)is a highly conserved protein in the Flavivirus genus,acting as both a methyltransferase(MTase)and an RNA-dependent RNA polymerase(RdRp).It has been well documented that NS5 plays a crucial role in the replication of viral RNA.Recent studies have shown that NS5 proteins from different flaviviruses interact with various proteins in host cells,aiding the virus in evading the immune system.This review summarizes the structure,subcellular localization,and function of NS5 proteins.Additionally,we outline how flavivirus NS5 proteins contribute to viral replication and immune evasion.Lastly,we present the recent developments of specific small molecule inhibitors that target NS5 proteins.
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@#There are more than 70 species of flaviviruses, including Zika virus, Dengue virus and Japanese encephalitis virus, and more than 33 species are known to be capable of infecting humans. Only three flavivirus vaccines have been approved, and there is a lack of safe and effective vaccines for most flaviviruses. Adenovirus-vectored vaccines have high safety, low cost, and convenience to store and transport. Currently, two adenovirus-vectored Zika vaccines are under early clinical trials, and adenovirus-vectored vaccines for Dengue virus, Japanese encephalitis virus, West Nile virus and yellow fever virus are still in the phase of animal experiment. In the development of adenovirus-vectored flavivirus vaccines, there are still problems of pre-existing immunity to adenovirus, the insufficient immunogenicity of adenovirus vectors and the antibody-dependent enhancement effects among flavivirus. Based on relevant publications from January 2006 to June 2023, this article reviews the current status, challenges and solutions of the research into adenovirus-vectored flavivirus vaccines, so as to provide the reference for the development of relevant vaccines.
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@#Abstract: Objective To elucidate the antigenic antibody reaction of recombinant expression of non-structural protein 1 (NS1) of Japanese encephalitis (JE) virus with various mosquito-borne flaviviruses, including JE virus, and the antigenic antibody reaction of serum samples of patients infected with JE virus in acute stage. Methods In this study, Escherichia coli prokaryotic expression vector (pET) system was used to recombinant express Japanese encephalitis virus NS1 gene. Western Blot assay was performed to detect the antibody responses of the recombinantly expressed protein against a variety of mosquito-transmitted flaviviruses, including JE virus, as well as antigen-antibody reactions of serum from patients with acute JE virus infection. Results The NS1 gene expression product of JE virus (P3 strain) was in the form of an inclusion body, and the denatured and renatured expression product was displayed as a single band in the denatured gel (polyacrylamide gel electrophoresis, PAGE), with a molecular weight of about 45 000. The results of further antigen-antibody analysis showed that the antigen/antibody hybridization reaction of the expression product with polyclonal or monoclonal antibody of JE virus (mosquito isolates, encephalitis isolates) and serum samples of patients with acute JE virus infection could be completely consistent. The recombinant product showed negative antigen/antibody hybridization reactions with mosquito-transmitted flaviviruses, such as dengue virus and yellow fever virus polyclonal antibodies, but positive reactions with polyclonal antibodies to West Nile virus and Murray Valley encephalitis virus. Conclusions In this study, the recombinant expression of the NS1 protein of JE virus was successfully obtained, and the antigen/antibody reaction between the recombinant protein and samples of patients infected with mosquito-borne flavivirus and JE virus was analyzed. The study results provide important basic data for elucidating the antigen-antibody reaction between the NS1 protein of JE virus and mosquito-borne flavivirus. The recombinant expression protein obtained in this study provides an important material basis for further research on the function of JE virus NS1 protein.
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@#Antibody cross-reactivity among flaviviruses is a major limitation in understanding the prevalence without vector control measures. In this study, we investigated the presence of Zika virus (ZIKV)-specific antibodies and the significance of their cross-reactivity with other flaviviruses, which could affect the serological specificity in both symptomatic and asymptomatic pregnant women. Among the results obtained from 217 serum samples tested for ZIKV-specific IgM and IgG, no specific predictions regarding seropositivity or exposure due to extensive cross-reactivity with dengue virus (DENV) serology could be made. Clear-cut positivity was observed in 1.8% (n = 4) and 1.0% (n = 2) for ZIKV IgM and IgG, respectively. The same samples assessed for DENV showed 1.3% (n = 3) seropositivity each for IgM and IgG levels. None of the samples were positive for ZIKV and DENV IgM or IgG. However, one sample (0.4%) tested positive for ZIKV and DENV IgM. No significant correlation was observed between DENV IgM and IgG when comparing the overlapped serotiters. On the other hand, the ZIKV IgG-positive sample showed higher serotiters for DENV IgG, indicating cross-reactivity with ZIKV but without statistical significance. Therefore, screening for the incidence of ZIKV becomes particularly challenging in a population where the presence or pre-exposure to DENV is observed. Our observations further suggest that unless flavivirus prevalence is properly addressed, determining the prevalence of ZIKV antibodies, which may be confounded with other uninvestigated flaviviruses, will be complicated.
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ABSTRACT Objective This study verified the replication efficiency of the Rocio virus in a primary culture of mouse neural cells. Methods Mixed primary cultures (neurons/glia) obtained from the brains of newborn isogenic BALB/c mice were inoculated with Rocio virus on the 7 th day of culture, and the development of cytopathogenic effects was monitored. The infection was confirmed via immunocytochemistry (anti-ROCV), while viral replication was quantified in infected primary cultures. The titration method used depended on the infection period. Results Rocio virus efficiently infected primary cultured neural cells, with the highest viral titer causing cytopathic changes was observed at 2 days post infection. The virus-infected primary culture survived for up to 7 days post infection, and viral load quantitation showed viral replication kinetics compatible with the cell death kinetics of cultures. Conclusion The findings of this study suggest that mouse neural cell primary cultures support Rocio virus replication and could be used as an alternative system for studying Flavivirus infection in the central nervous system.
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Japanese encephalitis (JE) is a leading cause of viral encephalitis in Southeast Asia. It is a serious public health issue in India, and cases have been emerging in newer areas of the country. Although vaccination efforts have already been initiated in the country since 2006 and later through the Universal Immunization Programme in 2011, still a significant reduction in the number of cases has to be achieved since an escalating trend of JE incidence has been reported in certain States such as Assam, Uttar Pradesh and West Bengal. Moreover, fresh cases of JE have been reported from certain pockets in Odisha as well. Despite the mass JE vaccination programme implemented in prioritized endemic zones in the country in 2011, a shift in the age group of JE virus (JEV) infection was noticed affecting the adult population in West Bengal. The recent detection of the circulation of genotype I (GI) in Gorakhpur, Uttar Pradesh and the co-circulation of GI and genotype III (GIII) in West Bengal are probably a warning signal for the public health personnel to strengthen the surveillance system in all endemic hotspots in the country. The abrupt emergence of JEV genotype V (GV) in China and Korea in 2009, after its first detection in Malaya in 1952, endemic countries have been cautioned to strengthen their surveillance, because GV has been suspected of getting dispersed efficiently in other parts of Asia. Moreover, the reduced protection efficiency of the JEV GIII-based vaccine against the JEV genotype V further warrants careful evaluation of the ongoing vaccination strategies in the endemic countries, anticipating the possible incursion of GV and its impact on future control strategies. In view of the above facts, the present communication reviews the current knowledge on the molecular epidemiology of JEV in India vis-a-vis the global scenario and discusses the future priorities in JEV research in India for effectively designing control strategies.
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ABSTRACT Introduction: The Zika Virus (ZIKV) is a single-stranded RNA genome virus, belonging to the family Flaviviridae, genus Flavivirus. Outbreaks around the world have demonstrated that the presence of asymptomatic viremic blood donors provides an increase in the risk of transfusion transmission (TT) and nucleic acid test (NAT) screening has been proposed to ensure the blood safety. This study implemented an "in-house" method to detect ZIKV RNA in blood sample donations. Methods: Primary plasma tubes are submitted to nucleic acid extraction on an automated platform. After extraction, the NAT set-up is performed in the robotic pipettor, in which an amplification mixture containing primers and probes for ZIKV and Polio vaccine virus (PV) are added in duplex as an internal control. The real-time polymerase chain reaction is then performed in a thermocycler, using the protocol established by the supplier. Results: From May 2016 to May 2018, 3,369 samples were collected from 3,221 blood donors (confidence coefficient 95%), of which 31 were considered false positive (0.92%), as they did not confirm initial reactivity when repeated in duplicates and 14 (0.42%) had their results invalid due to repeat failure in the internal control, 4 (0.12%), due to insufficient sample volume and 2 (0.05%), due to automatic pipettor failures. No Zika RNA reactive sample was identified. Conclusion: The test showed feasible to be incorporated into the blood screening routine. Our data do not indicate the need to screen for ZIKV RNA in São Paulo during the evaluated period. However, a generic NAT system covering a group of flaviviruses which are circulating in the region, such as DENV and YFV, among others, could be a useful tool.
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Humanos , Reacción en Cadena en Tiempo Real de la Polimerasa , Virus Zika , Donantes de Sangre , Transfusión Sanguínea , FlavivirusRESUMEN
Objective: To identify unique immunogenic epitopes of Zika virus non-structural 1 (NS1) antigen and produce immunoglobulin Y (IgY) for potential use in he diagnosis of of Zika virus infection. Methods: Immunogenic epitopes were identified using in silico B-cell epitope prediction. A synthetic peptide analog of the predicted epitope was used to induce antipeptide IgY production in hens which was purified using affinity chromatography. Presence of purified IgY and its binding specificity were performed by gel electrophoresis and ELISA, respectively. Results: Out of the nine continuous epitopes identified, the sequence at position 193-208 (LKVREDYSLECDPAVI) was selected and used to produce anti-peptide IgY. The produced IgY was found to bind to the synthetic analog of the Zika virus NS1 immunogenic epitope but not to other flaviviruses and random peptides from other pathogens. Conclusions: In this study, we identified an immunogenic epitope unique to Zika virus that can be used to develop a serodiagnostic tool that specifically detect Zika virus infection.
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Introduction. Les méningites/méningo-encéphalites sont des urgences médicales d'étiologies variées. La technique de diagnostic Multiplex Polymerase Chain Reaction (PCR) permet de détecter la présence de bactéries et de virus dans le liquide céphalorachidien (LCR) avec une spécificité et une sensibilité ≥ 90%. L'objectif de cette étude était d'identifier en utilisant cette technique, les principaux germes responsables des méningites et méningo-encéphalites en réanimation à Libreville. Patients et méthodes. Nous avons mené une étude transversale allant d'octobre 2020 à septembre 2021. Les critères d'inclusion étaient : être admis en réanimation au CHUL et à l'HIAOBO pour suspicion de méningite ou méningo-encéphalite, obtenir l'accord des familles pour l'analyse du liquide céphalorachidien (LCR) par multiplex PCR. Les variables étudiées étaient : la fréquence, les données sociodémographiques, les aspects cliniques et paracliniques. Résultats. Soixante et onze patients ont répondu aux critères d'inclusion. L'âge moyen était de 21,1 ± 10,4 ans et le sex ratio de 1,2. Les motifs d'admission étaient l'altération de l'état de conscience (77%) et l'état de mal épileptique (21%). Plasmodium falciparum a été retrouvé seul chez 38 patients (53,5%) et associé à Listeria monocytogenes chez 4 patients (1,4%). Les méningo-encéphalites à Herpès simplex virus ont été observées chez 4 patients (1,4%) dont l'âge variait entre 40 ans et moins de 50 ans. Un patient (1,4%) présentait une coinfection à S. épidermidis, flavivirus et alphavirus. Des méningo-encéphalites sans germes ont été observées chez 5 patients (%). Conclusion. Le principal germe responsable de méningoencéphalite en réanimation à Libreville est P. falciparum. Des virus tels que le flavivirus et l'alphavirus non détectés par les méthodes usuelles ont aussi été mis en évidence grâce au multiplex PCR.
Introduction. Meningitis/meningoencephalitis are medical emergencies of various etiologies. The Multiplex Polymerase Chain Reaction (PCR) technique allows the detection of the presence of bacteria and viruses in the cerebrospinal fluid (CSF) with a specificity and sensibility of above 90%. The aim of this study was to identify the most common germs responsible for meningitis and meningoencephalitis in the intensive care units of Libreville using this technique,. Patients and methods. We conducted a transversal study from October 2020 to September 2021. Inclusion criteria were: being admitted to intensive care unit of CHUL and HIAOBO for suspicion of meningitis or meningoencephalitis and having the parent's approval for multiplex PCR analysis of CSF. Variables studied included frequency, sociodemographic data, clinical and paraclinical aspects. Results. Seventy one patients were included. Mean age was 21.1 ± 10.4 years and the sex ratio was 1.2. Reasons for admission were altered consciousness (77%) and epilepsy (21%). Plasmodium (P) faciparum was detected alone in 38 cases (53.5%) and associated to Listeria monocytogenes in 4 patients (5.6%). Herpex simplex viral meningoencephalitis was observed in 4 patients (5.6%) aged between 40 and less than 50 years. One patient (1.4%) had co-infection with S. epidermidis, flavivirus and alphavirus. Meningoencephalitis with no germs was found in 5 patients (7%). Conclusion. The main etiology of meningoencephalitis in intensive care units of Libreville is P. falciparum. Viruses not detected by usual methods like flavivirus and alphavirus were detected by multiplex PCR.
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Humanos , Masculino , Femenino , Líquido Cefalorraquídeo , Reacción en Cadena de la Polimerasa Multiplex , Meningitis , Meningoencefalitis , Diagnóstico , Servicios Médicos de UrgenciaRESUMEN
BACKGROUND In Brazil, the yellow fever virus (YFV) is maintained in a sylvatic cycle involving wild mosquitoes and non-human primates (NHPs). The virus is endemic to the Amazon region; however, waves of epidemic expansion reaching other Brazilian states sporadically occur, eventually causing spillovers to humans. OBJECTIVES To report a surveillance effort that led to the first confirmation of YFV in NHPs in the state of Minas Gerais (MG), Southeast region, in 2021. METHODS A surveillance network was created, encompassing the technology of smartphone applications and coordinated actions of several research institutions and health services to monitor and investigate NHP epizootics. FINDINGS When alerts were spread through the network, samples from NHPs were collected and YFV infection confirmed by reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and genome sequencing at an interval of only 10 days. Near-complete genomes were generated using the Nanopore MinION sequencer. Phylogenetic analysis indicated that viral genomes were related to the South American genotype I, clustering with a genome detected in the Amazon region (state of Pará) in 2017, named YFVPA/MG sub-lineage. Fast YFV confirmation potentialised vaccination campaigns. MAIN CONCLUSIONS A new YFV introduction was detected in MG 6 years after the beginning of the major outbreak reported in the state (2015-2018). The YFV strain was not related to the sub-lineages previously reported in MG. No human cases have been reported, suggesting the importance of coordinated surveillance of NHPs using available technologies and supporting laboratories to ensure a quick response and implementation of contingency measures to avoid YFV spillover to humans.
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ABSTRACT Background: Despite their worldwide occurrence, the distribution and role of insect-specific flaviviruses (ISFs) remain unclear. Methods: We evaluated the presence of ISFs in mosquitoes collected in São Paulo, Brazil, using reverse transcription and semi-nested polymerase chain reaction (PCR). Some of the positive samples were subjected to nanopore sequencing. Results: Twelve mosquito pools (2.8%) tested positive for flavivirus infection. Nanopore sequencing was successfully performed on six samples. Phylogenetic analysis grouped these sequences into genotype 2 of Culex flavivirus (CxFV). Conclusions: The identification of CxFV genotype 2 at new locations in São Paulo highlights the importance of understanding the role of ISFs in mosquito vector competence.
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Abstract Zika fever is a viral infection of great relevance in public health, especially in tropic regions, in which there is a predominance of mosquitoes of the genus Aedes, vectors of the disease. Microcephaly in neonatal children and Guillain-Barré syndrome in adults can be caused by the action of the Zika virus (ZIKV). Non-structural proteins, such as NS2B, NS3 and NS5, are important pharmacological targets, due to their action in the life cycle. The absence of anti-Zika drugs raises new research, including prospecting for natural products. This work investigated the in silico antiviral activity of bixin and six other derived molecules against the Zika viral proteins NS2B-NS3 and NS5. The optimized structure was subjected to molecular docking to characterize the interaction between bixinoids and ZIKV non-structural proteins, where significant interactions were observed with amino acid residues in the catalytic site in each enzyme. These results suggest that bixin and ethyl bixin has the potential to interfere with the enzymatic activity of NS2B, NS3 and NS5, thus being an indication of being a promising anti-Zika agent.
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Antivirales/uso terapéutico , Extractos Vegetales/uso terapéutico , Bixa orellana/uso terapéutico , Infección por el Virus Zika/tratamiento farmacológico , Fitoterapia , Replicación Viral/efectos de los fármacosRESUMEN
Abstract Zika virus (ZIKV) has gained great importance worldwide since the past epidemic that occurred in 2015 in Brazil. Early identification of ZIKV is critical to minimize transmission and prevents potentially devastating consequences, including microcephaly in neonates of infected women, congenital blindness, or Guillain-Barré Syndrome. However, this is not an easy task, considering that approximately 80% of ZIKV infection cases are asymptomatic or oligosymptomatic, there are diverse modes of transmission (vertical transmission is through vectors and horizontal transmission through blood, saliva, semen, and urine from infected people), and the fact that ZIKV has a high identity percentage with other cocirculating Flaviviruses such as dengue. Here, we review ZIKV diagnostic methods, with special emphasis on the development of point-of-care diagnostic assays, since these devices commonly have two important advantages: they provide prompt screening and are affordable.
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Humanos , Sistemas de Atención de Punto , Infección por el Virus Zika/diagnósticoRESUMEN
RESUMEN Objetivo. Identificar la presencia del virus del Oeste del Nilo en equinos y mosquitos en ocho municipios del departamento del Meta. Materiales y métodos. La investigación contó con el aval del Comité de bioética de la Universidad de los Llanos. Se analizaron mediante pruebas serológicas y moleculares 613 muestras de equinos criollos y de raza cuarto de milla, destinados a actividades deportivas y de trabajo, con un rango de edad de 2 a 15 años, en los transectos: Villavicencio-Restrepo-Cumaral, San Martín - Castilla la Nueva-Granada y Puerto López-Puerto Gaitán, analizados en 62 pool y 213 mosquitos. Los pool de sueros de equinos y mosquitos fueron analizados por ELISA y PCR. Resultados. No se encontraron animales seropositivos mediante la prueba de ELISA y las pruebas moleculares también fueron negativas. Conclusiones. Aunque en este estudio no se evidenció la presencia de anticuerpos IgM por la técnica de Elisa y las pruebas moleculares (RT-PCR) también fueron negativas para circulación viral, en los municipios objeto de estudio, es importante indicar que la detección molecular en sueros, requiere unos niveles de viremia representativos y que el animal se encuentre en la fase aguda de la enfermedad. Aunque es posible que la población equina se mantenga libre de contacto con el virus, se debe mantener la vigilancia epidemiológica frente a este importante patógeno para la salud humana, especialmente por la presentación de brotes de otros virus zoonóticos como la Encefalitis Equina del Este y Encefalitis Equina Venezolana en los departamentos del Meta y Casanare, contiguo a este.
ABSTRACT Objective. Identify the presence of West Nile virus in horses and mosquitoes in eight municipalities of the department of Meta. Materials and methods. The research was supported by the Bioethics Committee of the University of Los Llanos. 613 samples of Creole and quarter-mile equine horses, intended for sports and work activities, with an age range of 2 to 15 years, were analyzed using serological and molecular tests in the transects: Villavicencio-Restrepo-Cumaral, San Martín- Castilla la Nueva-Granada and Puerto López-Puerto Gaitán, analyzed in 62 pools and 213 mosquitoes. The pool of sera of horses and mosquitoes were analyzed by ELISA and PCR. Results. No seropositive animals were found by the ELISA test and molecular tests were also negative. Conclusions. Although in this study the presence of IgM antibodies was not evidenced by the Elisa technique, and molecular tests (RT-PCR) were also negative for viral circulation, in the municipalities under study, it is important to indicate that the molecular detection in sera, it requires representative levels of viremia and that the animal is in the acute phase of the disease. Although it is possible that the equine population remains free of contact with the virus, epidemiological surveillance should be maintained against this important pathogen for human health, especially due to the outbreak of other zoonotic viruses such as Eastern Equine Encephalitis and Encephalitis Venezuelan Equine in the departments of Meta and Casanare, adjacent to this.
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Animales , Virus del Nilo Occidental , Zoonosis , Reacción en Cadena de la Polimerasa , Monitoreo Epidemiológico , FlavivirusRESUMEN
In Argentina, many Flavivirus were recognised including West Nile virus (WNV). During 2009 several strains of Culex Flavivirus (CxFV), an insect-specific flavivirus, were isolated in the same region where circulation of WNV was detected. Hence, the objective of this study was to analyse the effect of co-infection in vitro assays using CxFV and WNV Argentinean strains in order to evaluate if CxFV could affect WNV replication. Our results showed that WNV replication was suppressed when multiplicity of infection (MOI) for CxFV was 10 or 100 times higher than WNV. Nevertheless, in vivo assays are necessary in order to evaluate the superinfection exclusion potential.
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Animales , Virus del Nilo Occidental/patogenicidad , Sobreinfección/virología , Culex/virología , Flavivirus/fisiología , Insectos Vectores/virología , Argentina , Ensayo de Placa Viral , Línea Celular , Aedes/virologíaRESUMEN
RESUMEN Algunos virus envueltos usurpan la maquinaria celular ESCRT (complejo de clasificación endosomal requerido para el transporte) para llevar a cabo funciones como la transcripción, la traducción, el ensamblaje y la liberación de partículas virales desde las células huésped. Aunque esta estrategia ha sido estudiada principalmente en retrovirus, son varios los virus envueltos que la usan. El objetivo del trabajo fue explorar la participación de una proteína accesoria de ESCRT, la proteína Alix, en la transcripción, traducción, ensamblaje y liberación del virus dengue (DENV), así como su interacción con la proteína viral NS3. Células A549 infectadas con DENV2 fueron tratadas con pequeños ARN de interferencia (siRNA) para disminuir la expresión ("knock-down") de la proteína Alix. Simultáneamente, se obtuvo una línea A549 que expresaba una proteína NS3 recombinante y sobre este sistema se hicieron ensayos de inmunoprecipitación y "pull-down" para detectar interacción entre NS3 y Alix. Los resultados mostraron que el "knock-down" de Alix no tuvo efecto notable en la transcripción o la traducción viral, pero sí en el ensamblaje y la liberación de DENV2, mientras que los ensayos de "pull-down" revelaron la interacción entre NS3 y Alix. La participación de Alix en la producción de DENV2 y su interacción con NS3 constituyen un potencial blanco para el diseño de estrategias dirigidas a controlar la propagación de DENV.
ABSTRACT Since the finding that HIV recruits cellular ESCRT (endosomal sorting complexes required for transport) machinery to accomplish viral budding, this strategy has emerged as an escape route for enveloped viruses also. The work aimed to explore the participation of the cellular protein Alix (a human protein that acts as an adapter in the ESCRT pathway) on the transcription, protein expression, assembly and release of Dengue virus (DENV), and explore for its potential interaction with the viral protein NS3. To this purpose, A549 cells were infected with DENV2 and treated with small interfering RNAs (siRNA) to generate an Alix stable knockdown cells line. Also, an A549 cells line expressing a histidine-tagged NS3 protein was obtained. Both cells lines were used in immunoprecipitation and pull-down assays to assess the interaction between NS3 and Alix. The results showed that Alix knockdown had no effect on viral transcription or viral protein expression but influenced the assembly and release of DENV2 negatively. Finally, pull-down assays revealed the interaction between NS3 and Alix. The finding of an Alix participation in the production of DENV2 and its interaction with NS3 provides a potential target for the design of control/inhibition strategies against DENV spread.
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RESUMEN Objetivo: Evaluar, bajo una perspectiva ecológica, la presencia de Aedes albopictus y su infección natural por virus dengue (DENV) en una zona de actividad piñera de Costa Rica. Método: Se colectaron mosquitos adultos en galerías forestales colindantes con piñeras, viviendas en proximidad a cultivos (<1 km) y viviendas en lejanía (110 km). Se empleó el índice de Shannon-Wiener para estimar biodiversidad. La infestación larvaria se evaluó en plantas de piña y viviendas y se calcularon índices aédicos de viviendas (IV) y de contenedores (IC). La detección de DENV en adultos (cuerpos y cabezas) y en larvas de Ae. albopictus se efectuó mediante RT-PCR y secuenciación. Resultados: Se colectaron 1376 adultos en total: Ae. albopictus (5,81%), Anopheles apicimacula (5,01%), Culex coronator (11,55%), Cx. inflictus (6,1%), Cx. nigripalpus (48,11%), Cx. quinquefasciatus (23,34%) y Limatus durhamii (0,07%). El índice de biodiversidad fue mayor en galerías forestales. Ae. albopictus adultos fueron colectados principalmente en el área de piñeras (73/80), aunque sólo dos larvas en las plantas de piña. Los índices aédicos en proximidad (IV: 40,7%, IC: 26,9%) y en lejanía (IV: 51,7%, IC: 29,6%) no mostraron diferencias significativas (IV Z=0,56, p=0,58; IC Z=0,16, p=0,87). Se detectó DENV-2 y DENV-3 en 2/20 grupos de cabezas y DENV-1 en 2/74 grupos de larvas de Ae. albopictus. Discusión: Las galerías forestales próximas a cultivos de piña podrían considerarse "islas ecológicas" adecuadas para el refugio de Ae. albopictus. La presencia de DENV en adultos y larvas sugiere un papel activo de Ae. albopictus en la transmisión de virus en este ecosistema.
ABSTRACT Objective To evaluate, under an ecological perspective, the presence of Aedes albopictus and the wild infection by dengue viruses (DENV) in an area of pineapple activity in Costa Rica. Materials and methods Adult mosquitoes were collected in forest galleries limiting pineapple plantations, houses adjacent to plantations (<1 km), and distant houses (1-10 km). Shannon-Wiener index was used to estimate biodiversity. Larval infestation was evaluated in pineapple plants and houses, and aedic house (HI) and container (CI) indices were calculated. Detection of DENV in Ae. albopictus adults (bodies and heads) and larvae was performed by RT-PCR and sequencing. Results A total 1376 adult mosquitoes were collected: Ae. albopictus (5.81%), Anopheles apicimacula (5.01%), Culex coronator (11.55%), Cx. inflictus (6.1%), Cx. nigripalpus (48.11%), Cx. quinquefasciatus (23.34%), and Limatus durhamii (0.07%). Biodiversity index was higher in forest galleries. Most adult Ae. albopictus were collected in forests close to pineapple fields (73/80), although only 2 larvae were detected in pineapple plants. Larval indices in adjacent houses (HI: 40.7%, CI: 26.9%) and distant houses (HI: 51.7%, CI: 29.6%) were similar (HI Z=0.56, p=0.58; CI Z=0.16, p=0.87). DENV-2 and DENV-3 were detected in 2/20 "pools" of Ae. albopictus heads and DENV-1 in 2/74 "pools" of larvae. Conclusion Forest galleries that are in proximity to pineapple plantations could be considered "ecological islands" that are suitable for refuge of Ae. albopictus. Presence of DENV in adults and larvae suggests an active role for Ae. albopictus in virus transmission within this ecosystem.
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ABSTRACT Several studies have been carried out to determine the presence and circulation of West Nile Virus (WNV) in several species that interact in important ecosystems of Ecuador, such as the Galapagos Islands, where presence and surveillance studies of WNV have been carried out in wild and migratory birds (2003) (2008 to 2010), penguins (2003 to 2004). Studies have also been carried out on birds from different locations in Guayaquil (2011), and on Jauneche horses (2007), but no virus has been demonstrated in any of them. Nevertheless, in the Abras de Mantequilla wetland, two studies were conducted in equines aged between 3 months to 12 years, all of them mixed race, male and female, with no previous vaccination history and with presence of symptoms only in the first study. In the two studies the serum analysis was performed by the ELISA technique (reactivity determination) and Plaque Reduction Neutralization Test (PRNT). In the first study, 8.12% (13/160) of reactivity was determined in 13 horses and 22.22% of reactivity in 2 of 9 people; and only 3.12% (5/160 horses) of the presence of IgM antibodies against WNV. In relation to the second study, 12.6% (52/412) reactivity and 10.4% (43/412 horses) confirmed the serological evidence of WNV, with a final prevalence of 6.76%. Consequently, the WNV is present and circulating in the equines of the Ecuadorian coastal zone, which is a potential risk to the public health, nevertheless there is no updated information on investigations conducted in this regard.
RESUMEN El presente es una revisión bibliográfica sobre estudios realizados para determinar la presencia y circulación del Virus del Nilo Occidental (VNO) en diversas especies que interactúan en importantes ecosistemas del Ecuador, como son las Islas Galápagos, en donde, se han realizado estudios de presencia y vigilancia del VNO en aves silvestres y migratorias (2003) (2008 al 2010) y pingüinos (2003 al 2004). También, se ha realizado estudios en aves de diversos lugares de Guayaquil (2011), y en equinos de Jauneche (2007) pero en ninguno de los lugares se evidenció la presencia del virus. Por otro lado, en el humedal Abras de Mantequilla, Coello y colaboradores realizaron dos estudios en equinos de edades entre 3 meses a 12 años, todos de raza mestiza, sexo machos y hembras, sin antecedentes de vacunación y con presencia de síntomas solo en el primer estudio. El análisis de los sueros en los dos estudios se realizó mediante la técnica de ELISA (determinación de reactividad) y la confirmación a través de Neutralización por Reducción del Número de Placas (NTRP). En el primer estudio se determinó el 8.12% (13/160) de reactividad en 13 equinos y el 22.22% de reactividad en 2 de 9 personas (no se confirmaron); del total de muestras reactivas en equinos, solo se confirmó el 3.12% (5 equinos/160) de la presencia de anticuerpos IgM contra VNO. Respecto al segundo estudio estableció el 12.6% (52/412) de reactividad y el 10.4% (43/412 equinos) se confirmó la evidencia serológica del VNO, con una prevalencia final del 6.76%. Por lo consiguiente, el VNO está presente y circulando en los equinos de la zona costera ecuatoriana, lo cual es un riesgo potencial para la salud pública, sin embargo no hay información actualizada de investigaciones realizadas al respecto.
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Animales , Virus del Nilo Occidental , Flavivirus , Caballos , Serología , CulicidaeRESUMEN
As a pathogen causing many infectious diseases, Flavivirus genus arborvirus has caused public health emergencies worldwide and posed a serious threat to human health. Attenuated vaccine is the most effective vaccine type against Flavivirus genus arborvirus. The attenuated vaccines against yellow fever virus and Japanese encephalitis virus obtained by consecutive cell passages play an important role in preventing viral infections. Recently, reverse genetics technique has been used to modify the flavivirus genome to obtain the attenuated phenotype, and this technique has made significant progress in the development of Flavivirus genus arbovirus vaccines. This review summarizes the history and the current status of attenuated vaccine of Flavivirus genus arborvirus.
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BACKGROUND Amazon, the largest tropical forest of the world, has suffered from dengue outbreaks since 1998. Cerebrospinal fluid (CSF) of patients, from Amazonas state, suspected of central nervous system (CNS) viral infection was studied using molecular and immunological methods. OBJECTIVE To evaluate the importance of CSF investigation in patients with acute dengue virus (DENV) infection of CNS. METHODS CSF samples of 700 patients were analysed by reverse transcription polymerase chain reaction (RT-PCR) to detect the presence of dengue virus (DENV) RNA and by enzyme-linked immunosorbent assay (ELISA) to detect presence of DENV specific IgM. FINDINGS DENV infection was detected in 4.3% of the CSF samples; 85.7% (24/28) by DENV IgM and 14.3% (4/28) by viral RNA. DENV detected by viral RNA were to be found serotypes DENV-2 (three patients) and DENV-1 (one patient). The neurological diagnosis in patients CNS infection of DENV included encephalitis (10), meningoencephalitis (10), meningitis (6), acute myelitis (1), and encephalomyelitis (1). The majority (89.3%) had intrathecal inflammation: pleocytosis, hyperproteinorrachia and DENV IgM antibodies. Hypoglycorrhachia and/or high levels of lactate in CSF were found in 36% of the patients. Co-infection (CMV, HIV, EBV, and/or Mycobacterium tuberculosis) was observed in eight (28.6%) cases. CONCLUSIONS We found intense inflammatory CSF that is unusual in CNS disorders caused by dengue infection. It may be due co-infections or the immunogenetic background of the local Amerindian Brazilian population. CSF examination is an important diagnostic support tool for neurological dengue diagnosis.