Caracterización biológica de cepas del virus Encefalitis San Luis en células de la inmunidad innata / Biological characterization of St. Louis Encephalitis virus strains in cells of innate immunity

Los flavivirus transmitidos por mosquitos son una amenaza actual y emergente en todo el mundo. Dentro de este género, el virus Encefalitis San Luis (VESL) causa una forma severa de enfermedad neuroinvasiva donde la respuesta inmune es un componente crucial de la defensa del huésped. En este trabajo se investigó la interacción entre VESL y células de la inmunidad innata, en un modelo de infección in vitro de monocitos humanos (células U937) con cepas de distinta virulencia y condiciones epidemiológicas de aislamiento (CbaAr-4005 y 78V-6507). Se evaluó la capacidad de infectar y replicar del virus, como también el efecto citopático y la cinética de viabilidad de monocitos durante la infección. Los resultados demostraron la susceptibilidad de los monocitos a la infección, replicación y muerte por ambas cepas virales. Sin embargo, se hallaron diferencias significativas entre ellas. La cepa epidémica y de mayor virulencia CbaAr-4005 registró una tasa de infección y replicación superior a la de la cepa endémica y de menor virulencia 78V-6507. Se comprobó también que el VESL indujo la muerte de monocitos humanos, dependiendo del tiempo post-infección (pi) y de la cepa. Así, CbaAr-4005 provocó a partir del día 3 pi el doble de mortalidad celular que 78V-6507. Además, en los monocitos infectados se observaron alteraciones de parámetros morfológicos que podrían relacionarse con el tipo de mecanismo de muerte celular asociado a la infección por VESL.

Mosquitoes borne Flavivirus infections are an actual and emergent worldwide threat to human health. Within this genus, Saint Louis Encephalitis Virus (SLEV) causes a severe neuroinvasive disease where immune response is crucial for host survival. In this study the interaction between SLEV and innate immune cells was evaluated. An in vitro infection model with human monocytes (U937 cells) and strains with variations in virulence and isolation conditions (CbaAr-4005 and 78V-6507) were used. Infection capacity, replication capacity, cytopathic effect and monocyte viability kinetics were measured. The results showed susceptibility to infection and replication to both strains. However, significant differences were found among them. CbaAr-4005, the epidemic and more virulent strain, showed higher infection and replication ratios compared to 78V-6507. SLEV infection that induces cell death of human monocytes was also found in a post-infection time and in a strain dependent manner. Since day 3 post-infection, twice the mortality in CbaAr-4005 infected cells was observed. Furthermore, infected monocytes showed alterations in morphologic parameters that could be related with apoptosis mechanisms associated to SLEV infections.

Os Flavivírus transmitidos por mosquitos são uma ameaça atual e emergente no mundo todo. Nesse gênero, o vírus Encefalite Saint Louis (VESL) causa uma forma grave de doença neuroinvasiva onde a resposta imune é um componente crucial da defesa do hospedeiro. Neste trabalho nos investigamos a interação entre VESL e células de imunidade inata em um modelo de infecção in vitro de monócitos humanos (células U937) com estirpe de diferentes virulências e condições epidemiológicas de isolamento (CbaAr-4005 e 78V-6507). Foi avaliada a capacidade do vírus de infectar e replicar , assim como o efeito citopático e a viabilidade cinética dos monócitos durante a infecção. Os resultados demonstraram a suscetibilidade dos monócitos à infecção, replicação e morte por ambas as estirpes virais. No entanto, foram detectadas diferenças significativas entre eles. A estirpe epidémica e de maior virulenta CbaAr-4005 teve uma maior taxa de infecção e replicação do que a estirpe endémica e menos virulenta 78V-6507. Foi comprovado também que o VESL induziu a morte de monócitos humanos, dependendo do tempo pós-infecção (pi) e da estirpe. Assim, a CbaAr-4005 causou a partir do dia 3 pi o dobro da mortalidade celular o que a 78V- 6507. Além disso, alterações nos parâmetros morfológicos foram observadas nos monócitos infectados que poderiam estar relacionadas ao tipo de mecanismo de morte celular associado à infecção pelo VESL.

Análise integrada à biologia de sistemas para avaliação de citocinas pró-inflamatórias e anti-inflamatórias na infecção por Zika vírus / Analysis integrated with the systems biology pro-inflammatory and anti-inflammatory cytokine evalution in Zica Virus infection

Objetivo: O presente estudo objetivou analisar as citocinas pró e anti-inflamatórias em pacientes infectados pelo Zika vírus. Métodos: Através da Biologia de Sistemas, que contribuiu de forma a sumarizar os dados quantitativos complexos. Resultados: Observamos em nossa pesquisa a elevação das citocinas IL-7, IL-9, IL-17a, RANTES, IP-10 e IL-1ra dos indivíduos infectados pelo ZIKV na fase aguda, relacionadas à atividade de linfócitos T e B,que indica uma possível proliferação desses tipos celulares mediante a infecção pelo ZIKV.Conclusão: Constatamos que nas infecções pelo ZIKV não ocorre uma grande liberação de citocinas, o que era esperado devido ao caráter benigno da doença.

Objective: The present study objected to analyze the pro and antiinflammatory cytokines in patients infected with zika vírus. Methods: Through the Systems Biology that contributed in a way to summarize the complex quantitative data. Results: In our study, we observed elevation of the cytokines IL-7, IL-9, IL-17a, RANTES, IP-10 and IL-1ra of the infected individuals by ZIKV in the acute phase, related to T and B lymphocyte activity, which indicate a possible proliferation of these cell types through ZIKV infection. Conclusion: We found that in the infections by the ZIKV, does not occur a great release of cytokines, which was expected due to the benign nature of the disease.

Importance of cerebrospinal fluid investigation during dengue infection in Brazilian Amazonia Region

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.

Enfermedad por virus de Zika y sus complicaciones neurológicas / Zika virus disease and its neurological complications

Resumen El virus de Zika es un Flavivirus, transmitido por picadura de mosquito, descubierto en África en 1947. La mayoría de personas afectadas con la infección por virus de Zika no tienen síntomas y cuando estos se presentan son generalmente leves e incluyen ebre, exantema máculo-papular, artralgia y conjuntivitis. Desde el comienzo del año 2015 el virus se ha diseminado a través de las Américas a más de 31 países y territorios hasta comienzos de este año. Personas de toda edad pueden enfermar con esta infección incluyendo fetos por transmisión materno-fetal. La evidencia sugiere que cuando el feto está expuesto al virus durante el embarazo, particularmente en los primeros meses, se asocia con microcefalia y otras malformaciones del sistema nervioso central. Las secuelas a largo plazo sin embargo de las presentaciones: congénita, perinatal y pediátrica son desconocidas. No existe vacuna disponible para prevenir la infección por este virus y el tratamiento es sólo de soporte. Este artículo revisa algunas características epidemiológicas, clínicas, exámenes de laboratorio, tratamiento y prevención con atención a los problemas neurológicos hasta la fecha.

Abstract Zika virus is a mosquito-borne avivirus identi ed in Africa in 1947. Most a ected people has no symptoms and when present they are mild and include: fever, maculopapular rash, athralgias, and myalgias. Since 2015 the virus has spread through the Americas to more than 31 countries and territories until the beginning of this year. People of all ages could be a ected by Zika including fetus. Maternal-fetal transmission has been documented. Evidence suggest that congenital Zika virus occurs when the fetus is exposed to the virus during the rst few months of gestation and is associated with microcephaly and other central nervous system malformations. Zika long term sequelae of congenital, perinatal and pediatric diseases are largely unknown. No vaccine to prevent Zika virus infection is available and the treatment is only of support. This review article is an update regarding the main epidemiologic, clinical, laboratory testing, treatment and prevention with particular attention to the neurological complications.

Búsqueda de flavivirus en individuos con sospecha clínica de dengue y resultado negativo para el antígeno NS1 en Paraguay / Search of flavivirus in individuals with clinical suspicion of dengue and negative for the NS1 antigen in Paraguay

Los flavivirus son responsables de una considerable morbi-mortalidad a nivel mundial. Entre ellos, el virus del dengue (DENV) es causante de graves problemas de salud pública en Paraguay. El objetivo del estudio fue detectar infecciones por flavivirus a través de una reacción de RT-nested PCR genérica para flavivirus en 195 muestras de individuos con sospecha de dengue, negativos por el test inmunocromatográfico (antígeno NS1 ­ DENV), provenientes del área metropolitana de Asunción entre 2011 y 2013. Las muestras positivas para flavivirus fueron sometidas a dos reacciones de RT-nested PCRs específicas para DENV. El límite de detección (LD) para flavivirus fue de 0,2 UFP/reacción. En total 43/195 muestras fueron positivas para flavivirus. De estas, 38/43 (88,4%) correspondieron a DENV (6 DENV-1, 30 DENV-2 y 2 DENV-3). Además, 5/43 casos (11,6%) positivos para flavivirus fueron negativos para DENV por ambas reacciones específicas, pudiendo deberse a infecciones por otros flavivirus. Los resultados sugieren que la utilización de una reacción genérica seguida de otras reacciones específicas para DENV en casos febriles negativos para NS1 por el método inmunocromatográfico permitiría detectar más casos de infecciones por DENV y además, podría contribuir a la identificación de casos debido a infecciones por otros flavivirus.

Flaviviruses are responsible for considerable worldwide morbidity and mortality. Among them, the dengue virus (DENV) causes serious public health problems in Paraguay. The objective of the study was to detect flavivirus infections using a generic RT-nested -PCR in 195 samples of individuals with suspected dengue and negative for the inmunochromatographic test (NS1 antigen ­ DENV), from the metropolitan area of Asuncion between 2011 and 2013. The flavivirus-positive samples were subjected to two reactions of DENV-specific RT-nested PCRs. The detection limit (DL) for flavivirus was 0.2 PFU / reaction. In total, 43/195 samples were positive for flavivirus. Of them, 38/43 (88,4%) corresponded to DENV (6 DENV-1, 30 DENV-2 and 2 DENV-3). In addition, 5/43 cases (11.6%) positive for flavivirus were negative for DENV by both specific reactions, and may be infections caused by other flaviviruses. The results suggest that the use of a generic reaction followed by other DENV specific reactions in febrile negative cases for NS1 by the immunochromatographic method would allow the detection of more cases of DENV infections and could contribute to the identification of cases due to infections by others flaviviruses.

Improvement of a RT-PCR assay for Yellow Fever virus genome detection

The aim of the present study was to describe an improved protocol of reverse transcription polymerase chain reaction (RT-PCR) for Yellow Fever virus genome detection. A strain of ribonucleic acid of Yellow Fever virus was submitted to the improved protocol of RT-PCR and the amplicons were visualized under ultraviolet transilluminator, purifed and sequenced. The nucleotide sequence obtained was compared with sequences available in GenBank using the tblastx tool. The amplicons produced by the strain of ribonucleic acid of Yellow Fever virus exhibited fragments of 400 and 800 base pairs and the consensus sequence exhibited a similarity of 100% with Yellow Fever virus sequences recorded in GenBank. The improved protocol described in this study allowed Yellow Fever virus genome detection and enabled the elimination of the nested-PCR step, which has been frequently associated with contamination. In addition, it reduced the time of reaction, the cost of reagents and the possibility of sample contamination. New methods of investigating these infections must be elaborated and a continuous vigilance of these viruses in their different vectors and hosts is required to avoid negative impacts on human health, tourism and trade.(AU)

Vigilancia de virus Zika: Síntesis al 17/08/2016 / Zika virus surveillance: synthesis 17/08/2016

El virus del Zika (ZIKV) es un Arbovirus del género Flavivirus (familia Flaviviridae), cercano filogenéticamente a otros virus como los del dengue, la fiebre amarilla, la fiebre del Nilo Occidental, la encefalitis de Saint Louis y la encefalitis japonesa. Se transmite principalmente por la picadura de mosquitos del género Aedes y también se ha documentado la transmisión vertical, sexual y, potencialmente, por transfusión sanguínea. El presente informe describe su manifestación clínica, la situación epidemológica a nivel mundial y nacional, y la situación en la Ciudad de Buenos Aires, con casos confirmados en residentes de la misma, hasta Agosto de 2016

Evaluation and optimization of SYBR Green real-time reverse transcription polymerase chain reaction as a tool for diagnosis of the Flavivirus genus in Brazil

Abstract: INTRODUCTION: The genus Flavivirus includes several pathogenic species that cause severe illness in humans. Therefore, a rapid and accurate molecular method for diagnosis and surveillance of these viruses would be of great importance. Here, we evaluate and optimize a quantitative real-time reverse transcription polymerase chain reaction (RT-PCR) method for the diagnosis of the Flavivirus genus. METHODS: We evaluated different commercial kits that use the SYBR Green system for real-time RT-PCR with a primer set that amplifies a fragment of the NS5 flavivirus gene. The specificity and sensitivity of the assay were tested using twelve flaviviruses and ribonucleic acid (RNA) transcribed from the yellow fever virus. Additionally, this assay was evaluated using the sera of 410 patients from different regions of Brazil with acute febrile illness and a negative diagnosis for the dengue virus. RESULTS: The real-time RT-PCR amplified all flaviviruses tested at a melting temperature of 79.92 to 83.49°C. A detection limit of 100 copies per ml was determined for this assay. Surprisingly, we detected dengue virus in 4.1% (17/410) of samples from patients with febrile illness and a supposedly negative dengue infection diagnosis. The viral load in patients ranged from 2.1×107to 3.4×103copies per ml. CONCLUSIONS: The real-time RT-PCR method may be very useful for preliminary diagnoses in screenings, outbreaks, and other surveillance studies. Moreover, this assay can be easily applied to monitor viral activity and to measure viral load in pathogenesis studies.

A mídia em meio às ‘emergências’ do vírus Zika: questões para o campo da comunicação e saúde / The media among the Zika virus ‘emergencies’: issues for thecommunication and health field / /Los medios de comunicación entre las ‘emergencias’ del virus Zika:preguntas para el campo de la comunicación y salud

Típico caso de um vírus emergente, o Zika havia circulado de forma restrita quando chegou ao Brasil, onde acabaria por se tornar parte de uma emergência em saúde pública e um tema com fortíssima presença nos meios de comunicação em 2015. Este artigo baseia-se em um trabalho realizado no contexto do Observatório Saúde na Mídia, no qual traçamos uma linha do tempo com os principais pontos da escalada de atenção sobre o vírus Zika na mídia brasileira em 2015, incluindo a cobertura midiática e os anúncios oficiais. Confrontamos essa linha do tempo com uma análise de capas de nove jornais impressos publicados nos meses de novembro e dezembro de 2015, período em que o Ministério da Saúde admitiu a possível correlação do vírus com o aumento de casos de microcefalia no país. Enfocamos referências a medo e risco e propusemos algumas reflexões sobre a relação entre a comunicação e a saúde...

Typical case of an emerging virus, Zika had circulated in a limited extent when it arrived in Brazil, where wouldbecome part of a public health emergency and a theme with very strong presence in the media in 2015. In thisarticle, based on a work prepared in the context of the Health in the Media Observatory, we draw a timelinethat seeks to outline the main points of attention on the Zika virus in Brazilian media in 2015, including mediacoverage and official announcements. This timeline was confronted with the analysis of covers from nine Braziliannewspapers, published in November and December 2015, when the Brazilian Ministry of Health admited apossible correlation between the Zika virus and the increase in microcephaly cases. We focus on references to fearand risk and propose some reflections on the relationship between communication and health...

Caso típico de un virus emergente, el Zika había circulado de forma limitada cuando llegó a Brasil, donde seconvertiría en parte de una emergencia de salud pública y un tema con presencia muy fuerte en los mediosde comunicación en 2015. En este artículo, basado en trabajo realizado en el marco del Observatorio de laSalud en los Medios de Comunicación, dibujamos una línea de tiempo que busca delinear los principalespuntos de atención sobre el virus Zika en medios brasileños en 2015, incluyendo la cobertura de los mediosde comunicación y los anuncios oficiales. Esta linea de tiempo fue confrontada con el análisis de lasportadas de nueve periódicos impresos en noviembre y diciembre de 2015, período en el cual el Ministeriode Salud de Brasil reconoció la posible correlación del virus con el aumento de los casos de microcefalia enel país. Enfocamos referencias a miedo y riesgoy y planteamos algunas reflexiones sobre la relación entrecomunicación y salud...

Plan de Contingencia de preparación y respuesta frente a la enfermedad por virus Zika del Hospital San Juan de Lurigancho / Contingency Plan for preparation and response to Zika virus disease at Hospital San Juan de Lurigancho

Ante el riesgo epidemiológico de Zika, la Unidad de Epidemiología y Salud Ambiental en forma conjunta con los demás unidades y servicios de salud del hospital San Juan de Lurigancho, ha elaborado el Plan de Contingencia de Preparación y Respuesta frente a la enfermedad por virus Zika - HSJL, 2016", el plan local, está fundamentado en las últimas recomendaciones de la Organización Panamericana de la Salud/Organización Mundial de la Salud (OPS/OMS) y MINSA/DGE, teniendo como finalidad reducir el impacto sanitario, social y económico ante la introducción del virus en el país

Deciphering emerging Zika and dengue viral epidemics: Implications for global maternal-child health burden

Since its discovery in 1947 in Uganda and control and eradication efforts have aimed at its vectors [Aedes mosquitoes] in Latin America in the 1950s, an absolute neglect of Zika programs and interventions has been documented in Aedes endemic and epidemic-prone countries. The current unprecedented Zika viral epidemics and rapid spread in the Western hemisphere pose a substantial global threat, with associated anxiety and consequences. The lack of safe and effective drugs and vaccines against Zika or dengue epidemics further buttresses the realization from the West Africa Ebola outbreak that most emerging disease-prone countries are still poorly prepared for an emergency response. This paper examines knowledge gaps in both emerging and neglected arthropod-borne flavivirus infectious diseases associated with poverty and their implications for fostering local, national and regional emerging disease preparedness, effective and robust surveillance-response systems, sustained control and eventual elimination. Strengthening the regional and Global Health Flavivirus Surveillance-Response Network [GHFV-SRN] with other models of socio-economic, climatic, environmental and ecological mitigation and adaptation strategies will be necessary to improve evidence-based national and global maternal-child health agenda and action plans

Emerging arboviruses and public health challenges in Brazil / Arboviroses emergentes e novos desafios para a saúde pública no Brasil

ABSTRACT Environmental modification by anthropogenic actions, disordered urban growth, globalization of international exchange and climate change are some factors that help the emergence and dissemination of human infectious diseases transmitted by vectors. This review discusses the recent entry of three arboviruses in Brazil: Chikungunya, West Nile, and Zika virus, focusing on the challenges for the Country's public health. The Brazilian population is exposed to infections caused by these three arboviruses widely distributed on the national territory and associated with humans. Without effective vaccine and specific treatment, the maintainance and integration of a continuos entomological and epidemiological surveillance are important so we can set methods to control and prevent these arboviruses in the Country.

RESUMO A modificação do ambiente por ações antrópicas, o crescimento urbano desordenado, o processo de globalização do intercâmbio internacional e as mudanças climáticas são alguns fatores que vêm facilitando a emergência e disseminação de doenças infecciosas humanas transmitidas por vetores. Este comentário aborda a recente entrada de três arbovírus no Brasil, Chikungunya (CHIKV), West Nile (WNV) e Zika (ZIKV), com enfoque nos desafios para a Saúde Pública do País. Transmitidos por mosquitos vetores amplamente distribuídos no território nacional e associados ao homem, a população brasileira encontra-se exposta à infecção por esses três arbovírus. Na ausência de vacina eficaz e tratamento específico, são importantes a manutenção e integração de uma vigilância entomológica e epidemiológica contínua, a fim de direcionarmos métodos de controle e prevenção contra essas arboviroses no País.

Plan nacional de preparación y respuesta frente a la enfermedad por el virus Zika / national plan for preparedness and response to the disease by Zika virus

El documento es una herramienta que forma parte de la preparación de la respuesta frente al riesgo inminente de introducción de la enfermedad del virus Zika en nuestro país y que sirve de referencia para la elaboración de los planes regionales de prevención que realizarán las demás instancias del sector salud público y privado, así como otros prestadores que brinden atenciones de salud en todo el país. Este plan establece las líneas de acción en todos los componentes que tienen competencia en la prevención, vigilancia y control de la enfermedad por virus Zika y de otras arbovirosis

Protocolo de vigilância e resposta à ocorrência de microcefalia relacionada à infecção pelo vírus zika / Protocol for surveillance and response to the occurrence of microcephaly related to zika virus infection / Protocolo de vigilancia y respuesta a la ocurrencia de casos de microcefalia relacionada con la infección por el virus zika

Este protocolo tem como objetivo prover a profissionais de saúde e áreas técnicas de vigilância em saúde informações gerais,orientações técnicas e diretrizes relacionadas às ações de vigilância das microcefalias em todo território nacional. Deve ser ressaltado que as informações e recomendações aqui presentes e agora divulgadas foram fundamentadas e estabelecidas a partir das discussões conduzidas entre áreas técnicas do Ministério da Saúde do Brasil e especialistas de diversas áreas da medicina, epidemiologia, estatística, geografia e laboratório,além de representantes das Secretarias de Saúde de Estados e Municípios afetados. O Sistema Único de Saúde (SUS) concluiu a primeira etapa para elucidação desse evento, com investigações realizadas desde outubro,quando o Ministério da Saúde recebeu as primeiras notificações da Secretaria de Saúde do Estado de Pernambuco,até 28 de novembro de 2015, quando o Ministério da Saúde reconheceu a relação entre a presença do vírus e a ocorrência de microcefalias e óbitos...

Protocolo de vigilância e resposta à ocorrência de microcefalia relacionada à infecção pelo vírus Zika / Surveillance protocol and response to the occurrence of microcephaly related to infection by viruses zika

Este protocolo tem como objetivo prover a profissionais de saúde e áreas técnicas de vigilância em saúde informações gerais, orientações técnicas e diretrizes relacionadas às ações de vigilância das microcefalias em todo território nacional. Deve ser ressaltado que as informações e recomendações aqui presentes e agora divulgadas foram fundamentadas e estabelecidas a partir das discussões conduzidas entre áreas técnicas do Ministério da Saúde do Brasil e especialistas de diversas áreas da medicina, epidemiologia, estatística, geografia e laboratório, além de representantes das Secretarias de Saúde de Estados e Municípios afetados. O Sistema Único de Saúde (SUS) concluiu a primeira etapa para elucidação desse evento, com investigações realizadas desde outubro, quando o Ministério da Saúde recebeu as primeiras notificações da Secretaria de Saúde do Estado de Pernambuco, até 28 de novembro de 2015, quando o Ministério da Saúde reconheceu a relação entre a presença do vírus e a ocorrência de microcefalias e óbitos. Esse reconhecimento é inédito na literatura nacional e internacional e só foi possível pelo empenho de médicos, pesquisadores e instituições de todo o Brasil que se uniram em prol de um objetivo comum que é a elucidação da causa da ocorrência dessas microcefalias. Até o momento, foram consolidadas algumas importantes evidências que sustentam a decisão do Ministério da Saúde no reconhecimento desta relação, como: Constatação de que os padrões de distribuição dos casos suspeitos de microcefalia pós-infecciosa apresentam características de dispersão e não indicam concentração espacial; Constatação de que os primeiros meses de gestação...

A Saint Louis encephalitis and Rocio virus serosurvey in Brazilian horses

Introduction Arboviruses are an important public health problem in Brazil, in especially flaviviruses, including the Saint Louis encephalitis virus (SLEV) and the Rocio virus (ROCV), are especially problematic. These viruses are transmitted to humans or other vertebrates through arthropod bites and may cause diseases with clinical manifestations that range from asymptomatic infection, viral hemorrhagic fever to encephalitis. Methods A serological survey of horses from various regions of Brazil using an enzyme-linked immunosorbent assay (ELISA) with recombinant SLEV domain III peptides and ROCV E protein as antigens. Results Overall, 415 (55.1%) of the 753 horses that were screened were seropositive for flavivirus and, among them, monotypic reactions were observed to SLEV in 93 (12.3%) and to ROCV in 46 (6.1%). These results suggested that these viruses, or other closely related viruses, are infecting horses in Brazil. However, none of the studied horses presented central nervous system infection symptoms. Conclusions Our results suggest that SLEV and ROCV previously circulated among horses in northeast, west-central and southeast Brazil. .

Value of CODEHOP RT-pCR in detection of Flavivirus / 病毒学报

This study aims to analyse the value of CODEHOP RT-PCR in the detection of Flavivirus. According to the amino acid sequences of polyproteins of different flaviviruses published in GenBank, a pair of primers was designed using the CODEHOP method. One-step RT-PCR was used to detect Japanese encephalitis virus strain JEV1201, Dengue virus strain JKD001, and yellow fever virus vaccine YV6161. BLAST analysis and phylogenetic analysis were performed after the RT-PCR products of nucleocapsid genes were sequenced. The results showed that this method could amplify Flavivirus specifically, and the size and sequence of the target fragment accorded with the anticipated result. JEV1201 had the highest homology to Japanese encephalitis virus strain YL2009-4/YC2009-3, belonging to the branch of the phylogenetic tree of Japanese encephalitis virus strains. JKD001 had the highest homology to Dengue virus strain DENV-2/ID/1022DN/1975, belonging to the branch of the phylogenetic tree of Dengue virus strains. YV6161 had the highest homology to Yellow fever virus strain 17D, belonging to the branch of the phylogenetic tree of Yellow fever virus strains. In conclusion, the method of CODEHOP RT-PCR can be effectively used to detect, identify, and phylogenetically analyse Flavivirus.

Persistence of experimental Rocio virus infection in the golden hamster (Mesocricetus auratus)

Rocio virus (ROCV) is an encephalitic flavivirus endemic to Brazil. Experimental flavivirus infections have previously demonstrated a persistent infection and, in this study, we investigated the persistence of ROCV infection in golden hamsters (Mesocricetus auratus). The hamsters were infected intraperitoneally with 9.8 LD50/0.02 mL of ROCV and later anaesthetised and sacrificed at various time points over a 120-day period to collect of blood, urine and organ samples. The viral titres were quantified by real-time-polymerase chain reaction (qRT-PCR). The specimens were used to infect Vero cells and ROCV antigens in the cells were detected by immunefluorescence assay. The levels of antibodies were determined by the haemagglutination inhibition technique. A histopathological examination was performed on the tissues by staining with haematoxylin-eosin and detecting viral antigens by immunohistochemistry (IHC). ROCV induced a strong immune response and was pathogenic in hamsters through neuroinvasion. ROCV was recovered from Vero cells exposed to samples from the viscera, brain, blood, serum and urine and was detected by qRT-PCR in the brain, liver and blood for three months after infection. ROCV induced histopathological changes and the expression of viral antigens, which were detected by IHC in the liver, kidney, lung and brain up to four months after infection. These findings show that ROCV is pathogenic to golden hamsters and has the capacity to cause persistent infection in animals after intraperitoneal infection.

Potential Therapeutics Against Flaviviruses

Flaviviruses have been important human pathogens after emerging and resurging flavivirus diseases over the past decades. Although effective therapeutic agents are not yet commercially available for use in humans, significant progress has been made toward developing effective therapeutics and treatments. Several studies have shown that antibodies against the flaviviral E and NS1 proteins play a central role in prophylaxis and/or treatment of flavivirus infection through passive immunization. In addition, many anti-flavivirals, including interferons, oligonucleotide-based platforms, and small compounds, have been developed and evaluated for their antiviral effects. This review provides an overview of various approaches to the development of anti-flaviviral candidates and new insights that could improve our strategies for designing effective therapeutics against flaviviruses.