Zika virus serological diagnosis: commercial tests and monoclonal antibodies as tools

Zika virus (ZIKV), an emerging arthropod-borne virus (arbovirus) of the Flaviviridae family, is a current issue worldwide, particularly because of the congenital and neurological syndromes associated with infection by this virus. As the initial clinical symptoms of all diseases caused by this group are very similar, clinical diagnosis is difficult. Furthermore, laboratory diagnostic efforts have failed to identify specific and accurate tests for each virus of the Flaviviridae family due to the cross-reactivity of these viruses in serum samples. This situation has resulted in underreporting of the diseases caused by flaviviruses. However, many companies developed commercial diagnostic tests after the recent ZIKV outbreak. Moreover, health regulatory agencies have approved different commercial tests to extend the monitoring of ZIKV infections. Considering that a specific and sensitive diagnostic method for estimating risk and evaluating ZIKV propagation is still needed, this review aims to provide an update of the main commercially approved serological diagnostics test by the US Food and Drug Administration (FDA) and Brazilian National Health Surveillance Agency (ANVISA). Additionally, we present the technologies used for monoclonal antibody production as a tool for the development of diagnostic tests and applications of these antibodies in detecting ZIKV infections worldwide.(AU)

Insect microbiomes and insect- specific viruses a new key for understanding the arboviruses diseases? / ¿Los microbiomas de insectos y los virus específicos de insectos son una nueva clave para entender las enfermedades de los arbovirus?

Abstract The last past two decades, there has been a tremendous expansion in the discovery and description of novel insect- specific viruses (ISVs). This has corresponded with progresses in metagenomic analyses for virus revealing and the increasing attention in insect microbiomes. Plentiful of the new ISVs seem to be members of the family Flaviviridae, genus Flavivirus, and are usual in insect populations in wildlife, with a global geographic circulation.

Pegivirus humano: potencial patogénico y riesgo de desarrollo de linfoma no Hodgkin / Human Pegivirus: pathogenic potential and non-Hodgkin lymphoma development risk

Resumen El pegivirus humano (HPgV) es un virus ARN que fue identificado en el año 1995. Actualmente se encuentra clasificado dentro de la familia Flaviviridae, género Pegivirus, relacionado filogenéticamente con el virus de la hepatitis C (VHC). El HPgV es un virus linfotrópico, con replicación en médula ósea, tejidos linfoides, y en células mononucleares de sangre periférica. Este virus se transmite por vía parenteral y sexual. Según estimaciones realizadas, en el mundo existen alrededor de 750 millones de personas infectadas por este agente. Se ha evidenciado que hasta en 25% de los casos se presenta una infección persistente, y aunque se considera que el HPgV es un virus no patogénico, existen evidencias epidemiológicas que sugieren una relación con el desarrollo de desórdenes linfoproliferativos, particularmente linfoma no Hodgkin (LNH). Algunos estudios han reportado una alta prevalencia de HPgV en pacientes con LNH comparado con donantes de sangre y/o pacientes con enfermedades hematológicas no malignas, lo que se asocia a un incremento en el riesgo relativo para el desarrollo de LNH en personas infectadas. De otra parte, existen estudios epidemiológicos que contradicen esta asociación, por lo que el rol de HPgV en la aparición de desórdenes lifoproliferativos es un tema actual de debate. En el presente manuscrito se discute el potencial patogénico derivado de los mecanismos de infección persistente del HPgV, así como las principales evidencias sobre la relación entre el HPgV y el riesgo de desarrollo de LNH.

The human pegivirus (HPgV), classified in the Flaviviridae family - Pegivirus genus, is an RNA virus identified in 1995. HPgV is a lymphotrophic virus, with replication sites in bone marrow and lymphoid tissue, as well as in peripheral blood mononuclear cells (PBMCs). Transmission is through sexual and parenteral routes, and recent estimations suggest nearly 750 million people are infected with HPgV worldwide. Almost 25% of infected individuals can develop persistent infection. Until now, HPgV has been considered a non-pathogenic virus; however, epidemiological studies suggest a potential role in lymphoproliferative diseases, particularly in the development of non-Hodgkin lymphoma (NHL). The evidence of this is controversial and the role of HPgV in lymphomagenesis has not yet been demonstrated. Several studies report a high prevalence of HPgV infection in patients with NHL compared to controls and patients with other hematological diseases. Therefore, analytic studies show that HPgV could be related to an increased risk of NHL development. Conversely, other studies indicate no association between HPgV and NHL, so the role of HPgV in lymphomagenesis is not clear. This review summarizes the main findings related to HPgV's pathogenic potential and association with NHL.

El virus de nilo occidental y sus vectores: reseña histórica, biología y ecología de aedes albopictus, culex pipiens y cx. quinquefasciatus / Western Nile virus and its vectors: a historic review, biology and ecology of Aedes albopictus, Culex pipiens and Cx. Quinquefasciatus

Resumen Este trabajo obedece a la primera iniciativa para compilar el conocimiento de los mosquitos vectores del Virus del Nilo Occidental en Costa Rica, como parte del primer Congreso para el estudio de la epidemiología de este arbovirus. Se incluye la revisión de las bases de datos de mayor prestigio y mayor cantidad de artículos para completar la información referente a lo que se ha informado acerca de las especies de mosquitos en Costa Rica, acerca de los cuales la información es fragmentaria y de difícil acceso en muchos casos. Se recomienda incentivar la investigación en este importante grupo de insectos, además de la necesidad de estudios de la ecología de estas especies en nuestro país. Se incluye una clave para los principales géneros de mosquitos hallados en Costa Rica en los cuales hay especies informadas como posibles vectores en otras latitudes. Se hace una sinopsis de la necesidad de incluir factores psicosociales en el diseño de las campañas educativas.

Abstract This work is the first initiative to compile the knowledge of mosquito vectors of West Nile Virus in Costa Rica, as part of the first Congress to study the epidemiology of this arbovirus. It includes a review of the most prestigious databases and a greater number of articles to complete the information regarding what has been reported about mosquito species in Costa Rica, about which the information is fragmentary and difficult to access in many cases. It is recommended to encourage research in this important group of insects, in addition to the need for studies of the ecology of these species in our country. A key is included for the main genera of mosquitoes found in Costa Rica in which there are species reported as possible vectors in other latitudes. A synopsis is made of the need to include psychosocial factors in the design of educational campaigns.

Understanding the Pathogenesis of Zika Virus Infection Using Animal Models

Zika virus (ZIKV) is a member of Flaviviridae family that has emerged as a pathogen of significant public health importance. The rapid expansion of ZIKV in the South and Central America has recently gained medical attention emphasizing the capacity of ZIKV to spread to non-endemic regions. ZIKV infection during pregnancy has been demonstrated to cause microcephaly and other fetal developmental abnormalities. An increased incidence of Guillain-Barre syndrome, an immune mediated neuropathy of the peripheral nervous system, has also been reported in ZIKV-infected patients in French Polynesia and Brazil. No effective therapies currently exist for treating patients infected with ZIKV. Despite the relatively short time interval, an intensive effort by the global scientific community has resulted in development of animal models to study multiple aspects of ZIKV biology. Several animal models have been established to investigate pathogenesis of ZIKV in adults, pregnant mothers, and developing fetuses. Here we review the remarkable progress of newly developed small and large animal models for understanding ZIKV pathogenesis.

Incidence of dengue virus infections in febrile episodes in Ile-Ife, Nigeria

Background: Dengue viruses have been identified as the most important arboviral pathogen in the world. They are transmitted by mosquitoes of Aedes species. While dengue infection is accompanied by little or no subclinical signs in many; about 1-2% may produce clinically severe Dengue Haemorrhagic Fever/Dengue Shock Syndrome. Early recognition; appropriate treatment and elimination of mosquito vectors will help control it. The study is aimed at determining the incidence of dengue infections in Ile-Ife. Materials and Methods: Three millilitres venous blood was collected from each of one hundred and seventy nine patients presenting with fever in the last two weeks; and analyzed for the presence of anti-dengue IgM antibodies using Dengue Virus IgM ELISA kit (DIA.PRO; Italy) according to the manufacturer's instructions while the results and demographic data were analyzed using SPSS version 16. Results: It was observed that 46 (25.7%) of the 179 had detectable IgM antibodies to dengue virus with 9 of them having no detectable malaria parasite. The incidence was 26.5% and 25% in male and female respectively. Further studies will be necessary to confirm the relatedness of blood transfusion as an important risk factor to the transmission of dengue virus.Conclusion: The study established the presence of fresh dengue infections for the first time in Ile-Ife among different groups of people. Clinicians are advised to prioritize laboratory diagnosis; especially of fever

Virtual Screening for Potential Inhibitors of NS3 Protein of Zika Virus

Zika virus (ZIKV) is a mosquito borne pathogen, belongs to Flaviviridae family having a positive-sense single-stranded RNA genome, currently known for causing large epidemics in Brazil. Its infection can cause microcephaly, a serious birth defect during pregnancy. The recent outbreak of ZIKV in February 2016 in Brazil realized it as a major health risk, demands an enhanced surveillance and a need to develop novel drugs against ZIKV. Amodiaquine, prochlorperazine, quinacrine, and berberine are few promising drugs approved by Food and Drug Administration against dengue virus which also belong to Flaviviridae family. In this study, we performed molecular docking analysis of these drugs against nonstructural 3 (NS3) protein of ZIKV. The protease activity of NS3 is necessary for viral replication and its prohibition could be considered as a strategy for treatment of ZIKV infection. Amongst these four drugs, berberine has shown highest binding affinity of –5.8 kcal/mol and it is binding around the active site region of the receptor. Based on the properties of berberine, more similar compounds were retrieved from ZINC database and a structure-based virtual screening was carried out by AutoDock Vina in PyRx 0.8. Best 10 novel drug-like compounds were identified and amongst them ZINC53047591 (2-(benzylsulfanyl)-3-cyclohexyl-3H-spiro[benzo[h]quinazoline-5,1'-cyclopentan]-4(6H)-one) was found to interact with NS3 protein with binding energy of –7.1 kcal/mol and formed H-bonds with Ser135 and Asn152 amino acid residues. Observations made in this study may extend an assuring platform for developing anti-viral competitive inhibitors against ZIKV infection.

Hepatitis C Viral Infection in Children: Updated Review / 대한소아소화기영양학회지

Hepatitis C virus (HCV) infection is a major medical challenge affecting around 200 million people worldwide. The main site of HCV replication is the hepatocytes of the liver. HCV is a positive enveloped RNA virus from the flaviviridae family. Six major HCV genotypes are implicated in the human infection. In developed countries the children are infected mainly through vertical transmission during deliveries, while in developing countries it is still due to horizontal transmission from adults. Minimal nonspecific and brief symptoms are initially found in approximately 15% of children. Acute and chronic HCV infection is diagnosed through the recognition of HCV RNA. The main objective for treatment of chronic HCV is to convert detected HCV viremia to below the detection limit. Children with chronic HCV infection are usually asymptomatic and rarely develop severe liver damage. Therefore, the benefits from current therapies, pegylated-Interferon plus ribavirin, must be weighed against their adverse effects. This combined treatment offers a 50-90% chance of clearing HCV infection according to several studies and on different HCV genotype. Recent direct acting antiviral (DAA) drugs which are well established for adults have not yet been approved for children and young adults below 18 years. The most important field for the prevention of HCV infection in children would be the prevention of perinatal and parenteral transmission. There are areas of focus for new lines of research in pediatric HCV-related disease that can be addressed in the near future.

Avaliação da Atividade Antiviral de Extratos Vegetais e de Fungos contra Dengue Virus

Produtos naturais são potenciais fontes alternativas para o desenvolvimento de antivirais para o tratamento da dengue, assim como de outras doenças causadas por vírus da família Flaviviridae ou mesmo para um amplo espectro de viroses. Neste estudo foi feita a triagem da atividade in vitro contra o Dengue virus 2 (DENV-2) de 3101 extratos, provenientes de plantas e de fungos da Coleção de Amostras para Bioensaios da Fiocruz. Para tal, células BHK-21 foram infectadas com DENV-2 e tratadas simultaneamente com 25 μg/mL de extrato sendo o resultado analisado por dois métodos: observação do grau de inibição do efeito citopático (ECP) por microscopia óptica e análise da viabilidade celular pelo ensaio colorimétrico do MTT. Dentre os 3101 extratos testados, 115 extratos apresentaram atividade antiviral contra DENV-2 e foram selecionados para a determinação da respectiva concentração efetiva 50 (CE50).

Cinquenta e cinco destes extratos foram obtidos de plantas pertencentes a 20 famílias distintas: Amaryllidaceae (3), Annonaceae (1), Asteraceae (5), Begoniaceae (1), Clusiaceae (1), Combretaceae (1), Erythroxylaceae (1), Fabaceae (4), Lythraceae (2), Malpighiaceae (8), Malvaceae(1), Melastomataceae (2), Melochia (1), Myrtaceae (3), Rubiaceae (8), Sapindaceae(9), Ochnaceae (1), Primulaceae (1) Vitaceae (1), Vochysiaceae (1). Os demais extratos (60) foram obtidos de culturas de fungos endofíticos coletados no Brasil, no continente Antártico e no Deserto do Atacama, ainda não identificados. Até o momento, os extratos vegetais mais promissores foram obtidos de plantas da família Amaryllidaceae (IS = 32,15) e da família Fabaceae (IS = 20,47) e (IS = 24,47). Vinte extratos fúngicos apresentaram valores de CE50 que variaram entre 3,1 a 12,5 μg/mL e sem citotoxicidade aparente até a concentração de 100 μg/mL. Nossos resultados mostram que tais plantas e fungos são fontes promissoras de substâncias com ação antiviral contra DENV.

Zoonotic encephalitides caused by arboviruses: transmission and epidemiology of alphaviruses and flaviviruses

In this review, we mainly focus on zoonotic encephalitides caused by arthropod-borne viruses (arboviruses) of the families Flaviviridae (genus Flavivirus) and Togaviridae (genus Alphavirus) that are important in both humans and domestic animals. Specifically, we will focus on alphaviruses (Eastern equine encephalitis virus, Western equine encephalitis virus, Venezuelan equine encephalitis virus) and flaviviruses (Japanese encephalitis virus and West Nile virus). Most of these viruses were originally found in tropical regions such as Africa and South America or in some regions in Asia. However, they have dispersed widely and currently cause diseases around the world. Global warming, increasing urbanization and population size in tropical regions, faster transportation and rapid spread of arthropod vectors contribute in continuous spreading of arboviruses into new geographic areas causing reemerging or resurging diseases. Most of the reemerging arboviruses also have emerged as zoonotic disease agents and created major public health issues and disease epidemics.

Los cambios histopatológicos del hígado durante dengue severo: [Editorial] / Histopathological changes in the liver during severe dengue: [Editorial]

El dengue es una enfermedad producida por el virus dengue perteneciente a la familia Flaviviridae , género Flavivirus y que es transmitido a los humanos por el vector Aedes , principalmente Aedes aegypti y Aedes albopictus . A la fecha se reconocen cuatro serotipos del virus, aunque recientemente el Doctor Nikos Vasilakis, virólogo de la Universidad de Texas durante la Tercera Conferencia internacional de Dengue y Dengue Hemorrágico, reportó el que podría ser el quinto serotipo (http://www.dengue2013bangkok.com/home/index/en). Esta sería la primera descripción de un nuevo serotipo para este virus en los últimos 50 años, lo que viene a opacar el panorama del desarrollo de una posible vacuna para esta infección, cada vez más prevalente en el mundo, particularmente en las regiones tropicales y subtropicales del planeta.

Dengue is a disease caused by the dengue virus belonging to the Flaviviridae family, genus Flavivirus, which is transmitted to humans by the Aedes vector, mainly Aedes aegypti and Aedes albopictus. To date, four serotypes of the virus are recognised, although recently Dr. Nikos Vasilakis, a virologist at the University of Texas during the Third International Conference on Dengue and Dengue Haemorrhagic Fever, reported what could be the fifth serotype (http://www.dengue2013bangkok.com/home/index/en). This would be the first description of a new serotype for this virus in the last 50 years, which would overshadow the outlook for the development of a possible vaccine for this increasingly prevalent infection worldwide, particularly in tropical and subtropical regions of the world.

Meningitis Associated Dengue Fever Imported from Vietnam

Dengue fever is an acute febrile disease caused by the dengue virus, which belongs to the family Flaviviridae. The increasing number of people traveling abroad has increased the number of cases of imported dengue fever in Korea. The most common symptoms in patients with dengue fever are malaise, fever, musculoskeletal pain, headache, nausea, vomiting, and abdominal pain. Neurological manifestations such as myelitis, encephalitis, and cranial nerve palsies have been recognized as clinical consequences of dengue infection, but meningitis is a rare complication. We report the case of a 38-year-old man who presented with fever, headache, and nuchal rigidity while traveling in Vietnam. The etiology of meningitis was confirmed by the presence of dengue IgM antibody in his serum. This case report highlights the potential of dengue infection as a cause of meningitis.

Distinct Humoral and Cellular Immunity Induced by Alternating Prime-boost Vaccination Using Plasmid DNA and Live Viral Vector Vaccines Expressing the E Protein of Dengue Virus Type 2

BACKGROUND: Dengue virus, which belongs to the Flavivirus genus of the Flaviviridae family, causes fatal dengue hemorrhagic fever (DHF) and dengue shock syndrome (DSS) with infection risk of 2.5 billion people worldwide. However, approved vaccines are still not available. Here, we explored the immune responses induced by alternating prime-boost vaccination using DNA vaccine, adenovirus, and vaccinia virus expressing E protein of dengue virus type 2 (DenV2). METHODS: Following immunization with DNA vaccine (pDE), adenovirus (rAd-E), and/or vaccinia virus (VV-E) expressing E protein, E protein-specific IgG and its isotypes were determined by conventional ELISA. Intracellular CD154 and cytokine staining was used for enumerating CD4+ T cells specific for E protein. E protein-specific CD8+ T cell responses were evaluated by in vivo CTL killing activity and intracellular IFN-gamma staining. RESULTS: Among three constructs, VV-E induced the most potent IgG responses, Th1-type cytokine production by stimulated CD4+ T cells, and the CD8+ T cell response. Furthermore, when the three constructs were used for alternating prime-boost vaccination, the results revealed a different pattern of CD4+ and CD8+ T cell responses. i) Priming with VV-E induced higher E-specific IgG level but it was decreased rapidly. ii) Strong CD8+ T cell responses specific for E protein were induced when VV-E was used for the priming step, and such CD8+ T cell responses were significantly boosted with pDE. iii) Priming with rAd-E induced stronger CD4+ T cell responses which subsequently boosted with pDE to a greater extent than VV-E and rAd-E. CONCLUSION: These results indicate that priming with live viral vector vaccines could induce different patterns of E protein- specific CD4+ and CD8+ T cell responses which were significantly enhanced by booster vaccination with the DNA vaccine. Therefore, our observation will provide valuable information for the establishment of optimal prime-boost vaccination against DenV.

Distinct Humoral and Cellular Immunity Induced by Alternating Prime-boost Vaccination Using Plasmid DNA and Live Viral Vector Vaccines Expressing the E Protein of Dengue Virus Type 2

BACKGROUND: Dengue virus, which belongs to the Flavivirus genus of the Flaviviridae family, causes fatal dengue hemorrhagic fever (DHF) and dengue shock syndrome (DSS) with infection risk of 2.5 billion people worldwide. However, approved vaccines are still not available. Here, we explored the immune responses induced by alternating prime-boost vaccination using DNA vaccine, adenovirus, and vaccinia virus expressing E protein of dengue virus type 2 (DenV2). METHODS: Following immunization with DNA vaccine (pDE), adenovirus (rAd-E), and/or vaccinia virus (VV-E) expressing E protein, E protein-specific IgG and its isotypes were determined by conventional ELISA. Intracellular CD154 and cytokine staining was used for enumerating CD4+ T cells specific for E protein. E protein-specific CD8+ T cell responses were evaluated by in vivo CTL killing activity and intracellular IFN-gamma staining. RESULTS: Among three constructs, VV-E induced the most potent IgG responses, Th1-type cytokine production by stimulated CD4+ T cells, and the CD8+ T cell response. Furthermore, when the three constructs were used for alternating prime-boost vaccination, the results revealed a different pattern of CD4+ and CD8+ T cell responses. i) Priming with VV-E induced higher E-specific IgG level but it was decreased rapidly. ii) Strong CD8+ T cell responses specific for E protein were induced when VV-E was used for the priming step, and such CD8+ T cell responses were significantly boosted with pDE. iii) Priming with rAd-E induced stronger CD4+ T cell responses which subsequently boosted with pDE to a greater extent than VV-E and rAd-E. CONCLUSION: These results indicate that priming with live viral vector vaccines could induce different patterns of E protein- specific CD4+ and CD8+ T cell responses which were significantly enhanced by booster vaccination with the DNA vaccine. Therefore, our observation will provide valuable information for the establishment of optimal prime-boost vaccination against DenV.

Fatores prognósticos e associados à efetividade do tratamento da hepatite C crônica / Prognostic and associated factors to the effectiveness of chronic hepatitis C treatment

A hepatite C é uma doença recentemente reconhecida cujo tratamento é de eficácia aquém da desejável. O objetivo deste estudo é conhecer os fatores prognósticos de resposta virológica sustentada (RVS) e de efetividade do tratamento da hepatite C crônica e propor um modelo teórico que contenha as principais relações identificadas. A prevalência do HCV no Brasil é estimada entre 0,94% a1,89%, com tendência a aumentar. Há populações especificamente sob maior risco como detentos, usuários de drogas e renais crônicos em diálise. Devido ao seu caráter crônico e progressivo estima-se que as complicações relacionadas aumentem nas próximas décadas caso não haja tratamento efetivo. O tratamento é caro, com efeitos colaterais importantes e promove RVS apenas em uma parcelados indivíduos, mesmo sob condições ideais. São descritos como fatoresprognósticos para RVS: genótipo, carga viral pré-tratamento, cinética viral,transaminases, estágio de fibrose, sexo, idade, peso, raça, esteatose e aderência ao tratamento. Dispensado de acordo com critérios do Ministério da Saúde, otratamento utiliza interferon peguilado para o genótipo 1 e interferon convencional para os genótipos 2 e 3, associado à ribavirina. Associados a RVS, além do custo, outros fatores concorrem para a efetividade do tratamento: diagnóstico precoce doscasos, implementação de pólos de aplicação, qualidade e disponibilidade damedicação, critérios e interrupção precoce através da cinética viral, redução da necessidade de re-tratamento e de transplante hepático. Para aumentar a efetividade do tratamento concluímos ser necessário melhor rastreamento dos casosde infecção pelo VHC, disseminação de pólos de aplicação dos medicamentos eviabilizar exames para cinética viral.

Chronic C hepatitis is a recently recognized entity which treatment efficacy is not definitely established. The aim of this study is to know the prognostic factors for sustained virologic response and effectiveness of the treatment, as well as propose atheoretical model concerning its main issues. Brazilian prevalence of hepatitis C is around 0,94% to 1,89%, with an increasing tendency. Prisoners, drug addicts and patients in dialysis are at greater risk of infection. Related complications tend to increase in the next decades due to the chronic and progressive disease’s character.Only part of treated patients obtain virologic sustained response even in optimal conditions. VHC genotype, pretreatment viral load, viral kinetic, aminotransferases levels, fibrosis, gender, age, body weight, race, steatosis and treatment adherenceare prognostic factors associated with a sustained virologic response. According to the Brazilian control strategy peguilated interferon is used for treatment of genotype 1 and conventional interferon for genotypes 2 and 3. Other factors act along virologicsustained response for treatment effectiveness, such as related costs, early diagnosis, quality and availability of medication, “pólos de aplicação”, early stop criteria implementation, reduced number of retreatments and liver transplantations. In conclusion, to improve hepatitis C treatment effectiveness is necessary to optimizescreening programs, implement more “pólos de aplicação” and make viral kinetic viable.

Hantavirus y otros virus hemorrágicos / Hantavirus and other henorrhagic virus

Las fiebres hemorrágicas virales (FHV) han sido la causa de alias tasas de morbilidad y mortalidad alrededor del mundo. El termino fiebre hemorrágica viral (FHV) describe un síndrome caracterizado por la presencia de fiebre y hemorragias, causado por virus pertenecientes a distintas familias (Filoviridae, Arenaviridae, Bunyaviridae y Flaviviridae), y transmitidos al hombre por artrópodos (mosquitos y garrapatas), reservorios vertebrados, e incluso por transmisión directa. Los virus hemorrágicos causan una infección aguda con una sintomatología inespecífica, que se vuelve mas característica en las fases tardías de la enfermedad cuando se produce el fallo orgánico que puede conducir a la muerte. Dos grupos importantes de virus de ARN pertenecientes a la familia arenaviridae y Bunyaviridae (género Hantavirus) son la causa principal de las fiebres hemorrágicas transmitidas por roedores. El genero Hantavirus identificado como agente etiológico de la Fiebre Hemorrágica con Síndrome Renal en Asia y Europa, y del Síndrome Cardiopulmonar por Hantavirus en Las Américas, lo constituye un grupo de virus transmitidos por roedores. Los arenavirus son patógenos transmitidos por roedores identificados como una causa importante de fiebres hemorrágicas en África y Sur América, se agrupan en dos grandes complejos: Arenavirus del Viejo Mundo o complejo Linfocoriomeningitis, y Arenavirus del Nuevo Mundo o complejo Tacaribe, que comprende 3 grupos: A, B y C. Actualmente, el dengue causa más enfermedades y muertes que cualquier otro Arbovirus en seres humanos. Cada ano, un estimado de 100 millones de casos de fiebre por dengue y algunos cientos de miles de fiebre hemorrágica por dengue ocurren en todo el mundo. Hasta la fecha, cuatro serotipos virales de dengue han sido descritos: el DEN-1, DEN-2, DEN-3 y DEN-4. El virus de la fiebre amarilla es el prototipo de la familia Fiaviviridae, y fue la primera fiebre hemorrágica descrita. Es endémica y epidémica en 33 países del África Su.

Neutralizing Antibody Induction and Cytotoxic T Lymphocyte Response to Nakayama-NIH and Beijing-1 as Japanese Encephalitis Virus Vaccine Strains

The Japanese encephalitis virus (JEV), a member of the Flaviviridae family and Flavivirus genus, is transmitted by mosquitoes. JEV, of which some 35,000 cases are recorded every year, is a positive RNA virus. Two types of JEV vaccines have been developed to prevent the onset of encephalitis in humans, namely formalin-inactivated and liveattenuated vaccines. JEV inactivated vaccines are usually made using the Nakayama-NIH or Beijing-1 strains of the JEV virus. In this study, the immunological response to the Nakayama-NIH and Beijing-1 strains was analyzed as part of the effort to compile basic data which could lead to the selection of a suitable vaccine strain. To this end, the virus titer of Beijing-1 was found to be two-fold higher than that of Nakayama-NIH by plaque assay. Moreover, Beijing-1-induced neutralizing antibodies showed a higher level of titers when confronted by Korean JEV isolates than Nakayama-NIH-induced neutralizing antibodies (1:320 vs. 1:160, respectively). However, as a minimum ratio of 1:10 neutralizing antibody titers are required to protect against JEV infection, both strains in effect exhibited a sufficient level of neutralizing antibody titers. What's more, Beijing-1 was found to induce a somewhat higher cytotoxic T lymphocyte (CTL) response than Nakayama-NIH. Taken together, this can be taken to mean that Beijing-1 may in fact be a more effective vaccine candidate strain when it comes to inducing a high level of protective immunity against JEV infection.

Genetic variations and relationship among dengue virus type 3 strains isolated from patients with mild or severe form of dengue disease in Indonesia and Thailand.

Sequence analysis was conducted on structural and non-structural genes of 7 strains of dengue virus type-3 (DENV-3 virus) isolated in Indonesia and Thailand in the year 1973, 1994, and 1998 from patients with different clinical manifestations. In general, sequence similarity among isolates was greater than 93%, indicating that the mutation rate of DENV-3 circulating in this region was not more than 7% in the last 3 decades and suggesting that sequences that may responsible for viral architectures and/or biological function were strictly conserved. Mutations unique to viral strains associated with specific clinical manifestations were not found. Alignment of PrM/M and E nucleic acid sequences followed by parsimony analysis of sequences obtained in this study and published elsewhere allowed generation of phylogenetic trees, demonstrating that DENV-3 strains isolated in Indonesia in 1998 belonged to a separate cluster (subtype 2) from those isolated between 1973-1985 (subtype 1).

A influencia da infeccao pelo virus da hepatite G (HGV) na evolucao da doenca pelo HIV/AIDS / Influence of hepatitis G virus infection (HGV) on the evolution of HIV/AIDS disease

O virus da hepatite G (HGV) é um Flavivirus recem-identificado e cuja presenca e verificada em doadores de sangue e grupos especificos de pacientes em todo o mundo. Este virus e transmitido principalmente por contato sexual e tambem pela via parenteral, responsavel pelas altissimas prevalencias encontradas em usuarios de drogas endovenosas e pacientes politransfundidos. No entanto, ja esta demonstrado que o HGV e um virus linfotropico, nao sendo o hepatocito sua celula-alvo, e esta praticamente descartada sua associacao com hepatite. Mais recentemente, pesquisadores de diversos paises tem descrito um efeito benefico da presenca do RNA viral (HGV) no aumento da sobrevida de pacientes infectados pelo HIV. Os mecanismos pelos quais ocorre este efeito ainda nao esta esclarecidos. Entretanto, foi demonstrada a inibicao da expressao de receptores celulares para HIV na superficie dos linfocitos infectados pelo HGV, como a molecula CCR5, o que poderia impedir ou retardar a queda na contagem de celulas CD4, justificando o melhor prognostico

A Case of Dengue Fever / 대한피부과학회지

Dengue fever is caused by the dengue virus which belongs to the flaviviridae family and is transmitted by mosquitos. It occurs in the tropical climates of central and south america, asia, and africa and is considered one of the most important arthropod-borne viral diseases as regards morbidity and mortality, especially due to its hemorrhagic forms, dengue hemorrhagic fever and dengue shock syndrome. We report a case of dengue fever which presented with typical systemic symptoms and signs such as fever, headache, nausea and characteristic erythroderma (white islands in a sea of red) on travelling Bangladesh.