Molecular survey of flaviviruses and orthobunyaviruses in Amblyomma spp. ticks collected in Minas Gerais, Brazil / Investigação molecular de flavivírus e orthobunyaviruses em carrapatos do gênero Amblyomma spp. coletados em Minas Gerais, Brasil

Abstract Due to anthropic environmental changes, vector-borne diseases are emerging worldwide. Ticks are known vectors of several pathogens of concern among humans and animals. In recent decades, several examples of tick-borne emerging viral diseases have been reported (Crimean Congo hemorrhagic fever virus, Powassan virus, encephalitis virus, heartland virus, severe fever with thrombocytopenia syndrome virus). Unfortunately, few studies addressing the presence of viruses in wild ticks have been carried out in South America. With the aim of detecting flaviviruses and orthobunyaviruses in ticks, we carried out molecular detection in wild ticks collected in the state of Minas Gerais, Brazil. No Flavivirus-positive ticks were detected; however, we detected activity of Orthobunyavirus in 8 Amblyomma tick specimens. One of those individuals was positive for Bunyamwera orthobunyavirus, which represents the first report of this virus among ticks in South America. Further studies related to the ecology of zoonotic diseases are needed to increase knowledge of this topic, including attempts at viral isolation, full genome sequencing and biological characterization. In this way, we will obtain a better picture of the real risk of ticks as a vector for viral diseases for humans and animals on our continent, where no tick-borne viral disease is known to occur.

Resumo Alterações ambientais causadas pelo homem têm levado à emergência de doenças transmitidas por vetores no mundo. Carrapatos são vetores conhecidos de vários patógenos de importância médica e veterinária, tendo sido reportado nas últimas décadas um grande número de enfermidades virais emergentes transmitidas por eles (vírus da Febre Hemorrágica da Crimeia-Congo, vírus Powassan, vírus da Encefalite, vírus Heartland e vírus da Síndrome da Febre Trombocitopênica Severa). Infelizmente, poucos estudos envolvendo a pesquisa de vírus em carrapatos foram conduzidos na América do Sul até o momento, e nas últimas décadas um elevado número de enfermidades virais emergentes transmitidas por estes artrópodes foi relatado. Com o objetivo de investigar a presença de flavivírus e orthobunyavírus em carrapatos, foi conduzida uma análise molecular em espécimes coletados no estado de Minas Gerais, Brasil. Em nenhum carrapato foi detectada a presença de Flavivirus, no entanto, em 8 espécimes do gênero Amblyomma, foi detectada a presença de Orthobunyavirus, dos quais um espécime foi positivo para Bunyamwera orthobunyavirus. Novos estudos relacionados à ecologia de doenças zoonóticas, incluindo tentativas de isolamento viral, sequenciamento completo do genoma e caracterização biológica, são necessários. Desta forma, será possível ter uma base sobre os riscos da transmissão de vírus patogênicos por carrapatos em nosso continente, uma vez que até agora isso é desconhecido.

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)

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.

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.

Levantamento soroepidemiológico para arbovírus em macaco-prego-galego (Cebus flavius) de vida livre no estado da Paraíba e em macaco-prego (Cebus libidinosus) de cativeiro do nordeste do Brasil / Epidemiologic survey for arbovirus in galician capuchin monkeys (Cebus flavius) free living in Paraíba and captive capuchin monkey (Cebus libidinosus) from northeast Brazil

Este estudo descreve a primeira investigação de anticorpos para arbovírus em primatas não humanos do Novo Mundo no nordeste brasileiro. No período de março de 2008 a setembro de 2010 foram colhidos soros sanguíneos de 31 macacos-prego-galegos (Cebus flavius) de vida livre na Paraíba e de 100 macacos-prego (Cebus libidinosus) em cativeiro nos estados de Alagoas, Paraíba, Pernambuco, Piauí e Rio Grande do Norte. Para a pesquisa de anticorpos utilizou-se o teste de inibição da hemaglutinação (IH), usando antígenos de 19 diferentes tipos de arbovírus, pertencentes aos gêneros Flavivirus,Alphavirus e Bunyavirus. As amostras de soro foram testadas nas diluições de 1:20 a 1:1280. Dentre as amostras examinadas, todas as de C. flavius foram negativas e 46 por cento das de C. libidinosus em cativeiro apresentaram anticorpos para arbovírus. Foram detectados anticorpos para nove (9/19) arbovírus. Foram observadas 17 reações heterotípicas, para dois ou mais vírus, do gênero Flavivirus, e 15 para o gênero Alphavirus, com títulos variando de 1:20 a 1:1280. Quinze amostras apresentaram reação monotípica para ILHV (n=4), MAYV (n=6), SLEV (n=1), ROCV (n=2), OROV (n=1) e MUCV (n=1). Estes resultados sugerem que houve intensa circulação de arbovírus na população estudada de macacos-prego em cativeiro.

This paper describes the first investigation of arbovirus antibodies on New World non-human primates from Northeast Brazil. From March 2008 to September 2010 blood serum samples were collected from 31 wild blond capuchin monkeys (Cebus flavius) from Paraíba and 100 captive capuchin monkeys from Alagoas, Paraíba, Pernambuco, Piauí and Rio Grande do Norte. The haemagglutination-inhibition test (HI) was employed for 19 arbovirus of the Flavivirus,Alphavirus and Bunyavirus genus. Serum samples were tested from 1:20 to 1:1280 dilutions. Among the primates tested all C. flavius were negative and 46 percent C. libidinosus presented antibodies to arbovirus. Antibodies were detected for nine arbovirus (9/19). Seventeen heterotypic reactions were observed for at least two Or Flavirus and 15 for Alphavirus, at titers varying between 1:20 to 1:1280. Fifteen samples presented monotypic reaction for ILHV (n=4), MAYV (n=6), SLEV (n=1), ROCV (n=2), OROV (n=1) and MUCV (n=1). These results suggest that there was an intense arbovirus circulation in the studied population of captive capuchin monkeys.

Characterisation of divergent flavivirus NS3 and NS5 protein sequences detected in Rhipicephalus microplus ticks from Brazil

Transcripts similar to those that encode the nonstructural (NS) proteins NS3 and NS5 from flaviviruses were found in a salivary gland (SG) complementary DNA (cDNA) library from the cattle tick Rhipicephalus microplus. Tick extracts were cultured with cells to enable the isolation of viruses capable of replicating in cultured invertebrate and vertebrate cells. Deep sequencing of the viral RNA isolated from culture supernatants provided the complete coding sequences for the NS3 and NS5 proteins and their molecular characterisation confirmed similarity with the NS3 and NS5 sequences from other flaviviruses. Despite this similarity, phylogenetic analyses revealed that this potentially novel virus may be a highly divergent member of the genus Flavivirus. Interestingly, we detected the divergent NS3 and NS5 sequences in ticks collected from several dairy farms widely distributed throughout three regions of Brazil. This is the first report of flavivirus-like transcripts in R. microplus ticks. This novel virus is a potential arbovirus because it replicated in arthropod and mammalian cells; furthermore, it was detected in a cDNA library from tick SGs and therefore may be present in tick saliva. It is important to determine whether and by what means this potential virus is transmissible and to monitor the virus as a potential emerging tick-borne zoonotic pathogen.

Ecological aspects of mosquitoes (Diptera: Culicidae) in the gallery forest of Brasilia National Park, Brazil, with an emphasis on potential vectors of yellow fever

Introduction We analyzed the vertical and monthly distributions of culicid species in the gallery forest of Brasília National Park, with an emphasis on the potential vectors of yellow fever (YF). Methods Between September 2010 and August 2011, mosquitoes were captured on the ground and in the canopy of the forest for five consecutive days per month, from nine to 15 hours. The mosquitoes were examined to verify natural infection with flaviviruses by isolation in Aedes albopictus Skuse, 1864 cells followed by indirect immunofluorescence. Results We identified 2,677 culicids distributed in 29 species. Most of the mosquitoes were captured at ground level (69%) during the rainy season (86%). The most abundant species were Sabethes (Sabethes) albiprivus Theobald, 1903; Limatus durhamii Theobald, 1901; Haemagogus (Conopostegus) leucocelaenus Dyar & Shannon, 1924; Haemagogus (Haemagogus) janthinomys Dyar, 1921; Aedes (Ochlerotatus) scapularis Rondani, 1848; Psorophora (Janthinosoma) ferox Von Humboldt, 1819; and Aedes (Ochlerotatus) serratus Theobald, 1901. Limatus durhamii, Limatus durhamii, Psorophora ferox, Aedes scapularis and Aedes serratus showed significant differences (p<0.05) in their habitat use. Limatus durhamii was found more often in the canopy, unlike the other species. During the rainy season, the most abundant species were Sa. albiprivus, Haemagogus leucocelaenus and Limatus durhamii. During the dry season, the potential YF vectors exhibited a very low frequency and abundance, except Aedes scapularis and Aedes serratus. No flavivirus was detected in the 2,677 examined mosquitoes. Conclusions We recommend continued and systematic entomological monitoring in areas vulnerable to the transmission of YF in the Federal District of Brazil. .

Notification of the first isolation of Cacipacore virus in a human in the State of Rondônia, Brazil / Notificação do primeiro isolamento do vírus Cacipacoré em um ser humano, no Estado de Rondônia, Brasil

Flavivirus is a genus of arthropod-transmitted viruses of the family Flaviviridae, and in Brazil, up to eleven different Flavivirus have been isolated. We collected blood from farmers in the municipality of Theobroma, which is located 320km from the City of Porto Velho, the former capital of the Brazilian State of Rondônia. For viral isolation, we used newborn mouse brain, followed by RT-PCR with specific universal Flavivirus primers. We obtained fragments 958bp and 800bp in length. Based on BLAST, these sequences were 91% similar to a sequence of Cacipacore virus.

Flavivirus é um gênero dos vírus transmitidos por artrópode da família Flaviviridae e, no Brasil, são isolados onze Flavivirus diferentes. Foi coletado o sangue de um agricultor, no município de Theobroma situado a 320km de distância da Cidade de Porto Velho, capital do Estado Brasileiro, Rondônia. Para isolamento viral, foi usado cérebro de camundongos recém-nascido, seguido por RT-PCR com primers universais específicos de Flavivirus. Nós obtivemos fragmentos com 958bp e 800bp de comprimento. Ao Blast das sequências obtivemos 91% de similaridade com uma sequência do vírus de Cacipacoré.

Genes de susceptibilidad/resistencia a Flavivirus, implicaciones en la severidad de la infeccion / Susceptibility/Resistance Genes to Flavivirus, Implications on Disease Severity

Las infecciones transmitidas por Flavivirus se encuentran entre las enfermedades transmisibles con mayor incidencia en el mundo. La mayoría de ellas se manifiestan clínicamente como un síndrome febril que puede estar o no acompañado de diversos síntomas. La severidad de estas infecciones es variable con casos asintomáticos y otros que pueden llegar a ser letales. La razón de esta variabilidad en la presentación clínica, se desconoce en humanos. En ratones se han identificado cepas susceptibles y cepas resistentes a la infección por algunos Flavivirus. Por clonación posicional se mapeó el gen responsable de la resistencia a virus West Nile en el cromosoma 5 de ratón y se identificó como oligoadenilato sintetasa 1b (Oas1b). Este gen codifica una proteína que sintetiza oligómeros de adenina que activan la RNasaL, que a su vez degrada los RNAs virales. Células provenientes de ratones resistentes a la infección por Flavivirus producen menor cantidad de virus que su contraparte susceptible. Recientemente en humanos, se identificó un polimorfismo asociado con susceptibilidad a infección por virus West Nile en el gen de OasL. Sin embargo, el mecanismo bioquímico y molecular exacto por el cual se produce la susceptibilidad no ha sido completamente dilucidado. Este conocimiento permitiría aclarar aspectos de la fisiopatología de estas enfermedades y enfocar la terapéutica desde un punto de vista más específico.

Respuestas serologicas secundarias en la epidemia de dengue de 1998 em Salta, Argentina, donde co-circulan otros flavivirus / Secondary serologic responses to dengue epidemic in 1998 in Salta, Argentina, where other flavivirus co-circulate

En 1998, ocurrió una epidemia de dengue (serotipo 2) en la provincia de Salta, Norte de Argentina, después de la primera detección de dengue en esa zona en 1997. En este trabajo se clasificaron las respuestas serológicas de los casos ocurridos en 1998 como primarios o secundarios, dado que riesgo de la enfermadad severa es mayor en los casos secundarios. Se estudiaron 154 casos por las pruebas de neutralización (NT) e inhibición de la hemoaglutinación. Se clasificaron 38 casos ( 25 porciento) como respuestas primarias y 84 casos (54 porciento) como respuestas secundarias. Los restantes 32 casos (21 porciento) con títulos de IgG en el límite no pudieron ser clasificados. Se analizó la exposición previa a otros flavivirus (Encefalitis de San Luis [SLE] y Fiebre Amarilla [YF]) que pueden cruzar serológicamente, como posible causa de los patrones secundarios. Nuestros resultados indican que el 83 porciento de los casos clasificados como respuesta a dengue secundaria, podrían atribuirse a exposiciones previas a los virus SLE o YF, o a reacciones serológicas cruzadas. La vacunación contra YF fue un factor menor contribuyente al patrón de respuesta secundaria encontrado. El hallazgo de serología positiva para YF en personas que no reconocen vacunación previa debe alertar acerca de la posible circulación silenciosa del virus de la YF, en una área que puede soportar tantos ciclos urbanos como selváticos. Otros casos que mostraron respuesta secundarias permanecen sin explicación, surgirindo la ocurrencia de infecciones previas por otros serotipos de dengue o por otro flavivirus distintos a SLE o YF.

Isolamento do flavivírus Iguape a partir de mosquitos Anopheles (Kerteszia) cruzii em Juquitiba - Estado de Säo Paulo - Brasil / Isolation of flavivirus Iguape from mosquitoes Anopheles (Kerteszia) cruzii in Juqutiba - Säo Paulo State - Brazil

O flavivírus Iguape foi isolado pela primeira vez em 1979, a partir de camundongo sentinela, exposto em floesta no Município de Iguape, Estado de Säo Paulo, Brasil. Anticorpos inibidores da hemaglutinaçäo, monotípicos para o vírus Iguape, foram detectados em animais domésticos e silvestres na Regiäo do Vale do Ribeira, SP. Anticorpos monotípicos têm sido também detectados em soros humanos, embora näo haja evidência de doença clínica. O estudo foi realizado em maio de 1994, no Município de Juquitiba, SP, em área de floresta. Mosquitos foram capturados com armadilhas luminosas. Após identificaçäo sistemática, lotes de cerca de 30 mosquitos da mesma espécie foram processados para isolamento de vírus, empregando-se camundongos. A identificaçäo foi realizada por testes de Hemaglutinaçäo, Inibiçäo de Hemaglutinaçäo, Fixaçäo de Complemento, Neutralizaçäo em camundongos e sensibilidade ao desoxicolato de Sódio. Uma cepa de vírus (SPAr-158482) foi obtida apartir de mosquitos Anopheles (Kerteszia) cruzii. O agente isolado apresentou significante sensibilidade ao Desoxicolato de Sódio. A sorologia por Inibiçäo de Hemaglutinaçäo, Fixaçäo de Complemento e Neutralizaçäo em camundongos, indicou que a cepa isolada é idêntica ao vírus Iguape. Esses achados sugerem que o An. cruzii pode desenpenhar algum papel no ciclo de transmissäo do vírus Iguape, em ambientes naturais. (AU)

The flavivirus Iguape was isolated for the first time in 1979, from a sentinel mouse exposed in a forested area in Iguape County - SP, Brazil. Monotypic hemagglutination inhibition antibodies for Iguape virus were detected in domestic and sylvan animals, in Ribeira Valley region, S"o Paulo State. Monotypic antibodies have also been detected in human sera, although there is no evidence of clinical disease. The authors report the isolation of a new strain of Iguape virus from naturally infected mosquitoes. The study was conducted in May, 1994 in Juquitiba County ñ S"o Paulo State, in a forested area.Mosquitoes were captured by light traps . After systematics identification, pools of mosquitoes were processed for virus isolation in suckling mice. An isolate (SPAr-158482) was obtained from Anopheles (Kerteszia) cruzii. Tests of Hemagglutination, Hemagglutination Inhibition, Complement Fixation, Neutralization in suckling mice and sensitivity to Sodium Deoxycholate were employed for identification. (AU)

Antigenic relatedness of selected flaviviruses: study with homologous and heterologous immune mouse ascitic fluids

A relacao antigenica de 9 Flavivirus, febre amarela (YF), Wesselsbron (WSL), Uganda S (UGS), Potiskum (POT), West Nile (WN), Banzi (BAN), Zika (ZK), Dengue tipo 1 (DEN-1) e Dengue tipo 2 (DEN-2), foi avaliada por reacao de inibicao da hemaglutinacao cruzada (cross-HI) e reacao de fixacao do complemento cruzada (Cross-CF) entre cada um dos virus e seu fluido ascitico homologo em camundongos. Medias de titulos foram calculadas usando os titulos heterologos e homologos. Reacoes cruzadas CF revelaram maiores variacoes antigenicas entre virus do que reacoes cruzadas HI. Nao houve variacao antigenica significativa entre virus WSL, POT e YF usando cada um dos metodos. Todavia, diferencas definidas da antigenicidade foram observadas entre eles e os virus UGS, BAN e ZK. Nao existiram diferencas significativas entre UGS, BANe ZK ou entre DEN-1 e DEN-2. A relacao sorologica entre Flavivirus e importante para se estabelecer o diagnostico e a epidemiologia destas infeccoes na Africa

Prevalencia de anticuerpos contra flavivirus en jóvenes voluntarios ingresantes al servicio militar de la Provincia de Formosa, Argentina / Seropositive against Flavivirus in young recruits from the Province of Formosa, Argentina

El objetivo del presente trabajo fue conocer la prevalencia de anticuerpos en poblaciones de riesgo a los Flavivirus. Se analizaron 189 sueros humanos provenientes de 3 localidades de la Provincia de Formosa. La región estudiada fue seleccionada por su proximidad a Brasil y Paraguay con el fin de verificar la probable introducción de Flavivirus de estos pa1ses, especialmente dengue y fiebre amarilla o la emergencia de los ya existentes en nuestro país. Se realizaron las pruebas de inhibición de la hemoaglutinación (IH), fijación del Complemento (FC) y neutralización (NT), utilizando los virus de la encefalitis de San Luis (ESL), Bussuquara, Ilheus, fiebre amarilla (FA)y dengue subtipos 1 y 2. Todos los sueros fueron negativos por IH para dengue e Ilheus. Por esta prueba un suero fue positivo sólo para FA, y dos sólo para Bussuquara, confirmándose uno por NT. Un total de 22 sueros fue positivo para ESL por IH y 40 sueros reaccionaron por la prueba de NT contra el mismo virus. La prevalencia de anticuerpos IH y NT fue similar para las tres localidades estudiadas. Estos resultados muestran que el virus ESL circula efectivamente en la zona estudiada con un valor de prevalencia de anticuerpos IH y NT significativo y que el mencionado virus podría cumplir un rol importante en infecciones febriles de etiología viral no confirmados en esa zona de nuestro país

Synaptophysin and neurofilament expression in neurons infected with dengue virus

The expression of two genes encoding the neuronal specific proteins synaptophysin and high molecular weigh neurofilaments was investigated in primary cell cultures of embryonic mouse brain infected with dengue virus type 2, using immunocytochemistry and Western blot analysis with monoclonal antibodies. The viral infection leads to a 20-fold induction in the expression of the mentioned synaptogenesis-related proteins. These results suggest a correlation between virus infection and neuropathology of immature neurons in vivo

Virológica 91

In december 1975 a hitherto unknow Flavivirus was isolated from the cerebellum and upper spinal cord of a 39-years-old farmer in the region of Ribeira Valley, Säo Paulo, Brazil. The new virus, isolated and characterized by Lopes et al., was named Rocio (ROC), strain SP H34675. VEE virus is serologically grouped in the genus Alphavirus of family Togaviridae based upon cross-reactivity by hemagglutination inhibition (HI complement fixation (CF) and neutralization (N) tests

Rocio and Venezuelan eqüine encephalomyelitis virus activities in Brazil

Existem evidências em humanos e vertebrados silvestres da atividade do vírus rócio no Vale do Ribeira até 1991. Os dados sugerem a circulaçäo do vírus no ciclo selvático envolvendo mosquitos e possivelmente pássaros com infecçöes humanas tangenciais. Parece que o ciclo de transmissäo no meio ambiente modificado pelo homem, como certamente ocorreu na epidemia de 1975-77, näo está atualmente presente. Considerando os interesses econômicos e as mudanças no meio ambiente, aconselha-se um aperfeiçoamento na vigilância das infecçöes por Rócio

Outbreak of encephalitis in Bellary District of Karnataka & adjoining areas of Andhra Pradesh.

An outbreak of encephalitis in Bellary district of Karnataka state and adjoining areas of Andhra Pradesh which occurred during October 1986 to January, 1987, has been investigated. Out of the 219 patients reported, 110 were from Bellary district and the remaining 109 were from Anantapur and Kurnool districts of Andhra Pradesh; 131 (59.8%) were males and 88 (40.2%) females, while 192 (87.7%) patients were aged 10 yr and below. Sixty one patients died giving a case fatality rate of 27.9 per cent. Virological/serological investigations were carried out on 153 patients. Japanese encephalitis (JE) virus was isolated from the brain tissue of 2 cases. On the basis of the results of serological tests and virus isolation, a flavivirus (JE/WN/DEN) etiology could be established in 116 (75.8%) patients.