Using a metagenomic approach, we identified hepatitis A virus among cases of acute febrile illnesses that occurred in 2008-2012 in Brazil suspected as yellow fever. These findings reinforce the challenge facing routine clinical diagnosis in complex epidemiological scenarios.

This article discusses the peculiar conditions that favoured the unexpected introduction of Zika virus into the poorest northeastern region of Brazil in 2015, its speed of transmission to other Brazilian states, other Latin American countries and other regions, and the severity of related neurological disorders in newborns and adults. Contrasting with evidence that Zika had so far caused only mild cases in humans in the last six decades, the epidemiological scenario of this outbreak in Brazil indicates dramatic health effects: in 2015, an increase of 20-fold in notified cases of microcephaly and/or central nervous system (CNS) alterations suggestive of Zika congenital infection, followed by an exponential increase in 2016, with 2366 cumulative cases confirmed in the country by the end of December 2016. A significant increase in Guillain-Barré syndrome in adults has also been reported. Factors involved in viral dissemination, neural pathogenesis and routes of transmission in Brazil are examined, such as the role of social and environmental factors and the controversies involved in the hypothesis of antibody-dependent enhancement, to explain the incidence of congenital Zika syndrome in Brazil. Responses to the Zika outbreak and the development of new products are also discussed.

A tipagem de cepas é uma ferramenta fundamental para a análise epidemiológica molecular e pode fornecer informações importantes sobre a dispersão dos vírus dengue. Neste trabalho, foi realizada a caracterização molecular de amostras de vírus DEN-2 isoladas no Brasil entre 1990-2000, de áreas geograficamente e temporalmente distintas, com o objetivo de investigar a distribuição genética deste sorotipo circulante no país. A reação em cadeia pela polimerase baseada em sítios de restrição específicos (RSS-PCR) apresentou o mesmo padrão para as 52 amostras Brasileiras, mostrando a circulação de apenas uma variante de vírus DEN-2. A análise filogenética utilizando alinhamento progressivo de sequências de 240 nucleotídeos da junção E/NS1 de 15 cepas mostrou que estas pertencem ao genotipo III (genotipo Jamaica).

Strain typing is a critical tool for molecular epidemiological analysis and can provide important information about the spread of dengue viruses. Here, we performed a molecular characterization of DEN-2 viruses isolated in Brazil during 1990-2000 from geographically and temporally distinct areas in order to investigate the genetic distribution of this serotype circulating in the country. Restriction site-specific polymerase chain reaction (RSS)-PCR presented the same pattern for all 52 Brazilian samples, showing the circulation of just one DEN-2 variant. Phylogenetic analysis using progressive pairwise alignments from 240-nucleotide sequences of the E/NS1 junction in 15 isolates showed that they belong to genotype III (Jamaica genotype).

Dengue virus type 3 was isolated for the first time in the country as an indigenous case from a 40 year-old woman presenting signs and symptoms of a classical dengue fever in the municipality of Nova Iguaçu, State of Rio de Janeiro. This serotype has been associated with dengue haemorrhagic epidemics and the information could be used to implement appropriate prevention and control measures. Virological surveillance was essential in order to detected this new serotype.

This paper presents epidemiological, laboratory, and clinical data on 12 years of dengue virus activity in the State of Rio de Janeiro from the time the disease was first confirmed virologically in April 1986 through April 1998. DEN-1 and DEN-2 viruses are the serotypes circulating in the state and were responsible for the epidemics reported during the last 12 years. The results published here show both the impact of dengue virus infections on the population and laboratory advances that have improved dengue diagnosis.

Uma epidemia de dengue iniciou-se em março de 1986, no Rio de Janeiro, alcançando rapidamente outras partes do país. Febre dengue clássica foi observada, porém o vírus do dengue foi isolado de um caso fatal. As amostras de dengue 1 isoladas de pacientes e de fêmeas adultas de Aedes aegypti capturadas na área apresentaram efeito citopático na linhagem de células A. albopictus clone C6/36. A lesão celular foi estudada também em microscopia eletrônica, sendo descritos os dados observados. Um teste de captura para IgM (MAC-ELISA) foi utilizado durante a epidemia tanto para o diagnóstico como para avaliarr a circulação de vírus, com resultados claros e reprodutíveis; os anticorpos IgM apareceram precocemente após o início da doença clínica, permanecendo por cerca de 90 dias na maioria dos pacientes. A reação mostrou-se tipo específico em cerca de 50% dos pacientes, porém, um alto nível de respostas heterológas para dengue tipo 3 foi observado nos demais pacientes. Observou-se uma taxa total de isolamento de 46,8% (813 amostras de vírus de 1734 pacientes). Com a reação de IgM houve um momento de casos confirmados: 1479, em 2541 casos suspeitos (58,2%). A possível influência dos anticorpos dos pacientes sobre a taxa de isolamento de vírus é discutida, porém a questão não está esclarecida completamente. Os autores enfatizam a importância do diagnóstico laboratorial dos casos suspeitos de dengue em todas as regiões do país, onde os vetores são encontrados.

A dengue outbreak started in March, 1986 in Rio de Janeiro and spread very rapidly to other parts of the country. The great majority of cases presented classical dengue fever but there was one fatal case, confirmed by virus isolation. Dengue type 1 strains were isolated from patients and vectors (Aedes aegypti) in the area by cultivation in A. albopictus C6/36 cell line. The cytopathic effect (CPE) was studied by electron microscopy. An IgM capture test (MAC-ELISA) was applied with clear and reproducible results for diagnosis and evaluation of virus circulation; IgM antibodies appeared soon after start of clinical disease, and persisted for about 90 days in most patients. The test was type-specific in about 50% of the patients but high levels of heterologous response for type 3 were observed. An overall isolation rate of 46,8% (813 virus strains out of 1734 specimens) was recorded. The IgM test increased the number of confirmed cases to 58,2% (1479 out of 2451 suspected cases). The importance of laboratory diagnosis in all regions where the vectors are present is emphasized.

Vírus dengue tipo 1 foi isolado em cultura de células de Aedes albopictus, do soro de pacientes oriundos no município de Nova Iguaçu, RJ. O quadro clínico caracterizou-se por febre, cefaléia, dor retro-orbitária, mialgias, articulares e prostração. A análise de soros pareados confirmou a presença de infecção recente por dengue tipo 1. A epidemia expandiu-se para áreas próximas, inclusive a cidade do Rio de Janeiro (maio, 1986).

Dengue virus type 1 has been isolated in Aedes albopictus cell strain, from sera of patients living in the Nova Iguaçu county, by Rio de Janeiro. The clinical picture was characterized by fever, headache, retrobulbar pain, backache, pains in the muscles and the joints and prostration. Studies in paired sera confirmed the presence of recent infection by dengue virus type 1. The outbreak reached adjacent areas, including Rio de Janeiro city (May, 1986).

Os autores apresentam dados obtidos no estudo de soros com a finalidade de determinar os níveis de anticorpos para rubéola, no período de 1970 a 1975, na cidade do Rio de Janeiro. Estes soros induiram principalmente gestantes em contato com casos clínicos ou suspeitos de rubéola. Dentre as gestantes, de 2.155 casos em que as informações eram mais completas, analisaram-se os resultados da sorologia com a finalidade de estabelecer o grau de imunidade prévio ao contato e o nível de risco para o concepto. Verificou-se que 84,4% destas gestantes possuiam anticorpos, sendo que destas 8,1% alcançaram níveis iguais ou superiores a 1/320, sugerint infecção recente. Obteve-se conversão sorológica em 1,2%, comprovando-se a infecção atual por rubéola. A análise dos dados referentes a casos notificados de rubéola na cidade do Rio de Janeiro no período de 1965 a 1974 demonstrou uma incidência maior no segundo semestre, tendo ocorrido dois surtos da doença, um em 1968 e outro em 1974.

The authors present data obtained from the study of sera in order to determine antibody leveis for rubella in Rio de Janeiro city, during the period 1970/1975. These sera induded mainly pregnant women having had contact with suspect and clinically defined cases of the disease. Among the group studies, 2155 cases of pregnants which had more complete data were analized with the purpose of stablishing immunity degree before contact and risk levei for the concept. It was found that 84,4% of these pregnants had rubella circulating antibodies and 8,1% of them reached leveis equal or more than 1/320, suggestive of recent infection. Serologic conversion was obtained in 1,2%, firming present infection. Analysis of data refering to notified cases of rubella during the period from 1965 to 1974 showa greater incidence during the secondsemester, as well as two outbreaks of the disease which had occurred in 1968 and in 1974.