Expression of a hantavirus N protein and its efficacy as antigen in immune assays

Hantavirus cardiopulmonary syndrome (HCPS) has been recognized as an important public heath problem. Five hantaviruses associated with HCPS are currently known in Brazil: Juquitiba, Araraquara, Laguna Negra-like, Castelo dos Sonhos, and Anajatuba viruses. The laboratory diagnosis of HCPS is routinely carried out by the detection of anti-hantavirus IgM and/or IgG antibodies. The present study describes the expression of the N protein of a hantavirus detected in the blood sample of an HCPS patient. The entire S segment of the virus was amplified and found to be 1858 nucleotides long, with an open reading frame of 1287 nucleotides that encodes a protein of 429 amino acids. The nucleotide sequence described here showed a high identity with the N protein gene of Araraquara virus. The entire N protein was expressed using the vector pET200D and the Escherichia coli BL21 strain. The expression of the recombinant protein was confirmed by the detection of a 52-kDa protein by Western blot using a pool of human sera obtained from HCPS patients, and by specific IgG detection in five serum samples of HCPS patients tested by ELISA. These results suggest that the recombinant N protein could be used as an antigen for the serological screening of hantavirus infection.FAPES

Estudo sobre o diagnóstico laboratorial e sintomas do dengue, durante epidemia ocorrida na região de Ribeirão Preto, SP, Brasil Laboratory diagnosis and symptoms of dengue studied during an outbreak in the Ribeirao Preto Region, SP, Brazil

Uma epidemia de dengue tipo 1 se iniciou em Novembro de 1990 na Região de Ribeirão Preto, Norte do Estado de São Paulo. Foram confirmados por exames laboratoriais cerca de 3.500 casos até fevereiro de 1991. A Unidade de Pesquisa em Virologia da Faculdade de Medicina de Ribeirão Preto - USP, estudou soros de 502 pessoas suspeitas de apresentarem dengue. Fez-se o diagnóstico sorológico através do método da inibição da hemaglutinação (HAI) para dengue tipo 1 em 19% dos analisados. Passou-se a utlilizar um teste imuno-enzimático para dengue em culturas celulares infectadas (EIA-ICC), que permite identificação simultânea de IgG e IgM. O EIA-ICC embora menos sensível quando comparado ao HAI (89%), mostrou-se mais eficiente, porque: dispensou a obtenção de segundas amostras séricas para o diagnóstico; trata-se de técnica simples, podendo ser efetuada em apenas 5 horas. O vírus dengue tipo 1 foi isolado do sangue de 21 pacientes, por inoculação em células de mosquitos C6/36. Fez-se a identificação dos vírus isolados por método de imunofluorescência indireta, utilizando anti-soro contra todos os flavivirus e anticorpos monoclonais tipo-específicos de dengue. Os sintomas mais freqüentemente observados em 71 indivíduos com diagnóstico de dengue confirmado foram febre (90% dos casos), mialgias (57%) e artralgias (41%)<br>A dengue type 1 outbreak started in the Ribeirao Preto Region, North of Sao Paulo State, Brazil, in November of 1990. About 3500 dengue cases were confirmed by blood tests until February of 1991. The Virus Research Unit of The Faculty of Medicine of Ribeirao Preto - Sao Paulo State University, studied 502 dengue suspect cases. The Serologic diagnosis of dengue type 1 was confirmed by haemmaglutination inhibition test (HAI) in 19% of the cases. Diagnosis was done later by using an enzyme immuno assay on infected cultured cells (EIA-ICC) which discriminated IgG and IgM dengue, antibodies. EIA-ICC was less sensitive (89%) but more effective than HAI. EIA-ICC is a simple technique. It dispenses a second serum sample for diagnosis and it can be completed in about 5 hours. Dengue virus was isolated from the blood of 21 patients by innoculation in culture of mosquito C6/36 cells. The isolated virus were identified by indirect immunofluorescent test, by using an antisera pool to the flavivirus family and dengue type specific monoclonal antibodies. The dengue most frequent symptoms in 71 patients were observed: fever (90%), myalgias (57%) and arthralgias(41%

A prospective study with children whose mothers had dengue during pregnancy Estudo prospectivo com lactentes cujas mães tiveram dengue durante a gravidez

Dengue congenital disease was not confirmed in 10 children whose mothers had the infection during pregnancy. The fetal sera presented anti-dengue IgG antibodies which progressively declined, and disappeared after 8 months. IgM antibodies to dengue were not observed in the sera. Other normal data suggesting the healthy state of the children included: absence of malformations, pregnancy time, Apgar index, weight, and placenta aspect<br>Num estudo sobre doença congênita, com 10 lactentes de mães que tiveram dengue na gravidez, nao se detectou infecção intra-uterina. Os soros fetais apresentaram anticorpos IgG contra dengue tipo 1, por teste imuno-enzimático, provavelmente transferidos passivamente. Estes anticorpos, analisados de forma prospectiva em 8 casos, foram declinando progressivamente, até desaparecerem, aos 8 meses de idade. Anticorpos do tipo IgM contra dengue nao foram detectados. O tempo gestacional normal, os índices de Apgar, o peso e as placentas normais dos neonatos, bem como a ausência de malformações, foram evidências contrárias à infecção intra-uterina