Ausência de transmissão vertical do HTLV-I em crianças não amamentadas

The most frequent pathway of vertical transmission of HTLV-I is breast-feeding, however bottle fed children may also become infected in a frequency varying from 4 to 14%. In these children the most probable routes of infection are transplacental or contamination in the birth canal. Forty-one bottle-fed children of HTLV-I seropositive mothers in ages varying from three to 39 months (average age of 11 months) were submitted to nested polymerase chain reaction analysis (pol and tax genes). 81.5% of the children were born by an elective cesarean section. No case of infection was detected. The absence of HTLV-I infection in these cases indicates that transmission by transplacental route may be very infrequent.A amamentação é o meio mais freqüente de transmissão vertical do HTLV-I. No entanto, crianças não amamentadas mostram-se infectadas em freqüências que variam de 4 a 14%. Nestes casos, os meios mais prováveis de infecção devem ser através da placenta ou por contaminação no canal de parto. Quarenta e um filhos de portadoras do HTLV-I aleitados artificialmente foram submetidos a pesquisa do vírus pela reação em cadeia da polimerase. 81,5% destas crianças nasceram através de cesária eletiva. Nenhum caso de infecção pelo HTLV-I foi detectado. Este fato indica que a infecção por via transplacentária é pouco freqüente e que é provável que o parto artificial tenha contribuído para a ausência de transmissão do vírus

Distribuição dos genótipos do vírus GB-C (HGV) em indivíduos da cidade de São Paulo, Brasil

Há na literatura vários estudos filogenéticos e de distribuição de genótipos do chamado "Vírus GB-C" ou da "Hepatite G", mais conhecido pela dupla sigla "GBV-C/HGV". Ocorre que, em sua grande maioria, estas pesquisas foram realizadas com amostras de grupos ligados epidemiologicamente e não com indivíduos representativos da população geral. O presente estudo é uma continuação do primeiro trabalho no Brasil feito com este tipo de amostragem. Trata-se de análise filogenética e distribuição genotípica do GBV-C/HGV a partir de amostras isoladas dentre mais de 1.000 indivíduos da cidade de São Paulo. Para tanto, um fragmento de 728 pares de base da região 5' não-codificadora (5´NCR) do genoma viral, de 24 amostras, foi sequenciado e submetido à analise filogenética. Foram identificados os genótipos 1, 2a e 2b nas respectivas freqüências: 8,3% (2/24), 50% (12/24) e 41,7% (10/24). Concluindo, São Paulo apresenta uma distribuição de genótipos semelhante à publicada para outros estados e regiões do Brasil, endossando a idéia de que os tipos 1 e 2 teriam vindo com os africanos e europeus, respectivamente, e portanto estariam na população do país desde a sua formação.There has been several studies worldwide on phylogenetics and genotype distribution of the GB-virus C / Hepatitis G virus (GBV-C/HGV). However, in their great majority, those investigations were based on some epidemiologically linked group, rather than on a representative sampling of the general population. The present is a continuation of the first study in Brazil with such a population; it addresses the GBV-C/HGV phylogenetics and genotype distribution based on samples identified among more than 1,000 individuals of the city of São Paulo. For this purpose, a 728 bp fragment of the 5´non-coding region (5´NCR) of the viral genome, from 24 isolates, was sequenced and subjected to phylogenetic analysis. Genotypes 1, 2a and 2b were found at 8.3% (2/24), 50% (12/24) and 41.7% (10/24), respectively. In conclusion São Paulo displays a genotype distribution similar to the published data for other States and Regions of Brazil, endorsing the notion that types 1 and 2 would have entered the country with African and European people, respectively, since its earliest formation

The Brazilian Network for HIV-1 Genotyping External Quality Control Assurance Programme

The Brazilian network for genotyping is composed of 21 laboratories that perform and analyze genotyping tests for all HIV-infected patients within the public system, performing approximately 25,000 tests per year. We assessed the interlaboratory and intralaboratory reproducibility of genotyping systems by creating and implementing a local external quality control evaluation. Plasma samples from HIV-1-infected individuals (with low and intermediate viral loads) or RNA viral constructs with specific mutations were used. This evaluation included analyses of sensitivity and specificity of the tests based on qualitative and quantitative criteria, which scored laboratory performance on a 100-point system. Five evaluations were performed from 2003 to 2008, with 64% of laboratories scoring over 80 points in 2003, 81% doing so in 2005, 56% in 2006, 91% in 2007, and 90% in 2008 (Kruskal-Wallis, p = 0.003). Increased performance was aided by retraining laboratories that had specific deficiencies. The results emphasize the importance of investing in laboratory training and interpretation of DNA sequencing results, especially in developing countries where public (or scarce) resources are used to manage the AIDS epidemic

Near full-length genome analysis of low prevalent human immunodeficiency virus type 1 subclade F1 in São Paulo, Brazil

Background: The genetic diversity of the human immunodeficiency virus type 1 (HIV-1) is critical to lay the groundwork for the design of successful drugs or vaccine. In this study we aimed to characterize and define the molecular prevalence of HIV-1 subclade F1 currently circulating in Sao Paulo, Brazil. Methods: A total of 36 samples were selected from 888 adult patients residing in Sao Paulo who had previously been diagnosed in two independent studies in our laboratory as being infected with subclade F1 based on pol subgenomic fragment sequencing. Proviral DNA was amplified from the purified genomic DNA of all 36 blood samples by 5 fragments overlapping PCR followed by direct sequencing. Sequence data were obtained from the 5 fragments of pure subclade F1 and phylogenetic trees were constructed and compared with previously published sequences. Subclades F1 that exhibited mosaic structure with other subtypes were omitted from any further analysis Results: Our methods of fragment amplification and sequencing confirmed that only 5 sequences inferred from pol region as subclade F1 also holds true for the genome as a whole and, thus, estimated the true prevalence at 0.56%. The results also showed a single phylogenetic cluster of the Brazilian subclade F1 along with non-Brazilian South American isolates in both subgenomic and the full-length genomes analysis with an overall intrasubtype nucleotide divergence of 6.9%. The nucleotide differences within the South American and Central African F1 strains, in the C2-C3 env, were 8.5% and 12.3%, respectively. Conclusion: All together, our findings showed a surprisingly low prevalence rate of subclade F1 in Brazil and suggest that these isolates originated in Central Africa and subsequently introduced to South America.Fundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP)[06/50096-0

Nova estimativa da prevalência da infecção pelo vírus "TT" (TTV) em populações de baixo e alto risco de São Paulo, Brasil

A prevalência da infecção pelo vírus "TT" (TTV) foi investigada pela técnica da Reação da Polimerase em Cadeia (PCR) em grupos considerados de baixo risco (doadores de sangue e crianças/adolescentes saudáveis) e de alto risco de exposição parenteral (hemofílicos); todos provenientes da cidade de São Paulo. Oligonucleotídeos empregados como primers, homólogos à região não traduzível (UTR) do genoma viral, mostraram-se muito mais universais, revelando frequências muito mais altas em ambos os grupos ( >; ou = 81%) do que os primers anteriormente utilizados, baseados na região genômica traduzível "N22" (doadores de sangue, 5,5%, e hemofílicos, 42,3%). O "PCR-UTR" também revelou um perfil interessante em crianças/adolescentes saudáveis: alta prevalência nos primeiros anos de vida e queda significativa em meninos adolescentes. O "PCR-N22", por sua vez, apresentou alta frequência em hemofílicos que receberam derivados de sangue fresco (58%) relativa àqueles que foram tratados com fatores de coagulação submetidos à inativação viral (9,4%) e doadores de sangue (5,5%).The prevalence of TT virus (TTV) infection was investigated by Polymerase Chain Reaction (PCR) in low- (blood donors and healthy children/adolescents) and high-risk (hemophiliacs) groups from São Paulo, Brazil. Primers based on the untranslated region (UTR) of the viral genome proved to be much more ubiquitous, leading to much higher frequencies for both groups ( >; or = 81%) than the earlier N22-PCR directed to the open reading frame 1 (blood donors, 5.5%, and hemophiliacs, 42.3%). The UTR-PCR also revealed an interesting profile for healthy children/adolescents: very high prevalence at the early years and significant decrease in male teenagers. The N22-PCR, in turn, demonstrated higher frequency in hemophiliacs treated with fresh blood products (58%), than in those treated with virus-inactivated clotting factors (9.4%) and blood donors (5.5%)