BackgroundThe global burden of pediatric severe respiratory illness is substantial, and influenza viruses contribute to this burden. Systematic surveillance and testing for influenza among hospitalized children has expanded globally over the past decade. However, only a fraction of the data has been used to estimate influenza burden. In this analysis, we use surveillance data to provide an estimate of influenza-associated hospitalizations among children worldwide.Methods and FindingsWe aggregated data from a systematic review (n = 108) and surveillance platforms (n = 37) to calculate a pooled estimate of the proportion of samples collected from children hospitalized with respiratory illnesses and positive for influenza by age group (<6 mo, <1 y, <2 y, <5 y, 5–17 y, and <18 y). We applied this proportion to global estimates of acute lower respiratory infection hospitalizations among children aged <1 y and <5 y, to obtain the number and per capita rate of influenza-associated hospitalizations by geographic region and socio-economic status.Influenza was associated with 10% (95% CI 8%–11%) of respiratory hospitalizations in children <18 y worldwide, ranging from 5% (95% CI 3%–7%) among children <6 mo to 16% (95% CI 14%–20%) among children 5–17 y. On average, we estimated that influenza results in approximately 374,000 (95% CI 264,000 to 539,000) hospitalizations in children <1 y—of which 228,000 (95% CI 150,000 to 344,000) occur in children <6 mo—and 870,000 (95% CI 610,000 to 1,237,000) hospitalizations in children <5 y annually. Influenza-associated hospitalization rates were more than three times higher in developing countries than in industrialized countries (150/100,000 children/year versus 48/100,000). However, differences in hospitalization practices between settings are an important limitation in interpreting these findings.ConclusionsInfluenza is an important contributor to respiratory hospitalizations among young children worldwide. Increasing influenza vaccination coverage among young children and pregnant women could reduce this burden and protect infants <6 mo.

Influenza is a major cause of respiratory illness in Africa, especially in children. Further strengthening influenza surveillance, along with conducting special studies on influenza burden, cost of illness, and role of other respiratory pathogens will help detect novel influenza viruses and inform and develop targeted influenza prevention policy decisions in the region.

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Hepatitis B virus genotype E (HBV/E) is highly prevalent in Western Africa. In this work, 30 HBV/E isolates from HBsAg positive Angolans (staff and visitors of a private hospital in Luanda) were genetically characterized: 16 of them were completely sequenced and the pre-S/S sequences of the remaining 14 were determined. A high proportion (12/30, 40%) of subjects tested positive for both HBsAg and anti-HBs markers. Deduced amino acid sequences revealed the existence of specific substitutions and deletions in the B- and T-cell epitopes of the surface antigen (pre-S1- and pre-S2 regions) of the virus isolates derived from 8/12 individuals with concurrent HBsAg/anti-HBs. Phylogenetic analysis performed with 231 HBV/E full-length sequences, including 16 from this study, showed that all isolates from Angola, Namibia and the Democratic Republic of Congo (n = 28) clustered in a separate lineage, divergent from the HBV/E isolates from nine other African countries, namely Cameroon, Central African Republic, Côte d'Ivoire, Ghana, Guinea, Madagascar, Niger, Nigeria and Sudan, with a Bayesian posterior probability of 1. Five specific mutations, namely small S protein T57I, polymerase Q177H, G245W and M612L, and X protein V30L, were observed in 79-96% of the isolates of the separate lineage, compared to a frequency of 0–12% among the other HBV/E African isolates.

INTRODUÇÃOO estudo dos processos implicados na aquisição da linguagem escrita tem despertado o interesse de muitos investigadores que procuram sobretudo explicar as causas das dificuldades de aprendizagem de algumas crianças. Nos últimos 20 anos, as ideias acerca da natureza desta aprendizagem foram profundamente alteradas.Durante muito tempo, a leitura foi considerada uma habilidade mecânica de descodificação de signos escritos que exigia da criança uma determinada maturidade ao nível das aptidões psicológicas gerais como: a estruturação espacial e temporal, a organização perceptivo-motora, o desenvolvimento da função simbólica da linguagem, a organização do esquema corporal, o desenvolvimento intelectual (Mialaret, 1974). Esta perspectiva tradicional conduziu a que na prática pedagógica se reservasse um período (pré-escolar e início do 1.º ciclo) destinado à preparação da criança para a leitura, durante o qual se realizavam actividades com o objectivo de desenvolver essas capacidades no futuro aprendiz leitor e que, no decurso do ensino formal, se valorizasse sobretudo o domínio da técnica de descodificação. Do mesmo modo, originou práticas de diagnóstico e reeducação baseadas na estimulação, avaliação e treino das diversas aptidões consideradas como pré-requisitos para a aprendizagem da leitura (Alves Martins & Niza, 1998).A partir dos finais dos anos 60, início dos anos 70, tornou-se evidente a insuficiência desta perspectiva e surgiu a necessidade de se caracterizar o objecto (a leitura) e o sujeito (aprendiz-leitor) desta aprendizagem. A caracterização da leitura é necessária, porque só após a identificação dos mecanismos e processos nela implicados é possível perceber a natureza das dificuldades que a sua aprendizagem pode originar. É necessária a caracterização das representações dos aprendizes-leitores sobre os objectivos e natureza da leitura, porque estes conhecimentos e representações são determinantes na forma como o sujeito

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