Oswaldo Cruz Foundation

About: Oswaldo Cruz Foundation is a facility organization based out in Rio de Janeiro, Brazil. It is known for research contribution in the topics: Population & Trypanosoma cruzi. The organization has 18673 authors who have published 36752 publications receiving 802378 citations. The organization is also known as: Fundação Oswaldo Cruz & FIOCRUZ.

Amostras complexas em inquéritos populacionais: planejamento e implicações na análise estatística dos dados

Abstract: A avaliacao do desempenho dos sistemas de saude das nacoes vem ganhando importância crescente entre os gestores do setor saude. Entre os instrumentais de avaliacao do desempenho de saude, destacam-se os inqueritos nacionais de saude, cada vez mais utilizados para avaliar o estado de saude da populacao e a assistencia de saude prestada do ponto de vista do usuario. A maioria dos inqueritos nacionais de saude nao usa amostragem aleatoria simples, em parte por restricoes orcamentarias, em parte por limites de tempo associado a coleta de dados. Em geral, utiliza-se combinacao de varios metodos probabilisticos de amostragem para selecao de uma amostra representativa da populacao, chamada de desenho complexo de amostragem. Entre os metodos de amostragem mais utilizados conjuntamente, destacam-se a amostra aleatoria simples, a amostragem estratificada, e a amostragem por conglomerados. Resultante desse processo, a preocupacao subsequente e a analise de dados provenientes de amostras complexas. Este artigo trata de questoes relacionadas a analise estatistica de dados obtidos atraves de pesquisas com desenhos complexos de amostragem. Apresentam-se os problemas que ocorrem quando a analise estatistica nao incorpora a estrutura do plano amostral. Ao ignorar o desenho de amostragem, a analise estatistica tradicional, sob a suposicao de amostragem aleatoria simples, pode produzir incorrecoes tanto para as estimativas medias como para as respectivas variâncias, comprometendo os resultados, os testes de hipoteses e as conclusoes da pesquisa. Para a exemplificacao dos metodos, e utilizada a Pesquisa Mundial de Saude (PMS), realizada no Brasil em 2003.

The spectrum of neuropathological changes associated with congenital Zika virus infection

Abstract: A major concern associated with ZIKV infection is the increased incidence of microcephaly with frequent calcifications in infants born from infected mothers. To date, postmortem analysis of the central nervous system (CNS) in congenital infection is limited to individual reports or small series. We report a comprehensive neuropathological study in ten newborn babies infected with ZIKV during pregnancy, including the spinal cords and dorsal root ganglia (DRG), and also muscle, pituitaries, eye, systemic organs, and placentas. Using in situ hybridization (ISH) and electron microscopy, we investigated the role of direct viral infection in the pathogenesis of the lesions. Nine women had Zika symptoms between the 4th and 18th and one in the 28th gestational week. Two babies were born at 32, one at 34 and 36 weeks each and six at term. The cephalic perimeter was reduced in four, and normal or enlarged in six patients, although the brain weights were lower than expected. All had arthrogryposis, except the patient infected at 28 weeks gestation. We defined three patterns of CNS lesions, with different patterns of destructive, calcification, hypoplasia, and migration disturbances. Ventriculomegaly was severe in the first pattern due to midbrain damage with aqueduct stenosis/distortion. The second pattern had small brains and mild/moderate (ex-vacuo) ventriculomegaly. The third pattern, a well-formed brain with mild calcification, coincided with late infection. The absence of descending fibres resulted in hypoplastic basis pontis, pyramids, and cortico-spinal tracts. Spinal motor cell loss explained the intrauterine akinesia, arthrogryposis, and neurogenic muscle atrophy. DRG, dorsal nerve roots, and columns were normal. Lympho-histiocytic inflammation was mild. ISH showed meningeal, germinal matrix, and neocortical infection, consistent with neural progenitors death leading to proliferation and migration disorders. A secondary ischemic process may explain the destructive lesions. In conclusion, we characterized the destructive and malformative consequences of ZIKV in the nervous system, as reflected in the topography and severity of lesions, anatomic localization of the virus, and timing of infection during gestation. Our findings indicate a developmental vulnerability of the immature CNS, and shed light on possible mechanisms of brain injury of this newly recognized public health threat.