Thesis (doctoral)--Ludwig Maximilians-Universität zu München, 1979.

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Vitamin A deficiency and intestinal parasitism coexist in developing countries. This study evaluated whether a national program of vitamin A supplementation (200,000IU retinyl palmitate every 6 months), if combined with deworming (400mg albendazole), slows reinfection with Ascaris . A baseline survey of 595 indigenous preschool children in the Bocas del Toro region of Panama showed high rates of stunting (61%) and nematode infection (Ascaris 79.5%, Trichuris 19%). All children were dewormed and 328 were included in the 5 month follow-up study. Of these, 106 children received vitamin A supplementation through the Ministry of Health (Vit A S+) and 222 children received no supplementation (Vit A S-). At 3 months post deworming, both the prevalence (P= 0.0004) and intensity (P= 0.0124) of Ascaris infection were higher in Vit A S- children than in Vit A S+ children, indicating that reinfection occurred more slowly in supplemented children. When the two supplement groups were further sub-divided by stature, Vit A S+ resulted in lower reinfection rates (P=0.0002) only in normal height children, and not in stunted children. Despite the tendency of public health policy to target malnourished children our study provides evidence of increased benefit of vitamin A supplementation in normal height children living in areas with chronic parasitosis.

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Made available in DSpace on 2011-05-04T12:42:02Z (GMT). No. of bitstreams: 0 Previous issue date: 2010 / Ascaris lumbricoides e Trichuris trichiura são os helmintos intestinais de maior prevalência na população mundial e também no material arqueológico. Porém, na América do Sul pré-colombiana, o encontro de ovos de A. lumbricoides é raro. Recentemente um estudo de diagnóstico paleoparasitológico molecular apontou para um sub-diagnóstico de Ascaris sp. na América do Sul. No registro arqueológico de parasitos intestinais predominam achados de ovos de Trichuris sp. ao invés de Ascaris sp. Isto parece contraditório, em virtude do número de ovos eliminados por cada parasito. Os objetivos desta pesquisa foram: avaliar marcadores moleculares para o diagnóstico de Ascaris sp. e Trichuris sp. em material moderno pela caracterização molecular destes parasitos; caracterizar geneticamente isolados de sítios arqueológicos sul americanos para verificar a real paleodistribuição destes parasitos em uma perspectiva paleoepidemiológica e compará-la com a epidemiologia moderna destas infecções; avaliar os fatores envolvidos na paleodistribuição encontrada. As amostras foram submetidas ao diagnóstico por microscopia óptica, seguida da extração do DNA, PCR e sequenciamento nucleotídico. Na avaliação dos marcadores moleculares, a região ITS1 de Ascaris sp. apresentou variação intra-indivíduo, o que descartou seu uso com fins taxonômicos e diagnósticos. A caracterização molecular dos genes mitocondriais cox1 e nad1 de Ascaris sp. mostrou infecção cruzada de genótipos entre as espécies humana e suína, o que denota a necessidade de monitoramento das populações avaliadas assim como de outras regiões brasileiras para que a infecção não venha a se tornar uma zoonose em potencial no Brasil. Foi possível o diagnóstico molecular de Trichuris sp. pelo gene ribossomal 18S DNA. A análise paleogenética mostrou que há subdiagnóstico para ambas as infecções na América do Sul pré-colombiana. Este é o primeiro diagnóstico paleoparasitológico molecular de T. trichiura em material sul americano. Estes são também os primeiros registros de recuperação de DNA de parasitos intestinais em material de sítio arqueológico do tipo “sambaqui” e também do período colonial brasileiro. Comparando-se a paleoepidemiologia molecular de Ascaris sp. com a epidemiologia molecular moderna foi possível notar que há haplótipos antigos que ainda estão presentes hoje, no entanto a maioria dos haplótipos é característica ao material arqueológico. Observou-se que há haplótipos comuns ao Velho e Novo Mundo, contudo, há também especificidades regionais. Os resultados da análise genética claramente apontam para uma pobre preservação dos ovos no material arqueológico, principalmente de Ascaris sp. Os fatores principais envolvidos nessa paleodistribuição, seriam fatores tafonômicos que proporcionaram a quebra maior de ovos de Ascaris sp. do que de Trichuris sp., e evidências de consumo de plantas vermífugas pelos povos pré-históricos, as quais teriam maior ação sobre Ascaris sp. do que Trichuris sp. / Ascaris lumbricoides and Trichuris trichiura are the intestinal helminths with higher prevalence in the world today as it was in the past. However, in pre-Columbian South America the findings of A. lumbricoides eggs are rare. Recently a study of paleoparasitological molecular diagnosis showed a sub-diagnosis of Ascaris sp. in South America. In the archeological material, eggs of Trichuris sp. are more common compared with Ascaris sp. eggs. This is contradictory taking into account the number of eggs eliminated by each parasite. The aims of this research was: to evaluate molecular markers for Ascaris sp. and Trichuris sp. diagnosis in modern material; genetic characterization of the samples South American archeological sites aiming the paleodistribution of these parasites in a paleoepidemiological perspective; compare results with the modern epidemiology of these infections; evaluate the factors involved in paleodistribution. Extraction of DNA, PCR and nucleotide sequencing were performed after microscopy. In the evaluation of the molecular markers Ascaris sp. ITS1 region showed intra-individual variation. Therefore, this region to taxonomical and diagnoses studies was discarded. With the molecular characterization of Ascaris sp. cox1 and nad1 mitochondrial genes it was possible to identify cross infection of genotypes between human and pig hosts. Results showed that surveillance field works in modern populations are necessary to verify the zoonotic potential of this infection in Brazil. The molecular diagnosis of Trichuris sp. by ribossomal 18S DNA gene was possible. The paleogenetic analysis showed that there is subdiagnosis for both infections in pre-Columbian South America. This is the first paleoparasitological molecular record of T. trichiura in South American samples. These are also the first recovery of DNA of intestinal parasites in "sambaqui" archeological site, and also of the Brazilian colonial period. Molecular paleoepidemiology of Ascaris sp. infection compared with modern molecular epidemiology showed that there are ancient haplotypes still present today. However, most of the haplotypes are characteristic of the archaeological material. It was observed that there are common haplotypes both to the Old World and to the New World, but showing regional specificities. The results of the genetic analysis clearly pointed to a poor preservation of eggs in archeological material, mainly of Ascaris sp. Taphonomy may be the main factor involved in paleodistribution, breaking more eggs of Ascaris sp. than Trichuris sp. Evidences of consumption of vermifuge plants by prehistoric groups should also have influence, as some plants should have more efficacy eliminating Ascaris sp. than Trichuris sp.