Assuntos
Schistosoma mansoni/fisiologia , Animais , Sequência de Bases , Biomphalaria/parasitologia , Brasil , Camarões , Primers do DNA/química , DNA de Helmintos/análise , DNA de Helmintos/química , Vetores de Doenças , Feminino , Masculino , Camundongos , Dados de Sequência Molecular , Filogenia , Reprodução/genética , Schistosoma mansoni/genética , Comportamento Sexual AnimalRESUMO
Distributions of the intensities of helminth infections within their host populations are invariably aggregated. In the case of the intestinal nematodes, the degrees of aggregation have been shown to be species specific, and constant for any given species despite geographical variation in study sites. This species-specific aggregation can be quantified and used as a tool in planning control interventions. One practical application is that the prevalence of infection can be used to predict the prevalence of heavy infection and thus the risks of morbidity. This paper investigates the patterns of aggregation in schistosome egg counts in different endemic areas in Africa (data sets were obtained from Burundi, Cameroon, Tanzania, Zambia and Zaire). The analysis demonstrates that the degree of parasite aggregation, for both Schistosoma mansoni and S. haematobium, differs amongst the different study localities. This is probably due to area-specific differences in host exposure and immunity. This implies that for these schistosome species, it is not possible to predict egg count distributions or morbidity levels from prevalence data alone.
Assuntos
Schistosoma haematobium/crescimento & desenvolvimento , Schistosoma mansoni/crescimento & desenvolvimento , Esquistossomose Urinária/epidemiologia , Esquistossomose mansoni/epidemiologia , Adolescente , África/epidemiologia , Animais , Criança , Análise por Conglomerados , Fezes/parasitologia , Humanos , Modelos Estatísticos , Contagem de Ovos de Parasitas , Prevalência , Esquistossomose Urinária/patologia , Esquistossomose mansoni/parasitologia , Urina/parasitologiaRESUMO
Cette etude de la dynamique de transmission de schistosoma Mansoni aborde les facteurs sociaux comportementaux et environnementaux de la maladie; avec en prealable l'identification des sites a risque de transmission. Elle a finalement permis de preciser plusieurs points utiles a la mise en place d'une politique de lutte efficace contre la bilharziose a Nkolbisson
Assuntos
Meio Ambiente , Camundongos , Esquistossomose mansoni/transmissão , Condições SociaisRESUMO
Une etude de la transmission de la bilharziose a ete entreprise dans l'Extreme Nord du Cameroun. Les barrages de Ouro tada; de Douvar-Oudahay et de Ouazan ont ete etudies. Les facteurs malacologiques et botaniques ont ete evalues. Une polarisation des activites en fonction de la pente des berges de la retenue a ete observee. Les zones de faible pente sont les plus utilisees et correspondent aux sites privilegies par les plantes supportant les colonies de mollusques hotes intermediaires de schistosomiase. D'autres aspects de l'interaction homme-plantes aquatiques sont discutes