Spatial distribution of schistosomiasis foci on Itamaracá Island, Pernambuco, Brazil

Acute cases of schistosomiasis have been found on the coastal area of Pernambuco, Brazil, due to environmental disturbances and disorderly occupation of the urban areas. This study identifies and spatially marks the main foci of the snail host species, Biomphalaria glabrata on Itamaracá Island. The chaotic occupation of the beach resorts has favoured the emergence of transmission foci, thus exposing residents and tourists to the risk of infection. A database covering five years of epidemiological investigation on snails infected by Schistosoma mansoni in the island was produced with information from the geographic positioning of the foci, number of snails collected, number of snails tested positive, and their infection rate. The spatial position of the foci were recorded through the Global Positioning System (GPS), and the geographical coordinates were imported by AutoCad. The software packages ArcView and Spring were used for data processing and spatial analysis. AutoCad 2000 was used to plot the pairs of coordinates obtained from GPS. Between 1998 and 2002 5009 snails, of which 12.2 percent were positive for S. mansoni, were collected in Forte Beach. A total of 27 foci and areas of environmental risk were identified and spatially analyzed allowing the identification of the areas exposed to varying degrees of risk.

Studies on survival, biological activities and behavior of Biomphalaria glabrata, the host snail of Schistosomiasis, submitted to increased hydrostatic pressure: a technique

Para estudar mudanças na sobrevivência, atividades biológicas e comportamento de planorbídeos submetidos a aumento de pressäo hidrostática, desenvolvemos uma técnica que utiliza duas câmaras transparentes e um pistäo hidráulico. O aparelho permitiu a renovaçäo do meio líquido sem variaçöes substanciais na pressäo, eliminando assim os produtos de excreçäo e mantendo o nível de O2 disseolvido desejado, e desse modo permitido-nos avaliar o efeito da pressäo independente da ocorrência de anoxia. A pressäo foi mantida sem nenhum contato do meio líquido com o ar comprimido, situaçäo que produziu com relativa fidelildade o que ocorre na natureza, e assegurou a presença da mesma quantidade de gases nas duas câmaras de observaçäo. Biomphalaria glabrata foi capaz de sobreviver pelo menos 48 horas quando submetida a 49,02 x 10 Pa (equivalente a 48 m de profundidade) continuando a pôr massas ovíferas, e mostrando poucas modificaçöes comportamentais quando comparada com o grupo de controle