[Aspects of the focal transmission of malaria in the Island of São Luis, Maranhão].

The aim of the study was to typify a malaria focus in Guarapiranga, in the district of São José de Ribamar, MA. A questionnaire regarding identification, economic situation, habits of the residents and characteristic of the residences was applied to each family. Fifty four families were visited and 207 inhabitants were interviewed (113 men and 95 women); 95 individuals were aged between 5 and 24 years old. Agriculture and fishing are the basis of the local economy; 64.8% of the families earn less than one living wage. The majority of the residences are constructed of mud walls, straw roofs, a beaten earth floor, with no basic sanitation. 62.2% of the residences are partially protected against the entry of mosquitoes. Water for domestic use comes from natural waterholes in 78.8% of the residences. Rubbish is left in the open air in 53.7% of the residences. 106 cases of malaria by Plasmodium vivax were notified. Anopheles (N) aquasalis was the probable vector and treatment with chloroquine associated with primaquine showed good results.