Malaria is considered one of the most important public health problems in Brazil, and the Amazon Basin alone has been responsible for more than 80% of the cases registered in the country since the last decade. ln its spread throughout the Basin, mataria has always been intimately associated with the development projects conducted in the region. New highways, dams and colonization projects have been extensively undertaken by the government in the last two decades, stimulating thousands of people to migrate to Amazonia, especially small peasant farmers looking for land, gold mining and other activities.