Many malaria cases in the Americas are reported in Brazil (Silveira 2001; Oliveira-Ferreira, Lacerda et al. 2010). In 2011, 293,701 malaria cases were reported to the Brazilian National Reportable Disease Information System. Most of these cases (99.7%) occurred in the Amazon region, which encompasses the states of Acre, Amazonas, Amapa, Para, Maranhao, Mato Grosso, Roraima, Rondonia, and Tocantins. In this region, socio-economic and environmental conditions, such as presence of natural breeding sites and abundance of Anopheles mosquitoes, favor malaria transmission. Amazonas, Rondonia, Para, and Acre states were responsible for 85.5% of malaria cases in 2011 according to the Brazilian National Reportable Disease Information System. As in other regions of the world, malaria is seasonal in Brazil, cases increase during or after the rainy season (Costa 2009).