Malaria in the state of Rio de Janeiro,Brazil, an Atlantic Forest area: an assessment using the health surveillance service

The lethality of malaria in the extra-Amazonian region is more than 70 times higherthan in Amazonia itself. Recently, several studies have shown that autochthonousmalaria is not a rare event in the Brazilian southeastern states in the AtlanticForest biome. Information about autochthonous malaria in the state of Rio de Janeiro(RJ) is scarce. This study aims to assess malaria cases reported to the HealthSurveillance System of the State of Rio de Janeiro between 2000-2010. An average of90 cases per year had parasitological malaria confirmation by thick smear. The numberof malaria notifications due to Plasmodium falciparum increased overtime. Imported cases reported during the period studied were spread among 51% of themunicipalities (counties) of the state. Only 35 cases (4.3%) were autochthonous,which represents an average of 3.8 new cases per year. Eleven municipalities reportedautochthonous cases; within these, six could be characterised as areas of residual ornew foci of malaria from the Atlantic Forest system. The other 28 municipalitiescould become receptive for transmission reintroduction. Cases occurred during allperiods of the year, but 62.9% of cases were in the first semester of each year.Assessing vulnerability and receptivity conditions and vector ecology is imperativeto establish the real risk of malaria reintroduction in RJ.