Objective: To evaluate an algorithm developed for detecting variations in the incidence of malaria in the Brazilian Amazon.
Methods: An evaluation was conducted of an automated monitoring system based on an algorithm that had been previously developed by the authors. The algorithm employs quartile diagrams to classify municipalities according to variations in the incidence of malaria: group 1 (reduced incidence)-municipalities with below the expected incidence rates; group 2 (expected incidence)- within the expected incidence rates; group 3 (epidemics)-higher than the expected incidence rates; and group 4 (sporadic case)-a single case during a year. The period from 2003 to 2010 was analyzed. All the municipalities in the nine states that make up the Brazilian Amazon were studied (805 municipalities in 2003 and 807 starting in 2004).
Results: Based on this method, Amazonian municipalities were classified as follows: group 1, 152 (18.8%) municipalities in 2003 and 109 (13.5%) in 2010; group 2, 206 (25.6%) municipalities in 2003 and 331 (41.0%) in 2010; group 3, 391 (48.6%) municipalities in 2003 and 308 (38.2%) in 2010; and group 4, 56 (7.0%) municipalities in 2003 and 59 (7.3%) in 2010.
Conclusions: The use of the algorithm revealed that in 2010, the number of Amazonian municipalities in group 3 (epidemics) decreased when compared to 2003, while the number of municipalities in group 2 (expected incidence) increased. In the same period, there was no significant variation in the number of municipalities in group 1 (reduced incidence) and in group 4 (sporadic case).