Malaria in the Legal Amazon: a retrospective study of reported cases

Abstract

Malaria is an endemic disease in the tropical region of the Americas, with increasing trends in cases in the second decade of the 21st-century. This study analyzed cases reported by the Malaria Epidemiological Surveillance System (SIVEP-Malaria) from 2003 to 2018 in the Brazilian legal Amazon. A total of 6,017,752 cases were reported (annual average 376 thousand), and the following states stand out: Amazonas (2,081,231), Pará (1,460,252), Rondônia (964,526), and Acre (678,692), which correspond to 86.2% of reported cases. Three peaks of cases were observed: 2005 (757,514), 2010 (415,264), and 2018 (243,180). A growing trend in the number of cases between 2003 and 2005 (average of 597 thousand cases). Decrease from 2006 to 2016 (average reduction of 12%) with a new upward trend until 2018. The spatial distribution shows that 67% of cases is located in the Western Amazon and 33% in the Eastern Amazon. Brazil presented good results in combating malaria during the study period. Fluctuations in the number of cases are an expression of the complex system that involves the transmission of the disease, which makes monitoring and follow-up by health services necessary