Challenges for malaria elimination in Brazil

Abstract

Brazil currently contributes 42 % of all malaria cases reported in the Latin America and the Caribbean, a region where major progress towards malaria elimination has been achieved in recent years. In 2014, malaria burden in Brazil (143,910 microscopically confirmed cases and 41 malaria-related deaths) has reached its lowest levels in 35 years, Plasmodium falciparum is highly focal, and the geographic boundary of transmission has considerably shrunk. Transmission in Brazil remains entrenched in the Amazon Basin, which accounts for 99.5 % of the country's malaria burden. This paper reviews major lessons learned from past and current malaria control policies in Brazil. A comprehensive discussion of the scientific and logistic challenges that may impact malaria elimination efforts in the country is presented in light of the launching of the Plan for Elimination of Malaria in Brazil in November 2015. Challenges for malaria elimination addressed include the high prevalence of symptomless and submicroscopic infections, emerging anti-malarial drug resistance in P. falciparum and Plasmodium vivax and the lack of safe anti-relapse drugs, the largely neglected burden of malaria in pregnancy, the need for better vector control strategies where Anopheles mosquitoes present a highly variable biting behaviour, human movement, the need for effective surveillance and tools to identify foci of infection in areas with low transmission, and the effects of environmental changes and climatic variability in transmission. Control actions launched in Brazil and results to come are likely to influence control programs in other countries in the Americas.

Keywords: Brazil; Malaria; Malaria control; Malaria control challenges; Malaria elimination.

Fig. 1

Annual number of houses sprayed with dichloro-diphenyl-trichloroethane (DDT) in Brazil between 1945 and 1997. Data for the years 1945–1959 and 1965–1986 were obtained from the Brazilian Institute of Geography and Statistics, available at: http://seculoxx.ibge.gov.br/pt/populacionais-sociais-politicas-e-culturais/busca-por-palavra-chave/saude/985-malaria. Data for the years 1960–1964 were extracted from PAHO/WHO reports [199]. Data for 1987–1997 were extracted from Loiola [52]

Fig. 2

Extension of the malaria endemic areas in Brazil in 1960 and 2014. The figure shows how the malaria map in Brazil shrunk between 1960 and 2014. Currently, transmission is virtually limited to the Amazon Basin, an area that covers 60 % of the Brazilian territory and houses 13.4 % of the country’s population. States that compose the Amazon region have their names written in uppercase. Data obtained from the National Malaria Prevention and Control Program, Ministry of Health of Brazil

Fig. 3

Annual number of laboratory-confirmed malaria cases reported in Brazil from 1959 to 2014. The total number of cases, those due to Plasmodium falciparum, and the number of malaria-related deaths are shown. Data obtained from the National Malaria Prevention and Control Programme, Ministry of Health of Brazil

Fig. 4

Area covered by the Atlantic Forest biome in Brazil, where pockets of bromeliad-malaria transmission persist. The extension of the Atlantic forest biome was defined by a federal law in 2006. More than 60 % of the population lives in large urban centers located in the Atlantic forest biome, thus, of the original biome area (which represents 17.4 % of the Brazilian territory), only about 8 % remains as forest. States that compose the Amazon region have their names written in uppercase

Fig. 5

Current Plasmodium falciparum foci in Brazil. Municipalities indicated with circles in the map accounted for about 75 % of the laboratory-confirmed P. falciparum infections recorded in the Amazon in 2014. The circle sizes are proportional to the absolute number of cases in each municipality. Four high-risk municipalities (Cruzeiro do Sul, Mâncio Lima, Rodrigues Alves, and Guajará) are situated in Juruá Valley, westernmost Brazil, close to the border with Peru