Health threats related to road paving in the eastern Brazilian Amazon

Economic development is often invoked as a driving force able to improve social and health conditions of remote areas. However, development projects produce “unequal and combined” impacts on local communities due to their diverse insertion in the society. This work examines the spatial distribution of three major health threats in the Brazilian Amazon, which may be altered by the construction of roads. Homicide mortality, Aids incidence and Malaria prevalence rates were calculated for 70 municipalities located in the influence area of the Cuiabá-Santarém road (BR-163), i.e., the west of Pará state and north of Mato Grosso state. The municipalities were characterized using social and economic indicators such as GDP, urban and indigenous populations, and recent migration. Connections among municipalities were identified by assigning those situated along the main transportation lines of the region (BR-163, Transamazonica road, Amazon and Tapajós rivers). Multiple regression was used to identify the major driving forces and constraints in the distribution of health threats. The main explanatory variables of malaria are: proximity to Transamazonica road, high indigenous population and low proportion of migrants. Homicide distribution is explained by the high proportion of migrants while the connection to the Amazon River plays a protective role. Aids incidence is higher in municipalities with recent increase of GDP and high proportion of urban population. Roads induce social and environmental changes and play different roles in the spread and maintenance of diseases and injuries. The most remote areas are still protected against violence but vulnerable to malaria. Rapid economic and demographic growth increase risks of Aids transmission and violence. Roads connect secluded localities and may threat local population. The region has been undergoing rapid and localized development outbreaks, such as mining and wood extraction activities which act as spots of disease and health hazards.