The impact of hydropower dam construction on malaria incidence: Space-time analysis in the Brazilian Amazon

Abstract

During the first two decades of the 21st century, Brazil carried out massive public investments on infrastructure projects, such as large hydropower dams, with potential impact on population health. Here we characterize local malaria transmission and its potential spread during the construction of three large hydropower dams in the Brazilian Amazon. We focus on Porto Velho (PVH), in Rondônia state, where the Santo Antônio and Jirau dams were built (2008–2013), and Altamira region (ATM), in Pará state, where the construction of the Belo Monte dam took place (2011–2016). Analyzed data cover 4 years before, 6 years during, and 4 years after each dam construction. In total, we utilized malaria case notifications entered into the electronic malaria notification system of the Ministry of Health of Brazil between January 2004 and December 2020 (n = 39,977,167 malaria notifications). First, we used Interrupted Time-Series Analysis (ITSA) to assess temporal changes in malaria notifications in the study sites. Then, we conducted a space-time cluster analysis to investigate the potential of malaria spread from the study sites (sources) to elsewhere (sinks). Finally, we present the sociodemographic characteristics of exported cases over time using multivariate logistic regressions. Our results show that there was no upsurge in malaria cases in the study sites and exported cases did not trigger outbreaks in other localities. Exported malaria infections originating from PVH and ATM were typically found in working age literate males involved in mining, farming or traveling. We suggest that efficient control measures, such as ensuring timely diagnosis and treatment; fostering integrated vector control; promoting health education; and prevention, detection and containment of outbreaks, if properly implemented and sustained, may prevent local and introduced malaria outbreaks during and after hydropower dam construction in the Amazon.

Poverty–Food Insecurity Nexus in the Post-Construction Context of a Large Hydropower Dam in the Brazilian Amazon

“…Notwithstanding the frequent failures in the monitoring of environmental licensing processes for hydropower dams in the Brazilian Amazon, certain mitigation and compensation actions may have achieved some level of success. Data suggests that malaria control programs, which were implemented as part of the mitigation plan, were strengthened in areas where recent dams were constructed, including the influence area of Belo Monte, resulting in a significant decrease in malaria notifications [84]. Unfortunately, malaria control seems to be an exception, as other public health issues were not given equal priority by dam builders [85].…”

Ecosystem Links: Macrophytes, Snail Preferences, and Trematode Transmission in Man-Made Water Bodies

“…Ecological disturbances caused by both natural and human factors can lead to the emergence and spread of diseases (Lawler et al, 2021). Activities such as deforestation, human settlement, road construction, and water development projects have been linked to a rise in parasitic diseases (Ellwanger et al, 2020;Johansen et al, 2023;Kibret, 2018;Sokolow et al, 2017).…”

“…Ecological disturbances caused by both natural and human factors can lead to the emergence and spread of diseases (Lawler et al, 2021). Activities such as deforestation, human settlement, road construction, and water development projects have been linked to a rise in parasitic diseases (Ellwanger et al, 2020; Johansen et al, 2023; Kibret, 2018; Sokolow et al, 2017). The mechanisms by which these factors increase disease transmission are diverse and can include changes in water quality due to pollution or disruption, alterations in aquatic community structure, or the introduction of new species, and the expansion of snail habitats caused by the proliferation of macrophytes (Carolus et al, 2019; Lange et al, 2013; Steinmann et al, 2006).…”