Banner: Yanomami ornament. Source: Paolo Terzi, Wikimedia Commons (CC BY-SA 3.0)
Deep in the Amazon rainforest, on the border between Venezuela and Brazil, live the Yanomami, a group of around 36,000 indigenous people whose in villages span across 192,000 km2. The Yanomami hunt, fish, forage, and grow plantain and bananas; their deep knowledge of the rainforest means their use of local resources is usually aligned with the natural cycles of the environment. Yet in recent years, their territory has become the centre of a humanitarian emergency marked by hunger, displacement and collapsing health services.
And among these many concerns - malaria
Transmitted by the bite of Anopheles mosquitoes, malaria remains one of the world’s most serious infectious diseases. Although Brazil made significant progress in reducing malaria through strengthened control efforts in the early 2000s, this success has not been consistent across the region.
In recent decades, malaria has resurged in Indigenous territories and areas affected by deforestation and illegal gold mining. During a period of weakened environmental protections, intensified mining and deforestation expanded rapidly across the Amazon. These land use changes are known to increase malaria risk by altering mosquito habitat and disrupting local ecosystems.
Taking a closer look
A new study by de Angeli Dutra and colleagues, published in Biology Letters, examines how these shifts have changed malaria risk in Yanomami territory over the past twenty years. The researchers combined two decades of malaria records from Yanomami lands with satellite data tracking forest loss, forest fragmentation, and the rapid spread of illegal gold mining. Each malaria case was tied to a precise location and local population size, allowing the researchers to follow how disease patterns changed as the landscape transformed.
To understand the recent surge in malaria, the team used a statistical approach that compares each place to itself over many years. This helped them separate the effects of land‑use change from broader influences like national policy shifts or climate variation. They analysed both total malaria cases and infections caused by Plasmodium falciparum, the most dangerous of the malaria parasite species.
The findings
The results were striking. After years of relative stability, malaria cases began rising around 2015 and then climbed sharply as illegal gold mining expanded. By 2022, more than 20,000 cases were recorded. This rise wasn’t uniform: some health districts were hit hard while others barely changed, suggesting strong local drivers. Forest edges and secondary vegetation grew rapidly near infection sites, creating conditions that favour mosquito breeding.
When the team tested these patterns statistically, illegal gold mining emerged as a major driver of malaria. Increases in mining activity were linked to higher malaria incidence one to two years later, suggesting longer‑term ecological and social effects rather than immediate spikes. Forest fragmentation also played a key role: expanding forest edges were associated with substantial increases in malaria, while forest regrowth appeared to reduce risk. Interestingly, climate showed no consistent influence at this scale.
In context
The analyses by de Angeli Dutra and colleagues indicate that illegal gold mining has been a major driver of recent malaria increases, with mining expansion linked to significantly higher malaria incidence one to two years later. This delay suggests that mining reshapes local conditions in lasting ways, through forest fragmentation, altered mosquito habitat and possibly longer‑term effects (e.g., mercury contamination).
In a wider context, these findings mirror patterns seen across the Amazon and other malaria‑endemic regions, where mining concentrates mobile, often untreated populations in remote areas and undermines control efforts. In the Yanomami case, the surge in mining coincided with rising gold prices and a period of weakened environmental and Indigenous protections, helping explain why malaria worsened even as Brazil reduced transmission elsewhere.
On January 2023, the Brazilian authorities declared a public health emergency, and after two years of federal interventions some good news started to emerge: illegal mining had decreased, and healthcare access improved across Yanomami territory. The challenge now is making this progress last. Eliminating malaria requires sustained action and a commitment to environmental justice for Indigenous communities who have carried the burden of extractive pressures for decades.
Learn more about the Yanomami:
https://www.yanomamifoundation.org/yanomami
https://sumauma.com/en/nao-estamos-conseguindo-contar-os-corpos/
https://en.wikipedia.org/wiki/Yanomami_humanitarian_crisis