In July 2026, MapBiomas awarded second place to a study outlining the link between illegal gold mining and malaria cases in the Yanomami Indigenous Territory in the Brazilian Amazon.
Published in November 2025, the study examined malaria and mining data from 2010 to 2023, including the surge in cases during Jair Bolsonaro’s presidency from 2019 to 2022. The researchers say his far-right government weakened environmental protections and threatened Indigenous rights as illegal mining expanded in the territory, which is home to more than 31,000 Yanomami.
The report outlines how the illegal miners, known as garimpeiros, contributed to a humanitarian and health crisis among the local population by spreading disease, contaminating water sources with mercury, and scaring away wildlife.
The study, led by researcher Márcia Castro from the Harvard TH Chan School of Public Health, found that a 1% increase in annual area mined was associated with a 24% increase in monthly malaria cases in the Yanomami. It was also estimated that an increase in mining activity caused an excess of 102,870 malaria cases between 2018 and 2023.
The researchers found that malaria cases also increased in areas that were used as routes by miners, even where no mining was taking place.
Speaking to Mongabay, Castro says the movement of miners carrying equipment and supplies through Indigenous lands helps spread the disease beyond active mining areas.
The study notes long-term measures are needed to strengthen enforcement against illegal mining, protect Indigenous rights, and improve cooperation between health, law enforcement, and environmental sectors.
Castro and her team are developing a strategy to help eliminate malaria in Brazil. The researchers plan to use the data on mining, deforestation, and climate to create an alert system that would warn local health authorities of potential outbreaks.
This system would rely on a new MapBiomas tool under development that is intended to outline new mining sites weekly. Mining data are currently published annually, with Mongabay reporting that the weekly alert may be ready by early 2027.
MapBiomas is a multi-institutional network of universities, non-governmental organisations, and technology companies. It creates land-cover and land-use maps using satellite imagery, machine learning, and cloud computing through Google Earth Engine.
Write to Amy Rotman at Mining.com.au
Main image: Fernando Frazão/Agência Brasil
