Belém, Brazil – Gland, Switzerland (11 SEPTEMBER 2025) — New research published today in Communications Earth and Environment, a Nature Group journal, finds that municipalities in the Amazon region closest to healthy forests on Indigenous lands face less risk from rising cases of two categories of disease: cardiovascular and respiratory diseases due to forest fires and illnesses spread when humans come into closer contact with animals and insects.
The findings, released at the onset of forest fire season in the region and in advance of the climate negotiations (COP30) in Belem, Brazil, is the latest study in a growing body of evidence showing that Indigenous land rights are critical to tackling climate change, biodiversity loss and disease spread that, in the case of forest fires, create immediate and widespread health hazards.
"Indigenous forests in the Amazon bring health benefits to millions," said Paula Prist, Senior Programme Coordinator of the Forests and Grasslands Programme of the International Union for Conservation of Nature (IUCN)."We have long known that the rainforest is home to medicinal plants and animals that have cured countless illnesses. This study offers new evidence that forests themselves are a balm for fire-related threats to people's lungs and hearts, to illnesses like Chagas, malaria and spotted fevers. Ensuring Indigenous communities have strong rights over their lands is the best way to keep forests and their health benefits intact."
Researchers examined 20 years of data on 27 health issues – 21 fire-related and six zoonotic (spread from animals to people) or vector-borne (spread from insects to people) diseases – across eight Amazonian countries: Bolivia, Brazil, Colombia, Ecuador, Peru, Suriname, Venezuela, and French Guiana. The study "Indigenous Territories Can Safeguard Human Health Depending on the Landscape Structure and Legal Status" revealed that lands managed by Indigenous Peoples consistently decrease disease incidence.
"The study comes just as forest fire season arrives in Amazon countries," said Ana Filipa Palmeirim, visiting professor, Federal University of Pará and co-first author of the study. "These fires fill the air with thick, choking smoke, sending droves to the hospital for respiratory ailments. As daily life comes to a complete standstill, children and the elderly must stay home to avoid hospital visits. Even when fires take place in remote forest areas, winds spread the pollution far and wide, creating deadly public health emergencies."
Between 2001 and 2019, almost 30,000,000 cases of fire-related, zoonotic, and vector-borne diseases were reported in the Amazon rainforest. Illnesses studied include Chagas disease, malaria, hantavirus, visceral and cutaneous leishmaniasis and spotted fevers. Studies have shown that deforestation is directly linked to a rise in these so-called neglected tropical diseases, which don't have readily-available cures. Across the region, deforestation is increasing due to aggressive agriculture expansion, oil drilling and large infrastructure projects like roads and hydropower plants.
Intentionally set forest fires have emerged as a particularly significant threat to the Amazon region and the people living there. Many fires are started by illegal actors who cut down forests without permission to do so, then burn the remaining vegetation to make room for cattle grazing or crops. Climate change impacts – such as high temperatures and decreased rainfall– increase the frequency and intensity of wildfires and the area burned.
Exposure to these fires leads to increased respiratory symptoms, heart disease, stroke, emphysema and lung cancer, as well as bronchitis, asthma, chest pain, chronic lung and heart problems. In the Amazon, forest fire smoke is directly linked to an increase in hospitalizations for these ailments. In the Brazilian Amazon alone, between 2002 and 2011, the fires were responsible for, on average, 2,906 premature deaths from cardiopulmonary disease and lung cancer.
The study released today builds on recent research findings that the Indigenous forests in the Brazilian Amazon can potentially prevent about 15 million cases of respiratory and cardiovascular infections each year by soaking up pollutants emitted by forest fires.
