In MalariaWorld this week there is a link to an article in The Conversation, ‘Illegal gold mining causes surges in malaria in the Amazon, and the association is far worse than we suspected’ by de Angeli Dutra and Casagrande. Malaria cases reported have increased from around 5,000 to 20,000 annually in Yanomami indigenous territory since then president of Brazil, Jair Bolsonaro, deregulated gold mining in indigenous territories of Brazil in 2019.
Since that time the number of illegal gold miners in Yanomami territory, the largest Indigenous territory in the Amazon, had surged to 20,000, roughly two-thirds the number of the local Yanomami population. The picture from the article is of a man with a phrase in Portuguese painted on his back that translates to “Mining Kills,” from a protest against the increase of mining activities that are encroaching on his land, in front of the Ministry of Mines and Energy in Brasilia, Brazil, in 2022.
Three explanations are given for the surge in malaria cases. The first two are a hat tip to the unproven mosquito-plasmodium hypothesis. The miners’ activities create pools for mosquito breeding (as if there were not already enough water pools for mosquito breeding in the Amazon basin), and miners travel potentially bringing the illness from hotspots for malaria transmission across South America (it is not clear where these hotspots are).
The third explanation and, in the opinion of Understanding Malaria, the most likely reason is that small-scale gold miners often use mercury to cheaply and easily extract gold particles. This mercury is dumped into waterways across the region, poisoning the people who rely on the rivers for water and for fish, weakening their immune systems and making them more susceptible to malaria. The most likely cause of malaria is malnutrition – both absence of nutrients and poisoning, and there are few poisons more toxic to mammals than mercury.
I visited an artisanal gold mine in Kenya and the final purification step was mixing a slurry of the final densest dust with mercury to form an amalgam. The mercury was later burned off to leave the gold metal. The people who do this with no protection will be poisoned and mercury poisoning symptoms are similar to malaria symptoms.
The authors were shocked by the results. The relationship was far stronger than they had suspected. Every 0.03% increase in mining led to a 20-46% increase in malaria one to two years later, resulting in a 300% increase in malaria in the Yanomami territory between 2016-2023.
This is no surprise to Understanding Malaria. We covered the link between mining and malaria previously in August 2024. Mining operations expose people to many toxic materials they would not otherwise be exposed to.