NewsLatin AmericaA study quantifies how mining and deforestation revived malaria in Venezuela

A study quantifies how mining and deforestation revived malaria in Venezuela

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In the 1950s, Venezuela began to position itself as the leading country in combating malaria. Thanks to an impressive fumigation campaign and studies carried out at that time by the Venezuelan doctor and health worker Arnoldo Gabaldon, the country became one of the first to eliminate this disease in a large part of the territory. By 1961, malaria was not present in 68% of Venezuela, and between 1936 and 1962, the mortality rate dropped from 164 deaths per 10,000 people to a staggering zero.

But the success that Gabaldon achieved today is a ghost. The 2020 World Malaria Report estimated that cases in Venezuela had increased 1,200% between 2000 and 2019. And in the first two weeks of 2022 alone, the UN diagnosed 2,796 cases of malaria throughout the country. Gabaldon’s legacy had crumbled.

“The first thing was that the malaria control programs stopped working. Access to anti-malaria drugs and vector control tools decreased,” recalls Dr. Maria Eugenia Grillet, tenured professor and researcher at the Institute of Zoology and Tropical Ecology of the Central University of Venezuela in an interview with America Futura. “Then, due to the political and economic situation in the country, many went to work in the gold mines in southern Venezuela, affecting and modifying the landscape, opening roads through the forest.” Deforesting.

Added to this were two factors that are known to promote malaria: heat and increased rainfall. “Heat not only accelerates the development of the parasite that causes malaria disease – Plasmodium -, but of the mosquitoes that transmit them – the anopheles -”, explains Isabel Fletcher, a doctor graduated from the London School of Hygiene and Tropical Medicine, United Kingdom. The rains, for their part, end up in stagnant water that mosquitoes need to complete their reproduction cycle.

A group of miners search for diamonds in Parai-Tepui, Venezuela, on May 14, 2019.Michael Robinson Chavez (Getty Images)

But what role does each of these factors play in the increase in malaria? What percentage can be related to the boom of mining that lives in southern Venezuela? This was the type of questions that began to haunt the heads of a team of researchers that Fletcher and Grillet are part of. After creating a model with malaria cases since 1996 and potential associated variables such as soil temperature, rainfall, deforestation, and mining footprint, among others, they found that, in the case of the parasite Plasmodium falciparum, mining could explain 27% of the variation and temporal increase in malaria, while for the Plasmodium vivax the figure was 23%.

“We made this separation because in Latin America the P. vivax It is the one that affects us the most, with approximately 70% prevalence. While the P.falciparum, which causes more serious disease, is only responsible for 30% in our region. This last species is more present in Africa”, explains Grillet.

In addition, in the results of this research, which was published in The Lancetpoint out that, in the areas without mining but that did register an increase in temperature, there was no higher incidence of malaria cases, pointing again to the strong role played by this extractive activity.

In the state of Bolivar, for example, where mine sources have been identified (2,460, representing 96% of those in the entire country), malaria increased between 1996 and 2016: 1,609% for P.falciparum and 2.986% for P. vivax. In these areas, Fletcher comments, a series of triggering factors come together again: deforestation, lack of medical services, water wells left behind by mining, and the conglomeration of people who have come looking for work. What is worrisome, Grillet adds, is that when workers return to their home states they may also be carrying malaria with them, spreading this parasite across the country.

“This is important research insofar as it can identify with great certainty how a factor of the landscape and the climate interact in the transmission of malaria,” concludes Rachel Lowe, Fletcher’s tutor, co-author of the study and a researcher at the School of Hygiene. and Tropical Medicine of London. “And this is relevant to early warning systems in a country or region, because it indicates that we can use climate information to try to predict malaria risk.”

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