Malaria Outbreak Linked to Illegal Mining Practices

An ongoing malaria outbreak in Colombia has been linked to illegal mining practices in the South American country, according to an April 30th report from news wire service Agence France-Presse (AFP).

The unusual—but not all together surprising, at least from the perspective of public health experts—connection has been made at a time in which the mosquito-borne disease has been largely eradicated throughout the region. Colombia’s National Health Institute has reported a 30 percent increase in reported malaria cases over the past three years, a period that has seen a significant uptick in mining activities (primarily gold) in the country. Overall, the World Health Organization (WHO) reports that the malaria death rate in South America has dropped 72 percent since 2000. WHO expects to eradicate the disease in eight Latin American countries by 2020.

According to Ravinder N.M. Sehgal, PhD, associate professor, Department of Biology, San Francisco State University, the accumulation of standing water in mining areas has likely created the ideal environment for an outbreak. For many of these mines, effectively “strip mines,” activists in the area say that excavators remove vegetation and dig huge holes in the ground, which allow water to accumulate.

“For a malaria outbreak to occur, you need to have people, you need to have the right conditions, and you need to, of course, have mosquitoes,” Dr. Sehgal, whose research focuses on the “ecology of infectious disease,” told Contagion. “It’s not exactly clear what’s going on in Colombia at this point, but we likely have a situation where you have human beings coming into an area to work in the mines—migrant workers essentially—who may have malaria and are infecting the indigenous population, and you have standing water associated with the mining activities. It’s not surprising that an outbreak has occurred.”

AFP reports that mining is a major source of revenue for Colombia. In 2012, the last year for which official figures are available, legal mining accounted for 2.3 percent of GDP, or $8.5 billion (US). However, it is estimated that more than half of Colombia's mining sites are illegal, and this widespread activity in Colombia has already come under intense scrutiny because of the environmental impact—pollution and deforestation, among other damaging effects—at least based on media reports emanating from the country.

Dr. Sehgal said there is a growing body of research linking deforestation with malaria transmission in other parts of the world. In addition, what makes preventing, or at least managing, new outbreaks all the more challenging is that malaria is asymptomatic in as many as 75 percent of all cases. If mining workers are coming to western Colombia from areas where the disease is still active, Dr. Sehgal explained, they may be transmitting it to new populations, without even knowing it.

“Once you delete malaria from a country, it’s very difficult for it to come back,” he continued. “But once it’s back, many of these communities lack access to healthcare facilities to treat the disease, the necessary medicine, and the resources for prevention, such as mosquito nets, making control problematic.”

Brian P. Dunleavy is a medical writer and editor based in New York. His work has appeared in numerous healthcare-related publications. He is the former editor of Infectious Disease Special Edition.