Malaria in gold-mining areas in Colombia

Abstract

Gold-mining may play an important role in the maintenance of malaria worldwide. Gold-mining, mostly illegal, has significantly expanded in Colombia during the last decade in areas with limited health care and disease prevention. We report a descriptive study that was carried out to determine the malaria prevalence in gold-mining areas of Colombia, using data from the public health surveillance system (National Health Institute) during the period 2010-2013. Gold-mining was more prevalent in the departments of Antioquia, Córdoba, Bolívar, Chocó, Nariño, Cauca, and Valle, which contributed 89.3% (270,753 cases) of the national malaria incidence from 2010-2013 and 31.6% of malaria cases were from mining areas. Mining regions, such as El Bagre, Zaragoza, and Segovia, in Antioquia, Puerto Libertador and Montelíbano, in Córdoba, and Buenaventura, in Valle del Cauca, were the most endemic areas. The annual parasite index (API) correlated with gold production (R2 0.82, p < 0.0001); for every 100 kg of gold produced, the API increased by 0.54 cases per 1,000 inhabitants. Lack of malaria control activities, together with high migration and proliferation of mosquito breeding sites, contribute to malaria in gold-mining regions. Specific control activities must be introduced to control this significant source of malaria in Colombia.

Fig. 1A. : gold-mining distribution in malaria endemic areas in Colombia. Name and geographic gold-mining districts (GMD) distribution in Colombia. Source: modified from simco.gov.co/Simco/Portals/0/mapaDistritosMineroscolombia2008.pdf; B: gold-mining production units or municipalities (spot) by GMD. Source: modified from Cuales son los distritos mineros de Colombia? (simco.gov.co/simco/Politicasdelsector/MejoramientodelaProductividadyCompetitividad/Gesti%C3%B3ndelosDistritosMineros/tabid/86/Default.aspx); C: total morbidity of malaria distribution in Colombia by parasite species in 2010-2013.

Fig. 2. : correlation between annual parasite index (API) and gold-mining district (GMD) production. The increased value of API is explained by tons of gold produced in a GMD (northeast Antioquia) from 2010-2013 (A: 2010; B: 2011; C: 2012; D: 2013). Populations with greater than 50 tons of gold produced had higher risk of malaria infection than those with a lower production. CI: confidence interval.

Fig. 3. : distribution of Anopheles species in gold-mining areas of Colombia. Illegal gold mines are shown in yellow and legal mines are shown in red. Dark dots show the distribution for the indicated mosquito species in each map. Source: modify from Montoya-Lerma et al. (2011).