Prevalence of Plasmodium spp. in illegal gold miners in French Guiana in 2015: a hidden but critical malaria reservoir

Abstract

BackgroundMalaria is endemic in French Guiana, an overseas territory of France on the Guiana Shield. Since 2005, notified malaria cases are decreasing. However, new data show that malaria affects many Brazilian gold miners working illegally in French Guiana, the majority of whom are not counted in official data. In addition, one major concern is the usual practice of improper self-treatment in this mining population, raising fear of the development of anti-malarial resistance. This prospective study, conducted in 2015, aimed to estimate the prevalence of Plasmodium spp. in illegal gold miners working in French Guiana.MethodsThe recruitment of gold miners was carried out in resting sites along the French Guiana-Suriname border, where they go for supplies, medical care or leisure. After recording agreement, three malaria diagnostic methods were performed: rapid diagnostic test, microscopy and PCR.ResultsAmong 421 persons recruited in the study, malaria prevalence, detected by nested-PCR, was 22.3 % (CI [18.3–26.3], n = 94/421) of which 84 % were asymptomatic.ConclusionsThis significant malaria reservoir in a mobile and illegal population with difficult access to a health care system raises the threat of artemisinin resistance and puts the population of the Guiana Shield at risk of new transmission foci while countries of the region aim at malaria elimination. Even though French legislation may hamper dealing with this population, France must face the reality of malaria in illegal gold miners in order to meet its commitment to malaria elimination.

Malaria in Gold Miners in the Guianas and the Amazon: Current Knowledge and Challenges

“…was 22%; the situation was heterogeneous depending on the mining site with prevalence figures ranging from 4% up to 48%. A large proportion were asymptomatic: from 49 to 84% [39,12].…”

“…In Colombia, P. vivax represents 68% of malaria cases recorded nationally while P. falciparum is highly prevalent (46.7%) in the mining districts on the Pacific coast [5]. On the Guiana Shield, the incidence of P. falciparum has decreased in the general population to a minority level in Suriname as well as in French Guiana since 2005 [14,40] but remains predominant in gold miners, representing 58.5 to 70.7% of the identified cases [39,12]. At the border between French Guiana and Brazil, 40% of imported cases from French Guiana were due to P. falciparum [41].…”

Malaria in Southern Venezuela: The Hottest Hotspot in Latin America

“…These gold-mining areas likely make malaria transmission resilient to interventions, as they not only sustain transmission but also can restore it (“rescue effect”) after interventions have reduced malaria locally or even achieved local elimination in other areas as has been observed in Venezuela [15,57]. Transmission in such settings is considered the Gordian knot for achieving malaria elimination in Latin America [5,58,59]. Hotspot-targeted control has been hypothesized as an effective approach to reduce the burden of malaria in areas of heterogeneous malaria transmission [57,60].…”

Resurgence risk for malaria, and the characterization of a recent outbreak in an Amazonian border area between French Guiana and Brazil

“…At the onset of this type of change in power dynamics, there is often an administrative discontinuity of local governments, which may have consequences on public services [26]. Finally, political and economic regional crises, particularly in Venezuela but also in Brazil, have led to large-scale human migration into Brazil and is associated with an increase of illegal gold mining [4,27]. Unexpectedly, our results on incidence and spatial distribution revealed an additional human factor within the specific population of Amerindians.…”

“…The Oyapock river forms the border between French Guiana and Brazil. This area has engaged in a regional malaria control program [3], which faces challenges in controlling malaria among autochthonous and illegal gold miner populations living generally in remote areas and along the borders with Surinam and Brazil [2][3][4][5]. Malaria control interventions are carried out by free distribution of insecticide-treated nets and free access to diagnosis and artemisinin-based therapy on both side of the border [3].…”