Multiple independent introductions of Plasmodium falciparum in South America

Abstract

The origin of Plasmodium falciparum in South America is controversial. Some studies suggest a recent introduction during the European colonizations and the transatlantic slave trade. Other evidence—archeological and genetic—suggests a much older origin. We collected and analyzed P. falciparum isolates from different regions of the world, encompassing the distribution range of the parasite, including populations from sub-Saharan Africa, the Middle East, Southeast Asia, and South America. Analyses of microsatellite and SNP polymorphisms show that the populations of P. falciparum in South America are subdivided in two main genetic clusters (northern and southern). Phylogenetic analyses, as well as Approximate Bayesian Computation methods suggest independent introductions of the two clusters from African sources. Our estimates of divergence time between the South American populations and their likely sources favor a likely introduction from Africa during the transatlantic slave trade.

Evolutionary structure of Plasmodium falciparum major variant surface antigen genes in South America: Implications for epidemic transmission and surveillance

“…(2012). These isolates were collected between 2002 and 2008 from individuals presenting with clinical malaria from five study site locations in four countries from South America: Peru (Iquitos), Venezuela (El Caura), Colombia (Turbo), and French Guiana (Camopi and Trois Sauts) (Figure 1a).…”

“…Strong founder effects, resulting from global migration, have led to P. falciparum geographic variation in single nucleotide polymorphisms (SNPs) and microsatellites (MS) with the greatest diversity being observed within Africa. This spatial variation is particularly striking in South America where two main genetic clusters, previously shown through SNPs and MS variation, suggest independent introductions of P. falciparum from Africa through the transatlantic slave trade about 500 years ago (Yalcindag et al., 2012). Yalcindag and colleagues provided evidence for structuring of the parasite population into a northwestern cluster (Colombia) and a southeastern cluster (French Guiana/Brazil/Bolivia; Yalcindag et al.…”

“…Yalcindag and colleagues provided evidence for structuring of the parasite population into a northwestern cluster (Colombia) and a southeastern cluster (French Guiana/Brazil/Bolivia; Yalcindag et al. 2012). This structure is believed to have originated through distinct human population movements related to the subdivision of the continent into the Portuguese and Spanish empires and is maintained today through the admixture of populations (Venezuelan and Peruvian) between these two clusters.…”

“…The genetic markers used in the study of P. falciparum population structure in South America by Yalcindag et al. were putatively neutral allowing for inference of population history as well as demographic events (Yalcindag et al., 2012). They, however, do not define characteristics of parasite fitness (Kirk & Freeland, 2011).…”

“…Structuring of var genes across local populations on the South American continent, however, has not been established. In this study, using next‐generation 454 sequencing, we have successfully genotyped the var DBLα domains of 128 P. falciparum clinical field isolates collected from four countries in South America between 2002 and 2008 and for which SNP and MS data were available for comparison (Yalcindag et al., 2012). Population genetic analysis using var genes has allowed us to address the following questions: (i) What are the limits of var gene diversity in these South American populations?…”