Genome-wide characterization of Plasmodium vivax infections in local travelers and non-travelers from the Peruvian Amazon

In areas progressing toward malaria elimination, distinguishing locally acquired from imported malaria infections is essential for targeted surveillance. We used whole-genome sequencing (WGS) to characterize Plasmodium vivax infections in individuals with reported local travel and non-travelers in three communities in the Peruvian Amazon: Libertad (n = 24), Gamitanacocha (n = 23), and Urco Miraño (n = 9). Among 56 confirmed P. vivax infections, 16 were identified in local travelers. DNA was extracted from whole blood, selectively amplified, and parasite species were confirmed by qPCR. Genetic diversity was assessed using expected heterozygosity and nucleotide diversity, genetic differentiation using Fst, population structure using PCA, DAPC, and ADMIXTURE, and relatedness using IBD analysis. Traveler-associated infections in Libertad showed higher diversity than non-travelers (mean He = 0.432 vs 0.304; mean π = 0.290 vs 0.168). Pairwise Fst showed low differentiation between Libertad and Gamitanacocha (Fst = 0.056), but higher differentiation between Urco Miraño and Libertad (Fst = 0.548) and Gamitanacocha (Fst = 0.773). PCA and DAPC showed clear clustering of Urco Miraño parasites, while Libertad and Gamitanacocha partially overlapped. Traveler-associated infections did not form distinct clusters and mostly remained connected to non-traveler infections. ADMIXTURE indicated greater heterogeneity among travelers, and IBD identified two unconnected traveler-associated infections overall. These findings support integrating genomic and epidemiological data to interpret mobility-associated malaria transmission.