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 traveler-associated infections. 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 F st , population structure using Principal Component Analysis (PCA), Discriminant Analysis of Principal Components (DAPC), and ADMIXTURE, and relatedness using Identical by descent (IBD) analysis. Traveler-associated infections in Libertad showed higher genetic diversity than non-travelers (median = 0.375 vs. 0.153). Pairwise fixation index (F st ) showed low differentiation between Libertad and Gamitanacocha (F st =0.056), but higher differentiation between Urco Miraño and Libertad (F st =0.548) and Gamitanacocha (F st =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.