02060nas a2200301 4500000000100000008004100001260004400042653003400086653005700120653002200177100001400199700001400213700001800227700001200245700001300257700001400270700001900284700001700303700001300320700001400333700001500347700001500362700001400377245013500391490000700526520121100533022001401744 2021 d bSpringer Science and Business Media LLC 10 aGeneral Physics and Astronomy 10 aGeneral Biochemistry, Genetics and Molecular Biology 10 aGeneral Chemistry 1 aBerger DJ 1 aCrellen T 1 aLamberton PHL 1 aAllan F 1 aTracey A 1 aNoonan JD 1 aKabatereine NB 1 aTukahebwa EM 1 aAdriko M 1 aHolroyd N 1 aWebster JP 1 aBerriman M 1 aCotton JA 00 aWhole-genome sequencing of Schistosoma mansoni reveals extensive diversity with limited selection despite mass drug administration 0 v12 3 aAbstractControl and elimination of the parasitic disease schistosomiasis relies on mass administration of praziquantel. Whilst these programmes reduce infection prevalence and intensity, their impact on parasite transmission and evolution is poorly understood. Here we examine the genomic impact of repeated mass drug administration on Schistosoma mansoni populations with documented reduced praziquantel efficacy. We sequenced whole-genomes of 198 S. mansoni larvae from 34 Ugandan children from regions with contrasting praziquantel exposure. Parasites infecting children from Lake Victoria, a transmission hotspot, form a diverse panmictic population. A single round of treatment did not reduce this diversity with no apparent population contraction caused by long-term praziquantel use. We find evidence of positive selection acting on members of gene families previously implicated in praziquantel action, but detect no high frequency functionally impactful variants. As efforts to eliminate schistosomiasis intensify, our study provides a foundation for genomic surveillance of this major human parasite. a2041-1723