Challenging the phylogenetic relationships among Echinococcus multilocularis isolates from main endemic areas

Abstract

Alveolar echinococcosis (AE) is a rare but severe disease that affects more than 18,000 peopleworldwide per year. The complete sequencing of the mitochondrial genome of Echinococcus multilocularis has made it possible to study the genetic diversity of the parasite and its spatialand temporal evolution. We amplified the whole mitochondrial genome by PCR, using oneuniplex and two multiplex reactions to cover the 13,738 bp of the mitogenome, and thensequenced the amplicons with Illumina technology. In total, 113 samples from Europe, Asia, ,the Arctic and North America were analyzed. Three major haplogroups were found: HG1,which clustered samples from Alaska (including Saint-Lawrence Island), Yakutia (Russia) andSvalbard; HG2, with samples from Asia, North America and Europe; and HG3, subdivided intothree micro-haplogroups. HG3a included samples from North America and Europe, whereasHG3b and HG3c only include samples from Europe. In France, HG3a included samples frompatients more recently diagnosed in a region outside the historical endemic area. A fourthputative haplogroup, HG4, was represented by only one isolate from Olkhon Island (Russia).The increased discriminatory power of the complete sequencing of the E. multilocularis mitogenome has made it possible to highlight four distinct geographical clusters, one being divided into three micro-haplogroups in France.