| Summary: | International audience Echinococcus multilocularis is a common tapeworm in foxes and rodents in the northern hemisphere and the causal agent of Alveolar Echinococcosis (AE). Epidemiological discontinuities are known: highly endemic in China, in expansion in Europe and rarely described in North America. In this context, a part of the European project EchinoRisk aimed to focus on genetic diversity to explain the discrepancy amongst European foci. Moreover genetic analyses were performed to identify the parasite circulation amongst hosts in the environment on different spatial scales. A highly discriminant molecular marker was thus designed. It took ten years from the first description to the assessment of its discrimination power amongst E. multilocularis isolates from different geographical scales. The microsatellite EmsB was confirmed as a tandemly repeated sequence of about 250 bp present in about 40 copies in the parasite genome. Its original profile indicated high power of discrimination. First, regional E. multilocularis profiles were described by the analysis of EmsB in Europe, America and Asia. In Europe, the marker has permitted to distinguish a historical area surrounded by newly endemic areas. Moreover an Arctic origin was described for E. multilocularis recently discovered in Svalbard Island (Norway). In order to better understand its transmission pathway to human, a genotyping project on European AE has been started. The first results suggest a contamination in the close environment of the patient. In this context, an international EmsB database has been implemented in the EWET project (“EmsB Website for Echinococcus Typing”), comprising about 1200 genotyped E. multilocularis samples, to compare a new isolate to a reference collection. The next step after EmsB, will focus on large screening in the parasite genome. As regards to performances in Next Generation Sequencing technologies, whole-genome sequencing first based on EmsB profiles previously described have to be performed to highlight genes or ...
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