Genetic diversity of Echinococcus multilocularis from red foxes and humans in northern and northeastern Poland investigated using the microsatellite EmsB.

Background: Echinococcus multilocularis is the causative agent of alveolar echinococcosis (AE). We explored the diversity of EmsB profiles of E. multilocularis from red foxes and humans in northern and northeastern Poland, with a particular focus on autochthonous Asian variants.

Methods: We investigated 263 adult tapeworms from 59 red foxes hunted in selected districts of three voivodships and ten metacestodes extracted from AE patients who never visited Asia. We conducted hierarchical clustering of the obtained EmsB profiles combined with a custom Asian reference dataset and interpreted the resulting phenogram by applying the standard genetic distance threshold (GDT) of 0.08 and Dynamic Tree Cut (DTC).

Results: The GDT divided the 273 profiles into six units, with Pol-B being the most frequent (220/273, 81 %) and widespread variant. DTC grouped the profiles into three phenons (PH). Eight out of ten people got infected with the predominant variant, PH-2/Pol-B. Among the 273 samples, thirty-six (13 %) matched the Asian reference set, including metacestodes from a Lithuanian patient and a Polish patient.

Conclusions: Genetically extra-European variants reach as far north as Pomorskie Voivodship. They likely come from East Asia. The autochthonous AE case with an Asian profile confirms that such tapeworms have penetrated the synanthropic cycle.