A foreign invader or a reclusive native? DNA bar coding reveals a distinct European lineage of the zoonotic parasite 'Schistosoma turkestanica' (syn. 'Orientobilharzia turkestanicum' (Dutt and Srivastava, 1955))

Natural foci of Schistosoma turkestanica (syn. Orientobilharzia turkestanicum) has been identified in the Gemenc Forest regions of Hungary utilising red deer as the definitive host. In order to identify the origins of this parasite in Europe standard DNA bar coding techniques were employed to sequence fragments of the cytochrome oxidase 1 (cox1) and the nuclear ribosomal internal transcribed region (ITS) from 10 individual adult male worms. Phylogenetic reconstruction using maximum likelihood phylogenetic reconstruction and haplotype networks of the cox1 showed all the worms to be of a distinct unique Hungarian lineage although some ITS haplotypes were shared with worms from populations in China and Iran. Molecular clock analysis suggests an early divergence event around 270, 000 years before present (YBP) between all S. turkestanica populations giving rise to the Chinese, Iranian and Hungarian lineages. However, divergence of the sequences within the Hungarian population appears to have occurred approximately 63, 000 YBP suggesting a long established population of S. turkestanica in Europe. This suggests that the Hungarian population of S. turkestanica has been native since the Ice Age and probably established itself during the last interglacial period as red deer moved into Europe from North Africa and the Middle East. This may also indicate that the parasite may have unknown populations established in several other countries in Eastern, Central and Southern Europe.