Helminth infections of wild European gray wolves (Canis lupus Linnaeus, 1758) in Lower Saxony, Germany, and comparison to captive wolves

This study aimed to investigate the endoparasite fauna of wild European gray wolves, which are currently recolonizing Germany. In total, 69 fecal samples of wild wolves were collected in Lower Saxony, Germany, from 2013 to 2015, analyzed by the sedimentation-flotation and McMaster techniques and compared to previous results on captive European Gray wolves living in zoological gardens in Germany. In addition to coproscopy, taeniid-positive samples from wild as well as captive wolves were differentiated by amplification and sequencing of small subunit ribosomal RNA ( SSU rRNA ) and NADH dehydrogenase 1 ( nad1 ) gene fragments. Missing Taenia krabbei SSU rRNA reference sequences were generated from two T. krabbei specimens. Overall, 60.87% (42/69) of wild wolve samples were microscopically positive for at least one of seven egg types. Capillaria / Eucoleus spp. showed the highest frequency (31.88% [22/69]), followed by Taeniidae (21.74% [15/69]), Ancylostomatidae (20.29% [14/69]), Alaria alata (15.94% [11/69]), Toxocara canis (13.04% [9/69]), and Toxascaris leonina and Trichuris vulpis (each 5.80% [4/69]). Amplification of SSU rRNA was successful for 7/15 Taeniidae-positive samples from wild and 20/39 samples from captive wolves, revealing T. hydatigena in two and 14 samples, respectively. Taenia krabbei was detected in two further samples of wild and three samples of captive wolves, while for the remaining samples, no differentiation between T. serialis / T. krabbei was possible. Echinococcus spp. were not detected. Sequence comparisons revealed that the SSU rRNA gene fragment was not suitable to differentiate between T. serialis and T. krabbei . Therefore, the use of this fragment alone cannot be recommended for species identification in future studies.