Prevalence and molecular typing of Giardia duodenalis in wildlife from eastern Poland

Faecal samples from 162 wild animals were collected from 32 distinct sites of Łęczyńsko-Włodawskie Lakeland (eastern Poland). The presence of Giardia duodenalis (Stiles, 1902) was assessed by a Direct Fluorescence Assay (DFA) and by Polymerase Chain Reaction (PCR) and sequencing of a fragment of the beta-giardin gene. DFA showed the presence of cysts of G. duodenalis in 12 of 162 faecal samples (7%), namely in four wild boars (15%), four foxes (19%), two roe deer (4%), and two wolves (29%). PCR identified 34 of the 162 (21%) samples as positive, including 11 wild boars (41%), five red deer (18%), 11 roe deer (23%), four moose (17%), two wolves (29%) and a single sample from the European badger. Thus, PCR detected a significantly higher number of infection than DFA (P = 0.0005). However, 14 of 34 PCR products could not be sequenced because of their insufficient amount; the low number of cysts, poor conservation of the faeces or presence of PCR inhibitors may have contributed to weak DNA amplification. Sequence analysis of the remaining 20 products showed the presence of assemblage B in wild boars, red deer and roe deer, whereas samples from wolves were identified as assemblage D. This is the first detection of assemblage B in wild boars and deer. As assemblage B has zoonotic potential, wild animals from eastern Poland may act as reservoirs of cysts of G. duodenalis infectious for humans.