Detection of Giardia duodenalis in free ranging alpine cervids

Survival and diffusion strategy of Giardia duodenalis consists of its being a generalist pathogen infecting a wide range of animal hosts in different environments, including humans. Recently, this protozoan has been detected in alpine chamois (Rupicapra rupicapra rupicapra). In order to provide further knowledge on circulation of this protozoa in alpine environment, we investigate the occurrence and genetic identity of G.duodenalis in red deer (Cervus elaphus) and roe deer (Capreolus capreolus). The study was carried in the Lepontine Alps in 2013-2014. Faecal samples were collected from soil in the protected area of the Alpe Veglia-Alpe Devero Natural Park and from culled animals in the contiguous VCO2 hunting district. A total of 196 faecal samples were collected from red deer and 119 from roe deer. Faeces were frozen at -20\ub0 and a commercial ELISA kit (RIDASCREEN\uaeGiardia) was used to detect protozoan copro-antigens. Positive samples were subjected to a nested PCR for molecular characterization. G.duodenalis prevalence was 2.5% (5/196) (95%CI=0,3-4,7) in red deer and 8.4% (10/119) (95%CI=3.4-13.4) in roe deer. G.duodenalis was molecularly confirmed in 4 red deer and 3 roe deer. Zoonotic assemblage A was identified in red deer, while sequencing of PCR fragments from roe deer samples was not possible due to the poor DNA quality. This study shows that wild alpine cervids harbour G.duodenalis, contributing to its spread in the alpine environment. Considering that G.duodenalis prevalence detected is not negligible and that zoonotic assemblage A was isolated, the increase of deer populations, outdoor and zootechnical activity suggest a potential zoonotic and economic risk. Moreover, assuming that the highest protozoan emission by deer occurs in the first weeks/months of life (at least for livestock), logistical difficulties due to late-spring field conditions in the protected area and sampling in autumn hunting season mean that real prevalence could actually be underestimated