Biodiversity and prevalence of gastrointestinal helminths in roe deer (Capreolus capreolus L.) in relation to wind farm presence in central Poland

Background The roe deer ( Capreolus capreolus ) is a widespread cervid in Europe and an important reservoir of gastrointestinal helminths of veterinary relevance. Although environmental and host-related drivers of parasite communities are well studied, the effects of anthropogenic infrastructure, such as wind farms, on host–parasite interactions remain poorly understood. This study aimed to characterize gastrointestinal helminth diversity in roe deer from central Poland and evaluate the impact of wind farm presence on nematode infections. Methods A total of 102 roe deer were examined from three regions in central Poland between 2022 and 2024. Animals were categorized based on occurrence within or outside wind farm areas (39 and 63 individuals, respectively). Helminths were collected from the abomasum, small intestine, large intestine, and cecum using standard parasitological methods. For molecular identification, nematodes morphologically assigned to the genera Oesophagostomum and Chabertia were analyzed based on the ITS2 gene region, whereas the cox1 gene was used for cestodes of the genus Moniezia . The effects of wind farm presence on parasite abundance were analyzed using generalized linear models with a negative binomial distribution. Results A diverse helminth community was identified, comprising 7 species in the abomasum, 7 in the small intestine, and 4 species each in the large intestine and cecum. Haemonchus contortus dominated the abomasum; Chabertia ovina was the most prevalent species in the small and large intestine; and Trichuri s sp. was the most prevalent parasite in the cecum. Tapeworms of the genus Moniezia were found in the small intestine of 4 animals. Molecular analyses confirmed Oe. venulosum and C. ovina , and revealed genetically distinct Moniezia sp. Apart from Trichuris sp. infection, roe deer from wind farm areas exhibited higher helminth abundance and greater species richness than those from control areas, with infection levels approximately twice as high. Conclusions The increased parasite burden in wind farm areas suggests that anthropogenic disturbance may influence host–parasite dynamics, potentially via stress-related mechanisms. These findings highlight the importance of incorporating wildlife health considerations into renewable energy impact assessments.