Regional Mountain Conference

Fasciola hepatica, the common liver fluke, is a trematode parasite of ruminants with zoonotic potential that impairs animal health and productivity worldwide. Its life cycle requires the amphibious intermediate host snail Galba truncatula, which thrives in wet habitats; therefore, climatic changes promoting moisture are expected to increase transmission. Alpine regions already show some of the highest prevalence levels in Europe. This study combined large-scale sero-epidemiological analyses with detailed field investigations to reassess liver fluke occurrence, infection dynamics, and production impacts in Tyrolean dairy farming characterized by alpine summer pasturing, high rainfall, small-holder structures, and dual-purpose breeds.

Bulk tank milk (BTM) samples from 3,645 farms were analysed by ELISA in 2023, and associations with milk yield and quality were evaluated using multivariate regression. To investigate transmission dynamics, longitudinal sampling across one grazing season on 14 farms and across two seasons on four focus farms included faecal, milk, and blood samples analysed by quantitative sedimentation, copro-antigen ELISA, and antibody ELISA.

Overall, 86.1% of farms were F. hepatica-positive, representing a 13.1% increase since 2005. F. hepatica infection was significantly associated with reduced milk yield, fat, and protein (p < 0.001). Infection dynamics revealed persistently high prevalence in dairy cows (40–100%), whereas first-season grazers remained largely negative until late summer and second-season grazers showed variable infection patterns. There were also indications that the treatment resulted in a suboptimal reduction of the infection.

These findings indicate insufficient current control under changing climatic conditions. Targeted treatment, pasture management, intermediate host habitat control, and improved slurry hygiene are essential for sustainable parasite control in alpine dairy systems, while hydro-epidemiological climate models may support future risk prediction.