Spread and dynamics of Calicophoron daubneyi and Fasciola hepatica in an extensively kept water buffalo herd and suitability of an ELISA for detecting antibodies against F. hepatica

Water buffalo are ideal for grazing in restored wetlands due to their anatomical and behavioural adaptations. Unlike cattle or sheep, the water buffalo thrive in such habitats, feeding on rushes and reeds while helping maintain open landscapes. However, these moist environments also harbor risks, particularly parasitic infections by liver flukes (Fasciola hepatica) and the recently widespread rumen flukes, which require aquatic snails as intermediate hosts. For the present study faecal samples were taken once a year from 2016 to 2024 and monthly in two 12-month periods (2019/20 and 2022/23) from a water buffalo herd established in 2014 on a southern German farm and examined for fluke eggs with a sedimentation technique. In addition, climate data were obtained from a nearby weather station to analyse the impact of rainfall and sunshine hours on the fluke prevalence. To test whether blood samples can be used to detect infection with F. hepatica, residual quantities of blood samples from disease surveillance were tested for F. hepatica antibodies using a commercially available ELISA test. Copromicroscopical results showed that fluke prevalence rose significantly within a few years, with F. hepatica prevalence being always higher than C. daubneyi prevalence. Co-infections were common and seasonal patterns inconsistent. Fluke prevalence increased with rainfall and sunshine hours. In the herd, older water buffalo were more prone to liver flukes. The ELISA test for fascioliasis failed even though F. hepatica eggs were present in the faeces. The findings of the study highlight that extensively reared water buffalo are at high risk of trematode infection, which spreads rapidly throughout the herd and reaches high prevalence rates. The specific wallowing behaviour of water buffalo and favourable climatic conditions for parasite development may contribute to this development.