Toxocara vitulorum infection in European bison (Bison bonasus) calves from Central Germany

Abstract Whitish roundworms were found in the faeces of a female (3 months old) and a male (1 month old) European bison calf from an animal park in Central Germany. Since the faeces samples were not assignable to the individual animals, it is not certain if both calves were infected. The worms were identified as Toxocara vitulorum by morphological and molecular analysis, and a treatment with doramectin was initiated. To monitor the success of the therapy, faecal samples were examined before and after treatment by combined flotation/sedimentation technique, followed by a quantitative McMaster analysis in case of positive results. Additionally, stages of several Eimeria species and Trichuris sp. were found. Eggs of T. vitulorum were detected one week after application of doramectin, so, a second treatment was performed. However, no eggs of T. vitulorum were found at the time of the second treatment. Because of the difficulty of T. vitulorum eradication in infected herds, further investigations in the following year will be conducted.