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Abstract: Dicrocoelium dendriticum can cause severe pathological changes of the liver and bile system in camelids, and therapeutic options for treatment are limited. To address this problem, the efficacy of two different dose rates of praziquantel was investigated in llamas suffering from natural D. dendriticum infections. 53 llamas were examined under field conditions on two occasions: before and two weeks after treatment. At the beginning of the study, the animals were weighed, randomly allocated to one of the treatment groups (n =21 each) or the control group (n =11) and dosed orally using a praziquantel-containing paste (250mg/ml) at a dose of either 25mg (group 1) or 50mg (group 2) per kg of body weight. Criteria for efficacy were faecal egg count reduction (FECR) and extensity effect. Animals treated with 25mg/kg of body weight showed a FECR of 85%. Therapy with 50mg/kg led to a FECR of 91%. Almost twice the number of animals of group 1 (33%) still shed eggs two weeks after treatment compared with group 2. The results of this study indicate that 50mg/kg oral praziquantel is required for efficacious dosing and that this dose rate is safe in llamas and thus is recommended for the treatment of camelids naturally infected with D. dendriticum. [Copyright &y& Elsevier]

Abstract: Dicroceliosis, a lancet fluke infection, is a frequent parasitosis of small ruminants and the anthelmintic drug albendazole (ABZ) is effective in control of this parasitosis. The aim of our project was to study the metabolism of ABZ and ABZ sulphoxide (ABZ.SO) in lancet fluke. Both in vitro (subcellular fractions of fluke homogenates) and ex vivo experiments (adult flukes cultivated in medium) were performed for this purpose. ABZ was metabolised in vitro by lancet fluke NADPH-dependent enzymes by two oxidative steps (sulphoxidation and sulphonation). The apparent kinetic parameters of these reactions have been determined. In the ex vivo experiments, only ABZ sulphoxidation was observed. The stereospecificity in ABZ sulphoxidation in vitro was slight, with preferential formation of (+)-ABZ.SO enantiomer. In contrast (−)-ABZ.SO formation predominated in ex vivo experiments. Sulphoreduction of ABZ.SO occurred neither in vivo nor ex vivo. The detection of ABZ oxidative metabolites indicates the presence of drug metabolising oxidases in lancet fluke. [Copyright &y& Elsevier]