Closantel treatment of lambs naturally infected by immature paramphistomes (Calicophoron daubneyi)

Few data are available on the treatment of the disease asso­ciated with the immature form of Calicophoron daubneyi. To study the efficacy of closantel in this infestation, ten lambs were kept for 42 days on a plot known to be infested by C. daubneyi and were then divided into two groups, control and treatment. They were autopsied seven to ten days after treat­ment. Parasites in the duodenum were counted by differentiat­ing free and intramucosal forms. The decrease in free parasites (61%) was highly variable and not significant. However, the decrease in the number of intramucosal parasites (56%) was highly significant (p = 0.002). As intramucosal larvae are path­ogenic, closantel could be used to treat newly infested ani­mals.