Cooperative Fish and Wildlife Research Units Program: Arizona
Education, Research and Technical Assistance for Managing Our Natural Resources

The anthelmintic drug, praziquantel, kills only the tapeworm stage of the Asian tapeworm life cycle. It does not kill the eggs, coracidia, or procercoid life stages, making it difficult to treat infected fish in systems containing the intermediate copepod host. Copepods would act as a refuge for the tapeworm from the praziquantal bath treatment. Using microcosms containing the intermediate copepod host, we tested the effectiveness of using a second application of praziquantel to kill tapeworms that may develop from eggs released during the first treatment. We found no evidence of recruitment in microcosms treated twice for Asian tapeworm. Tapeworm prevalence and intensity in the control tanks remained the same throughout the experiment. We also discuss the potential costs and benefits of using praziquantel to treat populations of fishes in the wild. A final report on this work was submitted spring 2007 and a publication on this work is currently in review.