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ARS Home » Southeast Area » Stuttgart, Arkansas » Harry K. Dupree Stuttgart National Aquaculture Research Cntr » Research » Publications at this Location » Publication #217437
Title: Efficacy of 6-, 12-, and 24-h praziquantel bath treatments against Asian tapeworm Bothriocephalus acheilognathi in grass carp

Author
item Mitchell, Andrew
item Darwish, Ahmed

Submitted to: North American Journal of Aquaculture
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/31/2008
Publication Date: 1/2/2009
Citation: Mitchell, A.J., Darwish, A.M. 2009. Efficacy of 6-, 12-, and 24-h praziquantel bath treatments against Asian tapeworm Bothriocephalus acheilognathi in grass carp. North American Journal of Aquaculture. 71:30-34.

Interpretive Summary: The purpose of this study was to develop a treatment that would eliminate intestinal tapeworms (Asian tapeworms) from fish. Praziquantel, a dog and cat de-wormer, was used as a water bath treatment. A single, 24-h treatment of 0.75 mg/L praziquantel given at a fish density of 60 g/L was found to eliminate tapeworms. Shorter exposures (6 and 12 h), even at more than 10 times the 0.75 mg/L concentration, were ineffective in eliminating the tapeworms. Raising the fish density to 120 g/L also made the 24-h, 0.75 mg/L, praziquantel treatment ineffective. Treatments tested that were applied twice were also ineffective; the best, a 12-h, 1.5 mg/L praziquantel treatment applied twice at a fish density of 60 g/L, resulted in a very low incidence (3.3%) of fish with tapeworms. Proper storage of the chemical was found to be important; the powder formulation used in this study had to be frozen. Improperly stored product may be weakened and give erroneous results.

Technical Abstract: Praziquantel is an effective antihelmintic that has been used in dogs and cats as a de-wormer. It has also been used successfully against tapeworms and trematodes in fish. The current study tested the efficacy of praziquantel bath treatments at various concentrations (0.187, 0.375, 0.75, 1.5, 3.0, 6.0, 9.0, 12.0 mg/L) for 6, 12, or 24 h in grass carp Ctenopharyngodon idellus naturally infested with Asian tapeworms Bothriocephalus acheilognathi (60-100% of the fish were infected with tapeworms). Treatments were given either as a single application or applied twice (3 d apart) at fish densities of 60 or 120 g/L. The objective of the study was to find a treatment that would completely eliminate tapeworms from all infected fish; a number of states require that imported fish be Asian tapeworm-free, therefore, fish with even greatly reduced tapeworms numbers can not be shipped. Most of the praziquantel treatments reduced the incidence of fish with tapeworms. Only single, praziquantel bath treatments at concentrations of 0.75 mg/L or higher applied for 24 h at a fish density of 60 g/L completely eliminated tapeworms. Raising the fish density from 60 g/L to 120 g/L prevented the 24-h, 0.75 mg/L praziquantel treatment from eliminating tapeworms (15% incidence of fish with tapeworms); fish density affects the success of the treatment. A 12-h, 1.5 mg/L praziquantel treatment applied twice at a fish density of 60 g/L resulted in low incidence (3.3%) of fish with tapeworms.