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ARS Home » Southeast Area » Stuttgart, Arkansas » Harry K. Dupree Stuttgart National Aquaculture Research Cntr » Research » Publications at this Location » Publication #155618

Title: EFFECTIVENESS OF PRAZIQUANTEL BATH TREATMENTS AGAINST BOTHRIOCEPHALUS ACHEILOGNATHI IN GRASS CARP

Author
item Mitchell, Andrew

Submitted to: Journal of Aquatic Animal Health
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/3/2004
Publication Date: 9/1/2004
Citation: Mitchell, A.J. 2004. The effect of praziquantel bath treatments against Bothriocephalus acheilognathi in grass carp. Journal of Aquatic Animal Health. 16:130-136.

Interpretive Summary: A number of states restrict the importation of cultured fish infected with Asian tapeworms. Treatments given in holding tanks with a completely effective tapeworm parasiticide would alleviate this importation concern for fish producers. A population of grass carp (88 g average weight) that were very heavily infected with the tapeworms served as test fish in the final study group. Following 4 tests it was determined that treatments with Praziquantel, an effective dog and cat de-wormer, greatly reduced the number of tapeworms present. However, only a 1.5 mg/L treatment given for 24 h duration was completely effective in eliminating the tapeworm infection at fish stocking densities of 6 g/L of water. Preliminary tests on another population of grass carp (22 g average weight) with a lighter tapeworm infection showed that 0.7 mg/L treatment for 24 h eliminated all the worms. These tests also indicated that to reduce the treatment duration to 12 h about 4 times the amount of chemical was needed.

Technical Abstract: Many states ban the importation of fish infested with the Asian tapeworm Bothriocephalus acheilognathi. Treatment with an effective tapeworm parasiticide prior to shipment would alleviate this problem and allow fish to be shipped that would otherwise be rejected. In this work, extended bath treatments of infected grass carp Ctenopharyngodon idellus with praziquantel were tested to determine efficacy against Asian tapeworms. Initial treatments of 0.7 mg praziquantel/L or more for an exposure period of 24 h at fish densities of 68.8g of grass carp/L were effective in eliminating all the worms from 22 g grass carp. When the treatment duration was lowered to 12 h, 2.8 mg praziquantel/L was required for effective treatment. When testing the efficacy of this chemical against a heavy infection of the tapeworm (30+ worms/fish) in larger 88 g fish, 1.5 mg/L (the maximum concentration tested) for 24 h was the only concentration that eliminated all tapeworms (the stocking density of fish was about 6 g/L). The other concentrations of praziquantel (0.5, 0.7 and 1.0 mg/L) tested for a 24 h exposure against fish with a heavy infection all significantly reduced tapeworm infections in the grass carp from the infections found in control fish. When the density of fish was raised to 60g/L of water, 4 of 30 fish were found with a single worm after treatment with 1.5 mg praziquantel/L.