Single dose treatment with praziquantel for human Diphyllobothrium nihonkaiense infections.

Diphyllobothrium nihonkaiense is a large pseudophyllid cestode and one of the commonest parasites derived from fish in Japan. Three Japanese patients infected with D. nihonkaiense were treated with a single oral dose of 7, 23 or 25 mg/kg of praziquantel. All patients expelled the tapeworm with scolex, and no side effect was noted. This study indicates that single-dose treatment with praziquantel is effective against D. nihonkaiense infection.