Clonorchis sinensis: epidemiology in Taiwan and clinical experience with praziquantel

The human infection rate of clonorchiasis in Taiwan was estimated with 0.012-1.5%. Three endemic areas were noted, e.g. Mei-Nung in the south (52%), SunMoon lake area in the centre (52%), and Miao-Li in the middle (57%) of Taiwan. Those are areas where local people customarily eat raw fresh-water fish. From December 1979 to December 1981, a new trematodicide, praziquantel (2-cyclohexylcarbonyl-1,2,3,6,7,11b-hexahydro-4H-pyrazino[2,1-a]++ +isoquinolin-4-one, EMBAY 8440, Biltricide), was evaluated in the treatment of 67 cases of clonorchiasis sinensis, 62 inpatients and 5 outpatients at National Taiwan University Hospital. Two dosages of praziquantel, namely, 25 mg per kg of body weight 3 times daily for one or two days were used in a single-blind method. This study revealed nearly 100% egg reduction in either dosage but the cure rate of the one-day dosage initially was 96% at 2 months follow-up, then 91% at 6 months and 81% at one year. However, the cure rate of the two-day dosage schedule remained 100% throughout one year follow-up. Patients tolerability to either dosage was good in hospitalized and ambulatory cases, 39% were without any complaints. Side effects were noted mostly in nervous and gastrointestinal systems but were only mild and transient in nature.