BackgroundBoth tribendimidine and mebendazole are broad-spectrum drugs for anti-intestinal nematodes. We aim to assess the efficacy and safety of tribendimidine and mebendazole in patients with co-infection of Clonorchis sinensis and other helminths.MethodWe performed a randomized open-label trial in Qiyang, People's Republic of China. Eligible participants were randomly assigned to one of four groups: (i) a single dose of 400 mg tribendimidine, (ii) 200 mg tribendimidine twice daily, (iii) 75 mg/kg praziquantel divided in four doses within 2 days, and (iv) a single dose of 400 mg mebendazole. Cure rates and egg reduction rates were assessed, and adverse events were monitored after treatments. Uncured patients accepted the second treatment with the same drugs after the first treatment.Results156 patients were eligible for the study. Results from the first treatment showed that the cure rates of single-dose tribendimidine and praziquantel against C. sinensis were 50% and 56.8%, respectively; the single-dose tribendimidine achieved the cure rate of 77.8% in the treatment for hookworm, which was significantly higher than that of praziquantel; Low cure rates were obtained in the treatment of single-dose tribendimidine against Ascaris lumbricoides and Trichuris trichiura (28.6% and 23.1%). Results of the second treatment illustrated the cure rates of tribendimidine and praziquantel against C. sinensis were 78.1% and 75%, respectively. Most adverse events were mild and transient. Adverse events caused by tribendimidine were significantly less than praziquantel.ConclusionSingle-dose tribendimidine showed similar efficacy against C. sinensis as praziquantel with less adverse events, and achieved significantly higher cure rate in the treatment for hookworm than those of praziquantel and mebendazole. Low cure rates, which were still higher than other drugs, were obtained in the treatment of single-dose tribendimidine against Ascaris lumbricoides and Trichuris trichiura.Trial RegistrationControlled-Trials.com ISRCTN55086560

Background Clonorchiasis is caused by eating of raw or undercooked freshwater fish containing the larvae of Clonorchis sinensis ; the Kato-Katz method is widely applied in diagnosis. The improvement of repeated Kato-Katz smears from multiple stool samples has been well illuminated in many helminths other than C. sinensis . Methods A cross-sectional investigation was implemented to capture the epidemiology and risk factors of clonorchiasis among middle school students in Qiyang county, China. Students with complete data of six Kato-Katz thick smears from two stool samples were included in this analysis. Data on the habits of eating raw freshwater fish were also collected and compared. Results Altogether, 397 students had complete information of six smears, out of which 394 reported the information on eating habits. According to the ‘gold’ standard by six smears, 77 students (19.4%) were detected with C. sinensis . However, only 45 (11.3%) were detected using a single smear, with an underestimation of 41.6% compared to the ‘gold’ standard. However, the geometric mean of eggs per gram of feces in detected cases was 126.4 in a single smear, overestimated by 105.2% compared to 61.6 by the ‘gold’ standard. The linear relationship between prevalence and infection intensity of detected cases based on different smears was significantly negative. The habits of eating raw freshwater fish in the false negative cases was similar to those in the detected cases, but these two groups had significantly higher levels for habits of eating raw freshwater fish than negative individuals. Conclusions In low endemicity situations, underestimation of C. sinensis infection could not be avoided based on a limited number of Kato-Katz smears. Thus, repeated smears from at least two stool samples should be considered when an individual eats raw freshwater fish, drug efficacy is evaluated or elimination of C. sinensis is verified. Additionally, when logistics are insufficient for multiple samples to be taken for diagnosis for survey and surveillance in the areas or populations of low endemicity, prevalence accuracy needs to be corrected.

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