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Background: Clonorchiasis is attributed to the ingestion of raw freshwater fish harboring Clonorchis sinensis. Morbidity control is targeted through the administration of antihelminthics. This study modelled the cost yield indicated by effectiveness and utility of different treatment strategies against clonorchiasis. Methods: About 1000 participants were enrolled from each of 14 counties selected from four provincial-level administrative divisions namely Guangxi, Guangdong, Heilongjiang and Jilin in 2017. Fecal examination was adopted to detect C. sinensis infection, while behavior of ingesting raw freshwater fish was enquired. Counties were grouped into four categories based on prevalence, namely low prevalence group (< 1%), moderate prevalence group (1–9.9%), high prevalence group (10–19.9%) and very high prevalence group (≥ 20%), while population were divided into three subgroups, namely children aged below 14 years old, adult female and adult male both aged over 14 years old. The average of cost effectiveness indicated by the cost to treat single infected cases with C. sinensis and of cost utility indicated by the cost to avoid per disability-adjusted life years (DALYs) caused by C. sinensis infection was calculated. Comparisons were performed between three treatment schedules, namely individual treatment, massive and selective chemotherapy, in which different endemic levels and populations were considered. Results: In selective chemotherapy strategy, the cost to treat single infected case in very high prevalence group was USD 10.6 in adult male, USD 11.6 in adult female, and USD 13.2 in children. The cost increased followed the decrease of endemic level. In massive chemotherapy strategy, the cost per infected case in very high prevalence group was USD 14.0 in adult male, USD 17.1 in adult female, USD 45.8 in children, which were also increased when the endemic level decreased. In individual treatment strategy, the cost was USD 12.2 in adult male, USD 15.0 in adult female and USD 41.5 in children in very high prevalence group; USD 19.2 in adult male, USD 34.0 in adult female, and USD 90.1 in children in high prevalence group; USD 30.4 in adult male, USD 50.5 in adult female and over USD 100 in children in moderate prevalence group; and over USD 400 in any population in low prevalence group. As to cost utility, the differences by treatment strategies, populations and endemic levels were similar to those in cost effectiveness. Conclusions: Both cost effectiveness and cost utility indicators are highly impacted by the prevalence and population, as well as the treatment schedules. Adults especially men in the areas with a prevalence over 10% should be prioritized, in which selective chemotherapy was best and massive chemotherapy was also cost effective. In moderate endemic areas, the yield is not ideal, but selective chemotherapy for adult male may also be adopted. In low endemic areas, all strategies were high costly and new strategies need to be developed. [ABSTRACT FROM AUTHOR]

Clonorchiasis is an important food-borne parasitic disease in China, and infection with C. sinensis can cause hepatobiliary diseases. Comprehensive and systematic prevention and control of clonorchiasis requires the establishment of an effective surveillance. A total of 301 surveillance points were set up in 30 provinces across China in 2016, and 1000 people were selected by cluster sampling at each surveillance point annually for C. sinensis infection screening using Kato-Katz thick smear method. C. sinensis infection was detected in 6226 people following screening of 305081 people at the 301 surveillance points in 2016. Infection rate was 2.04%; with C. sinensis infection detected in 70 counties spread across 15 provinces, 89.37% of the infected people were distributed in Jilin, Heilongjiang, Guangdong and Guangxi provinces. Highest infection rate was observed in Da'an city, Jilin Province (49%). The national infection rate in male and female was 2.70% and 1.40% respectively. Infection rate between male and female was significantly different (P <0.01). Disease prevalence increases with age in both male and female, reaches peak in age group 40–49. Result obtained indicate that major C. sinensis endemic areas are distributed in the north and south of China, and areas with high prevalence are distributed along the river system at county level. Result, also, shows that middle-aged men are at high-risk of infection. These results suggest that surveillance activities should be sustained nationwide and highlight the need for an integrated approach to control C. sinensis transmission in regions with high disease prevalence in China. [ABSTRACT FROM AUTHOR]