Abstract:

Pucheng County was divided into 5 areas according to geographical location for the study based on the National Surveillance Plan on Chlonorcihasis and Soil-transmitted Helminthiasis; in each designated area, one village was selected from a township to serve as the surveillance site in 2016—2020. In each village, more than 200 permanent residents were randomly sampled for fecal examination with modified Kato-Katz thick smear method (duplicate slide-reading/one sample) to estimate the status of Clonorchis sinensis infection. Each year, 100 freshwater fish in each village were collected from natural water bodies such as fish ponds and streams, and C. sinensis metacercaria infection was detected through crushing microscopy. Twenty-five fecal samples from cats and dogs were collected from each village, and C. sinensis eggs in the feces were examined with the washing sedimentation method. In addition, at least 150 residents were randomly selected for questionnaire of their knowledge, attitudes, and behavior regarding clonorchiasis. A total of 5 553 residents were examined, and found an overall infection rate of 0.79% during 2016—2020. The infection rates from 2016 to 2020 were 0.6%, 1.02%, 1.16%, and 0.24%, respectively. In addition, C. sinensis infection was detected using washing and sedimentation method in 26 residents, with an infection rate of 0.47% (26/5 553); Metorchis orientalis infection was detected in 18 residents, with an infection rate of 0.32%. A total of 639 freshwater fish of 3 species were examined, and recorded 472 positives, with an infection rate 73.86%. Among the positives, the infection rate of Pseudorasbora parva reached highest (97.33%) in 2016. Examination for 129 feces samples of wild animals were conducted, and found 5 C. sinensis egg positive, and 2 Metorchis orientalis egg positive, with the infection rate of 3.88% and 1.55% respectively. From the questionnaire survey in residents, 752 valid responders were obtained, showing an overall awareness rate 37.10% (279/752). No significant difference was observed in the awareness rate between males and females (χ² = 0.99, P > 0.05). The infection rate of clonorchiasis sinensis knowledge was low in Pucheng County, and the residents had low awareness rate of C. sinensis. A high infection rate of metacercaria was found in freshwater fish, especially P. parva. Health education and control measures should be strengthened.

Key words: Clonorchis sinensis, Metorchis orientalis, Investigation, Pucheng County