[Investigation on epidemic status of clonorchiasis sinensis based on inpatients in Zhongshan City, China].

Objective To understand the prevalence and epidemiological features of clonorchiasis sinensis based on inpatients in Zhongshan City. Methods All of the 23 town hospitals in Zhongshan City were selected as the surveillance hospitals in 2016. Among the inpatients from those hospitals, those lived in the city longer than 6 months were selected as the surveillance subjects. The stool specimens of the subjects were collected and examined by the modified Kato-Katz thick smear method for the eggs of Clonorchis sinensis . The crude infection rates of C. sinensis of the subjects were standardized according to the age and sex compositions of the population in Zhongshan City, 2016. Meanwhile, the infection rates of the subjects from different towns and those combined with related clinical diseases were analyzed. Results A total of 2 667 people were included in the surveillance, among which 219 were tested as positives, with a crude infection rate of 8.21%. For the positives, the male accounted for 81.74% (179/219), and their age ranged from 4 to 89 years with the mean value of (62.20±13.80) years. After standardization by age and sex composition, the infection rate was 3.62% for the whole population, the rates of the male and the female were 5.46% and 1.53%, respectively, and the former was 3.57 times as high as the latter. Both the infection rates of the male and the female rose as the age increasing ( χ 2 male = 99.91, χ 2 female = 16.51, both P < 0.01). The standardized infection rates among the subjects in different towns ranged from 0 to 10.40%, and the rates in the north towns were higher than those in the south towns. The standardized rate was 9.22% for the subjects combined with gallstone, 3.40% for those not combined with gallstone, and the former was 2.71 times as high as that of the latter. Conclusion The people aged 30 years and above, with gallstone or living in towns with high C. sinensis infection rates are the key population for prevention and control of clonorchiasis in Zhongshan City.