Study on Risk Factors and Comprehensive Control and Prevention Mode of Clonorchis sinensis Infection in High-risk Areas in Hunan Province

Objective To investigate the epidemic status,risk factors,and the residents' knowledge,attitude and practice about Clonorchis sinensis infection in southern area of Hunan Province.To explore the effectiveness of praziquantel,health education,and comprehensive interventions in high-risk areas,and to provide the scientific evidence for making control and prevention programs and strategies of clonorchiasis. Methods Cluster random sampling was performed to survey the incidence of clonorchiasis at the boundary of Qiyang County and Lengshuitan District.The Kato-Katz method was used for etiological examination.Crushing-tabletting and manual digestion were used to test the infection status of intermediate host.The results of mammal infection were collected through dissection.The information of local production,lifestyle and custom related to infection was collected through discussion and field investigation.Questionnaire survey was conducted to collect the risk factors of Clonorchis sinensis infection and the surveyed residents' knowledge,attitude and practice of clonorchiasis.The database was established using Epi data 3.0 software,and then descriptive statistics,χ2 test and Logistic analysis were carried out with SPSS13.0 software. Results Totally 2,169 residents were test-positive for Clonorchis sinensis infection among 4,472 residents selected from 16 villages of 9 towns,and the average infection rate was 48.5%.The difference of the infection rates between male and female showed no statistical meaning(χ2=2.91,P0.05).The study showed that the infection rate of each age group was increased with the increasing age,and the differences in the infection rates were statistically significant among different age groups(χ2=430.799,P0.05).There were statistically significant differences in the infection rates among the populations with different occupations and with different educational backgrounds(χ2=407.720,P0.05;χ2=222.227,P0.05).A total of 1,307 valid questionnaires were retrieved.Multivariate unconditional Logistic regression analysis showed that the risk factors associated with Clonorchis sinensis infection were as follows: age,educational level,without washing hands before eating or after defecation,without washing chopping block after cutting fish,feeding fish with dejecta,eating fresh fish,considering the fresh fish eating was hygienic,and without hearing about clonorchiasis.After using praziquantel in whole population and conducting health education,the average infection rate of Clonorchis sinensis in the surveyed population was decreased by 27.2%,and the differences between before and after the interventions were statistically significant(χ2=55.725,P0.05).The infection rates of Clonorchis sinensis metacercarias in Parafossarulus striatulus and Alocinma longicornis were 17.4% and 7.4%,respectively,which indicated the two species of snails were the primary first intermediate hosts.The infection rates of Clonorchis sinensis metacercarias in crucian and carp were 69.2% and 5.3%,respectively.The infection rate of dogs as reservoir hosts was up to 85%. Conclusions Qiyang County and Lengshuitan District were the high-incidence areas of Clonorchis sinensis infection in Hunan Province.Comprehensive control and prevention measures should be taken to deal with the epidemic of Clonorchis sinensis in those regions.