Influence of geographic, knowledge and behavioral factors on Opisthorchis viverrini infection in the Northeast of Thailand

Objective:To determine the influence of geographic,knowledge and behavioral factors on Opisthorchis(O.)viverrini infection in the Northeast of Thailand.Methods:This cross-sectional study was conducted by using four datasets of years 2016 and 2017.Generalized linear mixed model was employed to analyze association between geographic,knowledge and behavioral factors and O.viverrini infection.Results:Totally there were 1885 participants.The prevalence of O.viverrini infection was 10.03%.Geographic factors that showed statistically significant association with O.viverrini infection in the Northeast region were featured by at least a dam and reservoir(Adj.OR=4.21,95%CI:2.49-7.13,P<0.001),at least a weir(Adj.OR=1.74,95%CI:1.09-2.77,P=0.020),>50 dogs and cats per village(Adj.OR=3.40,95%CI:2.17-5.31,P<0.001),and rice fields covered>50%of its areas(Adj.OR=1.91,95%CI:1.04-4.01,P=0.036),as well as low to moderate levels of knowledge(Adj.OR=1.60,95%CI:1.32 to 1.94,P<0.001),consumed raw fish(Adj.OR=1.90,95%CI:1.02 to 3.52,P=0.040)and consumed processed raw fish(Adj.OR=3.03,95%CI:2.20 to 4.18,P<0.001).Other significant covariates were gender and age of the respondents.Conclusions:O.viverrini infection still remains a public health problem of the Northeast of Thailand.Geographic and demographic factors,knowledge,and consumption behaviors of raw fish products are significantly associated with O.viverrini infection.

Repeated praziquantel treatment and Opisthorchis viverrini infection:a population-based cross-sectional study in northeast Thailand

Background:Opisthorchis viverrini infection is highly prevalent in northeast Thailand.This liver fluke is classified as a carcinogen due to its causal links with cholangiocarcinoma(CCA)development.Although treatment with praziquantel(PZQ)effectively cures O.viverrini infection,the prevalence remains high due to the traditional consumption of raw fish.Therefore,re-infection is common in the endemic community,leading to severe hepatobiliary morbidities including the fatal CCA.In this study,we evaluate the association between the frequency of previous PZQ treatment and current O.viverrini infections among Thai adults living in the endemic area of northeast Thailand.Methods:This study includes all participants who were screened for O.viverrini infection in the Cholangiocarcinoma Screening and Care Program(CASCAP),northeast Thailand.History of PZQ treatment was recorded using a health questionnaire.O.viverrini infections were diagnosed using urine antigen detection.Associations between PZQ and O.viverrini were determined by adjusted odds ratio(aOR)and 95%confidence interval(CI)using multiple logistic regression.Results:Among participants,27.7%had previously been treated once with PZQ,8.2%twice,2.8%three times,and 3.5%more than three times.Current O.viverrini prevalence was 17%(n=524).Compared with participants who never used PZQ,the aOR for infection among those who used the drug once was 1.09(95%CI:0.88-1.37),twice was 1.19(95%CI:0.85-1.68),three times was 1.28(95%C/:0.74-2.21),and more than three times was 1.86(95%C/:1.18-2.93;P=0.007).Conclusions:The population with a frequent history of PZQ use and still continued raw fish consumption showed high levels of repeated reinfection with O.viverrini.They were infected,treated and re-infected repeatedly.These findings suggest that certain participants continue raw fish consumption even after previous infection.This is a particular problem in highly endemic areas for O.viverrni and increases the risk of CCA.