Rural Population Dominance And Occult Hepatitis B Virus Infection, And Analysis Of Characteristics Of Molecular Evolution

Objective To investigate the prevalence of occult HBV infection and molecular characteristics of both overt and occult HBV S genes in a general rural population in Deqing county, Zhejiang Province. Methods We performed a cross-sectional study based on multi-stage sampling. Questionnaires and blood samples were collected on informed consent. Questionnaire information database was built using Epidata3.2software. ELISA detection of HBsAg and Real-time PCR detection of viral load were performed in all blood samples. PCR amplification and sequencing of HBV S gene was further performed in HBsAg positive or HBV viral load positive samples. Phylogenetic analysis was performed then using MEGA5.0software.Questionnaire and experimental database was analyzed using SPSS18.0software. Results Questionnaires and parallel blood samples of1720subjects were collected. HBV prevalence was9.42%(162/1720), with162HBsAg positive cases and4OBI cases. The history of hepatitis and gender were the two major factors that affected HBV prevalence. Subjects who had a history of hepatitis got a significantly higher risk than those who didn’t OR=2.525,95%CI:(1.520,4.196)),while female subjects got a significantly lower risk than male subjects(OR=0.522,95%CI:(0.359,0.759)). OBI prevalence was2.57%o(4/1558). Viral load in overt HBV strains was significantly higher than that in OBI strains(Wilcoxon ranksum test, z=3.080,P=0.002), Median and Inter-quatile range866(425,12500)(IU/ml) and314(216,677.5)(IU/ml), respectively. All of the occult HBV strains were were genotype C,and serotype adrq+. While54of overt HBV strains were genotype B, of which2was serotype adw3and52were serotype adw2,the other17were genotype C and serotype adrq+. The proportion of Genotype C is significantly higher in OBI strains than in overt HBV strains. I104F, L109V, I110L, S113T, T126I,P127T, Q129R, M133L, F134L, P135A, T140A, K141I, T143M/S, V159A, Y161F, A166G, and R169P mutations were found in Genotype B overt HBV strains, while I126S, I126T and F158S mutations were found in Genotype C overt HBV strains. I126T, Q129R, M133T and F161Y mutations were found in OBI HBV strains. Conclusion OBI occurs in general population. Viral load of OBI strains is probably lower. Genotype C is probably the prior genotype in OBI strains. OBI prevention issue should be paid attention to. Probable risk factors of OBI in general population could be further studied.