[Epidemiologic and genetic characteristics of hepatitis E virus in Shanghai, 1997-2012].

Objective: The aim of this study was to systemically analyze the epidemiologic, serological and genetic characteristics of hepatitis E virus (HEV) in Shanghai from 1997 to 2012.

Methods: We analyzed the data related to the epidemics of hepatitis E from China Information System for Disease Control and Prevention. We implemented serological surveillance program, based on community healthy population with enzyme-linked immunosorbent assay method and estimated the standardized sero-prevalence. We also obtained nucleotide sequences of hepatitis E patients using the nested RT-PCT assays, together with prototype sequences in the GenBank to construct a HEV genetic database in Shanghai.

Results: In this paper, we found that the distribution of hepatitis E patients was sporadic in the past 16 years in Shanghai. The morbidity kept declining, but with seasonal and periodical fluctuation. Morbidity in males was significantly higher than in females, with the hard hit population between 30 and 65 year-olds. In total, 3979 sera samples were collected through the serological surveillance programs in 2001, 2004, 2007 and 2012. The standardized sero-prevalence rates of the said years were 22.32%, 18.56%, 10.22% and 34.43% which all showing strong relationship with age groups and the regions where the populations were being monitored. 73 nucleotide sequences of hepatitis E patients from hospitals were identified, during 2004 and 2008.

Results: from phylogenetic analysis revealed that all HEV isolates belonged to genotype IV and including 4 known subtypes 4a, 4d, 4h and 4i which sharing 83.09% - 97.96%, 85.87% - 97.26% and 83.80% - 95.10% nucleotide sequence identities with the swine HEV genotype IV of GU188851, DQ450072 and EF570133. Meanwhile, 59 HEV isolates from different districts shared 99% nucleotide sequence identities with each other.

Conclusion: Hepatitis E would still be a challenge for long time and the zoonotic questions that related to hepatitis E, need to be explored and explained in the future.