Seasonal pattern and phylogenetic analysis with human isolates of genotype-IV hepatitis E virus in swine herds, eastern China / 中华预防医学杂志

ABSTRACT

<p><b>OBJECTIVE</b>To determine the seasonal prevalence of genotype-IV hepatitis E virus (HEV) in swine herds in Eastern China and explore the phylogenetic relationship between swine HEV and human HEV in the situation that zoonotic features of HEV had been confirmed.</p><p><b>METHODS</b>From September 2007 to June 2008, a total of 1200 swine bile specimens were collected from three slaughter houses located in Zhejiang, Anhui and Jiangsu, the Eastern China, and detected for HEV RNA by using nested RT-PCR. The positive PCR products were sequenced. Then the swine HEV were phylogenetically determined with human HEV isolated in Eastern China.</p><p><b>RESULTS</b>The positive rate for HEV RNA in swine herds was 4.5% totally. Significant differences of HEV detection were not observed among seasonal pattern (Sep - Oct 6%, Dec - Jan 4.33%, Mar - Apr 4.33%, May - Jun 3.33%) but in geographic distribution (Jiangsu 6%, Anhui 5%, Zhejiang 2.5%). Regardless of isolation from different areas,swine and human genotype-IV HEV shared a high similarity. Phylogenetically, there were 80% - 100% and 96% - 100% identities within swine genotype-lV HEV at the nucleotide and amino acid levels respectively. Between swine HEV and human HEV, there were also similarities of 76% -99% and 95% - 100%. It was noted that some human and swine isolates were clustered with bootstrap values of > 90%.</p><p><b>CONCLUSION</b>Genotype-IV HEV is widely prevalent in swine herds in Eastern China and original common ancestor of evolution and transmission was implied. The sustaining prevalence within swine herds should have a probable influence on the epidemic situation of hepatitis E in human beings.</p>