Seroprevalence of hepatitis E virus among pregnant women and control subjects in China.

Hepatitis E infection, caused by the hepatitis E virus (HEV), is an important global public health concern, with particularly high mortality in pregnant women. China is generally judged to be an HEV-endemic area, but epidemiological data for HEV among pregnant women are limited. Between June 2011 and July 2013, a case-control study was conducted to estimate the seroprevalence and potential risk factors associated with the acquisition of HEV infection by pregnant women in China. Nine-hundred and ninety pregnant women who visited hospitals for antenatal follow-up or medication in Qingdao and Weihai and 965 control subjects matched by age, gender and residence were examined for the presence of anti-HEV IgG and IgM antibodies by enzyme immunoassays. Socio-demographic and behavioral characteristics from the study subjects were obtained. The overall prevalence of anti-HEV IgG in all 1,955 samples was 20.7%. In pregnant women, 16.2% of samples were anti-HEV IgG positive whereas, in control subjects 25.3% of samples were anti-HEV IgG positive, (P < 0.01). For anti-HEV IgM detection, 62 (3.2%) of the 1,955 serum samples were positive and the seroprevalence in pregnant women and control subjects was 2.6% and 3.6%, respectively. Age, contact with cats, contact with pigs and exposure to soil were found to be associated with HEV infection. These findings demonstrated the high prevalence of HEV and the considerable potential for the transmission of HEV infection in pregnant women in China.