Detection of Hepatitis E Virus in the Pig Livers and Retail Pork Samples Collected in Selected Cities in China

Hepatitis E virus (HEV) is a biological hazard that must be controlled and is a recognized etiological agent in viral hepatitis. This is a zoonotic virus and can be transmitted through the fecal-oral route. The pig is an important reservoir host of HEV, and is a source of contamination for the consumer after the consumption of raw or undercooked pork products. When detected, the most prevalent genotype of HEV in China is genotype 4 (denoted as HEV-4). To ensure the safety of this food of animal origin, we undertook a survey of HEV contamination in pig livers and pork samples available for sale, in retail outlets in selected cities in China. Viral RNA was purified from samples collected by lysing in Trizol followed by purification using trichloromethane and virus RNA extract kit. An additional step was applied to improve the recovery rate by adding RNase OUT when extracting virus RNA from pig livers, and the RNA productions were washed in 75% (v/v) ethanol to remove inhibitors. In total, 158 pig livers and 80 pork samples were procured and analyzed by reverse transcription-quantitative polymerase chain reaction (RT-qPCR). After purification of total RNA from all samples taken and analyzed by RT-qPCR, a single pig liver was positive by this method for HEV. The positive rate was calculated as 0.63%. In this study, a single positive sample was detected. Considering the dietary habits of Chinese people, pork is a popular food that on occasion may be contaminated with HEV, thereby posing a threat to consumer health. Ongoing surveillance is required to assess the risk to human health arising from HEV-contaminated pork being offered for sale, at retail outlets, especially in the areas of China where pig production is practiced.