Detection of hepatitis E virus RNA in raw sausages and liver sausages from retail in Germany using an optimized method

Hepatitis E virus (HEV) is a pathogen of increasing importance, which can be zoonotically transmitted from domestic pigs, wild boar, and deer to humans. Foodborne transmission by consumption of raw and undercooked liver, meat, or sausages prepared from infected animals has been documented. The aim of this study was to investigate the distribution of HEV in different types of sausages sold in Germany. As no standardized methods for HEV detection in food exist, several techniques of sample homogenization, virus concentration and nucleic acid extraction followed by real-time RT-PCR were compared using artificially contaminated sausages. A method using TRI Reagent® Solution showed the best efficacy of matrix disruption and a treatment with chloroform followed by a silica-based RNA extraction method resulted in the highest HEV detection rates. The detection limit of the method was 2.9×103 and 5.3×104 genome equivalents per 5g raw sausage and 2g liver sausage, respectively. Application of the method to raw and liver sausages from retail in Germany resulted in the HEV genome detection in 14 out of 70 (20%) raw sausages and in 11 out of 50 (22%) liver sausages. The detected HEV sequences showed a high diversity and belonged to different subtypes of HEV genotype 3. The results indicate a broad distribution of HEV-RNA in meat products sold in Germany; however, the infectivity of the detected virus remains to be assessed in future.