Evaluation of a molecular method for hepatitis E virus (HEV) detection in pancreatin of porcine origin

Pancreatin is a combination of enzymes, principally amylase, lipase, and protease, used in the treatment of pancreatic endocrine insufficiency in humans. Pancreatin manufactured from imported porcine pancreas carries the risk of hepatitis E virus (HEV) contamination. About 1 % of the starting material for pancreatin manufacture is invariably constituted of the small intestine, which is known to be a major extrahepatic site of HEV replication in pigs. The aim of this study was to evaluate a method to detect and quantify HEV in pancreatin of porcine origin. Because HEV cannot be easily grown by conventional cell culture, an approach based on an established quantitative RT-PCR (RT-qPCR) was selected. This entailed the use of a non-HEV internal control to monitor RNA extraction efficacy and the production of HEV synthetic RNA as a reference to account for the efficacy of reverse-transcription. The method was evaluated by experiments in which HEV (from naturally infected pigs) was spiked in both the starting material (i.e., porcine pancreas homogenate for industrial production) and in the pancreatin itself. A laboratory protocol matching the industrial production workflow was set up and RT-qPCR experiments were carried out to evaluate the method's ability to detect HEV in pancreatin made from HEV-contaminated porcine tissues. The results showed that the method may be employed in two different strategies: to test the porcine pancreas homogenate (quantitative performance) or directly on pancreatin (qualitative assay). While the risk of HEV contamination in pancreatin may be low, it cannot be completely ruled out. Testing for HEV based on the precautionary principle ought to be the guiding rule.