Hepatitis E Virus RNA in Commercial Porcine Livers in The Netherlands

Abstract

Human hepatitis E virus (HEV) infections by genotype 3 strains in industrialized countries are hypothesized to be caused by pigs. To examine this hypothesis, the potential health risks of transmission routes should be examined. Possible foodborne transmission was studied by quantifying the presence and infectivity of HEV in commercial porcine livers in The Netherlands. A comparison of four tissue disruption and seven RNA extraction methods revealed that mechanical disruption followed by silica-based RNA extraction gave the highest RNA yields and was therefore employed on commercial porcine livers. Four (6.5%) of 62 porcine livers were HEV RNA positive by reverse transcriptase PCR and Southern blot hybridization. Each positive liver was estimated to contain approximately 65 PCR-detectable units per g. Sequences were obtained for three of four positive livers and classified as HEV genotype 3. Ninety-three percent similarity to Dutch human HEV sequences and 97% similarity to Dutch swine HEV sequences were observed. To determine whether positive livers contained infectious HEV particles, extracts from livers with known HEV RNA sequences were inoculated intravenously in pigs. Two control pigs were included: one was inoculated with a high dose known to result in infection (10(4) PCR-detectable units of HEV RNA), and the other was inoculated with a lower concentration of virus that equaled the concentration of PCR-detectable units in commercial livers ( approximately 20 PCR-detectable units). Infection was observed in the high-dose control, but not in other pigs, suggesting a dose-dependent response in pigs. Hence, the implications of HEV RNA in commercial porcine livers in The Netherlands are unknown. However, HEV RNA is present in commercial porcine livers, and sufficient heating of porcine livers before consumption as precautionary measure is recommended.

Detection of hepatitis E virus genome in pig livers in Antioquia, Colombia

“…These reports found much lower HEV RNA-positive samples compared to grocery stores tested in this study, for which the average was 25%. This positivity average was 13-, 4.2-, 2.3-, and 6.3-fold greater than that found in Japan (Yazaki et al, 2003), Holland (Bouwknegt et al, 2007), USA (Faegins et al, 2007), and Germany (Wenzel et al, 2011), respectively. Faegins et al (2007 reported that livers from grocery stores in the US contained HEV RNA.…”

“…Regarding livers from grocery stores for human consumption, HEV RNA was detected in 1.9% (363 samples) of tested livers originating from supermarkets in Japan (Yazaki et al, 2003), 6% (62 samples) of packets of liver in Holland (Bouwknegt et al, 2007), and 11% (127 samples) of packets of liver in the USA (Faegins et al, 2007). Additionally, Wenzel et al (2011) that in 200 liver samples in Germany, 4% were positive for HEV RNA.…”

Transmission routes and risk factors for autochthonous hepatitis E virus infection in Europe: a systematic review

“…In The Netherlands, 4/62 (6 . 5 %) pig livers on retail sale were found positive for HEV RNA and sequencing analysis found HEV gt3 to be closely related to HEV gt3 of pigs (97 %) and humans (93 %) in The Netherlands [44].…”

Molecular Epidemiology of Hepatitis E Virus (Hev) in South America: Current Status

“…Yazaki et al (2003) investigated a series of 29 cases of sporadic hepatitis E occurring in Japan and identified nine patients with a history of having recently ingested grilled or undercooked pig liver 2-8 weeks before the onset of the disease. Additionally, HEV RNA has been detected in 6.5 and 11% of commercial pig liver in Netherlands and United States, respectively (Bouwknegt et al 2007;Feagins et al 2007). All strains detected were classified as HEV genotype 3.…”