Susceptibility of Pigs to Zoonotic Hepatitis E Virus Genotype 3 Isolated from a Wild Boar

Abstract

In Europe, zoonotic hepatitis E virus (HEV) genotype 3 strains mainly circulate in humans, swine and wild boar. The aim of this study was to investigate the potential transmission of a wild boar originating HEV strain (WbHEV) to swine by intravenous or oral inoculation and to study the consequences of infection of a WbHEV strain, a WbHEV strain previously passaged in a pig and a swine HEV strain after oral inoculation. Firstly, an intravenous infection was performed for which five piglets were divided into two groups with three pigs inoculated with a WbHEV field strain and two pigs inoculated with a HEV-negative swine liver homogenate. All pigs were necropsied 8, 9 and 10 days post-inoculation. Secondly, an oral infection of 56 days was performed on 12 piglets divided into four groups inoculated with a WbHEV strain, a WbHEV strain previously passaged in swine, a swine HEV strain or a HEV-negative swine liver homogenate. After intravenous inoculation, HEV RNA was detected in serum, bile, liver, spleen, duodenum, jejunum, colon, lung, gastro-hepatic lymph nodes and faeces in all infected piglets. After oral inoculation, HEV RNA was detected in serum, bile, liver, gastro-hepatic lymph nodes and faeces. Most of HEV-inoculated pigs became seropositive at day 15. This study provides experimental evidence of early viral spread throughout the organism after intravenous infection with a WbHEV strain and supports the notion that such a zoonotic strain could be transmitted via the natural faecal-oral route of infection between wild boar and pigs but also between pigs.

Molecular survey of HEV infection in wild boar population in Italy

“…Wild boars might represent a source of autochthonous HEV transmission to humans in those regions where consumption of wild boar meat is common or where there is frequent contact between pigs and wild boars. Indeed, the transmission of HEV between domestic and wild swine has been clearly demonstrated (Thiry, Rose, et al., ). Moreover, wild boars intended for human consumption are mainly captured by hunting and game meat follows a food chain different from pigs, where rules for food safety could be less strict.…”

Wild Boar: A Reservoir of Foodborne Zoonoses

“…High seroprevalences of hepatitis E (>30%) in wild boars were reported in Japan and several European countries (Charrier et al, 2018, Hara et al, 2014, Kukielka et al, 2016, Larska et al, 2015, Mazzei et al, 2015, Motoya et al, 2016, Schielke et al, 2015, Spancerniene et al, 2016, Thiry et al, 2017, Weiner et al, 2016, Žele et al, 2016 (Tables 1 and 1S). In North-Central Italy, the seroprevalence of hepatitis E varied significantly between provinces: the lowest prevalence in wild boars was 4% and the highest 49% (Martinelli et al, 2015).…”

Recent knowledge on hepatitis E virus in Suidae reservoirs and transmission routes to human

“…Thus, the search for HEV RNA in blood or serum for diagnosis and prevalence studies may not be the best method to detect acute HEV infection in natural settings. Also, experimental infection of pigs shows that viremia can be influenced by the inoculation route [ 22 ]. Viral RNA was detected more frequently in the blood of infected animals after intravenous inoculation than after oral inoculation [ 22 ].…”

“…Also, experimental infection of pigs shows that viremia can be influenced by the inoculation route [ 22 ]. Viral RNA was detected more frequently in the blood of infected animals after intravenous inoculation than after oral inoculation [ 22 ].…”