Hepatitis E Virus and Related Viruses in Animals

Abstract

Hepatitis E is an acute human liver disease in healthy individuals which may eventually become chronic. It is caused by the hepatitis E virus (HEV) and can have a zoonotic origin. Nearly 57,000 people die yearly from hepatitis E-related conditions. The disease is endemic in both developing and developed countries with distinct epidemiologic profiles. In developing countries, the disease is associated with inadequate water treatment, while in developed countries, transmission is associated with animal contact and the ingestion of raw or uncooked meat, especially liver. All human HEV are grouped into at least four genotypes, while HEV or HEV-related viruses have been identified in an increasing number of domestic and wild animal species. Despite a high genetic diversity, only one single HEV serotype has been described to date for HEV genotypes 1-4. The discovery of new HEV or HEV-related viruses leads to a continuing increase in the number of genotypes. In addition, the genome organization of all these viruses is variable with overlapping open reading frames (ORF) and differences in the location of ORF3. In spite of the role of some domestic and wild animals as reservoir, the origin of HEV and HEV-related viruses in humans and animals is still unclear. This review discusses aspects of the detection, molecular virology, zoonotic transmission and origin of HEV and HEV-related viruses in the context of 'One Health' and establishes a link between the previous and the new taxonomy of this growing virus family.

Assessment of Domestic Pigs, Wild Boars and Feral Hybrid Pigs as Reservoirs of Hepatitis E Virus in Corsica, France

“…Surprisingly, the seroprevalence detected in closed systems was significantly lower than the one detected in open systems. Despite the specificities of the different pig breeding systems, the overall seroprevalence observed in our limited sample of Corsican pigs obtained during the first year of life (41.70%), remains comparable to the one reported in other European countries [6,30,31]. A possible explanation is that despite in open systems the density of pigs is likely to be lower than in intensive pig farms, animals in open or semi-open systems tend to concentrate around food and water points reaching densities that are sufficiently high to allow regular exposure to most of the herd through the contamination of food and water.…”

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

“…From the livers of two young wild boars that were shot in the same Belgian forest during the same hunt in Walloon Region, a HEV‐3 subtype f, phylogenetically similar to the analysed sequences (Thiry et al., ,b) (GenBank accession no. and ), was isolated and used for the production of inoculum for the intravenous and the oral infections, thereafter named WbHEV.…”

“…These results suggest that a zoonotic HEV from wild boar may spread among pigs after being introduced in a pig population. An especially high prevalence has often been observed in pigs and wild boars in Western Europe (Thiry et al., , ,b). This epidemiological situation, combined with the capacity of the virus to cross the wild boar – pig barrier, raises the question of natural transmission events occurring between these animals, at least in the context of outdoor pig breeding.…”

“…Sera from days 0, 4, 8, 9 and 10 were analysed in duplicate with a double antigen sandwich ELISA strictly developed for veterinary use (HEV ELISA kit 4.0V, MP Biomedicals, Illkirch, France) (Hu et al., ; Bouwknegt et al., ; Rutjes et al., ; Thiry et al., , ,b) according to the manufacturer's instructions.…”

“…Genotypes HEV‐3 and 4 have been detected worldwide in both humans and animals. An increasing number of animal species have been also recognized as susceptible to HEV or genetically related viruses (Thiry et al., ,b). Zoonotic transmission associated with symptomatic infections has been documented several times with genotype HEV‐3 strains present in uncooked meat, especially liver, from wild boars, deer and pigs infected with HEV (Tei et al., ; Li et al., ; Renou et al., ; Riveiro‐Barciela et al., ).…”