Zoonotic origin of hepatitis E

• Hepatitis E virus is transmitted mainly via waterborne, foodborne and zoonotic routes.
• Genotypes 3 and 4 (HEV-3 and HEV-4) are the only genotypes confirmed to be zoonotic.
• The main animal reservoirs of zoonotic HEV are domestic pigs and wild boars.
• Novel HEV variants are identified from an increasing number of animal species.
• Understanding HEV interspecies transmission is needed to implement efficient prevention and control measures.

The concept of zoonotic viral hepatitis E has emerged a few years ago following the discovery of animal strains of hepatitis E virus (HEV), closely related to human HEV, in countries where sporadic cases of hepatitis E were autochthonous. Recent advances in the identification of animal reservoirs of HEV have confirmed that strains circulating in domestic and wild pigs are genetically related to strains identified in indigenous human cases. The demonstration of HEV contamination in the food chain or pork products has indicated that HEV is frequently a foodborne zoonotic pathogen. Direct contacts with infected animals, consumption of contaminated animal meat or meat products are all potential means of zoonotic HEV transmission. The recent identification of numerous other genetically diverse HEV strains from various animal species poses additional potential concerns for HEV zoonotic infection.