HEV infection in wild boars in Japan

Detection of hepatitis E virus (HEV) in a demographic managed wild boar (Sus scrofa scrofa) population in Italy

Hepatitis E virus (HEV) is the causative agent of Hepatitis E. Swine and human HEV strains are genetically related, suggesting the occurrence of zoonotic transmission. Recently, in Japan, cases of food-borne HEV transmission have been described in people after consuming raw or undercooked meat from wild boars or pigs. Although, swine HEV strains have been detected in pig herds in many European countries, only minimal information is presently available about the circulation and the prevalence of HEV in wild boars in Europe. In this study, we investigated the presence of HEV in a demographic managed wild boar population in Italy. Detection of HEV RNA was accomplished using a nested reverse-transcription polymerase chain reaction on bile samples from 88 shot animals. HEV RNA was detected in 22 out of 88 animals tested (25%). Phylogenetic analysis on the nucleotide sequences obtained from 10 positive PCR products indicated that only one HEV strain was circulating in the wild boar population considered, and that this strain was closer to human and swine HEV strains circulating in Europe than to wild boar Japanese strains.

[Recent topics on hepatitis E virus: emerging, zoonotic, and animal-to-human transmission in Japan]

Hepatitis E is undoubtedly a zoonosis. Recent observations suggest that the zoonotic food-borne mode of transmission has played an important role in the spread of hepatitis E virus (HEV) among Japanese people (who in general likes eating everything uncooked or undercooked: Sushi, Sashimi, Tataki, Namagimo, Shabu-shabu, etc). Moreover, the situation seems to be worsening. Wild boar (and deer also) has recently been increasing in its number, becoming a more potent HEV reservoir to humans than before. Pork, replacing beef in people's recent fear of BSE, is being consumed increasingly, particularly in Hokkaido. It may be Japanese people that an effective HEV vaccine is most longed for by.

Complete or near-complete nucleotide sequences of hepatitis E virus genome recovered from a wild boar, a deer, and four patients who ate the deer

Zoonosis has been implicated in hepatitis E virus (HEV) transmission. We examined wild boar living in a forest of Hyogo prefecture, Japan, and found HEV RNA in three of seven boars. A full-genome HEV isolate from one of them was revealed to be 99.7% identical to a previous isolate from a wild deer hunted in the same forest and to those from four patients who contracted hepatitis E after eating raw meat of the deer. These findings suggest an interspecies HEV transmission between boar and deer in their wild life, and that both animals might serve as an infection source for human beings as suggested previously.