TDK conference 2016

Hepatitis E virus (HEV) is a non-enveloped virus with small, icosahedral particles and an about 7.2 kb positive-sense single-stranded RNA genome. Virus strains classified into genotype 1-4 of Orthohepevirus A (Family Hepeviridae, Genus Orthohepevirus) can cause acute hepatitis in humans, which, in case of elderly and pregnant women, can have a fatal outcome. In developed countries, HEV strains belonging to the 3rd and 4th genotypes have been detected. These strains can infect not only humans, but animal species (swine, wild boar, deer, roe deer and rabbit) as well; the source of the faecal-oral infection in humans is not only the manure, but also the raw or undercooked meat of the infected animals.

According to the results of a survey performed between 2004 and 2010, HEV is present in swine, wild boar, deer and roe deer in Hungary. The aim of our study was to detect HEV in rabbit and hare, and estimate the food safety and occupational health significance of the infection.

Altogether 231 blood samples were collected from the 0.5-1-year-old age group of rabbits kept at 5 and 6 farms of the two producing integrations operating in Hungary. The results of serological investigations found HEV infection in 5 out of 6 investigated farms of one of the integrations, while all 5 surveyed farms of the other integration were found to be free from the virus. Altogether 44 blood samples were collected from hares shot at 3 hunting areas; seroconversion was not detected in any of the examined samples.

Liver, meat and faecal samples of 30 rabbits (in the age of 4-13weeks group associated with the weight of 0,7-2,85 kg) sent for pathological investigation and 100 animals (11 weeks of age) sent for slaughter were investigated by real-time RT-PCR method. Among the necropsied animals, 7 (23%) was found to be HEV-positive, while viral RNA was detected in liver samples of 42 slaughtered rabbits. Seroconversion was detected in 2 and 5 of the necropsied and slaughtered rabbits, respectively.

Sequencing the 148 bp long PCR product of 48 positive samples, 15 different virus variants were identified. All of them were rabbit-specific HEV strains.

According to our results, the rabbits got infected at around the time of slaughter, 42% of the animals spread the virus at the time of slaughter, and moreover, HEV RNA was detected in the meat of 6% of the slaughtered rabbits, which raises food safety and occupational health concerns. However, by the results of phylogenetic analysis performed on the short genome fragment, the zoonotic potential of rabbit-specific HEV is not clear therefore further investigations are needed to determine the food safety and occupational health significance of the HEV infection of rabbits.