PCR detection of swine hepatitis E virus (HEV) in italian pig farms

HEV, the causative agent of hepatitis E, represents an important public health concern in many developing countries where the infection is primarily transmitted by the faecal-oral route. The disease has been sporadically reported also in industrialized countries, including Italy, in person with and without a history of travelling in endemic areas. Increasing evidences support the hypothesis that HEV is also a zoonotic disease, with pigs as the main reservoir. The first swine HEV strain was characterized in USA in 1997; since then, many isolates have been identified worldwide. The objective of this study was to evaluate the presence of HEV in Italian pig farms. 31 faecal and 22 serum samples were collected from 5 farms. Viral RNA was extracted using a commercial kit and detected by a nested RT-PCR. Reverse transcription was performed using random hexamers and was followed by a nested PCR employing degenerate HEV primers located within the ORF2 region. Amplified products were visualized on a 2% agarose gel and positive products sequenced. Sequences were assembled with SEQMAN (DNASTAR) and alignement was performed using Cluslal X algorithm. HEV genome was detected in two faecal samples from two different farms. All serum samples tested were negative. As other swine and human European indigenous strains, our two isolates belonged to genotype 3, but differed significantly one to the other. This survey represents the first report of the presence of HEV in Italian pig herds. Further studies are in progress to evaluate the prevalence of the infection. Genetic comparison of swine and human HEV will help to understand if there is the potential zoonotic transmission of HEV in Italy.