Prevalence of hepatitis E virus in Italian pig herds. Preliminary results

Hepatitis E virus (HEV) is the causative agent of hepatitis E, and is an unenveloped positive sense single-stranded RNA virus. Swine HEV strains are genetically closely related to human strains from the same area, suggesting the occurrence of zoonotic transmission. Recently, human cases of hepatitis E have been linked to the consumption of raw or undercooked meat or organs from deer, wild boars or pigs. The disease is now considered an emerging food-borne transmitted zoonosis. During 2006, a pilot investigation was performed to determine the prevalence of HEV in pig farms located in Northern Italy., 274 faecal samples were collected from healthy fattening animals (3-4 and 8-9 months of age) and from healthy breeding animals (gilts and sows) from 6 different farms and analyzed using a Nested-RT-PCR targeting the open reading frame 2 (ORF2) region. Stool samples were suspended in water, and viral RNA extraction was performed using a commercial kit. Extracted viral RNA was subjected to RT-PCR amplification using degenerate primers conA1-conS1 for the first amplification, and degenerate primers conA2-conS2 for the nested PCR, yielding a final fragment of 145 bp. HEV RNA was detected in sixty-nine of the 274 (25.2%) examined samples. None of the six farms resulted negative and the prevalence within the farms ranged between 2% and 60.5% For the characterization of the strains, randomly selected positive samples were subjected to nucleotide sequencing, and aligned with those present in the NCBI Data Bank Sequence analysis showed that all strains were Swine Hepatitis E belonging to Genotype 3. These preliminary results confirm that swine HEV is widespread in Italian swine farms.