Hepatitis E in Italy: a long-term prospective study

Background & Aims: In developed countries, hepatitis E is usually associated with travelling to endemic areas, but a growing number of sporadic cases are also seen in patients with no travel history. The aim of this study was to assess the impact and the molecular epidemiology of hepatitis E in Italy. Methods: Between January 1994 and October 2009, we analyzed 651 patients with acute non-A-C hepatitis. Diagnosis of hepatitis E was based on the presence of IgM anti-HEV and/or the detection of HEV RNA by RT-PCR. Viral isolates were sequenced and phylogenetically characterized. Results: A total of 134 out of 651 (20.6%) patients tested had acute hepatitis E. All were anti-HEV IgM and IgG positive and 96 (71.6%) were also positive for HEV RNA. Moreover, 39 (6%) patients were anti-HEV IgG positive but negative for both IgM anti-HEV and HEV RNA. A total of 109 (81.3%) patients developed hepatitis E travelling to endemic areas, 3 (2.3%) acquired intra-familial infection from relatives who developed travel-related disease, while 22 (16.4%) patients denied having travelled abroad. In all patients, acute disease had a self-limited course with ALT normalization within 3-6 weeks. Phylogenetic analysis of 39 isolates from patients with a travel-related disease showed that they belonged to genotype 1, while sequences from five patients with autochthonous hepatitis E belonged to genotype 3. Conclusions: In Italy, most cases of hepatitis E are travel related, caused by viral genotype 1, while autochthonous cases are caused by genotype 3. The prevalence of genotype 3 among pigs and boars suggests that HEV infection may have zoonotic origins in non-endemic countries.