Molecular detection and phylogenetic analysis of hepatitis E virus strains circulating in wild boars in south-central Italy.

Hepatitis E virus (HEV) is a zoonotic pathogen with a worldwide distribution, and infects several mammalian species, including pigs and wild boars, which are recognized as its natural reservoirs. The virus causes a usually self-limiting liver disease with a mortality rate generally below 1%, although mortality rates of 15%-25% have been recorded in pregnant woman. Chronic infections can also occur. The prevalence of HEV has been extensively studied in wild boars and pigs in northern Italy, where intensive pig herds are predominantly located. In contrast, few data have been collected in south-central Italy, where small pig herds are surrounded by large regional parks populated with heterogeneous wild fauna. In this study, 291 liver samples from wild boars caught in south-central Italy were analysed with the molecular detection of viral RNA. Our results confirm the circulation of HEV in these animals, with a mean prevalence of 13.7% (40 of 291). A nucleotide sequence analysis showed that the HEV strains were highly conserved within the same geographic areas. The wild boar HEV strains belonged to the HEV-3c subtype, which is frequently described in wild boars, and to an uncommon undefined subtype (HEV-3j-like).The viral prevalence detected is concerning because it could represent a potential risk to hunters, meat workers and consumers of wild boar liver and derivative products. The hypothesized inter-species transmission of HEV to pigs and the possibility that the virus maintains its virulence in the environment and the meat chain also present potential risks to human health, and warrant further investigations in the near future.

Tracing sources of Listeria contamination in traditional Italian cheese associated with a US outbreak: investigations in Italy.

In 2012 a US multistate outbreak of listeriosis was linked to ricotta salata imported from Italy, made from pasteurized sheep's milk. Sampling activities were conducted in Italy to trace the source of Listeria monocytogenes contamination. The cheese that caused the outbreak was produced in a plant in Apulia that processed semi-finished cheeses supplied by five plants in Sardinia. During an 'emergency sampling', 179 (23·6%) out of 758 end-products tested positive for L. monocytogenes, with concentrations from <10 c.f.u./g to 1·1 × 106 c.f.u./g. Positive processing environment samples were found in two out of four processing plants. A 'follow-up sampling' was conducted 8 months later, when environmental samples from three out of six plants tested positive for L. monocytogenes and for Listeria spp. PFGE subtyping showed 100% similarity between US clinical strains and isolates from ricotta salata, confirming the origin of the outbreak. The persistence of strains in environmental niches of processing plants was demonstrated, and is probably the cause of product contamination. Two PFGE profiles from clinical cases of listeriosis in Italy in 2011, stored in the MSS-TESSy database, were found to have 100% similarity to one PFGE profile from a US clinical case associated with the consumption of ricotta salata, according to the US epidemiological investigation (sample C, pulsotype 17). However, they had 87% similarity to the only PFGE profile found both in the US clinical case and in 14 ricotta cheese samples collected during the emergency sampling (sample B, pulsotype 1). Sharing of molecular data and availability of common characterization protocols were key elements that connected the detection of the US outbreak to the investigation of the food source in Italy. Simultaneous surveillance systems at both food and human levels are a necessity for the efficient rapid discovery of the source of an outbreak of L. monocytogenes.