RESUMO
Hepatitis E caused by hepatitis E viruses of the genotype 3 (HEV-3) is a major health concern in industrialized countries and due to its zoonotic character requires a "One Health" approach to unravel routes and sources of transmission. Knowing the viral diversity present in reservoir hosts, i.e., pigs but also wild boars, is an important prerequisite for molecular epidemiology. The aim of this study was to gain primary information on the diversity of HEV-3 subtypes present along the food chain in Switzerland, as well as the diversity within these subtypes. To this end, samples of domestic pigs from slaughterhouses and carcass collection points, as well as from hunted wild boars, were tested for HEV RNA and antibodies. HEV positive meat products were provided by food testing labs. The HEV subtypes were determined using Sanger and next generation sequencing. The genetic analyses confirmed the predominance of a Swiss-specific cluster within subtype HEV-3h in pigs, meat products, and wild boars. This cluster, which may result from local virus evolution due to the isolated Swiss pig industry, supports fast differentiation of domestic and imported infections with HEV.
RESUMO
Hepatitis E virus (HEV) is an important cause of acute hepatitis in humans worldwide. In industrialised countries, most infections are caused by the zoonotic genotype 3. The main reservoir was found in pigs, with fattening pigs as the main shedders. The aim of this study was to establish a screening tool to detect HEV in pig farms. HEV-positive samples were sequenced using Sanger sequencing. First, different sample materials, including floor swabs, slurry, dust swabs and faeces were tested for HEV. Floor swabs turned out to give the best results and, in the form of sock swabs, were used for the screening of Swiss pig herds. A total of 138 pig farms were tested, with a focus on fattening pigs. Overall, 81 farms (58.8%) were HEV positive. Most sequences belonged to subtype 3h, in which they formed a specific cluster (Swiss cluster). In addition, subtype 3l and two unassigned sequences were detected. As a conclusion, sock swabs were found to be a helpful tool to screen pig herds for HEV and establish a sequence collection that may enable molecular epidemiology and support outbreak investigation and prevention.
