In high-income countries, the hepatitis E virus (HEV) is considered an emerging threat causing autochthonous acute hepatitis in humans, with an increased number of reported cases over the last 10 years and related increased burden of chronic hepatitis in immunocompromised and transplant patients. Pigs are the main reservoir of the HEV-3 genotype, which is the most common in Europe, and can be transmitted to humans through the consumption of raw and undercooked pork products. Extensive sequencing revealed the existence of several HEV-3 subtypes in both humans and pigs, confirming a broad heterogeneity of the virus, with some subtypes, such as 3e, 3f, and 3c, which are predominant in Europe. In this study, 291 HEV sequences were obtained from pig feces sampled in more than 74 farms located in Austria, Bulgaria, Czech Republic, Germany, Italy, Poland, the United Kingdom, as well as an unknown number of farms in Netherlands. Of the 99 nonidentical sequences (99/291), 90 were assigned to seven established HEV-3 subtypes: 3a, 3c, 3e, 3f, 3g (here named 3g-like), 3i, and 3l (named 3l-like), already described in Europe, while nine sequences of HEV-3 could not be assigned to any existing subtype (here named 3 ∗ ). The 3e subtype was the most common, detected in six out of eight countries, followed by 3f and 3c, which were also present in several countries; 3g-like, 3i, and 3l-like subtypes showed only a limited circulation. The distribution of frequently (3e, 3f, and 3c) and rarely (3g-like, 3i, and 3l-like) detected HEV-3 subtypes in pigs was correlated with their detection rates in human patients in Europe. The results from this study confirm the wide circulation of several HEV-3 strains in European pigs and confirm that sequencing is needed to monitor the different strains and to identify possible zoonotic transmission paths.

Animal and Plant Health Agency Weybridge Addlestone UK

Centre for Infectious Disease Control National Institute for Public Health and the Environment Bilthoven Netherlands

Department Food Safety Nutrition and Veterinary public Health Istituto Superiore di Sanità Rome Italy

Department of Food and Environmental Virology National Veterinary Research Institute Al Partyzantów 57 24 100 Puławy Poland

Department of Public Health Masaryk University Brno Czech Republic

Department of Swine Diseases National Veterinary Research Institute Al Partyzantów 57 Puławy 24 100 Poland

Division for Animal Health Austrian Agency for Health and Food Safety Mödling Austria

German Federal Institute for Risk Assessment Max Dohrn Strasse 8 10 10589 Berlin Germany

Istituto Zooprofilattico Sperimentale della Lombardia e dell'Emilia Romagna Bruno Ubertini Brescia Italy

Laboratory of Neurobiology and Pathological Physiology Institute of Animal Physiology and Genetics The Czech Academy of Sciences Brno Czech Republic

National Diagnostic and Research Veterinary Medicine Institute National Food Safety Centre Sofia 1606 Bulgaria

Wageningen University and Research Houtribweg 39 8221 RA Lelystad Netherlands

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