Human-swine interface: is the hepatitis E virus a real risk for humans?

Abstract Background Hepatitis E virus (HEV) is the agent of hepatitis E, an emerging public-health infection with an increasing incidence in Europe. Due to the apparent lack of species barriers, HEV is considered a zoonotic agent, with swine as the main reservoir. This study investigated HEV prevalence in humans and domestic pigs in Northern Italy, a highly anthropic area with the highest pig farm density, to gain insights into the risk of HEV transmission from swine to humans. Methods A total of 508 blood samples were collected from blood donors (341 males and 167 females; from 18 to 66 years old) and from 1619 pigs in 40 different farms. Serological analyses were performed with ELISA to detect anti-HEV antibodies. In addition, 120 faecal pool samples collected from the pig farms with the highest seroprevalence and 69 salami produced in the same area were analysed to detect viral genome by Real-time PCR. Results In humans, HEV seroprevalence was 4.9% (CI95% 0.03-0.07); positive donors were mainly males, with seroprevalence increasing up to 12% (CI95% 0.09-0.15) in the 46-55 age group. Seroprevalence in swine was 53.00% (CI95% 0.50-0.55), with HEV detected in only 1% (CI95% 0.001-0.045) faeces. All food samples tested negative. Conclusions Even if the seroprevalence in pigs highlighted that HEV was actively circulating in the farms, the low seroprevalence in humans, the scarce HEV detection in swine faeces, and the absence in food products suggested that HEV transmission via faecal-oral or foodborne routes is unlikely, probably due to the implementation of severe biosecurity measures and high standards of hygiene in swine farms, and the continuous assessment of the critical points in the pig supply chain (from farm to fork). The serological surveillance of humans and the monitoring of farmed animals are needed to support the competent authorities in timely managing public health issues, improving human health and veterinary safety from a One Health perspective. Key messages • In the human-swine interface is important to monitor HEV presence. • The One Health approach is essential to control zoonotic diseases.