Constant Hepatitis E Virus (HEV) Circulation in Wild Boar and Red Deer in Spain: An Increasing Concern Source of HEV Zoonotic Transmission

Abstract

Hepatitis E is a viral zoonosis that affects multiple hosts. The complete dynamics of infection in wildlife are still unknown, but the previous fact facilitates the maintenance and circulation of the virus, posing a risk to human health in the case of meat consumption from susceptible animals. In Spain, it has been shown how domestic pigs, cattle and wildlife (i.e. wild boar and red deer) clearly interact in hunting farms, generating a complex epidemiological situation in terms of interspecies pathogen transmission. Therefore, in this study, we aimed to (i) evaluate the circulation of the virus in geographically close domestic (Iberian pigs) and wild animals (wild boar and deer) living in hunting areas from central Spain over an 8-year period (2003-2010) and (ii) to determine whether HEV could be used as a marker of domestic-wildlife contact. For these purposes, a longitudinal analysis of Iberian pig, wild boar and red deer samples (n = 287) through virological and serological tests was conducted to shed light upon the circulation events of HEV. Regarding HEV RNA detection by real-time RT-PCR, 10.12% samples (95% CI: 5.44-14.8) from wild boar and 16.05% samples (95% CI: 8.06-24.04) from red deer were positive. As for the Iberian pigs, none of the 48 samples was positive for HEV RNA detection. In the serological analysis, 43.75% (95% CI: 29.75-57.75) from Iberian pig, 57.40% (95% CI: 48.10-66.70) from wild boar and 12.85% (95% CI: 5.01-20.69) samples from red deer presented anti-HEV antibodies. Positive samples were distributed among all study years (2003-2010). These results depict the urgent need to improve the inspection and surveillance of these species and their products. In the case of HEV, it is clear that the stable and constant presence of the virus in wildlife and its contact with Iberian pigs pose a risk for human health as they are all destined for human consumption.

Assessment of Domestic Pigs, Wild Boars and Feral Hybrid Pigs as Reservoirs of Hepatitis E Virus in Corsica, France

“…Surprisingly, the seroprevalence detected in closed systems was significantly lower than the one detected in open systems. Despite the specificities of the different pig breeding systems, the overall seroprevalence observed in our limited sample of Corsican pigs obtained during the first year of life (41.70%), remains comparable to the one reported in other European countries [6,30,31]. A possible explanation is that despite in open systems the density of pigs is likely to be lower than in intensive pig farms, animals in open or semi-open systems tend to concentrate around food and water points reaching densities that are sufficiently high to allow regular exposure to most of the herd through the contamination of food and water.…”

“…Several authors have described an association between densities of wild boars and HEV seroprevalence [4,31,33,34]. In our study, data on densities of wild boar were not available.…”

“…The prevalence rates observed in wild boars were substantially higher than in continental France, which ranged between 7.2% to 22.7% [10] but lower than those observed in Southern Europe where densities are known to be high [31,32]. Differences in prevalence across years are unlikely to be due to different storage or laboratory conditions since all the samples were stored, managed and analyzed in a standardized way.…”

Molecular Investigation on the Presence of Hepatitis E Virus (HEV) in Wild Game in North-Western Italy

“…The presence of HEV in roe deer was studied only in the Netherlands, Hungary, and Poland. In the Netherlands, no HEV RNA was detected in eight analyzed roe deers (Rutjes et al 2010) and no sera resulted positive in roe deer from Poland (Larska et al 2014 Kukielka et al (2015) showed that 16.05 % samples from red deer were HEV positive by real-time RT-PCR in Spain. All European hare (Lepus europeaus) samples tested negative for HEV in the present study.…”

Evidence for the presence of autochthonous (locally acquired) cases of acute hepatitis E virus infections in Italy since the 80s

“…HEV has been found in domestic pigs, wild boar, deer, mongoose and bivalves [9][10][11][12]. The most likely route of transmission to humans is consuming raw or undercooked meat of infected wild animals such as meat of boars and deers and domestic animals such as pigs [13][14][15].…”