First Serologic Survey of Erysipelothrix rhusiopathiae in Wild Boars Hunted for Private Consumption in Portugal

SIMPLE SUMMARY: Swine erysipelas (SE), caused by the bacterium Erysipelothrix rhusiopathiae, is a relevant zoonotic disease affecting domestic pigs. However, there are scarce studies on the occurrence of SE in hunted wild boar and, consequently, on its role as a reservoir and spill over to other animals and humans. This lack of knowledge, which also applies to the Portuguese wild boar, triggered the development of this first survey. Of the 111 wild boars sampled, seroprevalence was 16.2% (95% CI: 19.9–24.4%), pointing out the importance of this infection in the wild boar population. Given its zoonotic nature, it can have serious repercussions on people who handle and eviscerate the carcasses of hunted wild boar, especially hunters. Thus, the need for further studies to improve the epidemiological knowledge of ES in the wild boar population in Portugal is emphasized. Moreover, the need to adopt preventive measures and train the various stakeholders, especially hunters, who are in direct contact with these wild populations on a daily basis and are at risk of exposure to this infectious agent, is underlined. ABSTRACT: Erysipelothrix rhusiopathiae is a relevant zoonotic infectious agent causing swine erysipelas (SE) in wild boar. In Portugal, there is no information on its occurrence. For this reason, this study aims to perform a first serosurvey of SE in hunted wild boars in Portugal. During the 2019/2020 hunting season, 111 sera from hunted wild boar were collected and analysed serologically in the laboratory with a commercial ELISA kit. No animals were eviscerated and examined after the hunt. The hunters took it all for private consumption. The results identified 18 animals that were exposed to SE, corresponding to a seroprevalence of 16.2% (95% CI: 19.9–24.4%). No statistical significance was observed on the effect of gender and age on seropositivity. However, wild boar hunted in Pinhel County, had five times more likely to be seropositivity (p-value < 0.05; OD = 5.4). Apart from its potential debilitating capacity and chronicity in the wild boar population, SE is also a very serious occupational zoonosis. Thus, the result of this first serosurvey in Portugal should raise awareness and alert competent national veterinary authorities and those involved in the hunting sector, especially hunters who directly handle these carcasses. Further studies should be conducted to better understand the role of wild boar as a reservoir and spillover of this disease to other animals and humans.