The occurrence of Leptospira spp. serogroup Pomona infections in wild boars

Leptospirosis is a worldwide zoonosis caused by different pathogenic serovars of the genus Leptospira, with very complex aetiology and epidemiology. Recent publications suggest that wild boar (Sus scrofa) has an important role in the epizootiology of leptospirosis, representing a potential source of infection. Wild boar populations in urban environments are increasing, posing not only agricultural and ecosystem concerns, but also a public health concern. The aim of this study was to assess the prevalence, temporal patterns and risk factors of Pomona infection in wild boars from areas with pronounced human activity. A total of 159 wild boar serum samples were collected within a health monitoring project in Medvednica Nature Park over a period of six hunting seasons (2012–2016; 2018) and 25.2% samples tested positive. Seropositivity against seven different serogroups was observed, with the highest number of positive reactions to the serogroup Pomona. Annual variation in Pomona reactivity was also detected, and positive reactions were five times more common in females than in males. In most of studies, adults had a higher seroprevalence than younger categories; however, in this study,seroprevalence against Pomona was higher in piglets and subadults. The results indicate that wild boar has the potential of maintaining serovars from the serogroup Pomona in certain natural foci. Due to the expansion of wild boar populations and their intrusion into urban areas, they should be considered a potentially important source of infection for humans and domestic animals.