Wild boars as reservoirs of zoonotic and swine-relevant pathogens: serological evidence from southern Brazil

The wild boar ( Sus scrofa ), native to Eastern Europe, was introduced into South America for meat production, and its subsequent spread has caused significant negative impacts on native fauna and flora, being considered one of the worst invasive species worldwide. Although isolated studies have been conducted in Brazil, investigations simultaneously addressing zoonotic agents and pathogens of productive relevance in free-ranging wild boar populations remain scarce, highlighting the epidemiological importance of the present survey. Given their role as reservoirs of infectious agents, this study aimed to investigate the presence of antibodies to zoonotic and production-relevant pathogens in free-ranging wild boars from a municipality in the state of Rio Grande do Sul, southern Brazil. Blood samples from 50 animals were tested for antibodies to Brucella spp., Toxoplasma gondii , Leptospira spp., Mycoplasma hyopneumoniae , and Senecavirus valles (SVA). Serofrequency was 28% (14/50) for T. gondii , 24% (12/50) for Leptospira spp., with serovar Pomona being the most frequently detected, and 28% (14/50) for M. hyopneumoniae . Five animals (10%) showed serological co-exposure with T. gondii and Leptospira spp., and three adult wild boars presented simultaneous triple seropositivity ( T. gondii + Leptospira spp. + M. hyopneumoniae ). Antibodies to SVA were detected in a single animal (titer 16), whereas no seropositive animals were observed for Brucella spp. These findings reinforce the epidemiological relevance of wild boars as potential reservoirs and disseminators of sanitary hazards at the wildlife livestock interface, underscoring the need for continuous surveillance and evaluation of population control measures for this invasive species.