Seroprevalence of Leptospira spp. infection in sheep from northwest of Rio Grande do Sul, Brazil

ABSTRACT: Leptospirosis is a zoonosis that is widely distributed in tropical countries. This infection is also associated with reproductive losses in livestock, which has a significant economic impact. The objective of this study is to investigate the seroprevalence and risk factors associated with leptospiral infection in commercial sheep flocks from the northwestern mesoregion of Rio Grande do Sul. Serum samples were analyzed in 319 sheep using the Microscopic Agglutination Test (MAT). At the time of sampling, an individual and herd questionnaire was carried out to investigate the risk factors. On an individual level, positive reactions were observed in 5.6% (18/319) of the studied sera, with Sejroe being the most prevalent serogroup. Animals >3 years old were more likely to be seropositive than animals 1-3 years old (OR 14.4; 95% CI 1.9-110). The predominance of Sejroe serogroup in this manner draws attention to how subclinical infection is associated with economic losses. Therefore, the importance of maintaining measures for the prevention and control of leptospirosis among the sheep flocks of the studied region is reiterated.