Infecção natural por Leptospira spp. em touros destinados a reprodução

Abstract

The objective of this study was to investigate the prevalence of pathogenic Leptospira infection in breeding bulls used as semen donors. A total of 101 blood serum and semen samples were analyzed from clinically healthy bulls that were not vaccinated against leptospirosis and belonged to a reproduction center in the Triângulo Mineiro region of Minas Gerais, Brazil. Serological detection was performed using the microscopic agglutination test (MAT), and molecular detection was carried out by polymerase chain reaction (PCR) targeting the 16S rRNA, LipL32, and Loa22 genes, in addition to qPCR quantification of leptospiral DNA for the LipL32 gene. Semen quality was assessed using computer-assisted semen analysis (CASA), considering progressive motility, sperm concentration, and morphological defects. The results demonstrated seroreactivity in 13/101 (12.87%) of the bulls, with a predominance of reactions to Wolffi and Grippotyphosa. Molecular detection revealed a higher frequency for the LipL32 gene 47/101 (46.5%), demonstrating the presence of leptospiral DNA in semen, even in seronegative animals. Clinically healthy bulls may act as carriers of pathogenic Leptospira spp.