Describing diagnosis (MAT + PCR) and control (vaccine + streptomycin sulfate) of a leptospirosis outbreak in dairy cows with reproductive disorders.

Leptospirosis is a zoonosis caused by bacteria of the genus Leptospira. In cattle, the infection mainly manifests in the genital form. However, there are still few studies about this manifestation. The aim of this study was to describe the control of an outbreak of leptospirosis in dairy cows with reproductive disorders, through the combination of diagnostic methods and the integration of vaccination with antibiotic therapy. Between December 2022 and April 2023, 17 cows presented reproductive disorders. After the outbreak, two consecutive blood collections and one cervicovaginal mucus (CVM) collection were carried out. The blood samples were tested by the microscopic seroagglutination test (MAT), using a collection of antigens with eight strains of Leptospira and a cutoff point ≥ 1:200. The CVM samples were analyzed by polymerase chain reaction (PCR), with the lipL32 gene as target. The control was carried out with the CattleMaster® GOLD FP 5/L5 vaccine, in addition to the application of streptomycin (25 mg/kg) in positive cows. After one year of sanitary management, the CVM PCR was repeated to evaluate the effectiveness of the integrated control. In serology, 58.8% (10/17) of the cows were reactive, with 100% (10/10) for the serogroup Sejroe. In the molecular analysis, 58.8% (10/17) of the cows were positive. When combining the two methods, the result was 82.3% (14/17) reagent/positive. After the integrated control, 0.0% (0/17) of cows were positive. It was concluded that the outbreak was related to bovine leptospirosis. Furthermore, the combination of diagnostic methods and integrated control proved to be efficient.