Revisiting genital leptospirosis in large animals: impacts on reproductive health, diagnostic challenges, and future directions

Leptospirosis, caused by <i>Leptospira</i> spp. infection, is a globally significant zoonotic disease that affects a wide range of animals. Although renal colonization is well-documented, genital infection by leptospires remained less explored for decades, despite its impact on reproduction. Evidence suggests that genital infection occurs as a primary condition rather than secondary to renal colonization, particularly in cattle suffering from bovine genital leptospirosis (BGL), linked to chronic infections by strains of the Sejroe serogroup. In horses, a similar condition is suggested to be associated with strains of serogroup Australis. Molecular studies confirmed the presence of <i>Leptospira</i> DNA in uterine, follicular, and vaginal samples, strengthening the hypothesis of an independent genital physiopathology. Despite significant advances in molecular diagnostics, the detection of genital carriers remains challenging, requiring refined methodologies beyond standard serology. This review critically examines the historical detection of <i>Leptospira</i> spp. in genital samples of cattle, small ruminants, swine, and equines, emphasizing its relevance to reproductive health. Moreover, we highlight the limitations of current diagnostic approaches, advocating for increased use of genital samples in leptospirosis research of large animals and shedding light on future directions regarding genital leptospirosis in livestock research. Enhanced understanding and diagnosis of genital leptospirosis will contribute to better livestock reproductive management and disease prevention.