Bull urine and semen as potential vectors of disease transmission for <i>Leptospira borgpetersenii </i>serovar Hardjo: SupplementaryTables.xlsx &amp; Supplementary Figure 1

<b>ABSTRACT</b>Bovine leptospirosis can result in infertility, abortion, placentitis, weak offspring, stillbirths, and decreased milk production. The leading cause of bovine leptospirosis globally is<i> Leptospira</i><i> </i><i>borgpetersenii</i> serovar Hardjo. Asymptomatic cattle with leptospirosis serve as reservoir hosts of infection that can shed infectious leptospires for months to years. Sites of bacterial colonization include the kidney and/or the genital tract in both cows and bulls. In this observational study, we investigated leptospirosis in a herd of asymptomatic bulls; 24.1% (14/58) were shedding leptospires via urine as confirmed by <i>lipL32</i> rtPCR. The viability of leptospires in selected rtPCR-positive bull urine samples was confirmed by culture. Given that bovine semen may also act as a vector of disease transmission, we investigated frozen semen samples for evidence of leptospires; 1.5% (4/268) were <i>lipL32</i> rtPCR positive and, of these, one was culture positive. All isolates cultured from bull urine or semen were classified as <i>L</i>. <i>borgpetersenii</i> serogroup Sejroe serovar Hardjo. The viability and infectivity of the semen isolate was confirmed in the hamster model of leptospirosis. Our results report for the first time the ability to culture serovar Hardjo directly from frozen semen and highlight the potential role for bull urine and semen in the transmission of bovine leptospirosis.