Bovine leptospirosis due to persistent renal carriage of Leptospira borgpetersenii serovar Tarassovi

Authors: HAMOND, CAMILA - Animal And Plant Health Inspection Service (APHIS); LECOUNT, KAREN - Animal And Plant Health Inspection Service (APHIS); STUBER, TOD - Animal And Plant Health Inspection Service (APHIS); Putz, Ellie; Bayles, Darrell; CAMP, P - Animal And Plant Health Inspection Service (APHIS); GORIS, MARGA - University Of Amsterdam; VAN DER LINDEN, HANS - University Of Amsterdam; STONE, NATHAN - Northern Arizona University; SCHLATER, LINDA - Animal And Plant Health Inspection Service (APHIS); SAHL, JASON - Northern Arizona University; WAGNER, DAVID - Northern Arizona University; Nally, Jarlath

Submitted to: Frontiers in Veterinary Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/7/2022
Publication Date: 4/5/2022
Citation: Hamond, C., Lecount, K., Stuber, T., Putz, E.J., Bayles, D.O., Camp, P., Goris, M.G., Van Der Linden, H., Stone, N.E., Schlater, L., Sahl, J.W., Wagner, D.M., Nally, J.E. 2022. Bovine leptospirosis due to persistent renal carriage of Leptospira borgpetersenii serovar Tarassovi. Frontiers in Veterinary Science. 9. Article 848664. https://doi.org/10.3389/fvets.2022.848664.
DOI: https://doi.org/10.3389/fvets.2022.848664

Interpretive Summary: Leptospirosis is a global zoonotic disease that causes significant morbidity and mortality in human and animal populations. Leptospira borgpetersenii is a leading cause of bovine disease and cattle throughout the world are recognized as carriers of L. borgpetersenii serovar Hardjo. This serovar is transmitted to other cattle via urine, semen and uterine discharges resulting in abortion and poor reproductive performance. In order to prevent disease, cattle are immunized with vaccines that contain serovars known to cause disease, including L. borgpetersenii serovar Hardjo as well as several others. In order to ensure vaccines contain the correct serovars, surveillance is required to identify what serovars are in circulation. In this study, we identified a new serovar associated with bovine leptospirosis; L. borgpetersenii serovar Tarassovi. No U.S. leptospirosis animal vaccines contain serovar Tarassovi.

Technical Abstract: Leptospirosis is a global zoonotic disease that causes significant morbidity and mortality in human and animal populations. Leptospira interrogans is a leading cause of human disease and L. borgpetersenii is a leading cause of animal disease. Cattle are reservoir hosts of L. borgpetersenii serovar Hardjo which is transmitted via urine, semen and uterine discharges resulting in abortion and poor reproductive performance. Bovine bacterin vaccines can only protect against those serovars included in vaccine formulations and typically include serovar Hardjo among others. Genotyping and serotyping represent two different and unique methods for classifying leptospires that do not always correlate well; comprehensive characterization using either method requires recovery of isolates from infected animals. In this study, we report for the first time, isolation of L. borgpetersenii serovar Tarassovi from the urine of a dairy cow in the U.S. The classification of the isolate, designated strain MN900, was confirmed by whole genome sequencing, serotyping with reference antisera and monoclonal antibodies, MALDI, and immunoblotting with reference antisera. Strain MN900 was excreted in urine samples for 18 weeks even as the cow was seronegative for serovar Tarassovi. Strain MN900 has an unusual morphology since it is not as motile as other leptospires and lacks hooked ends. Serovar Tarassovi is not included in U.S. bacterin vaccines. These results demonstrate the importance of culture and concomitant genotyping and serotyping to accurately classify leptospires, and as required to design efficacious vaccine and diagnostic strategies to not only limit animal disease but reduce zoonotic risk.