Clinical and epizootiological study of a leptospirosis outbreak due to Leptospira canicola in a feedlot.

This report describes the epizootiology, clinical presentation, diagnosis and treatment of an outbreak of leptospirosis caused by Leptospira canicola in feedlot calves. The infection appeared to be of high morbidity with a cumulative clinical incidence of 15.6%, cumulative subclinical incidence of 39% and high mortality (8.3%). Clinical disease was diagnosed in 4-8-month-old calves, while subclinical infection occurred in 9-12-month-old calves. Subclinical infection was based on serological evidence only. The zoonotic aspects of the infection are emphasised.