Prognostic factors for survival of canine patients infected with Leptospira spp.

The objectives of this study were to describe the epizootiological and clinical features of canine patients with leptospirosis, and to determine the association between the health parameters observed and patient survival. The study population consisted of sixty patients admitted to the Department of Microbiology and Infectious diseases with Clinic, Faculty of Veterinary Medicinein Zagreb, Croatia from 2009 to 2017. The majority of the infections were caused by serogroup Pomona (50%), while serogroups Icterohaemorhagiae, Grippotyphosa, Australis and Sejroe were identified in 30%, 8.3%, 5% and 1.7% of the patients, respectively. At initial presentation, the most frequently detected organ dysfunction was renal failure (85%), followed by pulmonary (60%) and hepatic injury (58.3%). When the frequency of animals with involvement of organ systems was calculated, 31.7% had three systems involved, 46.7% had two systems involved, 13.3% had one, and 5% did not have any system involved. The mortality risk in the group that had 0, 1, 2 and 3 systems involved was 0%, 62.5%, 46.4%, and 89.5%, respectively. In the univariable analysis, several factors were univariably associated with the risk of a lethal outcome including: day of admission (P<0.01), sex (P = 0.09), Leptospira vaccination status (P = 0.11), the presence of moderate to severe acute kidney injury (P<0.01), pulmonary involvement (P = 0.11), and several other parameters. In the multivariable Cox's model, the presence of moderate and severe kidney injury was identified as a statistically significant factor associated with lower survival. The frequency of severe clinical cases of canine leptospirosis caused by the serogroup Pomona found in this study supports the need to consider inclusion of strains of this serogroup in vaccines available on the European market.