Analysis of the leptospirosis etiologic structure among dogs in Kyiv over 2020–2025

Leptospirosis is a dangerous zoonotic infectious disease, caused by the agent from genus Leptospira, and dogs are extremely susceptible to this pathogen. In the context of increasing morbidity among animals and the risk of transmission of the pathogen to humans, the study of the etiological structure of leptospirosis in this species is of particular relevance. The study allows not only to assess the epizootic situation, but also to optimize diagnostic and preventive measures. The material for the study was 1888 blood serum samples from dogs suspected in the disease, collected in veterinary clinics from Kyiv during 2020–2025. To detect antibodies, a microagglutination reaction with 8 serovar-specific antigens was performed. Confidence intervals were calculated using the Clopper-Pearson method with a significance level of 0.95 in R-epitools software. Specific antibodies to pathogenic leptospores were detected in 61% of the samples examined. Copenhageni serovar (serogroup Icterohaemorrhagiae) prevailed in the structure of positive reactions (BCI, 51.6-57.4%), while Canicola and Grippotyphosa were detected in 4.3% and 2.4% of samples, respectively. Mixed infections accounted for a significant proportion – up to 75% of cases were seropositive to several serovars simultaneously, with the dominance of the combination of Icterohaemorrhagiae and Canicola. The obtained results indicate the dominance of the Icterohaemorrhagiae serogroup in the structure of canine leptospirosis in Kyiv. The high level of mixed reactions emphasizes the need for an integrated approach to laboratory diagnosis and further monitoring of the pathogen circulation in order to improve the effectiveness of disease prevention and control measures.