Etiological structure and spatiotemporal analysis of leptospirosis in pigs in Ukraine for the period of 2009-2024

Leptospirosis is a widespread infection among pigs worldwide and in Ukraine in particular. In order to diagnose leptospirosis in animals, in most cases, only the serological method is used – the microagglutination reaction (MAT). From 2009 to 2024, 1497047 pig blood serum samples were tested in Ukraine by the PMA and 36507 positive reactions for leptospirosis were obtained, which is 2.4% of the studied livestock of this species. In the etiological structure, the dominant serological groups of leptospira were as follows: Icterohaemorrhagiae - 28.4%, Australis - 27.4%, Tarassovi - 4.0%, Canicola - 2.9% and Pomona - 2.6%. Antibodies to other serological groups were recorded in smaller numbers, namely: Grippotyphosa (1.8%), Sejroe (1.2%) and Hebdomadis (0.7%), so they played a secondary role in the etiologic structure. During the analyzed period, a large number of positive reactions with several serogroups of leptospira (mixed reactions) were observed, their number was 32.8 % of the total number of positive animals. The article presents a retrospective analysis of the circulation of eight main diagnostic serogroups of leptospira among the pig population in Ukraine: Sejroe, Hebdomadis, Tarassovi, Pomona, Grippotyphosa, Canicola, Icterohaemorrhagiae, Australis. The mapping of the territory of Ukraine for leptospirosis was carried out, which allows to evaluate the data and determine the risk zones of infection of pigs with leptospira of eight main diagnostic serogroups. It was found that they have a certain eco-regional confinement. The prevalence and etiological structure of porcine leptospirosis differed for each administrative (region) during the analyzed period. Thus, there was a decrease in the number of positive reactions to leptospira of the Australis, Pomona, Tarassovi, Canicola, Sejroe and Hebdomadis serogroups and an increase in the number of reactions to the Icterohaemorrhagiae and Grippotyphosa serogroups. Key words: leptospira, pigs, etiologic structure, serogroup, serovar, microagglutination test (MAT), mapping, GIS.