Incidence of leptospiral antibodies in different game species over a 10-year period (1996–2005) in Croatia

Abstract

During the 10-year survey (1996–2005), a total of 868 blood samples from different game species in Croatia were analyzed for the presence of leptospiral antibodies. The specific antibodies (AB) were detected in 242 samples (27.88%). According to the species in red deer (Cervus elaphus), the antibodies against six different leptospiral serovars were found in 43 of 226 analyzed sera (19.02%). The most frequent antigen serovars in the deer population were Pomona and Ballum (with the same frequency of 23.6%), whereas the highest titer was recorded for serovar Sejroe (1:800). In the analyzed roe deer (Capreolus capreolus) serum samples, a low level of leptospiral antibodies (6.07%) was determined, with just two AB for antigen serovars—Australis and Sejroe. In wild boar (Sus scrofa), leptospiral antibodies were detected in 151 of 431 samples analyzed (35.03%), with AB for nine antigen serovars. The serovars most frequently found were Australis (48.70%) and Pomona (22.70%), and these serovars also recorded the highest titer (1:3,200). Among brown bear (Ursus arctos) samples, leptospiral antibodies were detected in 25.00% of the samples, with four AB for antigen serovars, of which the most frequent was Icterohaemorrhagiae (>40%). This serovar had the highest recorded titer (1:400). From 112 analyzed red fox (Vulpes vulpes) samples, leptospiral antibodies were found in 35 samples (31.25%). The determined antibodies were specific for four antigen serovars, of which the most frequent (46.2%) and with highest titer (1:1600) was serovar Australis. No antibodies (28/0) were recorded in mouflon (Ovis musimon). The most important game species from an epizootiological point of view in the studied area were certainly wild boar and red foxes. With strong serological reactions, these two species could be emphasized as important hosts for Leptospira interrogans sv. Australis in Croatia, but for their declaration as ‘maintaining hosts,’ isolation of sv. Australis is needed. According to aerial distribution, the highest number of positive samples from different game species was recorded in the central and eastern parts of Croatia, known as the ‘historical natural foci’ of leptospirosis—the regions of Posavina, Podravina, Slavonija, and Baranja. In contrast, the areas of Kordun and Gorski Kotar are declared as leptospira low-risk regions for the game species studied.