Serological study of leptospirosis among dairy cattle in Bosnia and Herzegovina
A total of 75,206 blood serum samples from dairy cattle and quarantined heifers was collected between 2001 and 2007 and analyzed for bovine leptospirosis by the microscopic agglutination test (MAT). Serovar Hardjo was used for testing of all sera, with the addition of 2 or 3 randomly chosen other serovars (Grippotyphosa, Icterohaemorrhagiae, Pomona, Bataviae, Canicola, and/or Saxcoebing). From the total number of sera tested, 1197 (1.59%) were serologically positive, with a decreasing tendency over the years of research. The most prevalent serovar was Pomona (1.32%), followed by Hardjo (0.52%) and Grippotyphosa (0.37%). The differences among the studied regions in terms of the distribution of serovars and seroprevalence values may be attributed to different farm management approaches and climatic conditions. It is believed that the decrease in seroprevalence toward the last years of investigation may be due to the application of permanent control strategies against leptospirosis and antibiotic therapy for all seropositive animals with an antibody titer equal to or higher than 1:100.