Seroprevalence of leptospiral infection in horses, donkeys and mules in East Azerbaijan province

This study was conducted on 490 animals (390 horses, 80 donkeys and 20 mules) in East Azarbaijan province in Iran in order to verify seroprevalence of leptospiral infection in 2011. Sera were initially screened at dilution of 1:100 against 6 live serovars of Leptospira interrogans: Pomona, Canicola, Hardjo, Ballum, Icterohaemorrhagiae and Grippotyphosa using the microscopic agglutination test. The prevalence of leptospiral infection was 39.18% in animals. 153 horses (39.23%), 33 donkeys (41.25%) and 6 mules (39.18%) were positive and the difference between them was significant (P < 0.05); furthermore, 176 males (42.93%) and 25 (31.25%) females were positive. There was significant difference between males and females (P < 0.05). There was no significant relationship between aging and the incidence of leptospiral infection. The highest number of reactors in samples (38.96%) was due to serovar Pomona, followed by Grippothyphosa (32.73%), Icterohaemorrhagiae (15.15%), Canicola (10.39%), Hardjo (1.73%) and Ballum (1.04%). Most titre levels were between 100 and 200 for all the serovars. These results confirm that the majority of leptospiral infections are asignologic and the presence of antibodies in apparently healthy animals indicates exposure to leptospires.   Key words: Equines, cross sectional study, seroprevalence, Leptospira, Iran.