Evaluation of risk factors of prevalence of leptospirosis in sheep flocks

Leptospirosis is a worldwide bacterial zoonoses that its main source are wild animals and rodents That leptospirals excrete in their urine. This disease causes fever, hemoglobinuria, jaundice, abortion, mastitis, reduced milk production, reproductive disorders and death in cattle, that major complications in sheep are abortion and pyelonephritis. The purpose of this study is the evaluation of risk factors for leptospirosis disease and its association with high prevalence of infection in the sheep flocks. Accordingly, 260 serum samples were collected from 20 flocks of sheep. Then with microscopic agglutination test (MAT) using 6 live antigen Leptospira interrogans include Pomona , canicola, icterohaemorrhagiae, gryppotyphoza, ballum and hardjo was studied. MAT test results of the serum samples showed the contamination was 28.46%. Most contamination of the samples was allocated to sheep who lived in swampy areas, so that 70.28% of positive samples were included. 56.25% of positive samples among the samples showed positive reaction with serotype canicola. On the other hand, 76.56% of the positive samples belonged to animals which in their environment, rodents in very large numbers were observed. The sheep that kept in moist and wet environment to be had 60% of positive samples , and finally the highest frequency of positive animals were ranged among ages 3 to 6 years old, the incidence of the disease increased in older animals. By attention to the results, increasing of age, living in swampy and wet bed, being infectious dogs in side of flocks and also very large number of rodents in environment are of the most important causes of seroprevalense of leptospirosis.