An evaluation of the semi-automated complement fixation test and the microscopic agglutination test for the serological diagnosis of bovine leptospirosis

Abstract

Groups of cows were selected from each of 22 herds which had recent evidence of leptospirosis or abortions. Blood and urine samples were collected from each animal on a number of occasions over a period of 11 months. Attempts were made to detect leptospiruria by microscopic and cultural procedures. Sera were examined by the semi-automated complement fixation test (CFT)and the microscopic agglutination test (MAT) using Leptospira interrogans serotypes pomona, hardjo, copenhageni and ballum as antigens.

Leptospiruria was detected in 107 cows. Pomona was cultured from 43 animals, hardjo from 13. The identity of the organism was not determined in the remaining 51 cases. Highest CFT and MAT titres occurred with serotypes pomona and hardjo. There was no bacteriological or serological evidence of infection with copenhageni or ballum.

There were no significant differences between the number of CFT or MAT reactions in cattle with leptospiruria. The CFT gave fewer reactions in cattle that did not show leptospiruria and, in most cases, CFT antibodies were detectable for a shorter time than agglutinins. Both tests gave reactions with the same number of aborting cows that showed leptospiruria near the time of abortion.

Our results indicate that the CFT would be useful in Animal Health Laboratories for the serological diagnosis of bovine leptospirosis.