Bovine leptospirosis: serological findings in aborting cows

Area of Science:

• Veterinary Medicine
• Immunology
• Bacteriology

Background:

• Leptospirosis is a significant cause of abortion in cattle.
• Accurate diagnosis of leptospiral abortion is crucial for herd management and disease control.
• Microscopic agglutination (MA) testing is a common method for detecting antibodies against Leptospira.

Purpose of the Study:

• To evaluate the diagnostic utility of antibody titres determined by the microscopic agglutination (MA) test in cows experiencing abortions.
• To compare the effectiveness of MA testing with complement fixation and plate agglutination tests for diagnosing leptospiral abortion.

Main Methods:

• Antibody titres were determined using the microscopic agglutination (MA) test.
• The study involved 149 cows that aborted leptospire-infected fetuses and 156 cows that aborted fetuses not apparently infected with leptospires.
• Complement fixation and plate agglutination tests were also assessed.

Main Results:

• Differences in MA titre distribution were observed between cows with infected and non-infected fetuses, but these differences had limited diagnostic value.
• 81.2% of cows with titres ≥ 1:1000 had infected fetuses, but these represented only 46.3% of all cows with leptospiral abortions.
• 22.8% of cows that aborted infected fetuses had no detectable antibodies.
• MA test was more valuable than complement fixation and plate agglutination tests.

Conclusions:

• The microscopic agglutination (MA) test has limited value in diagnosing leptospiral abortion in cattle due to variations in antibody titres.
• A significant percentage of cows with leptospiral abortions exhibit low or undetectable antibody titres, complicating diagnosis.
• MA testing is superior to complement fixation and plate agglutination tests for this diagnostic purpose.