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Comparison of three techniques to detect Leptospira interrogans serovar hardjo type hardjo-bovis in bovine urine
C A Bolin1, R L Zuerner, G Trueba
1USDA, National Animal Disease Center, Ames, IA 50010.
Abstract:
Nucleic acid hybridization, bacteriologic culture, and a fluorescent antibody test were compared for detection of Leptospira interrogans serovar hardjo type hardjo-bovis in bovine urine. Seventy-five urine samples were collected from pregnant cows challenge exposed with type hardjo-bovis. Twenty samples were collected from steers not exposed to hardjo-bovis. Sediments from each sample were examined, using fluorescent antibodies and a repetitive sequence element nucleic acid probe, to detect the presence of leptospires. Urine samples were processed for bacteriologic culture, using standard techniques. Under laboratory conditions typically used for these techniques, leptospires were detected in 60 of 75 urine samples from challenge exposed cows by nucleic acid hybridization, in 24 samples by fluorescent antibody test, and in 13 samples by bacteriologic culture. Leptospires were not detected in the urine of steers not exposed to hardjo-bovis.
Insights
Nucleic acid hybridization is the most sensitive method for detecting Leptospira interrogans serovar hardjo type hardjo-bovis in bovine urine, outperforming fluorescent antibody tests and bacteriologic cultures. This finding is crucial for diagnosing leptospirosis in cattle.
Area of Science:
- Veterinary Microbiology
- Diagnostic Immunology
- Molecular Diagnostics
Background:
- Leptospira interrogans serovar hardjo type hardjo-bovis causes significant reproductive losses in cattle.
- Accurate and sensitive detection methods are essential for managing leptospirosis outbreaks in bovine populations.
Purpose of the Study:
- To compare the diagnostic efficacy of nucleic acid hybridization, fluorescent antibody test, and bacteriologic culture for detecting L. interrogans serovar hardjo type hardjo-bovis in bovine urine.
- To identify the most sensitive method for early and accurate diagnosis.
Main Methods:
- Analysis of 75 urine samples from challenge-exposed pregnant cows and 20 from unexposed steers.
- Detection of leptospires using fluorescent antibodies, a repetitive sequence element nucleic acid probe, and standard bacteriologic culture techniques.
Main Results:
- Nucleic acid hybridization detected leptospires in 60/75 exposed cows.
- Fluorescent antibody test identified leptospires in 24/75 exposed cows.
- Bacteriologic culture detected leptospires in 13/75 exposed cows.
- No leptospires were detected in urine from unexposed steers.
Conclusions:
- Nucleic acid hybridization demonstrated superior sensitivity for detecting L. interrogans serovar hardjo type hardjo-bovis in bovine urine compared to other methods.
- This molecular technique offers a promising tool for improved diagnosis and control of bovine leptospirosis.