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Published on: July 1, 2011
Leptospira interrogans serovar pomona associated with abortion in cattle: isolation methods and laboratory animal
Abstract:
Leptospira interrogans serovar pomona was successfully isolated from cattle urine in the western Transvaal after an abortion storm had occurred. Direct inoculation of EMJH medium proved the most successful method. The selective agent, 5-fluorouracil, was most effective in controlling contamination when used at the 0,4 mg/ml level. The strain isolated was pathogenic in hamsters, but specific lesions and the leptospirae were seen only where overwhelming infection occurred.
Insights
Leptospira interrogans serovar pomona was isolated from cattle urine following an abortion storm. This research details successful isolation methods and selective agent effectiveness for diagnosing leptospirosis in livestock.
Area of Science:
- Veterinary Microbiology
- Bacteriology
- Infectious Diseases
Background:
- Leptospirosis outbreaks in cattle, particularly those causing abortion storms, pose significant risks to herd health and productivity.
- Accurate and timely diagnosis is crucial for managing and preventing the spread of Leptospira interrogans serovar pomona.
Purpose of the Study:
- To report the successful isolation of Leptospira interrogans serovar pomona from cattle urine in the western Transvaal.
- To evaluate different methods for isolating the bacteria and identify effective selective agents for diagnostic purposes.
Main Methods:
- Urine samples from cattle experiencing an abortion storm were cultured directly into EMJH medium.
- The efficacy of the selective agent 5-fluorouracil at a concentration of 0.4 mg/ml was assessed for controlling contaminants.
- Pathogenicity of the isolated strain was tested in a hamster model.
Main Results:
- Leptospira interrogans serovar pomona was successfully isolated from cattle urine.
- Direct inoculation into EMJH medium was the most effective isolation technique.
- 5-fluorouracil at 0.4 mg/ml proved highly effective in inhibiting contamination.
- The isolated strain demonstrated pathogenicity in hamsters, with visible lesions and bacteria observed in cases of overwhelming infection.
Conclusions:
- This study confirms the presence of Leptospira interrogans serovar pomona in cattle in the western Transvaal, linked to abortion storms.
- Direct inoculation into EMJH medium and the use of 5-fluorouracil are recommended for efficient isolation and diagnosis.
- While pathogenic, the manifestation of disease in hamsters was dose-dependent, highlighting the importance of infection levels.
