Use of a fluorescent antibody technique for the serological differentiation of leptospiral serotypes in cultures and in bovine urine

Authors: Hodges RT, Ekdahl MO
Publication: New Zealand Veterinary Journal, Volume 21, Issue 6, pp 109-115, Jun 1973
Publisher: Taylor and Francis

Animal type: Cattle, Livestock, Production animal, Ruminant
Subject Terms: Bacterial, Clinical pathology, Diagnostic procedures, Immune system/immunology, Zoonosis, Disease/defect, Infectious disease, Public health
Article class: Scientific Article

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Abstract: Leptospirosis is a common and important cattle disease in some parts of New Zealand and increasing numbers of human infections are being reported, particularly in dairy farming areas (Anon., 1972). In a recent survey it was found that 24 of 65 cattle (37%) from properties where human leptospirosis was recorded were excreting leptospira-like organisms in their urine. These cattle did not have serum agglutinating antibodies to a variety of commonly employed serotypes,at titres that were considered to be of diagnostic importance (D. E. Lake, pers. comm.). Investigations of the epidemiology of bovine leptospirosis, and the role played by cattle in the transmission of this disease to man, are hampered by difficulties in isolating these organisms from bovine urine. The relatively slow growth of these organisms in artificial media may result in a delay of several weeks before sufficient density of growth occurs to enable their serological identity to be determined. A rapid method is required for differentiating leptospirae which may be present in bovine urine from artefacts and other micro-organisms, and of determining their serological identity without the necessity for cultural procedures. Preliminary investigations have been made to determine whether a direct fluorescent antibody (F.A.) technique would fulfil these objectives. Antisera prepared against 8 leptospiral serotypes were labelled with fluorescein-isothiocyanate and tested against cultures of those serotypes and against urine samples from naturally and experimentally infected cattle. Where possible, attempts were also made to compare the results of F.A. examinations with the animal`s serological status and with isolation of the organisms.

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