The use of the enzyme-linked immunosorbent assay (ELISA) to detect the IgM and IgG antibody response to Leptospira interrogans serovars hardjo, pomona and tarassovi in cattle.

Leptospira interrogans serovars pomona, hardjo and tarassovi were each used to inoculate 6 cattle. Three-hundred and ninety-nine sera collected from the inoculated animals and from a control group over a 3-month period were tested using the microscopic agglutination test (MAT) and the enzyme-linked immunosorbent assay (ELISA). Leptospiruria was monitored by microscopic examination and culture. The ELISA detected specific IgM antibody against the serovars in all infected cattle 1 week after inoculation. This IgM antibody persisted in most of the animals for 3-5 weeks. Specific IgG antibody appeared at the same time or just after IgM, but persisted for much longer. Levels of antibody detected by the ELISA and the MAT did not correlate with each other, nor with the periods of leptospiruria found in the infected cattle.

Detection of leptospires in tissue using an immunoperoxidase staining procedure.

An immunoperoxidase technique for the localisation of leptospires in sections of formalin fixed paraffin embedded kidney tissue is described. The procedure utilises a two-layered antibody sandwich with rabbit anti-leptospiral immunoglobin. Using antiserum to specific leptospiral serovars the presence and distribution of specific serovar in the tissue could be determined. The technique was also used to detect leptospires of given serovars in smears made from infected tissues and fluids. There was good correlation between culture results and results of the immunoperoxidase staining method on kidneys infected with leptospires. The diagnostic possibilities of the technique on formalin fixed tissue specimens are discussed.