Developmental Trends of the Veterinary Laboratory Diagnostic in Differentiation of Pathogenic and Non-Pathogenic Leptospires

Abstract

Identification and classification of Leptospira species can be done by serological metods and molecular biology methods. This paper identifie, evaluate and recommend new diagnostic tools for Leptospira diagnostic in veterinary laboratories. Isolation and identification of Leptospira strains, serological tests and analysis of specific DNA and/or 16S rRNA were studied. The first group of diagnostic methods aims the isolation and identification of Leptospira strains. Isolation can be done on culture medium (e.g. EMJH, T80-40LH) or by IP/SC injection of fresh samples directly into 3-4 week old hamster. Serotyping of Leptospira strains can be made by immunofluorescence or immunohistochemistry with monoclonal antibodies. Currently the leptospirosis diagnostic is performed by the serological methods: (i) agglutination tests (microscopic agglutination, using live organisms; macroscopic agglutination, using killed antigen; one-point microcapsule agglutination test); (ii) complement fixation test; (iii) fluorescent antibody test; (iv) ELISA IgM; (v) slide agglutination tests; (vi) dot-ELISA; (vii) dip-stick methods. The third group of methods detect and analyze the specific DNA and/or 16S rRNA, and include: (i) arbitrarily primed polymerase chain reaction; (ii) restriction fragment length polymorphism analysis; (iii) pulsed-field gel electrophoresis; (iv) DNA-DNA hybridization analysis; (v) guanine-plus-cytosine mol percentages; (vi) detection of variable number of tandem repeats; (vii) randomly amplified polymorphic DNA fingerprinting; (viii) sequencing (multilocus sequencing typing, rrs sequencing, specific genes sequencing or gene fragments sequencing). Diagnosis of leptospirosis in veterinary laboratory can be made either by demonstrating the presence of Leptospira antigen or DNA in clinical samples or by specific immunoglobulin in blood.