Detection of antibodies to leptospiral genus-specific antigen in human and animal sera by indirect hemagglutination test with a partially purified genus-specific protein antigen.

Antibodies against leptospiral genus-specific antigen were detected in the sera from clinically diagnosed human leptospirosis and suspected animal leptospirosis by indirect hemagglutination (IHA) test with a partially purified genus-specific protein antigen (GP-Ag). The reaction was positive in the infected humans and animals irrespective of the leptospiral serovars. No significant correlation was found between IHA titer against GP-Ag and microscopic agglutination (MA) titer. IHA titer did not always develop in parallel with MA titers. Sera obtained from healthy individuals were negative in both IHA and MA tests.