Leptospira Antibody IgM

What is the Leptospira IgM antibodies by EIA - Serum test?
Leptospirosis is a zoonotic disease of worldwide prevalence, though the most major infections occur in warm, tropical climates. Wild mammals and typically rodents are the primary natural reservoir for the pathogenic strains of leptospira. However, domestic animals (e.g., dogs) also represent a major source of human infection.