General Information: Pathogenic strain. Causative agent of leptospirosis. This organism is the causative agent of leptospirosis, a tropical zoonosis transmitted by direct contact with the urine of infected animals. This motile and obligately aerobic organism grows optimally at 28-30 C. Many serovars are adapted for specific mammalian reservoir hosts, which harbor the organisms in their renal tubules and shed them in their urine. Because of the large spectrum of animal species that serve as reservoirs, leptospirosis is considered to be the world's most widespread zoonotic disease.