Morphology Leptospira are tightly coiled and flexible(5-15 um long and 0.1-0.2 um wide). One or two ends are usually bent to form hook-like shape. wHile stained with silver stain(Fontana stain), they show a deep brown color.11 Morphology •Leptospira are tightly coiled and flexible (5-15 µ m long and 0.1-0.2 µ m wide). One or two ends are usually bent to form hook-like shape. •While stained with silver stain (Fontana stain), they show a deep brown color