ABSTRACT
Leptospirosis is a disease caused by aerobic bacteria of the genus Leptospira (hereafter, these bacteria are called leptospires), which resemble both Gramnegative and Gram-positive bacteria (Vijayachari et al. 2008). Leptospira are exible microorganisms that have the appearance of a tightly wound screw (Figure 12.1). They are thin (less than 0.2 µm wide) and 10-20 µm in length. They can move by spinning around their axis or by wiggling their bodies from side to side; their mobility increases their chances of locating a host and moving through tissues once inside a host. Virulent leptospires have a hooklike structure on one or both ends of their bodies. They survive by infecting renal tubules of host animals. There are also nonvirulent leptospires that live in seawater, freshwater, and moist soil. Based on DNA, the genus Leptospira is divided into 17 species, but most infections are caused by L. interrogans (Bharti et al. 2003). There are more than 300 serovars of leptospires, 200 of which are known to produce disease (Victoriano et al. 2009).
