New insights into the pathogenicity of leptospires: evasion of host defences.

Major progress has been made in the basic research of leptospirosis a global zoonotic disease. Recent knowledge on the genome of L. interrogans and the emergence of new genetic tools for comparative genetic studies have further developed research into the genetic pathogenesis of this illness. Many of these studies have compared the putative pathogenicity factors found in L. interrogans, with representative strains of saprophytic leptospires. Leptospires display a rich repertoire of adhesins endowed with multifunctional biological activities such as adhesion to host tissue components, plasminogen activation, resistance to complement. These adhesins are proteins or liproteins located on the outer membrane. Some of them (LenA) escape innate defence such as complement killing and some escape phagocytosis. Much work has to be done to elucidate many other aspects of Leptospira pathogenic factors such as those switched on in chronic infection.