Myths, legends and realities of relapsing fever borreliosis.

Relapsing fever borreliosis is often shrouded in mystery. From its discovery, it has evaded fulfilment of Koch's postulates. It has resulted in epidemic waves of infection, although it is now mostly localized to particular endemic pockets of infection. Structurally, this spirochaete breaks many paradigms for conventional microorganisms, e.g. through its segmented genomic structure. Disclosure of host-microbial interactions is revealing a plethora of mechanisms, from antigenic variation to binding of various host-derived proteins. We dispel some of the myths and explore current understanding of this much neglected area through a series of reviews within this theme section.