Relapsing Fevers: Neglected Tick-Borne Diseases

Relapsing fever still remains a neglected disease and little is known on its reservoir, tick vector and physiopathology in the vertebrate host. The disease occurs in temperate as well as tropical countries. Relapsing fever borreliae are spirochaetes, members of the family which also contain Lyme disease spirochaetes. They are mainly transmitted by soft ticks, but some species are vectored by ixodid ticks. Traditionally a species is associated with a specific vector in a particular geographical area. However, new species are regularly described, and taxonomical uncertainties deserve further investigations to better understand vector/host adaptation. The medical importance of , transmitted by spp., has recently spawned new interest in this bacterial group. In this review, recent data on tick-host-pathogen interactions for tick-borne relapsing fevers is presented, with special focus on .