Francisella tularensis: unravelling the secrets of an intracellular pathogen.

Francisella tularensis has been recognized as the causative agent of tularaemia for almost a century. Since its discovery in 1911, it has been shown to infect a wide range of hosts, including humans. As early as the 1920s it was suggested to be an intracellular pathogen, but it has proven to be an enigmatic organism, whose interaction with the host has been difficult to elucidate, and we still have a very limited understanding of the molecular mechanisms of virulence. However, the recent availability of genome sequence data and molecular tools has allowed us to start to understand the molecular basis of F. tularensis pathogenicity, and will facilitate the development of a vaccine to protect against infection.