Francisella: a little bug hits the big time

Francisella tularensis, a small Gram-negative intracellular bacterium that causes the disease tularemia, had its first peak of research interest in the 1950s. Two biovars of this zoonotic disease were recognized: the more deadly F. tularensis subspecies tularensis (or Type A) that causes disease in North America, and F. tularensis subspecies holarctica (or Type B) that causes a milder (but still miserable) disease in Scandinavia, Europe and Asia. However, most researchers who worked with virulent Type A Francisella contracted tularemia, an issue that appears to have diminished its popularity as a research problem in parallel with a decline in disease incidence after World War II. Mostly using attenuated strains, some work on the organism as a general model for intracellular pathogens has continued. By the time several Swedish researchers convened the First International Conference on Tularemia in 1994, the group that assembled was enthusiastic but fairly small.