Trench fever in Belfast, and the nature of the 'relapsing fevers' in the United Kingdom in the nineteenth century.

Some evidence is assembled to suggest that trench fever, an infection with a strain of Rochalimaea, if not quintana, then vinsonii, was present in Belfast in the first half of the nineteenth century in endemic and epidemic form. It may have amounted at times to one half or more of 'fever'. This may account for the comparatively low mortality in some years from 'fever'. The phrase 'relapsing fever' in the nineteenth and twentieth century medical literature of the United Kingdom should not be taken necessarily to mean infection with Borrelia recurrentis. Much or most may have been infection with Rochalimaea, quintana or vinsonii. The newly discovered Irish vole should be examined to see if it carries a Rickettsia or Rochalimaea infection.