A cluster-focus of multiple sclerosis at Henribourg, Saskatchewan.

This study presents the clinical characteristics of 8 victims of multiple sclerosis from the hamlet of Henribourg, Saskatchewan with a population of less than 75 people. A diligent victim of the disease had observed that six female classmates from the early 1940's had later developed multiple sclerosis. Two male military personnel who had also resided briefly in close proximity, during the same common exposure time, also later developed multiple sclerosis. The mean onset time of developing the disease after leaving the area was 20 years. This cluster-focus suggests a common exposure to an environmental factor or a common infective agent in the etiology of multiple sclerosis.