INTRODUCTION Shigellosis continues to be a major public-health problem and remains endemic in many developing countries. Among Shigella species, Shigella dysenteriae type 1 poses a particular threat because of the severity of disease and its epidemic potential. Epidemics due to S. dysenteriae type 1 tend to occur at intervals of about a decade, and although few outbreaks have been reported over recent years, the problem should not be considered to be solved. There is no reason to believe that new outbreaks will not occur in the future because the same conditions that prevailed during outbreaks in the past are still present and include over-crowding, poor sanitation, sub-standard hygiene, and unsafe water supplies, while no other prevention measures have been developed in the interim.
