Acute, often
febrile, diarrheal
disease caused by
Shigella or, on rare occasions, invasive strains of Escherichia coli. The most common Shigella species in the US at present are S. sonnei and S. flexneri. A more severe form of
dysentery is caused by S. dysenteriae I ("Shiga"), an
organism associated with an
epidemic in
Mexico and
Central America during 1969-71 and occasionally isolated in the
US.
The unique feature of dysentery, distinct from other forms of diarrhea, is the exudative nature of the fecal effluent. In approximately 30 to 50% of patients, a bloody, purulent stool is passed. Microscopic examination of the stool reveals a sea of polymorphonuclear leukocytes and red blood cells. Lower abdominal pain is the rule, and patients will complain of incapacitating rectal pain. The onset of shigellosis is heralded by watery diarrhea, occasionally leading to dehydration, but the character of the feces usually changes in the subsequent days to a more mucoid and small volume type.
Bacillary dysentery is a disease mostly of childhood. It may be sporadic or associated with small outbreaks which can be related to food and water contamination. Person to person contamination is the general rule, as the organisms are highly infectious. Deaths are rare. Mortality is usually seen in very young, often malnourished children or the debilitated.