Bacillary dysentery is caused by infection with Shigella dysenteriae, flexneri, boydii or Shigella sonnei. All are enteroinvasive but some strains elaborate a toxin which is enterotoxic, neurotoxic and cytotoxic. The infection leads to an acute inflammation of the colon resulting in diarrhea containing a large number of leucocytes.
The incubation period is 2 days.
It starts with an acute onset of fever, abdominal pain and diarrhea. The diarrhea gradually becomes bloody with mucus (dysentery) with severe abdominal pain. Sometimes a cholera like picture may develop. Nausea and vomiting, headache and convulsions may occur and are probably due to the effect of a neurotoxin released by the bacteria.
Stool culture usually reveals the causative organism.
Symptomatic treatment and adequate rehydration. Ciprofloxacin given orally is the antibiotic of choice in the rather more severe cases. Ampicillin, co-trimoxazole and tetracycline may also be effective.