The Travel Health Guide To a Safer Journey blog posted recently about dysentery, which can be caused by Shigella or another bacterial infection. The description of what dysentery is and how it is caused is quite good:
Dysentery is caused when bacteria or parasites infect the large and small intestine. It is transmitted by direct or indirect ingestion of fecal matter. Dysentery is characterized by bloody mucoid diarrhea accompanied by fever, nausea,vomiting and abdominal cramps. It is may be caused by Shigella species or Entamoeba Histolytica. Shigella infections are often resistant to antibiotic treatment, possibly because these drugs were overused in the past.