Dysentery is an inflammation of GI (gastro-intestine) system caused by bacteria or parasite infection. It was seen more in hot or tropical area but is more commonly associated with poor hygiene and eating contaminated food.
Symptoms start with diarrhea, abdominal pain, fever, a feeling of incomplete defecation, and, as it progresses, diarrhea with blood/pus/mucous (bloody diarrhea). After a couple days, there are signs of severe dehydration due to continuous diarrhea and vomiting.
Please go to see your doctor if you have diarrhea beyond two days; see your doctor right way if there are signs of dehydration.