BACILLARY DYSENTERY.
This infection of the large intestine is caused by bacteria of the shigella group. The severity of the condition depends on the organisms involved. It is usually a relatively mild condition caused by shigella sonnei.
Shigella dysenteriae causes most severe type of infection and it occurs mainly in tropical countries. The only host is humans and the organisms are spread by faecal contamination of food,drink,hands and fomites.
The intestinal mucosa becomes inflamed,ulcerated and oedematous with excess mucus secretion. In severe infections ,the acute diarrhoea,containing blood and excess mucus,causes dehydration,electrolyte imbalance and anaemia. When healing occurs the mucous membrane is fully restored.
AMOEBIC DYSENTERY.
This disease is caused by Entamoeba histolytica. The only known hosts are humans and it is spread by feacal contamination of food,water,hands and fomites. Although many infected people do not develop symptoms they may become asymptomatic carries. Within the colon,the amoebae grow,divide and invade the mucosal cells,causing inflammation. Without treatment the condition frequently becomes chronic with mild,intermittent diarrhoea and abdominal pain. This may progress with ulceration of the colon accompanied by persistent and debilitating diarrhoea that contains mucus and blood. Complications are unusual but include severe haemorrhage from ulcers and liver abscesses.
