Dysentery

Dysentery, acute or chronic disease of the large intestine of human beings, characterized by frequent passage of small, watery stools, often containing blood and mucus, accompanied by severe abdominal cramps. Ulceration of the walls of the intestine may occur. Although many severe cases of diarrhoea have been called dysentery, the word properly refers to a disease caused by either a specific amoeba, Entamoeba histolytica, or a bacillus that infects the colon.

Amoebic dysentery, caused by the parasite Entamoeba histolytica, is endemic in many tropical countries, but is attributable more to unsanitary conditions than to heat. It is the most common type of dysentery in the Philippine Islands, the Malay Archipelago, and the Caribbean, but it also occurs in almost all temperate countries.

Amoebic dysentery is most commonly spread by water or contaminated, uncooked food or from carriers. Flies may carry the cysts to spread the amoeba from the faeces of infected people to food.

Various drugs, including metronidazole, ementine, and iodine-containing preparations, have been useful in treating severe cases of the disease.

Bacillary dysentery is caused by certain nonmotile bacteria of the genus Shigella. This form of dysentery is also most prevalent in unhygienic areas of the tropics, but, because it is easily spread, sporadic outbreaks are common in all parts of the world. This dysentery is usually self-limiting and rarely manifests the more severe organ involvements characteristic of amoebic dysentery. Bacillary dysentery is spread by contaminated water, milk, and food. Faeces from active cases as well as those from healthy carriers contain immense numbers of the disease-producing bacteria. Flies carry the bacteria on their feet or in their saliva and faeces, and deposit them on food; ants are also believed to spread the disease.

In the treatment of bacillary dysentery, proper replacement of fluid is important. Sulphonamides, tetracycline, and streptomycin were effective in curing acute cases until drug-resistant strains emerged. Chloramphenicol is sometimes used to treat these strains. Quinolones such as norfloxacin and ciprofloxacin are also effective against Shigella infection.