There are many other causes of diarrhea, which tend to occur in less developed countries. Shigella is another bacterium, which is identified as the cause in around 15% of diarrheal illnesses. Initially, the infection causes profuse, watery diarrhea and a high temperature. The symptoms then develop into loose, frequent stools containing blood and mucus that can last for up to a month. The illness can be very unpleasant, particularly for children, and requires treatment with antibiotics.
Salmonella is also a bacterium that is responsible for some cases of diarrhea. The symptoms usually last about a week and are limited to mild to moderate diarrhea that contain mucus but rarely any blood.
Typhoid is similar to salmonella infection and is a serious illness that can be fatal if not treated. Typhoid and rotaviruses can cause more severe diarrhea in children than in adults.
Giardia lamblia is an intestinal parasite that accounts for many of the cases of persistent diarrhea brought home by travelers. The early phase can vary from a mild condition to a very unpleasant, profuse, watery diarrhea. If untreated, it can lead to vitamin deficiencies. The second, chronic phase can persist for months or even years and is characterized by bulky, extremely foul-smelling, pale grey stools due to unabsorbed food.
Other parasites that may cause diarrhea include Entamoeba hystolytica, which causes a diarrheal condition known as amoebic dysentery, and Cryptosporidium, which is increasingly a cause of travelers’ diarrhea.
Cholera is not as dangerous as is commonly thought. Only around 2% to 5% of people infected will develop severe diarrhea. Most people (over 75%) will have no symptoms at all. Dehydration from diarrhea is the main cause for concern with this illness.