Diarrheal Diseases

Amongst the poor and especially in developing countries, diarrhoea is a major killer. In 1998, diarrhoea was estimated to have killed 2.2 million people, most of whom were under 5 years of age (WHO, 2000). Each year there are approximately 4 billion cases of diarrhoea worldwide (WHO).

Diarrhea defined: "a stool weight in excess of 200 grams per day. However, this definition is of little clinical value, since collecting and weighing stools is neither practical nor required except in a clinical research setting. A good working definition is three or more loose or watery stools per day or a definite decrease in consistency and increase in frequency based upon an individual baseline." (UpToDate)

"Diarrhea reflects increased water content of the stool, whether due to impaired water absorption and/or active water secretion by the bowel. In severe infectious diarrhea, the number of stools may reach 20 or more per day, with defecation occurring every 20 or 30 minutes. In this situation, the total daily volume of stool may exceed two liters, with resultant volume depletion and hypokalemia. Most patients with acute diarrhea have three to seven movements per day with total stool volume less than one liter per day. When diarrhea lasts for 14 days it can be considered persistent." (UpToDate)

Causes of Diarrhea

  • Viral
  • Bacterial
  • Parasitic
  • Helminths
  • Allergic
  • Autoimmune
  • Malabsorptive
  • Nutritional
  • Functional

Focusing on infective causes of Diarrhea we can consider:

  • Viral infections - Rotavirus, Norwalk virus
  • Bacterial infections - E. coli, Vibrio cholerae, Campylobacter jejuni, Shigella, C. diff, Salmonella,
  • Parasites - Giardia lamblia, Entamoeba
  • Helminths (intestinal worms) - Strongyloides

Leading causes of Diarrheal disease in developing world: E. coli and Rotavirus

Diarrheal disease in Honduras:
The prevalence of diarrheal diseases in children under 5 in Tegucigalpa and San Pedro Sula decreased from 25.5% in 1987 to 18.8% in 1991 and 14.8% in 1996. In rural areas, the prevalence has been variable (31.9% in 1987, 19.1% in 1991, and 21.1% in 1996). Cholera re-emerged in the country in October 1991, causing a hospital case fatality rate in children under 5 of 4.2% in 1992 and 2.0% in 1996. In 1995 there were 4,748 cases of cholera nationwide, with a case fatality rate of 1.6% (77 deaths); 56% of the cases were in males and 76% of those occurred in persons aged 15 and over. In 1996 there were 708 cases and 14 deaths, with a case fatality rate of 1.9%; 53.2% of the cases occurred in men and, of these, 40% were aged 15 and over. (WHO Health Situation Analysis and Trends Summary, 1998)


  1. Epidemiology and causes of acute diarrhea in developed countries
  2. Water Sanitation and Health (WHO): Water Related Diseases - Diarrhea
  3. Diarrhea in developed and developing countries: magnitude, special settings, and etiologies.
  4. Global Water Supply and Sanitation Assessment 2000 Report
  5. Health Situation Analysis and Trends Summary, 1998
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