Diarrhea Epidemiology
Diarrhea kills 1.8 million children under five in developing countries. This figure, however, is an improvement from 4.5 million deaths in last 20 years.
Annual incidence of diarrheal disease episodes in children less than five years old in developing countries thus stands at 2 billion diarrheal episodes globally with a median incidence rate of 3.2 episodes per child.
In community based studies the ratio between male children under five to female children under five suffering from acute diarrhea in 1.2 and 1.4 respectively. It is however important to note that some countries (e.g., in South Asia) have greater care seeking for boys than girls.
The identified microbes from diarrhea patients in community studies and health care facility studies respectively include:-
Percentage of identification of selected enteropathogens from children with diarrhea in 61 community-based studies
| Enteropathogen | Percentage % |
| Enterotoxigenic Escherichia coli | 14 |
| Enteropathogenic Escherichia coli | 9 |
| Rotavirus | 8 |
| Campylobacter | 8 |
| Cryptosporidium | 6 |
| Shigella | 5 |
Percentage identification of selected enteropathogens from children with diarrhea in 107 health facility-based studies
| Enteropathogen | Percentage % |
| Rotavirus | 25 |
| Enteropathogenic Escherichia coli | 16 |
| Enterotoxigenic Escherichia coli | 10 |
| Shigella | 6 |
| Campylobacter | 5 |
| Salmonella | 4 |
Apart from bacterial causes there are several viruses and parasites that may cause diarrheal diseases. Diarrheal diseases in 56.67 % of cases have a viral cause.
In the United States for example some agents are more important than others. A comparison of the relative importance of these viruses and bacteria in causing diarrheal diseases show:-
| Etiologic agent | Developing country | U.S. |
| Rotavirus | Important | Very Important |
| Noroviruses | Probably Important | Important |
| Enteric adenoviruses | Minor | Probably Important |
Comparison of bacterial etiologic agents of diarrhea in developing countries and the United States include:-
| Etiologic agent | Developing country | U.S. |
| Enterotoxigenic Escherichia coli | Very Important | Minor |
| Campylobacter | Important | Important |
| Shigella | Important | Minor |
| Salmonella | Variable | Important |
| Enterohem. Escherichia coli | Minor | Important |
Comparison of parasitic etiologic agents of diarrhea in developing countries and the United States show:-
| Etiologic agent | Developing country | U.S. |
| Cryptosporidium | Important | Minor |
| Giardia | Minor | Minor |
| Strongyloides | Minor | Minor |
| Entamoeba histolytica | Minor | Minor |
Seasonal variations are common. While bacterial diarrhea episodes are most common during summer and rains the viral diarrhoeas peak during winters. Transmission of diarrheal infections however is present throughout the year.
Viral diarrhoeas are more common in Europe, America and Asia and the Russia Federation. Of these the more important ones include rotaviruses and adenoviruses.
| Diarrhea incidence rates by WHO region for 2010 | |||||
| Age | |||||
| Episodes of Diarrhea per child year (Uncertainty bounds) | |||||
| Region | 0-5 months | 6-11 months | 12-23 months | 24-59 months | 0-59 months |
| Africa | 3.4 (2.1, 5.6) | 5.1 (3.4, 8.1) | 4.2 (2.7, 6.4) | 2.7 (1.7, 4.2) | 3.3 (2.2, 5.1) |
| Americas | 4.1 (2.9, 5.2) | 6.2 (4.7, 7.5) | 5.0 (3.9, 5.8) | 3.2 (2.3, 4.0) | 4.0 (3.1, 4.7) |
| Eastern Mediterranean | 3.1 (1.5, 5.2) | 4.7 (2.4, 7.0) | 3.8 (1.9, 5.4) | 2.4 (1.3, 3.6) | 3.0 (1.6, 4.4) |
| Europe | 4.1 (3.0, 5.3) | 6.3 (4.8, 7.6) | 5.1 (3.9, 5.9) | 3.2 (2.3, 4.1) | 4.0 (3.1, 4.7) |
| South East Asian | 2.4 (1.4, 4.0) | 3.7 (2.2, 5.6) | 3.0 (1.8, 4.3) | 1.9 (1.2, 2.6) | 2.4 (1.5, 3.3) |
| Western Pacific | 2.3 (1.3, 3.1) | 3.5 (2.0, 4.4) | 2.9 (1.6, 3.3) | 1.8 (1.1, 2.2) | 2.3 (1.3, 2.6) |
| Global | 2.9 (2.1, 4.3) | 4.5 (3.4, 5.7) | 3.6 (2.8, 4.4) | 2.3 (1.8, 2.8) | 2.9 (2.3, 3.4) |
According to the World Health Organization between 1990 to 2010 while diarrhea incidence has declined from an estimated 3.4 episodes/child year in1990 to 2.9 episodes/child year in 2010, the highest burden of disease has remained consistent with respect to age.
The incidence is highest among children under 5 years of age living in low- and middle-income countries.
Sources
- ocw.jhsph.edu/courses/EpiInfectiousDisease/PDFs/EID_lec11_Black.pdf
- academicpublishingplatforms.com/…/…al_characteristics_pp.72-77.pdf
- http://www.biomedcentral.com/content/pdf/1471-2458-12-220.pdf
- http://www.who.int/topics/diarrhoea/en/
Further Reading
- All Diarrhea Content
- What is Diarrhea?
- Diarrhea Treatment
- Diarrhea Symptoms
- Diarrhea Causes
Last Updated: Jun 4, 2019
Written by
Dr. Ananya Mandal
Dr. Ananya Mandal is a doctor by profession, lecturer by vocation and a medical writer by passion. She specialized in Clinical Pharmacology after her bachelor's (MBBS). For her, health communication is not just writing complicated reviews for professionals but making medical knowledge understandable and available to the general public as well.
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