Diarrhoea remains one of the leading causes of death among children under five globally. Out of the estimated 6.9 million child deaths, 11 per cent of deaths or over 750,000 child deaths are due to diarrhoea. It kills more children than AIDS and malaria and measles combined.
Diarrhoeal diseases: The basics
Diarrhoea is defined as loose or watery stools at least three times per day, or more frequently than normal for an individual. Although most episodes of childhood diarrhoea are mild, acute cases can lead to significant fluid loss and dehydration, which may result in severe consequences – even death – if fluids are not replaced at the first sign of diarrhoea. Most diarrhoea-related deaths in children are due to dehydration – the loss of large quantities of water and electrolytes (sodium, potassium and bicarbonate) from the body in liquid stools.
What causes diarrhoea?
Diarrhoea is a common symptom of gastrointestinal infections caused by a wide range of pathogens, including bacteria, viruses and protozoa. Just a handful of organisms are responsible for most acute cases of childhood diarrhoea, however. Rotavirus is the leading cause of acute diarrhoea, and is responsible for about 40 per cent of all hospital admissions due to diarrhoea among under-fives worldwide. Other major bacterial pathogens include E. coli, Shigella, Campylobacter, along with V. cholerae during epidemics. Cryptosporidium has been the most frequently isolated protozoan pathogen among children seen at health facilities and is frequently found among HIV-positive patients.
What are the main forms of childhood diarrhoea?
There are three main forms of childhood diarrhoea, all of which are potentially life-threatening and require different treatment courses:
How is diarrhoea prevented?
Many well-known child survival interventions are critical to reducing child deaths due to diarrhoea. These work in two ways: by either directly reducing a child’s exposure to diarrhoea-causing pathogens (through the provision of proper immunization and safe drinking water, for example) or by reducing a child’s susceptibility to severe diarrhoea and dehydration (through improved nutrition and overall health care).
Immunization (including rotavirus and measles vaccinations) helps reduce deaths from diarrhoea in two ways: by helping to prevent infections that cause diarrhoea directly, such as rotavirus, and by preventing infections that can lead to diarrhoea as a complication of an illness, such as measles.
Rotavirus is estimated to cause about 40 per cent of all hospital admissions due to diarrhoea among children under five worldwide. WHO has recently recommended the introduction of rotavirus vaccination on a global scale, and this needs to become a top international priority, especially for Africa and Asia, which are the regions with the greatest rotavirus burdens.
Measles is an acute viral infection that is often self-limiting. But some children, particularly those who are undernourished or have compromised immune systems, may experience serious side effects, including diarrhoea. Diarrhoea is one of the most common causes of death associated with measles worldwide.
How is diarrhoea treated?
The latest recommendations for treating childhood diarrhoea in the developing world are set out in a UNICEF and WHO joint statement issued in 2004.
Oral rehydration therapy:
Since the 1970s, ORT has been the cornerstone of treatment programmes to prevent life-threatening dehydration associated with diarrhoea. Fluid replacement should begin at home and be administered by the caregiver at the start of the diarrhoea episode. A solution made from oral rehydration salts (ORS) is the ‘gold standard’ of oral ORT, and a new formula has been developed (known as low-osmolarity ORS) that improves overall outcomes when compared to the original version. UNICEF and WHO recommend that all children with diarrhoea have access to this new ORS formula; making it widely available to children in need will require innovative delivery strategies.
When ORS packets are not available, other fluids will also work to prevent dehydration among children with diarrhoea, although they are not as effective in treating children who have become dehydrated. Such fluids (which many countries have designated as ‘recommended home-made fluids’) can be prepared using readily available and low-cost ingredients. Examples of rehydrating fluids include water with sugar and salt, cereal-based drinks made from a thin gruel of rice, maize, potato or other readily available low-cost grain or root crop that families have at home. Breastmilk is also excellent for fluid replacement and should be given to infants with diarrhoea simultaneously with other oral rehydration solutions. If ORS or other appropriate fluids are not available, increased amounts of almost any fluid can also help to prevent dehydration.
Continued feeding of the child during the diarrhoea episode further supports the absorption of fluids to prevent dehydration. Children receiving food during a diarrhoea episode are also more likely to maintain their nutritional status and their ability to fight infection.
Zinc supplements: A recent and important development in diarrhoea treatment is the addition of zinc to the regimen. A 10- to 14-day treatment course with zinc tablets effectively reduces both the duration and severity of diarrhoea episodes as well as the need for advanced medical care. Children receiving zinc often have better appetites and are more active during the diarrhoea episode; its use has also been associated with increased ORS uptake. The provision of zinc tablets by health workers may also reduce the demand from caregivers for other less effective drugs, such as antibiotics and antidiarrhoeal medications, which should not be routinely administered.
The UN Inter-agency Group for Child Mortality Estimation (IGME), Levels and Trends in Child Mortality: Report 2012, UNICEF, New York, 2012.
UNICEF, Committing to Child Survival: A Promise Renewed – Progress Report 2012, New York, 2012.
Liu L, Johnson HL, Cousens S, et al, for the Child Health Epidemiology Reference Group of WHO and UNICEF. Global, regional, and national causes of child mortality: an updated systematic analysis for 2010 with time trends since 2000. Lancet 2012; 379: 2151–61.
World Health Organization, World Health Statistics 2011, WHO, Geneva, 2011.
UNICEF, Pneumonia and Diarrhoea: Tackling the deadliest diseases for the world’s poorest children, New York, 2012.
UNICEF/WHO, Diarrhoea: Why children are still dying and what can be done, 2009.
WHO/UNICEF Joint Statement: Clinical management of acute diarrhoea, UNICEF New York and WHO Geneva, 2004.