There are three main forms of acute childhood diarrhoea, all of which are potentially life-threatening and require different treatment courses:
Acute watery diarrhoea includes cholera and is associated with significant fluid loss and rapid dehydration in an infected individual. It usually lasts for several hours or days. The pathogens that generally cause acute watery diarrhoea include V. cholerae or E. coli bacteria, as well as rotavirus.
Bloody diarrhoea, often referred to as dysentery, is marked by visible blood in the stools. It is associated with intestinal damage and nutrient losses in an infected individual. The most common cause of bloody diarrhoea is Shigella, a bacterial agent that is also the most common cause of severe cases.
Persistent diarrhoea is an episode of diarrhoea,
With or without blood, that lasts at least 14 days. Undernourished children and those with other illnesses, such as AIDS, are more likely to develop persistent diarrhoea. Diarrhoea, in turn, tends to worsen their condition.
Why are children more vulnerable?
Children with poor nutritional status and overall health, as well as those exposed to poor environmental conditions, are more susceptible to severe diarrhoea and dehydration than healthy children (Figure 5). Children are also at greater risk than adults of life-threatening dehydration since water constitutes a greater proportion of children’s bodyweight. Young children use more water over the course of a day given their higher metabolic rates, and their kidneys are less able to conserve water compared to older children and adults.
How is diarrhoea prevented?
Reducing childhood diarrhoea requires interventions to make children healthier and less likely to develop infections that lead to diarrhoea; clean environments that are less likely to transmit disease; and the support of communities and caregivers in consistently reinforcing healthy behaviours and practices over time.
Many well-known child survival interventions are critical to reducing child deaths from diarrhoea. They work in two ways: by either directly reducing a child’s exposure to the pathogens that cause diarrhoea (through the provision of safe drinking water, for example) or by reducing a child’s susceptibility to severe diarrhoea and dehydration (through improved nutrition and overall health).
WATER, SANITATION AND HYGIENE
Improvements in access to safe water and adequate sanitation, along with the promotion of good hygiene practices (particularly handwashing with soap), can help prevent childhood diarrhoea. In fact, an estimated 88 per cent of diarrhoeal deaths worldwide are attributable to unsafe water, inadequate sanitation and poor hygiene.14
Water, sanitation and hygiene programmes typically include a number of interventions that work to reduce the number of diarrhoea cases. These include: disposing of human excreta in a sanitary manner, washing hands with soap, increasing access to safe water, improving water quality at the source, and treating household water and storing it safely.
Improvements in sanitation reduce the transmission
Improvements in sanitation reduce the transmission of pathogens that cause diarrhoea by preventing human faecal matter from contaminating environments. Improving sanitation facilities has been associated with an estimated median reduction in diarrhoea incidence of 36 per cent across reviewed studies.15 (A recent survey in the British Medical Journal showed that their readers believed sanitation to be the most important medical milestone since 1840.16) However, a major challenge in this regard is scaling up sanitation facilities to the point where they are used by an entire community (‘total sanitation’).
Use of such facilities by all community members is necessary to significantly reduce diarrhoeal disease transmission (Box 3).17Washing one’s hands with soap is another important barrier to transmission (Box 4), and has been cited as one of the most cost-effective public health interventions.19 A number of studies have shown that handwashing with soap can reduce the incidence of diarrhoeal disease by over 40 per cent.20 Accessible and plentiful water has also been shown to encourage better hygiene, handwashing in particular, although the extent to which access to improved water sources reduces diarrhoea rates often depends on the type of water source available (such as public taps or standpipes, protected dug wells or boreholes).21
Interventions to improve water quality at the source
Interventions to improve water quality at the source, along with treatment of household water and safe storage systems, have been shown to reduce diarrhoea incidence by as much as 47 per cent.22 Proven and field-tested household water treatment options that are currently being promoted include chlorination, filtration, combined flocculation and disinfection, boiling, and solar disinfection. Household water treatment could potentially be scaled up quickly and inexpensively in both development and emergency situations. It has even become common practice in large cities where homes are connected to a municipal water supply, since water is often polluted between the source and the point of use.