Diarrhoea prevention: water quality & hand washing
Diarrhoea is a common cause of morbidity and a leading cause of death among children aged less than five years, particularly in low- and middle-income countries. Persistent diarrhoea can also contribute to malnutrition, reduced resistance to infections, and sometimes impaired growth and development. Many of the infectious agents are transmitted by ingesting contaminated food or drink, by direct person-to-person contact, or from contaminated hands.Interventions to improve water quality are generally effective in preventing diarrhoea, and interventions to improve water quality at the household level are more effective than those at the source.
Interventions that promote hand washing can reduce diarrhoea episodes by about one-third. This significant reduction is comparable to the effect of providing clean water in low-income areas.
Water-related diseases caused by faecal pollution:
Amoebiasis
Amoebic colitis is caused by the parasite Entamoeba histolytica. This protozoan is distributed throughout the world and is commonly acquired by ingestion of contaminated food or water. It is estimated that about 40 to 50 million people infected with E. histolytica develop amoebic colitis or extraintestinal abscesses, which result in up to 100,000 deaths per year. Adequate therapy for amoebic colitis is necessary to reduce the severity of illness, prevent development of complicated disease and extraintestinal spread, and decrease transmission.Tinidazole is more effective in reducing clinical failure compared with metronidazole and has fewer associated adverse events. Combination drug therapy is more effective in reducing parasitological failure compared with metronidazole alone. However, these results are based on trials with poor methodological quality so there is uncertainty in these conclusions.
Cholera
Cholera is caused by bacteria (Vibrio cholerae) ingested through contaminated food or water, and is commonly found where sanitation measures are poor. It causes severe diarrhoea and vomiting, which can lead to profound dehydration and potentially death.Oral rehydration solution (ORS) is used to treat dehydration caused by diarrhoeal diseases, including cholera. Formulations with lower osmolarity are safe and more effective than those with a higher osmolarity for treating non-cholera diarrhoea. As cholera causes rapid electrolyte loss, it is important to know if these benefits are similar for people with cholera.Injected cholera vaccines appear to be safe and relatively more effective than usually realized. Protection against cholera persists for up to two years following a single dose of vaccine, and for three years with an annual booster. However, they have been superseded by oral vaccines.Hepatitis A
Immunoglobulins for preventing hepatitis A“Immunoglobulins seem effective for preventing hepatitis A in both children and adults. However, the evidence, on which the conclusion is based, is not strong as the included trials appear to have risk of bias and their number is insufficient.”
Hepatitis A is a common, contagious viral disease in low-income countries. Hepatitis A is transmitted primarily by faecal-oral spread from person to person. Passive immunoprophylaxis for hepatitis A using immunoglobulin preparations was essential for prevention before the development of a specific hepatitis A vaccine (active immunization).
