Soap: the missing ingredient in the water and sanitation mix

Until now, water supply has had the bulk of development investment, but should sanitation and hygiene be receiving at least equal attention? Separately, or better, together, these three form our best means of preventing the gastro-intestinal or diarrhoeal diseases that are one of the leading killers of children in developing countries today.

These infections stem from microbes and parasites which multiply in the gut, exit in excreta and are transmitted from one person to another through the environment.

Good sanitation prevents excreta from entering the domestic environment and getting into water; good hygiene prevents the transmission of microbes from the environment into the human body via hands. Adequate disposal of excreta and safe hygiene practices could together prevent almost all gastro-intestinal infection.

A review of studies of the health impact of water, hygiene and sanitation shows that improving water quality reduces diarrhoea risk by an average of only 16%, whilst sanitation and hygiene promotion are twice as effective (see graph).

If hygiene promotion can have such a big impact on health, it is vital to understand what is meant by 'hygiene'. In many developing countries, practices believed to be 'good' and 'healthy' range from hair cutting and dishwashing to nipple cleaning and rubbish collection. The ability of hygiene promoters to effect major changes in a population's hygiene practices is very limited, efforts must therefore be more focused.

Tracing routes of faecal-oral contamination in households suggests that the microbe 'superhighway' is the hands. These carry faecal germs from toilets, baby potties, or defecation sites to utensils, water and food. A recent review of 17 studies suggests that handwashing with soap can cut diarrhoea risk by 42 to 47%. If the risk of death is reduced by as much as the risk of disease, then universal handwashing with soap could save over a million lives. Handwashing thus appears to be more effective in preventing diarrhoeal disease than even water and sanitation or hygiene promotion in general.

Though the message sounds simple - 'wash hands with soap to save lives' - the task remains huge. Handwashing with soap after contact with faecal material is not a common event. In studies in seven African, Asian and Latin American countries. mother's soap use after the toilet and after cleaning up a child ranged from 0 to 20% with median rates at about 14%. A recent study in the UK observed handwashing with soap after only 47% of nappy changes.

Classic health education which preaches and scolds has little impact on health-related behaviour. However, soap marketers know how to promote soap use and have managed to get soap into almost every household in developing countries (if only for clothes and body washing). Soap companies should therefore make excellent partners in handwash promotion. A group of agencies (the World Bank, Water and Sanitation Program, UNICEF, WHO and USAID) has begun to work with governments, soap companies, soap-makers' associations and small-scale producers to design full-scale handwash promotion programmes to cover a number of countries.

This new approach is now being trialled, with assistance from the London School of Hygiene and Tropical Medicine and the Academy for Educational Development. The experience so far shows that building understanding and trust between partners takes a long time. Efforts need to be made to provide equal opportunity for participation of all private sector organisations including the local soap industry as well as representatives of the multinational soap companies. Nevertheless, it is becoming clear that there is an excellent fit between the capacities and skills of the different partners to deliver modern and effective large-scale handwash promotion programmes for the poor.

Hygiene and sanitation are at least as important as water supply in improving public health. Hygiene (handwashing with soap in particular), should become a priority for investment. Recommendations to policy-makers include:

• handwashing with soap can reduce diarrhoeal risk by almost half
• focus on a limited number of practices, especially handwashing with soap and safe stool disposal
• public-private-partnerships between governments and soap companies offer a promising new approach for high-impact, large scale handwash promotion
• when soap or water are unavailable, scrubbing hands with ash or earth can still be effective.

Val Curtis
London School of Hygiene and Tropical Medicine
Keppel Street
London WC1E 7HT
UK

T +44 (0) 20 7927 2628
F +44 (0) 20 7636 7843
val.curtis@lshtm.ac.uk
www.lshtm.ac.uk/dcvbu/staff/valspage.htm

See also

• 'WHO World Health Report 2002', World Health Organization, Geneva, 2002
• 'Domestic hygiene and diarrhoea, pinpointing the problem', Tropical Medicine and International Health, 5 (1) pp 22-32, by V. Curtis, S. Cairncross and R. Yonli, 2000
• 'Hygiene: how myths, monsters and mothers-in-law can promote behaviour change', Journal of Infection, 43, pp 75-79, by V. Curtis, 2001
• 'Effects of improved water supply and sanitation on ascariasis, diarrhoea, dracunculiasis, hookworm infection, schistosomiasis and trachoma', Bulletin of WHO, by S. Esrey et al, 69 (5), 1991
• 'Prevention of diarrhoea in young children in developing countries', Bulletin of WHO, by S. Huttly, S. Morris & V. Pisani, 75 (2), 1997

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