Installation of city-wide sewerage in Salvador, Brazil, reduced diarrhoea prevalence in the city's children by an estimated 22%. Urban sanitation is thus a highly effective health measure that can no longer be ignored. These are the conclusions of authors of an article in this week's Latin America special edition of The Lancet.
The importance of adequate water supply and sanitation in the prevention of diarrhoeal diseases and other infections, and of their contribution to poverty eradication, was recognised by the international community when coverage targets for both were included in the Millennium Development Goals (MDGs). Sanitation seems to be just as effective a public health measure as is an adequate water supply, and the promotion of sanitation plus hygiene has emerged as one of the most cost-effective interventions against high-burden diseases in developing countries. A city-wide sanitation intervention was started in Salvador in 1997 to improve sewerage coverage from 26% of households to 80%.
Professor Mauricio Barreto, Instituto de Saude Coletiva, Federal University of Bahia, Salvador, Brazil, and colleagues did two studies of children aged 0-36 months, one in 1997-98 before the intervention (841 children) and one in 2003-04 after its completion (1007 children). Children were sampled from 24 random areas to represent the range of conditions in the city, and daily diarrhoea data were obtained during home visits twice per week.
They found that diarrhoea prevalence following the intervention was 21% lower than that before the sanitation programme. After adjustment for baseline sewerage coverage and potential confounding variables, the estimated overall prevalence reduction was 22%. The reduction was as high as 43% in areas where the baseline prevalence of diarrhoea was highest.
The authors say: "Because sewerage is mainly external to houses and the fact that it prevents disease transmission in the public domain, public responsibility is to ensure that sewerage is installed. At a typical cost per person of $160, investment in sewerage is too large to be left to cash-strapped municipalities, and needs the involvement of international organisations, and central government and its agencies. The health sector is not generally an investor, but it nevertheless has a key part to play, through promotion, advocacy, and regulation, to ensure that toilets and sewers are properly built, used, and maintained, so that their full health benefits are realised by all."
They conclude: "Our results show that urban sanitation is a highly effective health measure that can no longer be ignored, and they provide a timely support for the launch of 2008 as the International Year of Sanitation."
In an accompanying Comment, Dr David Durrheim, Hunter New England Population Health, Newcastle, NSW, and James Cooke University, Townsville, QLD, Australia, says: "An estimated 1.6 billion people will need access to improved sanitation over the period 2005-15 to meet the MDG target, and the UN General Assembly has declared 2008 an International Year of Sanitation. The obvious benefits to poor people of increased provision of sewerage facilities should serve as the mandate for greater investment by all levels of government and civil society in tackling one of the greatest scourges to communities in developing countries -- infectious diarrhoea due to poor sanitation."
And a linked Editorial concludes: "Adequate sanitation is the most effective public-health intervention the international community has at its disposal. Yet 40% of the world's population still lacks access to a toilet. It is time for toilets and sewage disposal systems to be taken more seriously, not just by governments and civil society, but also by funding bodies and the global health community."
Professor Mauricio Barreto, Instituto de Saude Coletiva, Federal University of Bahia, Salvador, Brazil T) + 55 71 3263-7445/ +55 71 9114-9119 E) mauricio@ufba.br
Dr David Durrheim, Hunter New England Population Health, Newcastle, NSW, and James Cooke University, Townsville, QLD, Australia E) david.durrheim@jcu.edu.au
Lancet Press Office T) +44 (0) 20 7424 4949 E) pressoffice@lancet.com
The paper associated with the press release is listed below:
http://multimedia.thelancet.com/pdf/press/Sanitation.pdf
Journal
The Lancet