Diarrhoeal disease is a leading cause of death and illness, killing 1.8 million people each year. Poor hygiene and lack of access to sanitation together contribute to 88 per cent of all deaths from diarrhoeal disease, with children paying the highest price: 5,000 deaths a day. Hundreds of millions of other children suffer reduced physical growth and impaired cognitive functions due to intestinal worms.

Improved access to sanitation would also lead to very high avoided health sector costs, according to UN research. On a typical day in sub-Saharan Africa, for example, half the hospital beds are occupied by people afflicted with faecal-borne disease. Treating preventable infectious diarrhoea consumes 12 percent of the region's total health budget.

Globally, $552 million in direct treatment costs would be avoided by meeting the MDG sanitation target.

Around the world, an estimated 200 million tons of human waste and untold millions of tons of wastewater are discharged uncontained and untreated, into watercourses every year. As a result, humans are regularly exposed to bacteria, viruses and parasites - spread through direct or indirect contact with these watercourses. Such exposure is the leading cause for diarrhoeal disease (including dysentery and cholera), parasitic infections, worm infestations and trachoma.