The international aid system is contributing to millions of preventable child deaths by neglecting illnesses most deadly to under-five children such as diarrhoea, according to a report by the UK-based international non-profit Wateraid.

In 'Fatal Neglect', Wateraid says the aid system must target resources to diseases that pose the greatest burden to a population, like diarrhoea caused by poor sanitation.

Significantly more funding goes to fighting HIV and malaria - two other main killers of children - than to fighting diarrhoea, even though diarrhoea kills more children worldwide than HIV and malaria combined, according to Wateraid. The organisation says it does not imply that tackling diarrhoea should come at the expense of these other diseases. "Rather, this paper questions how and why the international aid system is overlooking one of the biggest killers of children."

Henry Northover, Wateraid head of policy, told IRIN: "We need a system that analyses the disease burden and looks at the greatest causes of poor health. What we are seeing rather is a health system that focuses on the treatment of symptoms rather than causes."

He added: "We are dealing with a blind spot in the donor community; they see getting sanitation right as an end piece of the development process rather than, as history shows, it serving as a critical driver of poverty eradication efforts."

Wateraid and other health experts say safe water and sanitation are fundamental to health and poverty reduction.

The report says disease-specific funding mechanisms can distort national health priorities. Rather Wateraid calls for "the health system to be strengthened in such a way that no critical determinant of child health [such as sanitation] can be neglected."

The World Health Organization (WHO) in a 'report card' on Millennium Development Goals (MDG) progress released on 21 May said 9 million under-five children died in 2007, down from an estimated 12.5 million in 1990, the year against which MDG progress is measured. WHO says: "However, in many African countries and in low-income countries generally, progress has been insufficient to reach the MDG target that aims for a two-thirds reduction in child mortality by the year 2015."