The active involvement of health professionals in hygiene, sanitation, and water supply is absolutely crucial to accelerating and consolidating global health progress, says a new series of papers inPLoS Medicine by a leading group of public health academics and water advocates.

Professor Sandy Cairncross from the London School of Hygiene & Tropical Medicine (LSHTM) and colleagues show how water and sanitation issues are woefully neglected across the world and suggest that action could prevent more than 2 million children dying each year.

The authors say that in 2010, nearly 20% of the world's population still defecates in the open and 2.6 billion people do not have access to even a basic toilet. Unsafe sanitation and drinking water, as well as poor hygiene, account for at least 7% of the total global disease burden, and nearly 20% of all child deaths in the world. Most of these diseases, including diarrhoea, can easily be prevented with cheap and proven interventions such as pit latrines and hand-washing with soap, say the authors. Despite this, progress has been "painfully slow" in many developing countries. The series urges members of the health community—including international donors, UN agencies, developing country governments, and health care professionals—to take immediate action to reduce this "devastating disease burden."

Four papers form the PLoS Medicine series. In the first article, Jamie Bartram from the University of North Carolina, USA, and Sandy Cairncross argue that the massive burden of ill health associated with poor hygiene, sanitation, and water supply demands more attention from health professionals and policymakers. In the second article, Paul Hunter (University of East Anglia, United Kingdom) and colleagues focus on water supply and argue that much more effort is needed to improve access to safe and sustainable water supplies. David Trouba (Water Supply and Sanitation Collaborative Council, Geneva, Switzerland) and colleagues discuss the importance of improved sanitation to health and the role that the health sector can play in its advocacy in the third article. And in the final article, Sandy Cairncross and colleagues outline what needs to be done to make significant progress in providing more and better hygiene, sanitation, and water for all.