WHO publishes 54 pathogen background documents to support safe water and sanitation systems

In a move to strengthen global efforts against waterborne disease, WHO has released 54 WASH-related pathogens new technical background documents — announced yesterday at a global water microbiology conference in the Netherlands — that capture the latest science on pathogens linked to drinking-water and sanitation systems.

Unsafe water, inadequate sanitation and poor hygiene (WASH) continue to expose billions of people to harmful pathogens every day. These systemic failures are responsible for more than 1.4 million preventable deaths each year, disproportionately affecting young children.

The newly published documents offer a detailed overview of pathogens that pose a risk through water, sanitation, or both. WHO has included documents for several pathogens not traditionally considered waterborne, but for which questions have been raised about possible transmission through drinking-water.

Each background document provides a concise summary of the current science. This includes information on human health impacts, disease patterns, modes of transmission, and sources of faecal contamination. The profiles also detail how these pathogens occur in the environment – including in various parts of the water cycle – and how they are detected, prevented, and managed within drinking-water and sanitation systems.

The technical package also features a list of the top 10 water- and sanitation-related pathogens, developed to spotlight priority threats, raise awareness and support clear communication of the evidence and actions outlined in the background documents. Well-managed sanitation and drinking-water systems will effectively control WASH-related pathogens, including these top 10.

This summary, along with the background documents, is being launched at WaterMicro25, the 22^nd Health Related Water Microbiology Conference today, in the Netherlands.  Based on burden of disease data, evidence of WASH transmission and concerns such as antimicrobial resistance, the Top 10 pathogens include diarrhoea genic and enterohaemorrhagic Escherichia coli, Vibrio cholerae, Salmonella spp., Shigella, Campylobacter, Cryptosporidium, rotavirus, norovirus, adenovirus and hepatitis A.

“We know what’s making people sick and we know how to stop it,” said Bruce Gordon, Head of WHO’s Water, Sanitation, Hygiene and Health Unit. “Safe drinking-water, sanitation systems and strong regulations are the foundation for public health – yet millions still lack access to them. A key is for all countries to work within their means and make gradual improvements within their systems to stop these pathogens.”

A global problem, a preventable burden
Many of these pathogens are transmitted not just through drinking-water, but also through contaminated food, hands and the environment. Poorly managed sanitation systems, unreliable water supply and exposure to animal waste all contribute to transmission.

Although vaccines exist for some of these diseases – including cholera, rotavirus, typhoid and hepatitis A – most remain preventable only through long-term WASH investments, such as:

• water safety planning;
• sanitation safety planning;
• effective regulation for drinking-water and sanitation; and
• surveillance of wastewater for early detection of outbreaks

“Effective WASH, which can stop all pathogens, is an essential complement to vaccination,” said Dr Sophie Boisson, Lead Epidemiologist in WHO’s Water, Sanitation and Hygiene Unit. “Effective WASH provides the multiple barriers that stop transmission of over 50 waterborne pathogens – viruses, bacteria and protozoan parasites.”

WHO’s call to action
The background documents are supporting information for WHO’s Guidelines on sanitation and health and/or the Guidelines for drinking-water quality. They are intended to help public health practitioners assess and manage risks in water and sanitation systems more effectively.  WHO supports countries to develop WASH standards, build workforce capacity and monitor progress through global efforts such as the WHO/UNICEF Joint Monitoring Programme for Water Supply, Sanitation and Hygiene (JMP) and the UN-Water Global Analysis and Assessment of Sanitation and Drinking-Water (GLAAS).

By identifying the pathogens that matter most – and the systems that can stop them – WHO aims to strengthen disease prevention from the ground up.

“It’s time to align public health strategies with water and sanitation realities,” added Boisson. "Without addressing the root causes of pathogen transmission, we will keep responding to outbreaks rather than preventing them"