Sanitation and health: what do we want to know?

Experts meet to discuss reaching a consensus on what the evidence tells us.

Radu Ban

Jan Willem Rosenbom

This is the first of two blogs written about the “Sanitation and health evidence consensus meeting”, convened by the World Health Organization (WHO) in Seattle on May 24 and 25 of 2018. It was written by Jan Willem Rosenboom and Radu Ban, who are both Sr. Program Officers on the Water, Sanitation and Hygiene (WSH) team at the Bill & Melinda Gates Foundation. This first blog will describe the process used to arrive at the consensus, while the second blog will describe the outcome of the consensus and will come out once the results of the consensus meeting have been published. Also, mark your calendars for a session during the 2018 UNC Water and Health conference dedicated to this consensus!

Two sides of sanitation: rubbish and cleanliness. Credit Bill & Melinda Gates Foundation, Cambodia/India

Introduction: What is this about?

It is hard to imagine that making improvements in sanitation wouldn’t play a role in improving health. After all, we know that shit spreads disease and the F diagram shows us that sanitation is an important tool in blocking the transmission of pathogens from one person to the next, thus lowering exposure. And sure enough: we have strong evidence about the effectiveness of sanitation interventions and improving health and human capital outcomes from rigorous historical studies, from high- as well as low- and middle-income countries.

At the same time, looking at the specific impact of programmatic sanitation interventions, it can be hard to figure out what the evidence is really telling us. On the one hand, a systematic review of the whole body of evidence on sanitation and health (carried out by Freeman et al. in 2017) suggests that sanitation protects against diarrhoea, active trachoma, some soil-transmitted helminth (STH) infections and schistosomiasis. It also improves height-for-age scores of children (i.e. it decreases stunting, which is an important measure of human capacity). On the other hand, several recent sanitation intervention studies have found limited or no impact on different health outcomes. The table below (copied with permission from a presentation by Tom Clasen), provides a summary of key findings from the most recent sanitation studies:

1. Fewer observed flies and feces; no change in fecal contamination of water
2. Fewer observed soiled hands and less fecal contamination of water
3. Except in the study arm considering just water quality improvements

This seeming lack of agreement is confusing, and partly in response to questions from practitioners, on May 24 and 25 of this year WHO convened a meeting of experts to review the existing evidence and reach a consensus about what it is telling us. The group of experts consisted of researchers across multiple disciplines who had written extensively on the topic of sanitation and health. We thought it was necessary to reach consensus among researchers before engaging, in a unified voice, the practitioner community.

At the same time, to make sure that the concerns of practitioners would be considered in the meeting, we published a “request for input” online (through the SuSanA network as well as the Sanitation Updates blog) and we will summarise the responses here. But first…

Environmental Transmission of Diarrheal Pathogens in Low and Middle Income Countries

Environmental Transmission of Diarrheal Pathogens in Low and Middle Income Countries. Environmental Science: Processes & Impacts, June 2016.

• Full text, pdf

Author: Timothy R. Julian. Pathogens and Human Health, Department of Environmental Microbiology, Swiss Federal Research Institute of Aquatic Science and Technology (Eawag), 8600 Dübendorf, Switzerland.

Globally, more than half a million children die every year from diarrheal diseases. Recent studies have identified the diarrheal disease agents most responsible for moderate-to-severe diarrheal disease and diarrhea-related mortality. The agents – enterotoxigenic and enteropathogenic E. coli, Shigella spp., rotavirus, norovirus, and Cryptosporidium spp. – are characterized by high infectivity, high fecal shedding, and transmission through a wide range of environmental reservoirs.

This Perspective provides insight into the ecology of the diarrheal disease agents with emphasis on their relationship to environmental reservoirs. Based on this insight, the Perspective advocates for comprehensive interventions targeting exposure reductions across multiple environmental reservoirs. Single interventions are often inadequate, and this may be partly attributed to their failure to reduce environmental exposures below thresholds needed to initiate infection.

 

Human diarrhea infections associated with domestic animal husbandry

Human diarrhea infections associated with domestic animal husbandry: a systematic review and meta-analysis. Trop Med Intl Health, Mar 2014.

• Full text, pdf

Authors: Laura D. Zambrano, Karen Levy, Neia P. Menezes and Matthew C. Freeman

Domestic animal husbandry, a common practice globally, can lead to zoonotic transmission of enteric pathogens. However, this risk has received little attention to date. This systematic review and meta-analysis examines the evidence for an association between domestic exposure to food-producing animals and cases of human diarrhea and specific enteric infections.

We performed a systematic review of available literature to examine domestic livestock and poultry as risk factors for diarrhea and applied pre-determined quality criteria. Where possible, we carried out meta-analysis of specific animal–pathogen pairs.

We found consistent evidence of a positive association between exposure to domestic food-producing animals and diarrheal illness across a range of animal exposures and enteric pathogens. Out of 29 studies included in the review, 20 (69.0%) reported a positive association between domestic animal exposure and diarrhea. Domestic exposure to poultry revealed a substantial association with human campylobacteriosis (OR 2.73, 95% CI 1.90–3.93).

Our results suggest that domestic poultry and livestock exposures are associated with diarrheal illness in humans. Failure to ascertain the microbial cause of disease may mask this effect. Exposure to domestic animals should be considered a risk factor for human diarrheal illness and additional studies may identify potential mitigation strategies to address this risk.

 

 

WASHplus Weekly: Focus on WASH-related disesases

Issue 135 February 21, 2014 | Focus on WASH-Related Diseases

This issue contains recent studies and reports on several WASH-related diseases: neglected tropical diseases (NTDs), malnutrition, cholera, diarrhea, fluorosis, and malaria. Some of the resources include: a WASH and NTDs global manual and country reports from the Sightsavers Innovation Fund; an article on the origins of the cholera outbreak in Haiti; a review of evidence linking WASH, anemia, and child growth; Cochrane Reviews on the prevention and control of malaria; and additional studies and resources. 

We welcome your suggestions for future issues of the Weekly. Topics for upcoming issues include World Water Day 2014, WASH and nutrition, behavior change, community-led total sanitation, household water treatment, and menstrual hygiene management.

GENERAL/OVERVIEW

Human Health and the Water Environment: Using the DPSEEA Framework to Identify the Driving Forces of Disease. Science of the Total Environment, 2014. J Gentry-Shields.(Link)

There is a growing awareness of global forces that threaten human health via the water environment. A better understanding of the dynamic between human health and the water environment would enable prediction of the significant driving forces and effective strategies for coping with or preventing them. This report details the use of the Driving Force–Pressure–State–Exposure–Effect–Action (DPSEEA) framework to explore the linkage between water-related diseases and their significant driving forces.

Seasonal Effects of Water Quality: The Hidden Costs of the Green Revolution to Infant and Child Health in India, 2013. E Brainerd. (Link)
This paper examines the impact of fertilizer agrichemicals in water on infant and child health using water quality data combined with data on child health outcomes from the Demographic and Health Surveys of India. The results indicate that children exposed to higher concentrations of agrichemicals during their first month experience worse health outcomes on a variety of measures; these effects are largest among the most vulnerable groups, particularly the children of uneducated poor women living in rural India.

Water, Sanitation and Hygiene: Evidence Paper, 2013. Department for International Development. (Link)
This paper aims to provide an accessible guide to existing evidence, including a conceptual framework for understanding how WASH impacts health and well-being and a description of methods used for ascertaining the health, economic, and social impacts of WASH. It also presents the available evidence on the benefits and cost-effectiveness of WASH interventions.

NEGLECTED TROPICAL DISEASES

WASH and the Neglected Tropical Diseases: A Global Manual for WASH Implementers, 2014. Sightsavers, et al. (Link) | (Blog post)
These manuals are free to download and distribute. New users must create an account to download the manuals, which are divided into disease-specific chapters that describe the transmission cycle, symptoms, and disease burden of the WASH-related NTDs. Each chapter includes information about WASH activities that are most essential to the control of each disease. Maps of disease prevalence are provided to enable identification of disease-endemic communities most in need of sustainable WASH services. Country-specific versions of the manual are available so far for Brazil, Burkina Faso, Cameroon, Chad, Ethiopia, Indonesia, Kenya, Malawi, Mali, Mozambique, Nigeria, Sudan, Tanzania, and Uganda.

Eastern Africa drought: seven million people in need of WASH services

Seven million people, including over 700,000 refugees are in need of waster, sanitation and hygiene (WASH) services according to a United Nations report of 15 July 2011.

The drought affecting Kenya, Somalia, Ethiopia and Djibouti is being called the worst in 50 years. UN agencies have asked for US$ 1.6 billion to pay for essential programmes in the Horn of Africa, but have only received half that amount so far.

Water trucking is still needed in the driest areas as natural water points failed to refill sufficiently. Two million people have been given better access to safe drinking water so far in 2011.

Paradoxically, some areas in Ethiopia and Somalia are expected to receive above-normal rainfall in the June to September period. This is likely to increase the risk of flooding and subsequent outbreaks of waterborne diseases.

India: “edutainment” health camps focus on preventing diarrhoeal disease

A US-based health research firm, Abt Associates, has organised a series of diarrhoea prevention camps in low-income settlements in cities of Lucknow, Kanpur and Varanasi. The camps took place between May and July, the peak period of diarrhoeal outbreaks.

Saathi Bachpan Ke logo

The camps are part of the ‘Saathi Bachpan Ke‘ (Friends of Childhood) programme, funded through the USAID-India Market-Based Partnerships for Health Project.

Puppet theater teaches camp participants the importance of washing hands with soap, ORS use and purifying water to prevent and manage diarrhea. Photo: Abt Associates

The Abt team has produced an “edutainment” package for parents, caregivers and children participating in the camps. They are taught important life-saving behaviors – from washing hands with soap and purifying water to rehydrating children suffering with diarrhea. Key messages are reinforced through puppet shows, interactive games and quizzes.

Presentations and demonstrations are provided by physicians and other program supporters including manufacturers of soap, water purifiers, and oral rehydration salts, and public sector partners.

Related web site:  USAID India – Market-based Partnerships for Health (MBPH) – Saathi Bachpan Ke

See a promotional video of “Saathi Bachpan Ke” initiative on USAID India’s Facebook page.

Source: PTI / Deccan Herald, 07 Jul 2011 ; Abt Associates, 06 Jul 2011

Global deaths from diarrhoea, malaria, AIDS declining, study predicts

Under-five child mortality from diarrhoeal diseases, which was 1.7 million in 2005, is expected to fall to just over half a million by 2030 and around 130,000 in 2060, a new study [1] predicts.

The study notes that headway is being made in fighting communicable diseases such as diarrhoea, malaria and AIDS. At the global level disease burdens are shifting from communicable diseases to chronic ones such as cancer, diabetes and heart disease.

India: inadequate sanitation costs the equivalent of 6.4 percent of GDP

Inadequate sanitation costs India US$ 53.8 billion, which is equivalent to 6.4 percent of India’s GDP in 2006, according to a new report [1] from the Water and Sanitation Program (WSP).

The study analyzed the evidence on the adverse economic impacts of inadequate sanitation, which include costs associated with death and disease, accessing and treating water, and losses in education, productivity, time, and tourism. The findings are based on 2006 figures, although a similar magnitude of losses is likely in later years.

The report indicates that premature mortality and other health-related impacts of inadequate sanitation, were the most costly at US$ 38.5 billion, 71.6 percent of total impacts, followed by productive time lost to access sanitation facilities or sites for defecation at US$ 10.7 billion, 20 percent, and drinking water-related impacts at US$ 4.2 billion, 7.8 percent.

“The cost is more than I expected,” UNICEF’s water, sanitation and hygiene chief Clarissa Brocklehurst said in an interview with news site Bloomberg. “Yet, if you know the scale of open defecation in India, it’s not all that surprising.”

Robert Crane, biochemist who created oral rehydration therapy (ORT), dies

Dr. Robert Crane in 2009

Dr. Robert Kellogg Crane, a biochemist whose discoveries about how salt and sugar are absorbed by the body led to the development of oral rehydration therapy (ORT), has died on 31 October 2010 at the age of 90.

ORT is used to treat people, especially children, with diarrhoea and cholera and has been credited with saving millions of lives, particularly in developing countries.

Dr. Crane was researching metabolism at Washington University School of Medicine in St. Louis when he discovered that sodium and glucose are most efficiently absorbed in the small intestine when mixed. The breakthrough was described in 1978 as “potentially the most important medical advance this century” by The Lancet.

Acute diarrhoea prevention: field trial on efficacy of a probiotic

The National Institute of Cholera and Enteric Diseases (NICED), Kolkata has conducted one of the largest double blind, randomized, placebo controlled field trial to determine the effectiveness of a probiotic to prevent acute diarrhoea in children in a community setting of Kolkata. The trial was initiated by the Indian Council of Medical Research (ICMR). NICED is one of the 29 ICMR centres.

Yakult Honsha Co. Ltd, Japan, the collaborator of this trial, produces a probiotic drink, Yakult, which contains the Lactobacillus casei probiotic strain Shirota that was evaluated in the study [1].

The study on 3585 children in the age-group of 1-5 years was done to evaluate the effect of the probiotic in preventing acute diarrhoea. The children were randomly grouped to receive either the probiotic or the placebo (fermented milk drink without the probiotic strain) for a period of 12 weeks and were followed up for another 12 weeks.

The results of the 24-week study revealed that the incidence of diarrhoea was lower in the probiotic group as compared to the placebo. In spite of the fact that the probiotic was given only for 12 weeks it resulted in a significant reduction of diarrhoea episodes by 14 per cent in the probiotic group. Scientists at NICED expect a much better impact if the probiotic was to be given for a longer period of time, stated Dr Neerja Hajela, Head, Science, Yakult Danone India Private Limited.

The study suggests that daily intake of a probiotic drink can play an important role in the prevention of acute diarrhoea in young children in a community setting of a developing country like India, she added.

In India, diarrhoea is reported to be second largest fatal disease after pneumonia. Yakult Danone was keen to find a relief to the dreaded disease, stated Dr. Hajela.

Global statistics place diarrhoea as the second leading cause of death in children younger than 5 years. Nearly one in every five child deaths is due to diarrhoea which kills more children than AIDS, Malaria and Measles combined. According to The Lancet, around 1.5 million of the 9 million child deaths in 2008 were due to diarrhoea with 49 per cent of the deaths occurring in five countries namely India, Nigeria, Democratic Republic of the Congo, Pakistan and China.

[1] Sur, D, … [et al.] (2010). Role of probiotic in preventing acute diarrhoea in children: a community-based, randomized, double-blind placebo-controlled field trial in an urban slum. Epidemiology and infection. Available online 30 Jul 2010. doi:10.1017/S0950268810001780

Contact: Dr. Dipikar Sur, MBBS, M.D., National Institute of Cholera and Enteric Diseases, India. (Email: dipikasur@hotmail.com)

Source: Nandita Vijay, Pharmabiz.com, 26 Aug 2010