How does fighting diarrhoea stack up to malaria in effectiveness?

I saw an infographic about diarrhoea the other day that really caught my attention with some big statistics. It got me thinking that I had never really considered combating diarrhoea specifically as an avenue for improving global health. Typically I’ve focussed on Malaria, specifically through the Against Malaria Foundation (AMF). Below is a comparison between the impacts diarrhoea and malaria and the costs of combating them. The following figures for diarrhoea are taken from this infographic and compared where possible to figures from malaria (sources listed). The infographic didn’t have a logo, producer or sources on it, and after research some of the figures don’t seem to check out.

Diarrhoea is responsible for 1.5 million child deaths under 5 each year. (Note that according to (b) as of 2013 diarrhoea kills around 760,000 children under 5 per year, so this doesn’t seem to check out)

Malaria was responsible for 455,520 child deaths under 5 in 2013. (a)

Wash programs have the potential to save over 2500 lives per day (175,000 per year). (I’m always sceptical of the use of the word ‘potential’)

A safe water supply can reduce diarrhoea by 21%.

About half of the World’s Hospital [sic] beds are occupied by patients with a water-related illness such as diarrhoea. (Not a proper source, but (h) repeats this figure)

Diarrhoea kills more children than AIDS, measles and malaria combined.

Diarrhoea killed an estimated 1.26 million people in 2013 (e). In 2013, 1.5 million people died of HIV related illnesses (d), 145,700 people died from measles (c) and 584,000 people died from malaria (a), giving a total of 2.23 million deaths. This statement doesn’t seem to check out, and by this time I’m getting rather suspicious of the infographics’ validity.

In India alone, water-related diseases cost the economy 73 million working days per year. (Figure validated by (f))

I can’t find a recent figure for malaria to compare, but (g) has good related information.

For every $1 invested in water, sanitisation and hygiene, $8 is returned in increased productivity. (I can’t vet this, but (i) has good related information)

433 million school days are lost each year due to water-related diseases. (Not a proper source, but (h) repeats this figure)

WHO estimates that 94% of all occurrences of diarrhoeal diseases are completely preventable.

The latest figures suggest that AMF can save a life that would have been lost otherwise to malaria for ~$3,340 (j) by distributing bed nets to keep mosquitos away from people while they sleep.

In The Life You Can Save, Peter Singer says “WHO, for example, estimates that many of the 3 million people who die annually from diarrhea or its complications can be saved by an extraordinarily simple recipe for oral rehydration therapy: a large pinch of salt and a fistful of sugar dissolved in a jug of clean water. This lifesaving remedy can be assembled for a few cents, if only people know about it. UNICEF estimates that the hundreds of thousands of children who still die of measles each year could be saved by a vaccine costing less than $1 a dose… while these low figures are undoubtedly an important part of the charities’ efforts to attract donors, they are, unfortunately, not an accurate measure of the true cost of saving a life.

An article from The Guardian says “Right now Unicef is chlorinating water, making it safe to drink. At a cost of only 17p, it can provide the oral rehydration salts that will save a child from fatal diarrhoea.” (k) But there is a gap between providing the rehydration salts and directly saving one life. The child consuming the salts may not have died anyway, or they might not use it.

In Disease Control Priorities In Developing Countries (m; 2nd edition released 2006), it is stated that the cost of saving a life from diarrheal diseases is much more cost effective through educational intervention (~ US$500 “and could be as low as US$14”). “Scenarios with a high cost per life saved (more than US$6,000) are when prevalence rates are low or when implementation costs for quality-related interventions are high.”

This would suggest that educational interventions targeting diarrheal diseases is more cost effective at saving lives than distributing bed nets. However, this is an older figure (pre-2006) and isn’t backed up with the name of an organisation that can achieve this. It certainly highlights that diarrhoea may be worthy of more focus for reducing deaths due to widespread diseases than malaria. The last quotes also seem to suggest that perhaps an educational approach to combating malaria may be more effective than traditional approaches. This is rather typical of similar issues in developing countries.

I haven’t been able to find much research on water charities on the GiveWell website. A stub page exists, with the conclusion “In 2011, we identified 43 water charities and visited their websites to determine whether they published information online to answer the above question. By and large, we found limited information that answered our questions. We ultimately contacted six organizations and our reviews of 4 of them are still pending.” It would seem that a renewed focus on water charities should be undertaken.

The verdict

Some of the statements listed in the infographic don’t appear to be entirely accurate, though the scale of the problem of diarrhoea is comparable to that of malaria. Initial findings reported here suggest that treating diarrhoea may be as or even more cost effective than combating diarrhoea. It is recommended that more research into the effectiveness of water charities be undertaken given the potential for high effectiveness, especially through educational programs regarding diarrhoea and related diseases.

Note: Many figures listed have an uncertainty range. A mean value is generally taken for simplicity.

References

(a) http://​​www.who.int/​​malaria/​​areas/​​high_risk_groups/​​children/​​en/​​

(b) http://​​www.who.int/​​mediacentre/​​factsheets/​​fs330/​​en/​​

(c) www.who.int/​​mediacentre/​​factsheets/​​fs286/​​en/​​

(d) www.who.int/​​gho/​​hiv/​​epidemic_status/​​deaths/​en/​

(e) https://​​www.ncbi.nlm.nih.gov/​​pmc/​​articles/​​PMC4340604/​​

(f) www.wateraid.org/​​~/​​media/​​.../​​drinking-water-quality-rural-india.pdf

(g) http://​​www.ncbi.nlm.nih.gov/​​books/​​NBK1720/​​

(h) http://​​thewaterproject.org/​​health

(i) http://​​www.who.int/​​water_sanitation_health/​​wsh0404summary/​​en/​​

(j) http://​​www.givewell.org/​​international/​​top-charities/​​AMF

(k) http://​​www.theguardian.com/​​world/​​2000/​​mar/​​05/​​mozambique.theobserver

(l) http://​​www.effective-altruism.com/​​ea/​​5e/​​efficient_charity_do_unto_others/​​

(m) https://​​books.google.com.au/​​books?isbn=0821361805