1.2 burden of disease
DESCRIPTION
Burden of disease of water borne diseases Water and sanitation projectsTRANSCRIPT
Global Burden of Disease
Introduction to Household Water Treatment and Safe Storage, Module 1.2
Dr. Richard Johnston
WHO Collaborating Centre
for Sanitation and Water
in Developing Countries
Introduction to HWTS | 2
● Diseases caused by unsafe water
and sanitation ● Water-borne
● Water-washed
● Water-based
● Water-related
● Global burden of disease ● Mortality
● Morbidity
Introduction
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● 8.4 deaths/1,000 ● 55 million people per year
● 19.9 births/1,000 ● 135 million people per year
● About 1.1% increase per year ● Doubling every 60 years
Birth, taxes, and death
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“Bradley Classification”
●Water-borne
●Water-washed
●Water-based
●Water-related
Disease Classification System
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Water-borne diseases
Caused by ingestion of water
●Diarrheal diseases ● Rotavirus
● Cholera, Shigella
● Cryptosporidiosis
●Hepatitis A and E
●Polio
Improve water quality
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Water-washed diseases
Caused by poor hygiene due to
lack of water
●Most water-borne diseases
●Trachoma
●Acute respiratory infections
Increase water quantity
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Water-based diseases
Caused by parasites which live
part of their life cycle in water
●Schistosomiasis (bilharzia)
●Dracunculiasis (Guinea worm)
Target aquatic organism host
Protect surface water bodies
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Water-related diseases
Caused by insects which breed
in water
●Malaria
●Dengue fever
Remove habitat
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● Many diseases are related to poor
water, sanitation, and hygiene
● Water-borne diseases are caused
by ingestion of contaminated
drinking-water
● HWTS can reduce burden of water-
borne diseases ● Not water-washed, water-based, or water-
related diseases
Summary
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Mini-Quiz
● Arrange the following five diseases in order of the number of deaths per year
Tuberculosis
Diarrheal disease
Lower respiratory
infections
(e.g. pneumonia)
Malaria
Measles
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Mini-Quiz
● Source: WHO in 2014 published figures for 2012.
Tuberculosis
Diarrheal disease
Lower respiratory
infections
Malaria
Measles
935,000
1,498,000
3,051,000
618,000
130,000
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● Causes 1.5 million deaths per year
● 1 in 10 deaths for children < 5 years ● 1,000 child deaths per day
● Second only to respiratory infection
among infectious diseases
● 56% of diarrheal deaths attributed to
inadequate water, sanitation and
hygiene
Diarrheal disease
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Disability Adjusted
Life Years (DALYs)
● DALY = YLL + YLD
● YLL = Years of Life Lost
Number of deaths × Standard
life expectancy at age of death in
years
● YLD = Years Lived with Disability
Number of incident cases ×
Disability weight × Average
duration of the case (years)
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● Diarrhea causes 52.5 M DALYs/year ● 3.1% of global total
● 9% of child disease burden
● India 13.6 M
● China 3.9 M
● Nigeria 3.9 M
● Pakistan 3.3 M
● DRC 3.3 M ● 10% of all DALYs
Diarrheal morbidity
Source: WHO, 2008
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Global Burden of Disease 2010 Study (IHME)
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● Similar approach to WHO methods
● Not endorsed by WHO ● Methods not fully transparent
● Lacked full access to results for evaluation
● Some key differences with WHO
numbers ● Revised disability weights
● No hygiene risk factor
● No disease burden from ‘improved’ water and
sanitation
GDB 2010 Study
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http://www.healthmetricsandevaluation.org/gbd
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● 1.5 million diarrheal deaths
● 89.5 million DALYs ● India 27 M
● DRC 6.4 M
● Nigeria 6.2 M
● Pakistan 5.5 M
● China 1.3 M
● Only 25% diarrheal deaths due to
poor water and sanitation ● Water and sanitation: 0.9% of DALYs
● Hygiene not included
GDB 2010 Study
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● Burden of disease from poor WASH
is high
● Diarrheal disease is a leading cause
of mortality and morbidity
● Different online resources
● Next: Microbial Water Quality
Conclusion