• Water.org

Water and Public Health

• Pathogens and waterborne disease• 2 million deaths annually due to

unsafe water, sanitation and hygiene• 4% of the global disease burden could

be prevented by improving water supply, sanitation, and hygiene

– WHO 2013

http://www.smashinglists.com/10-leading-causes-of-mortality-worldwide/

Prüss-Üstün et al., 2008

Prüss-Üstün et al., 2008

Burden of Diarrheal Diease

• Diarrheal burden– 90% of deaths are in children <5– 80% of deaths in children <2

• 1 in 200 children die from diarrhea worldwide

• 88% of diarrheal disease due to unsafe water, inadequate sanitation and hygiene– Significant improvement in morbidity and mortality can be

achieved thru sanitation and minimal water treatment– 95% of diarrheal deaths in children <5 could be prevented

with sanitation upgrades and provision of safe water supply

WHO 2004; Green et al. 2009

Fecal-Oral Transmission

Enteric OriginBacteriaVirusesHelminthsProtozoa

Some Water Related Diseases

CampylobacteriosisSalmonellosis

ShigellosisLeptospirosisTyphoid fever

CholeraRotavirusNorovirusHepatitis A

AscarisRingworm

‘F-Diagram’Enteric Disease Transmission

Barriers to Transmission

Improved Sanitation

2.5 billion people still lacked access to improved sanitation facilities in 2011 (WHO, 2013)

Green et al. 2009

Barriers to Transmission

Improved Hygiene / Access

768 million people still relied on unimproved drinking water sources in 2011 (WHO, 2013)

Disinfection (~1905)

Efforts in Sanitation and Hygiene may need to be increased to ameliorate higher risk of enteric disease with

climate change

IPCC 2007. Working Group II

Water.org• More than 3.4 million people die each year from water, sanitation,

and hygiene-related causes. • Lack of access to clean water and sanitation kills children at a rate

equivalent of a jumbo jet crashing every four hours.• Of the 60 million people added to the world's towns and cities every

year, most move to informal settlements (i.e. slums) with no sanitation facilities.9

• 780 million people lack access to an improved water source; approximately one in nine people.14

• "[The water and sanitation] crisis claims more lives through disease than any war claims through guns." 11

• An American taking a five-minute shower uses more water than the average person in a developing country slum uses for an entire day.11

• Over 2.5X more people lack water than live in the United States.3

• More people have a mobile phone than a toilet.5

Cholera

Sanitation, Hygiene, Environment, Climate

Cholera

• Derived from Greek word referring to rain rushing from a gutter– Causes profuse watery diarrhea

• Known since Hippocrates• First epidemic described in 1563 in India• 7 seven known pandemics

– 7th began in 1961

icddr,b

1858 - London

Historical Perspective • Cholera linked to water

source– John Snow– London 1854 cholera

outbreak– 500 fatal cases, 10 days– Linked to Broad St. pump

• First link to water

• Causative agent identified– Robert Koch– 1883 isolated bacterium – Vibrio cholerae (comma)

http://www.sewerhistory.org/images/bm/bms9/1899_bms902.gif

Sanitation Improvements and Cholera, 1800s

• 2011, 58 countries from all continents reported cases (589,854 - vastly underestimates true burden)

• Case burden has shifted to the Americas (Haiti, Dominican Republic)

• Globally, cholera incidence has increased since 2004

Vibrio cholerae• Infection via

– Water– Shellfish (crabs and bivalves)– Person-to-person

• Only Vibrio that can grow in fresh waters (optimal growth at low salinities)– Vibrio are most commonly cultured bacterial genus from

marine waters• Since 1978, known to occur in warm estuarine waters

world-wide• Disease of sanitation AND the environment

Seventh Cholera Pandemic

2010

Environment and climate

Vibrio cholerae

• >200 serotypes– O1 in pandemics (El Tor &

Classical)– O139 new toxigenic strain

• Cholera toxin (CTX)– Phage encoded– Acts in intestines to produce

profuse diarrhea

Cholera Transmission Dynamics

Vibrio & V. cholerae are strongly temperature associated.

Very rapid doubling times as temperatures rise.

Vibrio cholerae in the EnvironmentUp to 104 cells/copepod

PROBLEM

Prevention of Cholera Transmission

Prevention of Cholera Transmission

0.2 – 0.8 µm

Prevention of Cholera Transmission

Prevention of Cholera Transmission

Colwell et al. 2003