Hands, water & health in non-networked communities:

Experience from Dar es Salaam

A. J. Pickering, J. Davis, S. P. Walters, H. M. Horak, D. P. Keymer, D. Mushi, R. Strickfaden, J. S. Chynoweth, J. Liu, A. Blum, K. Rogers, A. B. Boehm

2011 October 21

Roughly 3 billion people use non-networked water sources

• Household stored water often more contaminated than source water

• Causal mechanisms unclear

• Lack of quantitative research on hand-water connection

Research Objectives

1. Investigate quantitative relationship between bacteria on hands and bacteria in stored drinking water

2. Explore association between child health and FIB contamination in stored water and on hands

Tanzania: Causes of mortality in under-5 children

Source: World Health Organisation, 2006

Diarrhea 17%

Pneumonia 21%

Malaria 23%

Measles 1%

HIV 9%

Injuries 2%

Neonatal 27%

Study Site: Dar es Salaam, Tanzania

~1/2 of households covered by water network, <10% by sewer network

Three communities selected

334 households randomly selected with at least one child under 5

Methods: Stored water & hand sampling

Borewells

Piped network

Vendors

Microbial Sample Processing

All water and hand samples processed within in field lab

Membrane filtration

Two types of fecal indicator bacteria

E. coli

enterococci

Interview methods

• Households visited 4 times over three month period

• Interview with mother of child under five – Demographics – Socio-economic

characteristics – Hygiene behavior – Sanitation and water services – Satisfaction – Health status (HCGS, SRS)

using 48 hr recall

• Health measures defined by 2 or more symptoms – Gastrointestinal symptoms

• Stomach pain • 3 or more bowel movements

in 24 hrs • Watery/loose stools • Blood in stool • Vomit

– Respiratory symptoms • Coughing • Congestion • Difficulty breathing

FIB on hands

Correlates of high FIB on hands E. coli fecal streptococci

Variable β SE P β SE P Constant 3.0 0.64 <0.001 4.94 0.52 <0.001 Mother > primary education

-0.25 0.12 0.04 -0.35 0.10 0.001

Improved toilet -0.07 1.0 0.51 -0.34 0.08 <0.001 Infant in household 0.25 1.0 0.01 -0.09 0.08 0.28 Weekly expenses 0.02 0.07 0.76 -0.04 0.06 0.53

Dissatisfied with quantity of water available for hygiene

-0.15 0.12 0.21 0.23 0.10 0.02

Stored Water

• Most common method of extraction was hand dipping a cup or mug into the water container (94%)

• Other methods: – ladle with a long handle (N = 6) – pouring out of the top (N = 44) – releasing the water through a spigot or tap (N = 6)

• Water extracted by dipping versus other methods was dirtier

Stored water vs. source water

Matching Household Water to Source

• Matched 191 household stored water samples to the exact source from which they were collected

• Stored waters contained significantly higher levels of E. coli and fecal streptococci

• On average, household stored water had: – 1.42 log CFU more EC per 100ml

(P < 0.001) – 1.79 log CFU more FS per 100ml

(P < 0.001)

Treatment?

• 40% (N = 423) of samples reported by respondents to have been treated

• 85% (N = 354) of these samples were reported to have been boiled

• No significant difference between treated and those reported untreated

1

10

100

E. c

oli (

CFU

/100

mL)

Borewelltr

Borewelluntr

pipetr

pipeuntr

vendortr

vendorunt

Stored water quality correlated with hand contamination

• Significant correlation between FIB in household stored water and mean FIB on hands (p<0.001)

• FIB on hands is the only significant factor when FIB in stored water is modeled as a function of: – Household water management practices

• (length of storage time, treatment, cover, extraction method)

– Water source type

– FIB on hands

Hand contamination, stored water quality, and health

• Binary logit model for presence of diarrhea and respiratory symptoms (2 day) – Controlled for sanitation, household wealth,

education

• Bacteria in stored water not associated with diarrheal or respiratory illness

• Bacteria levels on hands associated with both diarrheal and respiratory illness

Conclusions

• Provision of improved, non-networked drinking water sources with high quality water did not ensure clean water at the household

• Hand contamination may have stronger effect on stored water quality than variation in water management practices (i.e. boiling, length of storage time)

• Successful hand hygiene interventions could improve drinking water quality in the home

Conclusions, cont. • For every 1- log increase in mean levels of

bacteria on hands, household was TEN times more likely to report diarrhea

• For every 1-log increase in hand bacteria, household was TWICE as likely to report respiratory illness

• Suggests hands are important transmission pathway for diarrheal and respiratory illness

Acknowledgments

Funding for this work was provided by the Woods Institute for the Environment and the Presidential Fund for Innovation in International Research, both of Stanford University.

We gratefully acknowledge the many contributions of our field team, The Community Water Supply & Sanitation Program of DAWASA, and the households participating in the study.

Further reading

A. J. Pickering, J. Davis, S. P. Walters, H. M. Horak, D. P. Keymer, D. Mushi, R. Strickfaden, J. S. Chynoweth, J. Liu, A. Blum, K. Rogers, A. B. Boehm. 2010. Hands, water, and health: fecal contamination in Tanzanian communities with improved, non-networked water supplies. Environmental Science & Technology DOI: 10.1021/es903524m.