Environmental Engineering Reference
In-Depth Information
Chapter 14
Solar Drinking Water Disinfection (SODIS) to
Reduce Childhood Diarrhea
Daniel Mäusezahl, Andri Christen, Gonzalo Duran Pacheco,
Fidel Alvarez Tellez, Mercedes Iriarte, Maria E. Zapata,
Myriam Cevallos, Jan Hattendorf, Monica Daigl Cattaneo,
Benjamin Arnold, Thomas A. Smith, and John M. Colford, Jr.
INTRODUCTION
Solar drinking water disinfection (SODIS) is a low-cost, point-of-use water purification
method that has been disseminated globally. Laboratory studies suggest that SODIS
is highly efficacious in inactivating waterborne pathogens. Previous field studies pro-
vided limited evidence for its effectiveness in reducing diarrhea.
We conducted a cluster-randomized controlled trial in 22 rural communities in
Bolivia to evaluate the effect of SODIS in reducing diarrhea among children under
the age of 5 year. A local nongovernmental organization (NGO) conducted a standard-
ized interactive SODIS-promotion campaign in 11 communities targeting households,
communities, and primary schools. Mothers completed a daily child health diary for
1 year. Within the intervention arm 225 households (376 children) were trained to ex-
pose water-fi lled polyethyleneteraphtalate (PET) bottles to sunlight. Eleven communi-
ties (200 households, 349 children) served as a control. We recorded 166,971 person-
days of observation during the trial representing 79.9% and 78.9% of the total possible
person-days of child observation in intervention and control arms, respectively. Mean
compliance with SODIS was 32.1%. The reported incidence rate (IR) of gastrointes-
tinal illness in children in the intervention arm was 3.6 compared to 4.3 episodes/year
at risk in the control arm. The relative rate (RR) of diarrhea adjusted for intracluster
correlation was 0.81 (95% confi dence interval (CI) 0.59-1.12). The median length of
diarrhea was 3 d in both groups.
Despite an extensive SODIS promotion campaign we found only moderate com-
pliance with the intervention and no strong evidence for a substantive reduction in
diarrhea among children. These results suggest that there is a need for better evidence
of how the well-established laboratory effi cacy of this home-based water treatment
method translates into fi eld effectiveness under various cultural settings and interven-
tion intensities. Further global promotion of SODIS for general use should be under-
taken with care until such evidence is available.
Globally, 1.8 million people die every year from diarrheal diseases the vast major-
ity of whom are children under the age of 5 year living in developing countries [1].
Unsafe water, sanitation, and hygiene are considered to be the most important global
risk factors for diarrheal illnesses [2].
 
 
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