Environ. Sci. Technol. 2009, 43, 5934–5939
Randomized Controlled Trial in Rural Ethiopia to Assess a Portable Water Treatment Device S O P H I E B O I S S O N , * ,† WOLF-PETER SCHMIDT,† TSEGAHIWOT BERHANU,‡ HENOCK GEZAHEGN,‡ AND THOMAS CLASEN† Department of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, Keppel Street, London, WC1E 7HT, United Kingdom, and Population Services International Ethiopia, Meskel flower road, P.O. Box 468 - code 1250, Addis Ababa, Ethiopia
Received January 26, 2009. Revised manuscript received May 12, 2009. Accepted May 15, 2009.
We conducted a randomized controlled trial to assess the Lifestraw Personal pipe-style water treatment device among a rural population in Ethiopia. A total of 313 households (including 1516 persons) were randomly assigned either to an intervention group in which each householder received a Lifestraw Personal or a control. Households were visited fortnightly over a five-month intervention period and asked to report any episode of diarrhea during the previous week. A random sample of 160 devices was tested each month to assess the presence of thermotolerant coliforms (TTC) and residual iodine in treated water and to measure flow rate under simulated use. Members of the intervention group had 25% fewer weeks with diarrhea than those of the control group (longitudinal prevalence ratio ) 0.75; 95% CI 0.60; 0.95). All 718 filtered water samples were free of TTC, were free of detectable iodine disinfectant, and showed a constant flow rate over time. After the five-month intervention period, 34% of participants reported use of device in the preceding week and 13% reported consistent use. While the device was associated with a 25% reduction in longitudinal prevalence of diarrhea, low levels of use suggest that much of this effect is likely to be attributable to reporting bias that is common in open trials with nonobjective outcomes.
Introduction An estimated 884 million people worldwide lack access to improved water sources (1). Even improved water supplies, however, such as wells, communal stand posts, and household connections often fail to deliver safe drinking water. Moreover, water of good quality at the source is subject to frequent and extensive fecal contamination during collection, transport, and storage in the home (2, 3). The World Health Organization (WHO) estimates that improving water, sanitation, and hygiene could prevent at least 9.1% of the global burden of disease and 6.3% of all deaths (4). Diarrhea represents a significant share of this * Corresponding author phone: (+44) 020 7958 8196; fax: (+44) 20 7636 7843; e-mail:
[email protected]. † London School of Hygiene and Tropical Medicine. ‡ Population Services International Ethiopia. 5934
9
ENVIRONMENTAL SCIENCE & TECHNOLOGY / VOL. 43, NO. 15, 2009
burden, resulting in an estimated 4 billion cases and 1.8 million deaths each year, mostly among young children in developing countries (5, 6). Studies have reported that treating water at the point of use (POU) improves the microbiological quality of drinking water and reduces the risk of diarrhea, particularly with higher levels of use (7, 8). The WHO has encouraged the development of new point-of-use water treatment technologies that are effective, affordable, and acceptable among populations who most need it (9). POU water treatment products designed for development and emergency settings include a variety of disinfection, filtration, flocculation, and hybrid products (10). Most of these products, however, are bulky or require contact time, making them less suitable for use outside the home. Experience with Guinea Worm filters has shown the need to provide such protection to vulnerable populations when not in the home (11). Vestergaard-Frandsen SA, the leading producer of Guinea Worm filters has developed a personal POU water treatment device known as the Lifestraw Personal. Like the Guinea Worm pipe filter, it is intended as a personal water treatment device that can protect users against waterborne pathogens whether or not they are at home where they may have access to safe drinking water. The device is designed to provide approximately 700 L of bacteriologically safe drinking water for approximately one year based on a minimum of 2 L of drinking water per person per day for basic hydration (12). A previous use and acceptability assessment in Ghana reported correct and consistent use by a vulnerable population and high levels of enthusiasm for the device (13). Here we report the results of the first randomized controlled trial to assess the impact of the filter on diarrheal disease, its microbiological performance, longevity in the field, and its acceptability among a population that do not have access to improved water sources for drinking.
Methods Study Setting. The study was conducted from October 2007 to June 2008 in Robe Gabia, a rural community located 50 km north of Addis Ababa, in the Oromiya region of Ethiopia. In Ethiopia, an estimated 60% of the rural population still lack access to improved water sources (14). Population Services International has been actively promoting POU water treatment products such as sodium hypochlorite solution in the country. The community was selected for the study because drinking water quality was an issue and use of effective water treatment methods was low. People relied mainly on agriculture and trading for their livelihood. Most people drank water from unprotected springs and rivers. Samples from twelve different water sources (10 springs and 2 streams) taken from around the study site revealed high levels of fecal contamination, with an arithmetic mean of 330 TTC/100 mL (range 0-1920 TTC/100 mL). Enrollment of Study Participants, Baseline Survey, and Random Allocation of Filter. Householders were eligible to participate in the study if (i) at least one member of the household worked away from home during the day in a setting without adequate water supply, and (ii) the household was not already practicing an effective POU water treatment method. Overall, 313 heads of eligible households volunteered to participate in the study and were enrolled after informed consent was secured. Five trained field investigators administered a standardized questionnaire to each head of household (female where possible) between October 25 and November 14, 2007. Baseline information was obtained on demographics, socio-economic characteristics, hygiene, 10.1021/es9000664 CCC: $40.75
2009 American Chemical Society
Published on Web 06/17/2009
sanitation, and water handling practices. Following completion of the survey, a lottery was organized to randomly allocate participants to two groups. Members of the intervention group each received a Lifestraw Personal filter while members of the control group were asked to continue their existing water management practices. We considered a blinded design, but no proven placebo was available. There were also ethical concerns that a device intended for use away from the home where other precautions could be taken might encourage behavior that would put members of the control group at greater risk. Intervention. The Lifestraw Personal is a portable device consisting of a 31 × 2.9 cm plastic pipe with a plastic mouthpiece on the proximal end. A lanyard is permanently affixed near the mouthpiece to allow the owner to carry the filter around the neck or hang it up when not in use. The device is used by inserting the distal end into untreated water and sucking on the mouthpiece. For children under 3 years, a 300 mL bottle with a snap on cap was affixed to the distal end of the filter so that they would simply fill up the bottle with untreated water and invert it like a baby bottle while sucking on the mouthpiece. The filter combines a 15 µm filter mesh with iodinated resin and granular activated carbon (GAC). Independent testing in the laboratory has shown the device to reduce waterborne bacteria by more than 6 logs (>99.9999) and viruses by 1.4-1.8 logs (95.6-98.2%), but showed very limited reduction in levels of waterborne parasitic cysts such as Cryptosporidium sp. and Giardia sp. (15). Testing has also confirmed that the water produced by the device contained no detectible residual iodine (
