TY - JOUR
T1 - The effectiveness of sanitary inspections as a risk assessment tool for thermotolerant coliform bacteria contamination of rural drinking water
T2 - A review of data from West Bengal, India
AU - Snoad, Christian
AU - Nagel, Corey
AU - Bhattacharya, Animesh
AU - Thomas, Evan
N1 - Publisher Copyright:
© 2017 by The American Society of Tropical Medicine and Hygiene.
PY - 2017
Y1 - 2017
N2 - The use of sanitary inspections combined with periodic water quality testing has been recommended in some cases as screening tools for fecal contamination. We conducted sanitary inspections and tested for thermotolerant coliforms (TTCs), a fecal indicator bacteria, among 7,317 unique water sources in West Bengal, India. Our results indicate that the sanitary inspection score has poor ability to identify TTC-contaminated sources. Among deep and shallow hand pumps, the area under curve (AUC) for prediction of TTC > 0 was 0.58 (95% confidence interval [CI] = 0.53-0.61) and 0.58 (95% CI = 0.54-0.62), respectively, indicating that the sanitary inspection score was only marginally better than chance in discriminating between contaminated and uncontaminated sources of this type. A slightly higher AUC value of 0.64 (95% CI=0.57-0.71) was observed when the sanitary inspection score was used for prediction of TTC > 0 among the gravity-fed piped sources. Among unprotected springs (AUC = 0.48, 95% CI = 0.38-0.55) and unprotected dug wells (AUC = 0.41, 95% CI = 0.20-0.66), the sanitary inspection score performed more poorly than chance in discriminating between sites with TTC < 1 and TTC > 0. Aggregating over all source types, the sensitivity (true positive rate) of a high/very high sanitary inspection score for TTC contamination (TTC > 1 CFU/100 mL) was 29.4% and the specificity (true negative rate) was 77.9%, resulting in substantial misclassification of the sites when using the established risk categories. These findings suggest that sanitary surveys are inappropriate screening tools for identifying TTC contamination at water points.
AB - The use of sanitary inspections combined with periodic water quality testing has been recommended in some cases as screening tools for fecal contamination. We conducted sanitary inspections and tested for thermotolerant coliforms (TTCs), a fecal indicator bacteria, among 7,317 unique water sources in West Bengal, India. Our results indicate that the sanitary inspection score has poor ability to identify TTC-contaminated sources. Among deep and shallow hand pumps, the area under curve (AUC) for prediction of TTC > 0 was 0.58 (95% confidence interval [CI] = 0.53-0.61) and 0.58 (95% CI = 0.54-0.62), respectively, indicating that the sanitary inspection score was only marginally better than chance in discriminating between contaminated and uncontaminated sources of this type. A slightly higher AUC value of 0.64 (95% CI=0.57-0.71) was observed when the sanitary inspection score was used for prediction of TTC > 0 among the gravity-fed piped sources. Among unprotected springs (AUC = 0.48, 95% CI = 0.38-0.55) and unprotected dug wells (AUC = 0.41, 95% CI = 0.20-0.66), the sanitary inspection score performed more poorly than chance in discriminating between sites with TTC < 1 and TTC > 0. Aggregating over all source types, the sensitivity (true positive rate) of a high/very high sanitary inspection score for TTC contamination (TTC > 1 CFU/100 mL) was 29.4% and the specificity (true negative rate) was 77.9%, resulting in substantial misclassification of the sites when using the established risk categories. These findings suggest that sanitary surveys are inappropriate screening tools for identifying TTC contamination at water points.
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U2 - 10.4269/ajtmh.16-0322
DO - 10.4269/ajtmh.16-0322
M3 - Review article
C2 - 28115676
AN - SCOPUS:85017264534
SN - 0002-9637
VL - 96
SP - 976
EP - 983
JO - American Journal of Tropical Medicine and Hygiene
JF - American Journal of Tropical Medicine and Hygiene
IS - 4
ER -