Sanitary inspection of wells using risk-of-contamination scoring indicates a high predictive ability for bacterial faecal pollution in the peri-urban tropical lowlands of Dar es Salaam, Tanzania

Mushi, Douglas; Byamukama, Denis; Kirschner, Alexander K. T.; Mach, Robert L.; Brunner, Kurt; Farnleitner, Andreas H.

doi:10.2166/wh.2012.117

Cited by 35 publications

(35 citation statements)

References 15 publications

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“…To our knowledge, there have been no previous studies of ambiguity in water source classification and only one previous study of inter-observer agreement in sanitary risk observation, despite widespread use of sanitary risk protocols (Mushi et al 2012;Parker et al 2010;Snoad et al 2017) Table 3 Cross-tabulation of water source type classification made by the most experienced observer (JOO-rows) versus five less experienced observers (columns) for 80 water sources during the first visit Our inter-observer agreement study indicates that where households adopt strategies to cope with water insecurity, their sources proved difficult to classify unambiguously using the standard typology used for international monitoring (WHO/UNICEF 2006). Such strategies included construction of 'hybrid' sources to cope with water insecurity, such as water tanks that stored both rainwater and piped water to cope with the sporadic nature of rainwater and frequent interruptions to piped water.…”

Section: Discussionmentioning

confidence: 99%

An Assessment of Inter-Observer Agreement in Water Source Classification and Sanitary Risk Observations

Okotto-Okotto¹,

Wanza

Kwoba

et al. 2019

Expo Health

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Sanitary risk inspection, an observation protocol for identifying contamination hazards around water sources, is promoted for managing rural water supply safety. However, it is unclear how far different observers consistently identify contamination hazards and consistently classify water source types using standard typologies. This study aimed to quantify inter-observer agreement in hazard identification and classification of rural water sources. Six observers separately visited 146 domestic water sources in Siaya County, Kenya, in wet and dry seasons. Each observer independently classified the source type and conducted a sanitary risk inspection using a standard protocol. Water source types assigned by an experienced observer were cross-tabulated against those of his colleagues, as were contamination hazards identified, and inter-observer agreement measures calculated. Agreement between hazards observed by the most experienced observer versus his colleagues was significant but low (intra-class correlation = 0.49), with inexperienced observers detecting fewer hazards. Inter-observer agreement in classifying water sources was strong (Cohen's kappa = 0.84). However, some source types were frequently misclassified, such as sources adapted to cope with water insecurity (e.g. tanks drawing on both piped and rainwater). Observers with limited training and experience thus struggle to consistently identify hazards using existing protocols, suggesting observation protocols require revision and their implementation should be supported by comprehensive training. Findings also indicate that field survey teams struggle to differentiate some water source types based on a standard water source classification, particularly sources adapted to cope with water insecurity. These findings demonstrate uncertainties underpinning international monitoring and analyses of safe water access via household surveys.Publisher's Note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

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Section: Discussionmentioning

confidence: 99%

An Assessment of Inter-Observer Agreement in Water Source Classification and Sanitary Risk Observations

Okotto-Okotto¹,

Wanza

Kwoba

et al. 2019

Expo Health

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“…Similar studies of the associations between source water quality and sanitary surveys have produced contradictory results. 3,28,29 In Port Harcourt, 85% of the respondents in our rainy season sampling frame (N = 399) used flush or pour-flush toilets connected to septic tanks, with the remainder relying on sanitation that drained into surface waters. The high prevalence of septic tanks may explain both the relatively low levels of fecal contamination that we observed in groundwater samples during the dry season and the lack of distinct spatial patterns of microbial water quality (Supplemental Figure 3).…”

Section: Discussionmentioning

confidence: 99%

Seasonal Variation in Drinking and Domestic Water Sources and Quality in Port Harcourt, Nigeria

Kumpel¹,

Cock-Esteb²,

Duret

et al. 2017

The American Society of Tropical Medicine and Hygiene

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Abstract. We compared dry and rainy season water sources and their quality in the urban region of Port Harcourt, Nigeria. Representative sampling indicated that municipal water supplies represent < 1% of the water sources. Residents rely on privately constructed and maintained boreholes that are supplemented by commercially packaged bottled and sachet drinking water. Contamination by thermotolerant coliforms increased from 21% of drinking water sources in the dry season to 42% of drinking water sources in the rainy season (N = 356 and N = 397). The most significant increase was in sachet water, which showed the lowest frequencies of contamination in the dry season compared with other sources (15%, N = 186) but the highest frequencies during the rainy season (59%, N = 76). Only half as many respondents reported drinking sachet water in the rainy season as in the dry season. Respondents primarily used flush or pour-flush toilets connected to septic tanks (85%, N = 399). The remainder relied on pit latrines and hanging (pier) latrines that drained into surface waters. We found significant associations between fecal contamination in boreholes and the nearby presence of hanging latrines. Sanitary surveys of boreholes showed that more than half were wellconstructed, and we did not identify associations between structural or site deficiencies and microbial water quality. The deterioration of drinking water quality during the rainy season is a serious public health risk for both untreated groundwater and commercially packaged water, highlighting a need to address gaps in monitoring and quality control.

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“…These malpractices are not uncommon among people of diverse socio-cultural origins in rural settings of Tanzania. Limited water supply, lack of water treatment and contamination of water with pathogens [17–19] aggravates situation by increasing risks for Campylobacter infection both in human and animal populations.…”

Section: Introductionmentioning

confidence: 99%

Epidemiology and RAPD-PCR typing of thermophilic campylobacters from children under five years and chickens in Morogoro Municipality, Tanzania

et al. 2016

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Background: Campylobacter species are gram negative and flagellated bacteria under the genus Campylobacter, family Campylobacteriaceae. These pathogens cause zoonotic infections among human and animal populations. This study was undertaken between December 2006 and May 2007 to determine prevalence, risk factors and genetic diversity of thermophilic Campylobacter isolates from children less than 5 years and chickens in Morogoro Municipality, Tanzania. Methods: The Skirrow's protocol was used for isolation and identification of Campylobacter from 268 human stool specimens and 419 chicken cloacal swabs. Patient biodata and risk factors associated with human infection were also collected. Genetic diversity of Campylobacter isolates was determined by a RAPD-PCR technique using OPA 11 primer (5′-CAA TCG CCG T-3′). Phylogenetic analysis and band pattern comparison were done by Bionumerics software and visual inspection. Results: Stool samples from 268 children and 419 cloacal swabs from chickens were analyzed. Prevalence of thermophilic Campylobacters in children was 19% with higher isolation frequency (p = 0.046) in males (23.5%) than females (13.8%). Campylobacter jejuni (78.4%) was more isolated (p = 0.000) than C. coli (19.6%) and 2% were unidentified isolates. In chickens, the prevalence was 42.5% with higher isolation rate (p = 0.000) of C. jejuni (87%) than C. coli (13%). Campylobacters were more frequently recovered (p = 0.000) from indigenous/ local chickens (75. 0%) followed by cockerels (52.2%), broilers (50.0%) and lowest in layers (22.7%). Keeping chickens without other domestic animals concurrently (p = 0.000), chicken types (p = 0.000) and flock size (p = 0.007) were risk factors for infection in chickens. One hundred and fifty two (152) thermophillic Campylobacter isolates were genotyped by RAPD-PCR of which 114 were C. jejuni (74 from chickens and 40 humans) and 38 C. coli (28 from chickens and 10 humans). Comparison of Campylobacter isolates from children and chickens revealed high diversity with only 6.1% of C. jejuni and 5.3% of C. coli being 100% genetically similar.

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Sanitary inspection of wells using risk-of-contamination scoring indicates a high predictive ability for bacterial faecal pollution in the peri-urban tropical lowlands of Dar es Salaam, Tanzania

Cited by 35 publications

References 15 publications

An Assessment of Inter-Observer Agreement in Water Source Classification and Sanitary Risk Observations

An Assessment of Inter-Observer Agreement in Water Source Classification and Sanitary Risk Observations

Seasonal Variation in Drinking and Domestic Water Sources and Quality in Port Harcourt, Nigeria

Epidemiology and RAPD-PCR typing of thermophilic campylobacters from children under five years and chickens in Morogoro Municipality, Tanzania

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