Waterborne exposure during non-consumptive domestic use of surface water: a population study across WASH service levels in rural India.

Exposure to pathogens from domestic use of surface water is understudied. In many low- and middle-income countries, surface water is used for hygiene, sanitation, amenity, and recreational purposes. In this study, self-reported use of and structured observations at community ponds were collected to measure waterborne exposure across water and sanitation service levels in a rural population of Khorda District, India. Overall, 86% of households (n = 200) reported using ponds on a regular basis. Among observed people (n = 765), 82% put water into their mouth at least once, with a median frequency of five occurrences per visit. Reported and observation data were combined to estimate the proportion (p) of the population that put water in their mouth at least once per day, and their mean daily rate of oral exposure (OE). These were highest for individuals with neither safely managed water nor basic sanitation access (p = 93%, OE = 14 day-1), but still high among those with both (p = 67%, OE = 6 day-1). The results suggest widespread exposure to waterborne pathogens in settings where non-potable surface water bodies continue to be used for domestic purposes, even among households with access to safely managed drinking water.

Estimating Cryptosporidium and Giardia disease burdens for children drinking untreated groundwater in a rural population in India.

BACKGROUND: In many low-income settings, despite improvements in sanitation and hygiene, groundwater sources used for drinking may be contaminated with enteric pathogens such as Cryptosporidium and Giardia, which remain important causes of childhood morbidity. In this study, we examined the contribution of diarrhea caused by Cryptosporidium and Giardia found in groundwater sources used for drinking to the total burden of diarrheal disease among children < 5 in rural India. METHODOLOGY/PRINCIPAL FINDINGS: We studied a population of 3,385 children < 5 years of age in 100 communities of Puri District, Odisha, India. We developed a coupled quantitative microbial risk assessment (QMRA) and susceptible-infected-recovered (SIR) population model based on observed levels of Cryptosporidium and Giardia in improved groundwater sources used for drinking and compared the QMRA-SIR estimates with independently measured all-cause (i.e., all fecal-oral enteric pathogens and exposure pathways) child diarrhea prevalence rates observed in the study population during two monsoon seasons (2012 and 2013). We used site specific and regional studies to inform assumptions about the human pathogenicity of the Cryptosporidium and Giardia species present in local groundwater. In all three human pathogenicity scenarios evaluated, the mean daily risk of Cryptosporidium or Giardia infection (0.06-1.53%), far exceeded the tolerable daily risk of infection from drinking water in the US (< 0.0001%). Depending on which protozoa species were present, median estimates of daily child diarrhea prevalence due to either Cryptosporidium or Giardia infection from drinking water was as high as 6.5% or as low as < 1% and accounted for at least 2.9% and as much as 65.8% of the all-cause diarrhea disease burden measured in children < 5 during the study period. Cryptosporidium tended to account for a greater share of estimated waterborne protozoa infections causing diarrhea than did Giardia. Diarrhea prevalence estimates for waterborne Cryptosporidium infection appeared to be most sensitive to assumptions about the probability of infection from ingesting a single parasite (i.e. the rate parameter in dose-response model), while Giardia infection was most sensitive to assumptions about the viability of parasites detected in groundwater samples. CONCLUSIONS/SIGNIFICANCE: Protozoa in groundwater drinking sources in rural India, even at low concentrations, especially for Cryptosporidium, may account for a significant portion of child diarrhea morbidity in settings were tubewells are used for drinking water and should be more systematically monitored. Preventing diarrheal disease burdens in Puri District and similar settings will benefit from ensuring water is microbiologically safe for consumption and consistent and effective household water treatment is practiced.

Processes and challenges of community mobilisation for latrine promotion under Nirmal Bharat Abhiyan in rural Odisha, India.

BACKGROUND: Despite efforts to eradicate it, open defecation remains widely practiced in India, especially in rural areas. Between 2013 and 2014, 50 villages in one district of Odisha, India, received a sanitation programme under the Nirmal Bharat Abhiyan (NBA - "Clean India Campaign"), the successor of India's Total Sanitation Campaign. This paper documents the strategies and processes of NBA community mobilisation for latrine promotion in these villages and assesses the strengths and limitations of the mobilisation activities. METHODS: NBA's community mobilisation activities were observed and assessed against the programme's theory of change in 10 randomly selected programme villages from start to finish. Additional data was collected through review of documents, individual interviews (n = 80) and focus group discussions (n = 26) with staff of the implementing NGOs and community members. RESULTS: Our study revealed the lack of a consistent implementation strategy, lack of capacities and facilitation skills of NGO staff to implement sanitation programmes, political interference, challenges in accessing government financial incentives for latrine construction, and lack of clarity on the roles and responsibilities among government and NGO staff, leading to failure in translating government policies into sustainable actions. Social divisions and village dynamics related to gender and caste further constrained the effectiveness of mobilisation activities. Meetings were often dominated by male members of upper caste households, and excluded low caste community members and views of women. Community discussions revolved largely around the government's cash incentive for latrines. Activities aimed at creating demand for sanitation and use of latrines often resonated poorly with community members. An assessment by the implementers, 1 year after community mobilisation found 19% of households had a completed latrine across the 50 villages, a marginal increase of 7 percentage points over baseline. CONCLUSIONS: In this setting, the Government of India's NBA programme to increase rural sanitation coverage and use is hampered by political, programmatic, logistical and socio-structural constraints. Sanitation demand generation was difficult for local implementing NGOs as village populations had lost trust in organisations due to previous indications of fraud. Agencies or organisations implementing sanitation campaigns and conducting sanitation promotions need to enhance their staff's knowledge and build capacity in order to address important social heterogeneity within villages. This trial's registration number is NCT01214785 (October 4, 2010).

Adopt or Adapt: Sanitation Technology Choices in Urbanizing Malawi.

This paper presents the results of a mixed-methods study examining adaptation strategies that property owners in low-income, rapidly urbanizing areas in Malawi adopt to address the limitations of pit latrines, the most common method of disposing human excreta. A particular challenge is lack of space for constructing new latrines as population density increases: traditional practice has been to cap full pits and simply move to a new site, but increasing demands on space require new approaches to extend the service life of latrines. In this context, we collected data on sanitation technology choices from January to September 2013 through 48 in-depth interviews and a stated preference survey targeting 1,300 property owners from 27 low-income urban areas. Results showed that property owners with concern about space for replacing pit latrines were 1.8 times more likely to select pit emptying service over the construction of new pit latrines with a slab floor (p = 0.02) but there was no significant association between concern about space for replacing pit latrines and intention to adopt locally promoted, novel sanitation technology known as ecological sanitation (ecosan). Property owners preferred to adapt existing, known technology by constructing replacement pit latrines on old pit latrine locations, reducing the frequency of replacing pit latrines, or via emptying pit latrines when full. This study highlights potential challenges to adoption of wholly new sanitation technologies, even when they present clear advantages to end users. To scale, alternative sanitation technologies for rapidly urbanising cities should offer clear advantages, be affordable, be easy to use when shared among multiple households, and their design should be informed by existing adaptation strategies and local knowledge.

Modeling Cryptosporidium and Giardia in Ground and Surface Water Sources in Rural India: Associations with Latrines, Livestock, Damaged Wells, and Rainfall Patterns.

Surface and groundwater contamination with fecal pathogens is a public health concern especially in low-income settings where these sources are used untreated. We modeled observed Cryptosporidium and Giardia contamination in community ponds (n = 94; 79% contaminated), deep tubewells (DTWs) (n = 107; 17%), and shallow tubewells (STWs) (n = 96; 19%) during the 2012 and 2013 monsoon seasons (June-August) in 60 villages in Puri District, India to understand sources and processes of contamination. Detection of Cryptosporidium and/or Giardia in a tubewell was positively associated with damage to the well pad for DTWs, the amount of human loading into pour-flush latrine pits nearby (≤15 m) for STWs, and the village literacy rate (for Giardia in STWs). Pond concentration levels were positively associated with the number of people practicing open defecation within 50 m and the sheep population for Cryptosporidium, and with the village illiteracy rate for Giardia. Recent rainfall increased the risk of Cryptosporidium in STWs (an extreme event) and ponds (any), while increasing seasonal rainfall decreased the risk of Giardia in STWs and ponds. Full latrine coverage in this setting is expected to marginally reduce pond Cryptosporidium contamination (16%) while increasing local groundwater protozoal contamination (87-306%), with the largest increases predicted for Cryptosporidium in STWs.

Human fecal and pathogen exposure pathways in rural Indian villages and the effect of increased latrine coverage.

Efforts to eradicate open defecation and improve sanitation access are unlikely to achieve health benefits unless interventions reduce microbial exposures. This study assessed human fecal contamination and pathogen exposures in rural India, and the effect of increased sanitation coverage on contamination and exposure rates. In a cross-sectional study of 60 villages of a cluster-randomized controlled sanitation trial in Odisha, India, human and domestic animal fecal contamination was measured in community tubewells and ponds (n = 301) and via exposure pathways in homes (n = 354), using Bacteroidales microbial source tracking fecal markers validated in India. Community water sources were further tested for diarrheal pathogens (rotavirus, adenovirus and Vibrio cholerae by quantitative PCR; pathogenic Escherichia coli by multiplex PCR; Cryptosporidium and Giardia by immunomagnetic separation and direct fluorescent antibody microscopy). Exposure pathways in intervention and control villages were compared and relationships with child diarrhea examined. Human fecal markers were rarely detected in tubewells (2.4%, 95%CI: 0.3-4.5%) and ponds (5.6%, 95%CI: 0.8-10.3%), compared to homes (35.4%, 95%CI: 30.4-40.4%). In tubewells, V. cholerae was the most frequently detected pathogen (19.8%, 95%CI: 14.4-25.2%), followed by Giardia (14.8%, 95%CI: 10.0-19.7%). In ponds, Giardia was most often detected (74.5%, 95%CI: 65.7-83.3%), followed by pathogenic E. coli (48.1%, 95%CI: 34.8-61.5%) and rotavirus (44.4%, 95%CI: 34.2-54.7%). At village-level, prevalence of fecal pathogen detection in community drinking water sources was associated with elevated prevalence of child diarrhea within 6 weeks of testing (RR 2.13, 95%CI: 1.25-3.63) while within homes, higher levels of human and animal fecal marker detection were associated with increased risks of subsequent child diarrhea (P = 0.044 and 0.013, respectively). There was no evidence that the intervention, which increased functional latrine coverage and use by 27 percentage points, reduced human fecal contamination in any tested pathway, nor the prevalence of pathogens in water sources. In conclusion, the study demonstrates that (1) improved sanitation alone may be insufficient and further interventions needed in the domestic domain to reduce widespread human and animal fecal contamination observed in homes, (2) pathogens detected in tubewells indicate these sources are microbiologically unsafe for drinking and were associated with child diarrhea, (3) domestic use of ponds heavily contaminated with multiple pathogens presents an under-recognized health risk, and (4) a 27 percentage point increase in improved sanitation access at village-level did not reduce detectable human fecal and pathogen contamination in this setting.

Infant and Young Child Feces Management and Enabling Products for Their Hygienic Collection, Transport, and Disposal in Cambodia.

In Cambodia, children's feces are rarely disposed of in an improved sanitation facility. This study examines current practices and the role that enabling products may play in increasing hygienic management of infant and young child (IYC) feces in households with access to improved sanitation. A survey was conducted with the primary caregiver of a child under 5 years of age in 130 homes with an improved latrine in 21 villages across two provinces in Cambodia. Two focus group discussions per province were conducted after the survey to obtain caregiver feedback on new enabling products for hygienic management. Among caregivers, 63% reported child feces disposal in an improved latrine but only 36% reported doing so consistently. Besides child age, years of latrine ownership, caregiver age, consistency of adult latrine use, and presence of child feces management tools in the latrine were associated with hygienic disposal. The youngest caretakers with the newest latrines and youngest children were least likely to dispose of IYC feces hygienically, representing a key target group for interventions to improve hygienic disposal in Cambodia. Reusable diapers, child-friendly potties, and possibly latrine seats, that offer child safety, time and cost savings, and easy disposal and cleaning could potentially facilitate hygienic disposal for these ages.

Socio-cultural and behavioural factors constraining latrine adoption in rural coastal Odisha: an exploratory qualitative study.

BACKGROUND: Open defecation is widely practiced in India. To improve sanitation and promote better health, the Government of India (GOI) has instituted large scale sanitation programmes supporting construction of public and institutional toilets and extending financial subsidies for poor families in rural areas for building individual household latrines. Nevertheless, many household latrines in rural India, built with government subsidies and the facilitation and support of non-government organizations (NGO), remain unused. Literature on social, cultural and behavioural aspects that constrain latrine adoption and use in rural India is limited. This paper examines defecation patterns of different groups of people in rural areas of Odisha state in India to identify causes and determinants of latrine non-use, with a special focus on government-subsidized latrine owners, and shortcomings in household sanitation infrastructure built with government subsidies. METHODS: An exploratory study using qualitative methods was conducted in rural communities in Odisha state. Methods used were focus group discussions (FGDs), and observations of latrines and interviews with their owners. FGDs were held with frontline NGO sanitation program staff, and with community members, separately by caste, gender, latrine type, and age group. Data were analysed using a thematic framework and approach. RESULTS: Government subsidized latrines were mostly found unfinished. Many counted as complete per government standards for disbursement of financial subsidies to contracted NGOs were not accepted by their owners and termed as 'incomplete'. These latrines lacked a roof, door, adequate walls and any provision for water supply in or near the cabin, whereas rural people had elaborate processes of cleansing with water post defecation, making presence of a nearby water source important. Habits, socialising, sanitation rituals and daily routines varying with caste, gender, marital status, age and lifestyle, also hindered the adoption of latrines. Interest in constructing latrines was observed among male heads for their female members especially a newlywed daughter-in-law, reflecting concerns for their privacy, security, and convenience. This paper elaborates on these different factors. CONCLUSIONS: Findings show that providing infrastructure does not ensure use when there are significant and culturally engrained behavioural barriers to using latrines. Future sanitation programmes in rural India need to focus on understanding and addressing these behavioural barriers.

Human and Animal Fecal Contamination of Community Water Sources, Stored Drinking Water and Hands in Rural India Measured with Validated Microbial Source Tracking Assays.

We examined pathways of exposure to fecal contamination of human and animal origin in 24 villages in Odisha, India. In a cross-sectional study during the monsoon season, fecal exposure via community water sources (N = 123) and in the home (N = 137) was assessed using human- and nonhuman-associated Bacteroidales microbial source tracking (MST) markers and fecal coliforms (FCs). Detection rates and marker concentrations were examined to pinpoint pathways of human fecal exposure in the public and domestic domains of disease transmission in study communities. Human fecal markers were detected much more frequently in the domestic domain (45% of households) than in public domain sources (8% of ponds; 4% of groundwater drinking sources). Animal fecal markers were widely detected in both domains (74% of ponds, 96% of households, 10% of groundwater drinking sources), indicating ubiquitous risks of exposure to animal feces and zoonotic pathogens. This study confirms an often suggested contamination link from hands to stored water in the home in developing countries separately for mothers' and children's hands and both human and animal fecal contamination. In contrast to MST markers, FCs provided a poor metric to assess risks of exposure to fecal contamination of human origin in this rural setting.

Cryptosporidium and Giardia in Humans, Domestic Animals, and Village Water Sources in Rural India.

Cryptosporidium parvum and Giardia lamblia are zoonotic enteric protozoa of significant health concern where sanitation, hygiene, and water supplies are inadequate. We examined 85 stool samples from diarrhea patients, 111 pooled fecal samples by species across seven domestic animal types, and water from tube wells (N = 207) and ponds (N = 94) across 60 villages in coastal Odisha, India, for Cryptosporidium oocysts and Giardia cysts to measure occurrence, concentration/shedding, and environmental loading rates. Oocysts/cysts were detected in 12% of diarrhea patients. Detection ranged from 0% to 35% for Cryptosporidium and 0% to 67% for Giardia across animal hosts. Animal loading estimates indicate the greatest contributors of environmental oocysts/cysts in the study region are cattle. Ponds were contaminated with both protozoa (oocysts: 37%, cysts: 74%), as were tube wells (oocysts: 10%, cysts: 14%). Future research should address the public health concern highlighted from these findings and investigate the role of domestic animals in diarrheal disease transmission in this and similar settings.

Pit latrine emptying behavior and demand for sanitation services in Dar Es Salaam, Tanzania.

Pit latrines are the main form of sanitation in unplanned areas in many rapidly growing developing cities. Understanding demand for pit latrine fecal sludge management (FSM) services in these communities is important for designing demand-responsive sanitation services and policies to improve public health. We examine latrine emptying knowledge, attitudes, behavior, trends and rates of safe/unsafe emptying, and measure demand for a new hygienic latrine emptying service in unplanned communities in Dar Es Salaam (Dar), Tanzania, using data from a cross-sectional survey at 662 residential properties in 35 unplanned sub-wards across Dar, where 97% had pit latrines. A picture emerges of expensive and poor FSM service options for latrine owners, resulting in widespread fecal sludge exposure that is likely to increase unless addressed. Households delay emptying as long as possible, use full pits beyond what is safe, face high costs even for unhygienic emptying, and resort to unsafe practices like 'flooding out'. We measured strong interest in and willingness to pay (WTP) for the new pit emptying service at 96% of residences; 57% were WTP≥U.S. $17 to remove ≥200 L of sludge. Emerging policy recommendations for safe FSM in unplanned urban communities in Dar and elsewhere are discussed.

Validation of Bacteroidales quantitative PCR assays targeting human and animal fecal contamination in the public and domestic domains in India.

We compared host-associated Bacteroidales qPCR assays developed in the continental United States and Europe for the purpose of measuring the effect of improved sanitation on human fecal exposure in rural Indian communities where both human and animal fecal loading are high. Ten candidate Bacteroidales qPCR assays were tested against fecal samples (human, sewage, cow, buffalo, goat, sheep, dog and chicken) from a test set of 30 individual human, 5 sewage, and 60 pooled animal samples collected in coastal Odisha, India. The two universal/general Bacteroidales assays tested (BacUni, GenBac3) performed equally well, achieving 100% sensitivity on the test set. Across the five human-associated assays tested (HF183 Taqman, BacHum, HumM2, BacH, HF183 SYBR), we found low sensitivity (17 to 49%) except for HF183 SYBR (89%), and moderate to high cross-reactivity with dog (20 to 80%) and chicken fecal samples (60 to 100%). BacHum had the highest accuracy (67%), amplified all sewage samples within the range of quantification (ROQ), and did not cross-react with any fecal samples from cows, the most populous livestock animal in India. Of the ruminant- and cattle-associated assays tested (BacCow, CowM2), BacCow was more sensitive in detecting the full range of common Indian livestock animal fecal sources, while CowM2 only detected cow sources with 50% sensitivity. Neither assay cross-reacted with human sources. BacCan, the dog-associated assay tested, showed no cross-reactivity with human sources, and high sensitivity (90%) for dog fecal samples. Overall, our results indicate BacUni, BacHum, HumM2, BacCan and BacCow would be the most suitable MST assays to distinguish and quantify relative amounts of human-associated and livestock/domestic animal-associated contributions to fecal contamination in Odisha, India.

Measuring the safety of excreta disposal behavior in India with the new Safe San Index: reliability, validity and utility.

Methods to assess household excreta disposal practices are critical for informing public health outcomes of efforts to improve sanitation in developing countries. We present a new metric, the Safe San Index (SSI), to quantify the hygienic safety of a household's defecation and human feces disposal practices in India, where behavioral outcomes from on-going public expenditures to construct household sanitation facilities and eliminate open defecation are poorly measured. We define hygienic safety of feces disposal as capture in a hygienic sanitation facility. The SSI consists of 15 self-report items and two sub-scales, Latrine Use Frequency and Seven-Day Open Defecation Rate. Households are scored on a standardized scale from 0 (no defecation safely captured) to 100 (all defecation safely captured). We present results of a pilot study in Odisha, India to apply the Index to assess excreta disposal behaviors among rural households and evaluate the reliability and validity of the Index for estimating the rate of correct and consistent sanitation facility usage of household with an improved latrine.

Opportunities to improve domestic hygiene practices through new enabling products: a study of handwashing practices and equipment in rural Cambodia.

BACKGROUND: Lack of a dedicated place and equipment for handwashing has been associated with poor practice of handwashing with soap in the home in developing communities where the practice is needed to reduce diarrhea diseases and respiratory infections. METHODS: We conducted formative research on handwashing knowledge, attitudes, practices and equipment and investigated the need and demand for dedicated handwashing equipment to enable improved hygiene practices and enhance handwashing performance for health in rural Cambodian homes where water is collected and stored. Responses to closed and open-ended questions and structured observation of a demonstration of handwashing by the mother or another female adult child caretaker in 79 households were used to identify handwashing occasions, evaluate handwashing equipment and competency, investigate attitudes and structural barriers to handwashing with soap, and assess use of and interest in dedicated handwashing equipment. RESULTS: We found significant evidence of the need for handwashing enabling equipment to eliminate unsafe domestic water handling during handwashing and reduce structural barriers to routine handwashing with soap in Cambodian homes dependent on stored water supplies. Substantial interest in dedicated handwashing equipment and in specific equipment features was measured. CONCLUSIONS: Findings suggest household demand for and uptake of affordable household handwashing facilities incorporating desired features and functionality could be generated in Cambodia to support improved domestic hygiene practices.

Relative benefits of on-plot water supply over other 'improved' sources in rural Vietnam.

OBJECTIVE: Access to improved water sources is rapidly expanding in rural central Vietnam. We examined one NGO-led piped water supply programme to assess the drinking water quality and health impacts of piped water systems where access to 'improved' water sources is already good. METHODS: This longitudinal, prospective cohort study followed 300 households in seven project areas in Da Nang province, Vietnam: 224 households who paid for an on-plot piped water connection and 76 control households from the same areas relying primarily on 'improved' water sources outside the home. The 4-month study was intended to measure the impact of the NGO-led water programmes on households' drinking water quality and health and to evaluate system performance. RESULTS: We found that: (i) households connected to a piped water supply had consistently better drinking water quality than those relying on other sources, including 'improved' sources and (ii) connected households experienced less diarrhoea than households without a piped water connection (adjusted longitudinal prevalence ratio: 0.57 (95% CI 0.39-0.86, P = 0.006) and households using an 'improved' source not piped to the plot: (adjusted longitudinal prevalence ratio: 0.59 (95% CI 0.39-0.91, P = 0.018). CONCLUSIONS: Our results suggest that on-plot water service yields benefits over other sources that are considered 'improved' by the WHO/UNICEF Joint Monitoring Programme.

Bacterial, viral and turbidity removal by intermittent slow sand filtration for household use in developing countries: experimental investigation and modeling.

A two-factor three-block experimental design was developed to permit rigorous evaluation and modeling of the main effects and interactions of sand size (d(10) of 0.17 and 0.52 mm) and hydraulic head (10, 20, and 30 cm) on removal of fecal coliform (FC) bacteria, MS2 bacteriophage virus, and turbidity, under two batch operating modes ('long' and 'short') in intermittent slow sand filters (ISSFs). Long operation involved an overnight pause time between feeding of two successive 20 L batches (16 h average batch residence time (RT)). Short operation involved no pause between two 20 L batch feeds (5h average batch RT). Conditions tested were representative of those encountered in developing country field settings. Over a ten week period, the 18 experimental filters were fed river water augmented with wastewater (influent turbidity of 5.4-58.6 NTU) and maintained with the wet harrowing method. Linear mixed modeling allowed systematic estimates of the independent marginal effects of each independent variable on each performance outcome of interest while controlling for the effects of variations in a batch's actual residence time, days since maintenance, and influent turbidity. This is the first study in which simultaneous measurement of bacteria, viruses and turbidity removal at the batch level over an extended duration has been undertaken with a large number of replicate units to permit rigorous modeling of ISSF performance variability within and across a range of likely filter design configurations and operating conditions. On average, the experimental filters removed 1.40 log fecal coliform CFU (SD 0.40 log, N=249), 0.54 log MS2 PFU (SD 0.42 log, N=245) and 89.0 percent turbidity (SD 6.9 percent, N=263). Effluent turbidity averaged 1.24 NTU (SD 0.53 NTU, N=263) and always remained below 3 NTU. Under the best performing design configuration and operating mode (fine sand, 10 cm head, long operation, initial HLR of 0.01-0.03 m/h), mean 1.82 log removal of bacteria (98.5%) and mean 0.94 log removal of MS2 viruses (88.5%) were achieved. Results point to new recommendations regarding filter design, manufacture, and operation for implementing ISSFs in local settings in developing countries. Sand size emerged as a critical design factor on performance. A single layer of river sand used in this investigation demonstrated removals comparable to those reported for 2 layers of crushed sand. Pause time and increased residence time each emerged as highly beneficial for improving removal performance on all four outcomes. A relatively large and significant negative effect of influent turbidity on MS2 viral removal in the ISSF was measured in parallel with a much smaller weaker positive effect of influent turbidity on FC bacterial removal. Disturbance of the schmutzdecke by wet harrowing showed no effect on virus removal and a modest reductive effect on the bacterial and turbidity removal as measured 7 days or more after the disturbance. For existing coarse sand ISSFs, this research indicates that a reduction in batch feed volume, effectively reducing the operating head and increasing the pore:batch volume ratio, could improve their removal performance by increasing batch residence time.

Interventions to improve disposal of human excreta for preventing diarrhoea.

BACKGROUND: Diarrhoeal diseases are a leading cause of mortality and morbidity, especially among young children in low-income countries, and are associated with exposure to human excreta. OBJECTIVES: To assess the effectiveness of interventions to improve the disposal of human excreta for preventing diarrhoeal diseases. SEARCH STRATEGY: We searched the Cochrane Infectious Disease Group Specialized Register; the Cochrane Central Register of Controlled Trials (CENTRAL), published in The Cochrane Library; MEDLINE; EMBASE; LILACS; the metaRegister of Controlled Trials (mRCT); and Chinese-language databases available under the Wan Fang portal, and the China National Knowledge Infrastructure (CNKI-CAJ). We also handsearched relevant conference proceedings, and contacted researchers and organizations working in the field, as well as checking references from identified studies. SELECTION CRITERIA: Randomized, quasi-randomized, and non-randomized controlled trials (RCTs) were selected, comparing interventions aimed at improving the disposal of human excreta to reduce direct or indirect human contact with no such intervention. Cluster (eg at the level of household or community) controlled trials were included. DATA COLLECTION AND ANALYSIS: We determined study eligibility, extracted data, and assessed methodological quality in accordance with the methods prescribed by the protocol. We described the results and summarized the information in tables. Due to substantial heterogeneity among the studies in terms of study design and type of intervention, no pooled effects were calculated. MAIN RESULTS: Thirteen studies from six countries covering over 33,400 children and adults in rural, urban, and school settings met the review's inclusion criteria. In all studies the intervention was allocated at the community level. While the studies reported a wide range of effects, 11 of the 13 studies found the intervention was protective against diarrhoea. Differences in study populations and settings, in baseline sanitation levels, water, and hygiene practices, in types of interventions, study methodologies, compliance and coverage levels, and in case definitions and outcome surveillance limit the comparability of results of the studies included in this review. The validity of most individual study results are further compromised by the non-random allocation of the intervention among study clusters, an insufficient number of clusters, the lack of adjustment for clustering, unclear loss to follow-up, potential for reporting bias and other methodological shortcomings. AUTHORS' CONCLUSIONS: This review provides some evidence that interventions to improve excreta disposal are effective in preventing diarrhoeal disease. However, this conclusion is based primarily on the consistency of the evidence of beneficial effects. The quality of the evidence is generally poor and does not allow for quantification of any such effect. The wide range of estimates of the effects of the intervention may be due to clinical and methodological heterogeneity among the studies, as well as to other important differences, including exposure levels, types of interventions, and different degrees of observer and respondent bias. Rigorous studies in multiple settings are needed to clarify the potential effectiveness of excreta disposal on diarrhoea.

Modelling latrine diffusion in Benin: towards a community typology of demand for improved sanitation in developing countries.

Latrine diffusion patterns across 502 villages in Benin, West Africa, were analysed to explore factors driving initial and increasing levels of household adoption in low-coverage rural areas of sub-Saharan Africa. Variables explaining adoption related to population density, size, infrastructure/services, non-agricultural occupations, road and urban proximity, and the nearby latrine adoption rate, capturing differences in the physical and social environment, lifestyles and latrine exposure involved in stimulating status/prestige and well-being reasons for latrine adoption. Contagion was most important in explaining adoption initiation. Cluster analysis revealed four distinct village typologies of demand for latrines which provide a framework for tailoring promotional interventions to better match the different sanitation demand characteristics of communities in scaling-up sanitation development and promotion programmes.

Intermittent slow sand filtration for preventing diarrhoea among children in Kenyan households using unimproved water sources: randomized controlled trial.

OBJECTIVE: Measure effectiveness of intermittent slow sand filtration for reducing child diarrhoea among households using unimproved water sources in rural Kenya. METHODS: A randomized controlled trail was conducted among populations meeting a high-risk profile for child diarrhoea from drinking river water in the River Njoro watershed. Intervention households (30) were provided the concrete BioSand Filter and instructed on filter use and maintenance. Control households (29) continued normal practices. Longitudinal monthly monitoring of diarrhoea (seven-day daily prevalence recall) and of influent, effluent, and drinking water quality for fecal coliform was conducted for 6 months. RESULTS: Intervention households had better drinking water quality than control households (fecal coliform geometric mean, 30.0 CFU vs. 89.0 CFU/100 ml, P < 0.001) and reported significantly fewer diarrhoea days (86 days over 626 child-weeks) compared to controls (203 days over 558 child-weeks) among children up to 15 (age-adjusted RR 0.46; 95 % CI = 0.22, 0.96). Greater child diarrhoea reduction due to the intervention (age-adjusted RR 0.23, 95 % CI = 0.10, 0.51) was observed among the sub-group using unimproved water sources all of the time. CONCLUSION: Intermittent slow sand filtration, a non-commercial technology, produces similar observed effects on child diarrhoea as commercial POU products, adding to the range of effective options for poor populations (chlorination, ceramic filtration, solar disinfection, flocculation/disinfection).

Identifying human and livestock sources of fecal contamination in Kenya with host-specific Bacteroidales assays.

Microbial source tracking to distinguish between human, livestock and wildlife fecal pollution using molecular techniques is a rapidly evolving approach in many developed countries, but has not previously been applied on the African continent. DNA extracts from cow, donkey, and human fecal specimens and raw domestic sewage samples collected in Kenya were tested against five existing quantitative PCR assays designed to detect universal (2), human-specific (2), and cow-specific (1) fecal Bacteroidales genetic markers. Water samples from the River Njoro in Kenya were evaluated using the five tested Bacteroidales markers and a multi-species assay for Cryptosporidium in a preliminary exploration of fecal pollution sources and health risks in this watershed. Diagnostic sensitivity on the validation set varied from 18 to 100% for the five assays while diagnostic specificity was 100%. Of the 2 universal assays, Total Bacteroidales [Dick, L.K, Field, K.G., 2004. Rapid estimation of numbers of fecal Bacteroidetes by use of a quantitative PCR assay for 16S rRNA genes. Appl. Environ. Microbiol. 70, 5695-5697] showed lower generic fecal diagnostic sensitivity, at 55%, than BacUni-UCD, at 100%, in detecting fecal markers on the 42-sample validation set. Human-specific assay HF183 demonstrated 65% sensitivity overall, and 80% on the human sewage samples, compared to 18% overall and 0% sewage for human-specific assay BacHum-UCD. Cow-specific assay BacCow-UCD had 94% sensitivity. Testing of 18 water samples indicates cows are a likely predominant source of fecal contamination in the Njoro Watershed (78% prevailing rate). Probabilistic assessment of human assay results indicates at most three of the river water samples contained human Bacteroidales. Cryptosporidium spp. markers were detected in samples from nine of the 12 sampling locations. Evidence suggesting widespread contamination by cow feces and Cryptosporidium in the Njoro watershed raises serious concerns for human and animal health.