Quantitative assessment of exposure to fecal contamination in urban environment across nine cities in low-income and lower-middle-income countries and a city in the United States.

BACKGROUND: During 2014 to 2019, the SaniPath Exposure Assessment Tool, a standardized set of methods to evaluate risk of exposure to fecal contamination in the urban environment through multiple exposure pathways, was deployed in 45 neighborhoods in ten cities, including Accra and Kumasi, Ghana; Vellore, India; Maputo, Mozambique; Siem Reap, Cambodia; Atlanta, United States; Dhaka, Bangladesh; Lusaka, Zambia; Kampala, Uganda; Dakar, Senegal. OBJECTIVE: Assess and compare risk of exposure to fecal contamination via multiple pathways in ten cities. METHODS: In total, 4053 environmental samples, 4586 household surveys, 128 community surveys, and 124 school surveys were collected. E. coli concentrations were measured in environmental samples as an indicator of fecal contamination magnitude. Bayesian methods were used to estimate the distributions of fecal contamination concentration and contact frequency. Exposure to fecal contamination was estimated by the Monte Carlo method. The contamination levels of ten environmental compartments, frequency of contact with those compartments for adults and children, and estimated exposure to fecal contamination through any of the surveyed environmental pathways were compared across cities and neighborhoods. RESULTS: Distribution of fecal contamination in the environment and human contact behavior varied by city. Universally, food pathways were the most common dominant route of exposure to fecal contamination across cities in low-income and lower-middle-income countries. Risks of fecal exposure via water pathways, such as open drains, flood water, and municipal drinking water, were site-specific and often limited to smaller geographic areas (i.e., neighborhoods) instead of larger areas (i.e., cities). CONCLUSIONS: Knowledge of the relative contribution to fecal exposure from multiple pathways, and the environmental contamination level and frequency of contact for those "dominant pathways" could provide guidance for Water, Sanitation, and Hygiene (WASH) programming and investments and enable local governments and municipalities to improve intervention strategies to reduce the risk of exposure to fecal contamination.

Water quality, sanitation, and hygiene among the tribal community residing in Jawadhi hills, Tamilnadu: An observational study from Southern India.

OBJECTIVES: To assess the water, sanitation, and hygiene (WASH) practice among the tribal population of Tamil Nadu, India and to determine the physiochemical and bacteriological quality of drinking water at the principal source and at the households along with the household-level determinants of WASH practices. METHODS: A door-to-door survey was conducted in 150 households, distributed across six villages of Jawadhi hills, a tribal area in the state of Tamil Nadu, India. Water samples were collected from the principal sources and a subset of households for assessing water quality. A composite scoring was formulated to determine the overall WASH practices. RESULTS: Overall, a poor WASH score (≤4) was found in 103 (68.7%; 95% CI: 60.7, 75.6) households. The majority (96.7%) of the household water samples showed the presence of fecal coliforms. Poor WASH score was uniformly distributed across the villages. Low per capita income (≤1000 INR) was strongly associated with the poor WASH score (Adjusted OR 2.4; 95% CI: 1.04, 5.7). The per capita income had a strong negative association with the high fecal coliform count (Adjusted OR 5.07; 95% CI: 1.08, 23.74). CONCLUSIONS: We conclude that WASH-related practices among the tribal population of Tamil Nadu is not acceptable. The lack of administrative function and poor economic conditions are the likely causes attributed to the poor WASH conditions and drinking water quality. Urgent action from the stakeholders is the need of the hour to improve the water quality and living standards of such marginalized populations.

Associations between open drain flooding and pediatric enteric infections in the MAL-ED cohort in a low-income, urban neighborhood in Vellore, India.

BACKGROUND: Open drains are common methods of transporting solid waste and excreta in low-income urban neighborhoods. Open drains can overflow due to blockages with solid waste and during rainfall, posing exposure risks. The goal of this study was to evaluate whether pediatric enteric infection was associated with open drains and flooding in a dense, low-income, urban neighborhood. METHODS: As part of the MAL-ED study in Vellore, India, a cohort of 230 children provided stool specimens at 14-17 scheduled home visits and during diarrheal episodes in the first two years of life. All specimens were analyzed for enteric pathogens. Caregivers in 100 households reported on flooding of drains and households and monthly frequency of contact with open drains and flood water. Household GPS points were collected. Monthly rainfall totals for the Vellore district were collected from the Indian Meteorological Department. Clustering of reported drain and house flooding were identified by Kulldorff's Bernoulli Spatial Scan. Differences in enteric infection were assessed for household responses and spatial clusters, with interactions between reported flooding and rainfall to approximate monthly drain flooding retrospectively, using multivariable, mixed-effects logistic regression models. RESULTS: Coverage of household toilets was low (33%), and most toilets (82%) discharged directly into open drains, suggesting poor neighborhood fecal sludge management. Odds of enteric infection increased significantly with total monthly rainfall for children who lived in households that reported that the nearby drain flooded (4% increase per cm of rain: OR: 1.04, 95% CI: 1.00-1.08) and for children in households in a downstream spatial cluster of reported drain flooding (5% increase per cm of rain: OR: 1.05, 95% CI: 1.01-1.09). There was no association between odds of enteric infection and frequency of reported contact with drain or floodwater. CONCLUSIONS: Children in areas susceptible to open drain flooding had increased odds of enteric infection as rainfall increased. Results suggested that infection increased with rainfall due to neighborhood infrastructure (including poor fecal sludge management) and not frequency of contact. Thus, these exposures may not be mitigated by changes in personal behaviors alone. These results underscore the importance of improving the neighborhood environment to improve children's health in low-income, urban settings.

Temporal trends of intestinal parasites in patients attending a tertiary care hospital in south India: A seven-year retrospective analysis.

BACKGROUND & OBJECTIVES: Intestinal parasitic infections and their associated complications are a major cause of morbidity in the developing world. This retrospective study was done to assess the prevalence of intestinal parasitic infections among patients in a tertiary healthcare setting and to analyze age-, gender- and time-related trends in the prevalence of these intestinal parasites over a seven year period (2006-2012). METHODS: The presence of various intestinal parasites in a tertiary care setting over a seven year period in different age groups was determined by performing routine stool microscopy. Modified acid-fast staining was performed for stool samples collected from children less than five years of age for the detection of intestinal coccidian parasites. Statistical analysis was carried out to analyze age-related trends in relation to the prevalence of commonly detected intestinal parasites. Seasonal fluctuations in parasite prevalence were evaluated by performing harmonic regression analysis. RESULTS: A total of 257,588 stool samples were received over the seven year period for examination. The highest percentage of intestinal parasites was in the 6-10 yr age group. Among the intestinal parasites, Giardia intestinalis had the highest prevalence across most age groups, except in those above 60 yr of age where hookworm became more prevalent. A significant decreasing trend with age was observed for G. intestinalis, whereas for hookworm and Strongyloides stercoralis, an increasing trend with age was seen. Significant linear temporal trends were observed for parasites such as G. intestinalis, Entamoeba histolytica and Ascaris lumbricoides. INTERPRETATION & CONCLUSIONS: While G. intestinalis was more common in the younger age groups, certain soil-transmitted helminths such as hookworm and S. stercoralis showed a higher prevalence in the older populations. Significant temporal trends and seasonality were observed for some of the common intestinal parasites.

Household sanitation is associated with lower risk of bacterial and protozoal enteric infections, but not viral infections and diarrhoea, in a cohort study in a low-income urban neighbourhood in Vellore, India.

OBJECTIVE: This study examined associations between household sanitation and enteric infection - including diarrhoeal-specific outcomes - in children 0-2 years of age in a low-income, dense urban neighbourhood. METHODS: As part of the MAL-ED study, 230 children in a low-income, urban, Indian neighbourhood provided stool specimens at 14-17 scheduled time points and during diarrhoeal episodes in the first 2 years of life that were analysed for bacterial, parasitic (protozoa and helminths) and viral pathogens. From interviews with caregivers in 100 households, the relationship between the presence (and discharge) of household sanitation facilities and any, pathogen-specific, and diarrhoea-specific enteric infection was tested through mixed-effects Poisson regression models. RESULTS: Few study households (33%) reported having toilets, most of which (82%) discharged into open drains. Controlling for season and household socio-economic status, the presence of a household toilet was associated with lower risks of enteric infection (RR: 0.91, 95% CI: 0.79-1.06), bacterial infection (RR: 0.87, 95% CI: 0.75-1.02) and protozoal infection (RR: 0.64, 95% CI: 0.39-1.04), although not statistically significant, but had no association with diarrhoea (RR: 1.00, 95% CI: 0.68-1.45) or viral infections (RR: 1.12, 95% CI: 0.79-1.60). Models also suggested that the relationship between household toilets discharging to drains and enteric infection risk may vary by season. CONCLUSIONS: The presence of a household toilet was associated with lower risk of bacterial and protozoal enteric infections, but not diarrhoea or viral infections, suggesting the health effects of sanitation may be more accurately estimated using outcome measures that account for aetiologic agents.

Effectiveness of Membrane Filtration to Improve Drinking Water: A Quasi-Experimental Study from Rural Southern India.

Since point-of-use methods of water filtration have shown limited acceptance in Vellore, southern India, this study evaluated the effectiveness of decentralized membrane filtration 1) with safe storage, 2) without safe storage, versus 3) no intervention, consisting of central chlorination as per government guidelines, in improving the microbiological quality of drinking water and preventing childhood diarrhea. Periodic testing of water sources, pre-/postfiltration samples, and household water, and a biweekly follow up of children less than 2 years of age was done for 1 year. The membrane filters achieved a log reduction of 0.86 (0.69-1.06), 1.14 (0.99-1.30), and 0.79 (0.67-0.94) for total coliforms, fecal coliforms, and Escherichia coli, respectively, in field conditions. A 24% (incidence rate ratio, IRR [95% confidence interval, CI] = 0.76 [0.51-1.13]; P = 0.178) reduction in diarrheal incidence in the intervention village with safe storage and a 14% (IRR [95% CI] = 1.14 [0.75-1.77]; P = 0.530) increase in incidence for the intervention village without safe storage versus no intervention village was observed, although not statistically significant. Microbiologically, the membrane filters decreased fecal contamination; however, provision of decentralized membrane-filtered water with or without safe storage was not protective against childhood diarrhea.

Molecular Identification of Hookworm Isolates in Humans, Dogs and Soil in a Tribal Area in Tamil Nadu, India.

BACKGROUND: Hookworms (Necator americanus and Ancylostoma duodenale) remain a major public health problem worldwide. Infections with hookworms (e.g., A. caninum, A. ceylanicum and A. braziliense) are also prevalent in dogs, but the role of dogs as a reservoir for zoonotic hookworm infections in humans needs to be further explored. METHODOLOGY/PRINCIPAL FINDINGS: As part of an open-label community based cluster-randomized trial in a tribal area in Tamil Nadu (India; 2013-2015), a total of 143 isolates of hookworm eggs from human stool were speciated based on a previously described PCR-RFLP methodology. The presence of hookworm DNA was confirmed in 119 of 143 human samples. N. americanus (100%) was the most prevalent species, followed by A. caninum (16.8%) and A. duodenale (8.4%). Because of the high prevalence of A. caninum in humans, dog samples were also collected to assess the prevalence of A. caninum in dogs. In 68 out of 77 canine stool samples the presence of hookworms was confirmed using PCR-RFLP. In dogs, both A. caninum (76.4%) and A. ceylanicum (27.9%) were identified. Additionally, to determine the contamination of soil with zoonotic hookworm larvae, topsoil was collected from defecating areas. Hookworm DNA was detected in 72 out of 78 soil samples that revealed presence of hookworm-like nematode larvae. In soil, different hookworm species were identified, with animal hookworms being more prevalent (A. ceylanicum: 60.2%, A. caninum: 29.4%, A. duodenale: 16.6%, N. americanus: 1.4%, A. braziliense: 1.4%). CONCLUSIONS/SIGNIFICANCE: In our study we regularly detected the presence of A. caninum DNA in the stool of humans. Whether this is the result of infection is currently unknown but it does warrant a closer look at dogs as a potential reservoir.

Identification of Ancylostoma ceylanicum in children from a tribal community in Tamil Nadu, India using a semi-nested PCR-RFLP tool.

BACKGROUND: It is generally assumed that hookworm infections in humans are caused by Necator americanus and Ancylostoma duodenale. However, previous studies have also reported the presence of the animal hookworm A. ceylanicum in human stools. METHODS: We determined hookworm infections in children in a tribal community in Tamil Nadu, India, using a semi-nested PCR-RFLP approach. RESULTS: The results indicate that human species account for a majority of the hookworm infections (N. americanus 39/41 [95%]; A. duodenale 6/41 [15%]), whereas the animal hookworm A. ceylanicum only accounts for a minority of the infections (5%; 2/41). CONCLUSIONS: The results emphasize the need to consider zoonotic ancylostomiasis while developing strategies to control hookworm infections.

Prevalence and clustering of soil-transmitted helminth infections in a tribal area in southern India.

OBJECTIVES: To estimate the prevalence, spatial patterns and clustering in the distribution of soil-transmitted helminth (STH) infections, and factors associated with hookworm infections in a tribal population in Tamil Nadu, India. METHODS: Cross-sectional study with one-stage cluster sampling of 22 clusters. Demographic and risk factor data and stool samples for microscopic ova/cysts examination were collected from 1237 participants. Geographical information systems mapping assessed spatial patterns of infection. RESULTS: The overall prevalence of STH was 39% (95% CI 36%­42%), with hookworm 38% (95% CI 35­41%) and Ascaris lumbricoides 1.5% (95% CI 0.8­2.2%). No Trichuris trichiura infection was detected. People involved in farming had higher odds of hookworm infection (1.68, 95% CI 1.31­2.17, P < 0.001). In the multiple logistic regression, adults (2.31, 95% CI 1.80­2.96, P < 0.001), people with pet cats (1.55, 95% CI 1.10­2.18, P = 0.011) and people who did not wash their hands with soap after defecation (1.84, 95% CI 1.27­2.67, P = 0.001) had higher odds of hookworm infection, but gender and poor usage of foot wear did not significantly increase risk. Cluster analysis, based on design effect calculation, did not show any clustering of cases among the study population; however, spatial scan statistic detected a significant cluster for hookworm infections in one village. CONCLUSION: Multiple approaches including health education, improving the existing sanitary practices and regular preventive chemotherapy are needed to control the burden of STH in similar endemic areas.

Studies on macrobenthic organisms in relation to water parameters at East Calcutta Wetlands.

East Calcutta Wetlands is an internationally important site for natural remediation of domestic sewage and organic waste and their successful recycling into habitat for pisciculture. Macrobenthic fauna is responsible for efficient utilization of sediments and their diversity indicates health of a wetland in accordance to its sediment quality. In the present study, several physico-chemical parameters such as DO (3.03-11.06 ppm), CO2 (4.02-20.0 ppm), alkalinity (36.83-164.0 ppm), total hardness (100.0-270.00 ppm), TDS (450.0-620 ppm), chloride(142.0-364.2 ppm), pH (7.3-8.5), water transparency (8.0-54.2 cm), organic contents like organic carbon (1.03-10.9 mg g(-1)) were studied. Variation in macrobenthic fauna from the selected fields were also examined by calculating Simpson's dominance index, evenness index (Pielou index), Shannon's diversity index. 12 taxa of mollusk and 1 taxa of annelid were found in the study and Bellamyo and Thiara were the most dominant species which indicated clean water of the pond. The correlation between macrobenthic diversity and physico-chemical parameters were also studied in selected ponds from East Calcutta Wetlands.

A comparison of the sensitivity and fecal egg counts of the McMaster egg counting and Kato-Katz thick smear methods for soil-transmitted helminths.

BACKGROUND: The Kato-Katz thick smear (Kato-Katz) is the diagnostic method recommended for monitoring large-scale treatment programs implemented for the control of soil-transmitted helminths (STH) in public health, yet it is difficult to standardize. A promising alternative is the McMaster egg counting method (McMaster), commonly used in veterinary parasitology, but rarely so for the detection of STH in human stool. METHODOLOGY/PRINCIPAL FINDINGS: The Kato-Katz and McMaster methods were compared for the detection of STH in 1,543 subjects resident in five countries across Africa, Asia and South America. The consistency of the performance of both methods in different trials, the validity of the fixed multiplication factor employed in the Kato-Katz method and the accuracy of these methods for estimating 'true' drug efficacies were assessed. The Kato-Katz method detected significantly more Ascaris lumbricoides infections (88.1% vs. 75.6%, p<0.001), whereas the difference in sensitivity between the two methods was non-significant for hookworm (78.3% vs. 72.4%) and Trichuris trichiura (82.6% vs. 80.3%). The sensitivity of the methods varied significantly across trials and magnitude of fecal egg counts (FEC). Quantitative comparison revealed a significant correlation (Rs >0.32) in FEC between both methods, and indicated no significant difference in FEC, except for A. lumbricoides, where the Kato-Katz resulted in significantly higher FEC (14,197 eggs per gram of stool (EPG) vs. 5,982 EPG). For the Kato-Katz, the fixed multiplication factor resulted in significantly higher FEC than the multiplication factor adjusted for mass of feces examined for A. lumbricoides (16,538 EPG vs. 15,396 EPG) and T. trichiura (1,490 EPG vs. 1,363 EPG), but not for hookworm. The McMaster provided more accurate efficacy results (absolute difference to 'true' drug efficacy: 1.7% vs. 4.5%). CONCLUSIONS/SIGNIFICANCE: The McMaster is an alternative method for monitoring large-scale treatment programs. It is a robust (accurate multiplication factor) and accurate (reliable efficacy results) method, which can be easily standardized.

Point-of-use interventions to decrease contamination of drinking water: a randomized, controlled pilot study on efficacy, effectiveness, and acceptability of closed containers, Moringa oleifera, and in-home chlorination in rural South India.

To assess water contamination and the relative effectiveness of three options for point-of-use water treatment in South India, we conducted a 6-month randomized, controlled intervention trial using chlorine, Moringa oleifera seeds, a closed valved container, and controls. One hundred twenty-six families participated. Approximately 70% of public drinking water sources had thermotolerant coliform counts > 100/100 mL. Neither M. oleifera seeds nor containers reduced coliform counts in water samples from participants' homes. Chlorine reduced thermotolerant coliform counts to potable levels, but was less acceptable to participants. Laboratory testing of M. oleifera seeds in water from the village confirmed the lack of reduction in coliform counts, in contrast to the improvement seen with Escherichia coli seeded distilled water. This discrepancy merits further study, as M. oleifera was effective in reducing coliform counts in other studies and compliance with Moringa use in this study was high.

Appropriate technology for rural India - solar decontamination of water for emergency settings and small communities.

A commercial solar water heating system was evaluated for its effectiveness in decontaminating drinking water with a view to use in emergency situations. A total of 18 seeding experiments carried out over 6 months with 10(5) to 10(7)Escherichia coli/ml showed that the solar heater produced 125 l of bacteriologically safe water in 4 h when the ambient temperature was above 30 degrees C, with a holding time of at least 2 h. The solar water heating system is inexpensive, easy to transport and set up and could provide safer drinking water for 50 people a day. It would be effective in the decrease and prevention of waterborne disease in emergency situations, and is appropriate for use in small communities.

Water contamination in urban south India: household storage practices and their implications for water safety and enteric infections.

Water contamination, at source and during household storage, is a major cause of enterically transmitted infections in developing countries. This study assessed contamination of the municipal water in a south Indian town, which obtains its water intermittently from a surface lake and by pumping subsurface water from a dry river bed, and monitored microbial contamination during household storage. All samples of the 'treated' municipal water were contaminated when freshly pumped, and on household storage, 25/37 (67%) showed increased contamination during storage periods from 1 to 9 days. Household storage in brass, but not in containers of other materials significantly decreased contamination of water (p = 0.04). This was confirmed in the laboratory by testing water seeded with 10(3) to 10(5) Escherichia coli per 100 ml stored in containers of different materials (p < 0.01). Despite the requirements for provision of safe drinking water in municipal areas, in practice the water supplied in Vellore is contaminated and current household storage practices increase the level of contamination in at least two-thirds of households. The implementation of locally appropriate point-of-use disinfection and safe household storage practices in developing countries is an urgent need to ensure a safe, reliable year-round supply in areas where clean water is not available.