Water, Sanitation and Hygiene: Interventions and Diarrhoea - A Systematic Review and Meta-analysis

This paper provides a formal systematic review and meta-analysis examining the evidence of the effectiveness of interventions intended to reduce illness through improvements in drinking water, sanitation facilities and hygiene practices. The comprehensive literature search and bibliographic review shows that in developing countries, water quality interventions, specifically point-of-use treatment, reduced diarrhea illness levels, but this effect was mainly seen with the provision of household connections and use of water without household storage. Hygiene interventions, especially those promoting hand-washing, were effective. Only limited data were available for sanitation interventions, but these suggested effectiveness in reducing diarrhea. Multifactorial interventions consisting of water supply, sanitation and hygiene education acted to reduce diarrhea but were not more effective than individual interventions

Friedel-Crafts Polymers Containing Thiophen

The reaction between p-di(chloromethyl) benzene (DCMB) and thiophen, catalysed by stannic chloride, has been studied with a view to elucidating the kinetics and mechanism of the reaction. In this way it was hoped to gain a clearer insight into the structure of the resultant polymer and so to account for its reported thermal stability. By studying the rate of production of involatile material it was established that the self-polymerisation of thiophen would have little or no effect on the DCMB-thiophen reaction. Analyses of these involatile materials were carried out using I.R., U-V and n. m. r. spectroscopy and molecular weight determinations. The rate of selfcondensation of DCMB was also found to be negligable, by studying the rate of evolution of HCl from DCMB-SnCl4 mixtures. Products of the DCMB-thiophen reaction, with molecular weights up to 850, have been separated using both gas liquid chromatography (GLC) and gel permeation chromatography (GPC), and identified using mass, I.R. and n. m. r. spectroscopy. A total of eight reaction products were separated and identified. However the techniques available did not permit separation and identification of products of molecular weight greater than 850 or an estimation of the extent of isomerism among the reaction products. A kinetic analysis of the reaction was carried out using both GLC and GPC for the separation and analysis of products. Using GLC the dependence of the rate of the first two reactions on the first power of the concentration of each of the reactants was established. This allowed a mechanism for the overall reaction to be proposed and rate constants and activation. energies for the first two steps in the polymerisation to be calculated. From the GPC results reaction curves for all the identified products were constructed. The extremely complex nature of the reaction and the resultant products prevented a complete kinetic analysis of the later stages of the reaction being made. It was possible, however, to arrive at semi-quantitative conclusions about the relative reactivity of the reaction products and hence construct a useful picture of the structure of the resultant polymer. Polymers were also prepared by reaction of DCMB with thiophen, 2-methyl thiophen, 3-meihyl thiophen, 2.5-dimethyl thiophen and 2-chlorothiophen and an assessment was made of their relative stabilities using both thermal gravimetric analysis and thermal volatilisation analysis. I.R. spectroscopy indicated that all the polymers had the same basic structure and so it was possible to correlate the observed degradative features with the differences in the thiophen monomers. These studies have allowed the following conclusions to be drawn concerning the reaction of DCMB with thiophen and the structure of the resultant polymer. The overall reaction may be represented by a series of competing, consecutive reactions of the type, As the reaction proceeds it rapidly becomes highly complex with a proliferation of isomers at each molecular level being brought about by the onset of branching through the disubstituted thiophen nuclei of the products The ultimate polymer has been shown to be a highly cross-linked, insoluble material which exhibits good thermal stability in vacuum, inert atmospheres and air

Evaluation of a pre-existing, 3-year household water treatment and handwashing intervention in rural Guatemala

Background The promotion of household water treatment and handwashing with soap has led to large reductions in child diarrhoea in randomized efficacy trials. Currently, we know little about the health effectiveness of behaviour-based water and hygiene interventions after the conclusion of intervention activities. Methods We present an extension of previously published design (propensity score matching) and analysis (targeted maximum likelihood estimation) methods to evaluate the behavioural and health impacts of a pre-existing but non-randomized intervention (a 3-year, combined household water treatment and handwashing campaign in rural Guatemala). Six months after the intervention, we conducted a cross-sectional cohort study in 30 villages (15 intervention and 15 control) that included 600 households, and 929 children <5 years of age. Results The study design created a sample of intervention and control villages that were comparable across more than 30 potentially confounding characteristics. The intervention led to modest gains in confirmed water treatment behaviour [risk difference = 0.05, 95% confidence interval (CI) 0.02-0.09]. We found, however, no difference between the intervention and control villages in self-reported handwashing behaviour, spot-check hygiene conditions, or the prevalence of child diarrhoea, clinical acute lower respiratory infections or child growth. Conclusions To our knowledge this is the first post-intervention follow-up study of a combined household water treatment and handwashing behaviour change intervention, and the first post-intervention follow-up of either intervention type to include child health measurement. The lack of child health impacts is consistent with unsustained behaviour adoption. Our findings highlight the difficulty of implementing behaviour-based household water treatment and handwashing outside of intensive efficacy trial

In-house nucleic acid amplification tests for the detection of Mycobacterium tuberculosis in sputum specimens: meta-analysis and meta-regression

BACKGROUND: More than 200 studies related to nucleic acid amplification (NAA) tests to detect Mycobacterium tuberculosis directly from clinical specimens have appeared in the world literature since this technology was first introduced. NAA tests come as either commercial kits or as tests designed by the reporting investigators themselves (in-house tests). In-house tests vary widely in their accuracy, and factors that contribute to heterogeneity in test accuracy are not well characterized. Here, we used meta-analytical methods, including meta-regression, to identify factors related to study design and assay protocols that affect test accuracy in order to identify those factors associated with high estimates of accuracy. RESULTS: By searching multiple databases and sources, we identified 2520 potentially relevant citations, and analyzed 84 separate studies from 65 publications that dealt with in-house NAA tests to detect M. tuberculosis in sputum samples. Sources of heterogeneity in test accuracy estimates were determined by subgroup and meta-regression analyses. Among 84 studies analyzed, the sensitivity and specificity estimates varied widely; sensitivity varied from 9.4% to 100%, and specificity estimates ranged from 5.6% to 100%. In the meta-regression analysis, the use of IS6110 as a target, and the use of nested PCR methods appeared to be significantly associated with higher diagnostic accuracy. CONCLUSION: Estimates of accuracy of in-house NAA tests for tuberculosis are highly heterogeneous. The use of IS6110 as an amplification target, and the use of nested PCR methods appeared to be associated with higher diagnostic accuracy. However, the substantial heterogeneity in both sensitivity and specificity of the in-house NAA tests rendered clinically useful estimates of test accuracy difficult. Future development of NAA-based tests to detect M. tuberculosis from sputum specimens should take into consideration these findings in improving accuracy of in-house NAA tests

Incidence and public health burden of sunburn among beachgoers in the United States.

The beach environment creates many barriers to effective sun protection, putting beachgoers at risk for sunburn, a well-established risk factor for skin cancer. Our objective was to estimate incidence of sunburn among beachgoers and evaluate the relationship between sunburn incidence and sun-protective behaviors. A secondary analysis, of prospective cohorts at 12 locations within the U.S. from 2003 to 2009 (n&nbsp;=&nbsp;75,614), were pooled to evaluate sunburn incidence 10-12&nbsp;days after the beach visit. Behavioral and environmental conditions were cross-tabulated with sunburn incidence. Multivariable logistic regression was used to estimate the association between new sunburn and sun-protective behaviors. Overall, 13.1% of beachgoers reported sunburn. Those aged 13-18&nbsp;years (16.5%), whites (16.0%), and those at beach locations along the Eastern Seaboard (16.1%), had the highest incidence of sunburn. For those spending ≥5&nbsp;h in the sun, the use of multiple types of sun protection reduced odds of sunburn by 55% relative to those who used no sun protection (Odds Ratio&nbsp;=&nbsp;0.45 (95% Confidence Interval:0.27-0.77)) after adjusting for skin type, age, and race. Acute health effects of sunburn tend to be mild and self-limiting, but potential long-term health consequences are more serious and costly. Efforts to encourage and support proper sun-protective behaviors, and increase access to shade, protective clothing, and sunscreen, can help prevent sunburn and reduce skin cancer risk among beachgoers

Disease transmission models for public health decision making: analysis of epidemic and endemic conditions caused by waterborne pathogens.

Developing effective policy for environmental health issues requires integrating large collections of information that are diverse, highly variable, and uncertain. Despite these uncertainties in the science, decisions must be made. These decisions often have been based on risk assessment. We argue that two important features of risk assessment are to identify research needs and to provide information for decision making. One type of information that a model can provide is the sensitivity of making one decision over another on factors that drive public health risk. To achieve this goal, a risk assessment framework must be based on a description of the exposure and disease processes. Regarding exposure to waterborne pathogens, the appropriate framework is one that explicitly models the disease transmission pathways of pathogens. This approach provides a crucial link between science and policy. Two studies--a Giardia risk assessment case study and an analysis of the 1993 Milwaukee, Wisconsin, Cryptosporidium outbreak--illustrate the role that models can play in policy making

Estimating the impact of unsafe water, sanitation and hygiene on the global burden of disease: evolving and alternative methods.

The 2010 global burden of disease (GBD) study represents the latest effort to estimate the global burden of disease and injuries and the associated risk factors. Like previous GBD studies, this latest iteration reflects a continuing evolution in methods, scope and evidence base. Since the first GBD Study in 1990, the burden of diarrhoeal disease and the burden attributable to inadequate water and sanitation have fallen dramatically. While this is consistent with trends in communicable disease and child mortality, the change in attributable risk is also due to new interpretations of the epidemiological evidence from studies of interventions to improve water quality. To provide context for a series of companion papers proposing alternative assumptions and methods concerning the disease burden and risks from inadequate water, sanitation and hygiene, we summarise evolving methods over previous GBD studies. We also describe an alternative approach using population intervention modelling. We conclude by emphasising the important role of GBD studies and the need to ensure that policy on interventions such as water and sanitation be grounded on methods that are transparent, peer-reviewed and widely accepted

Changes in Beliefs Identify Unblinding in Randomized Controlled Trials: A Method to Meet CONSORT Guidelines

Double-blinded trials are often considered the gold standard for research, but significant bias may result from unblinding of participants and investigators. Although the CONSORT guidelines discuss the importance of reporting evidence that blinding was successful , it is unclear what constitutes appropriate evidence. Among studies reporting methods to evaluate blinding effectiveness, many have compared groups with respect to the proportions correctly identifying their intervention at the end of the trial. Instead, we reasoned that participants\u27 beliefs, and not their correctness, are more directly associated with potential bias, especially in relation to self-reported health outcomes. During the Water Evaluation Trial performed in northern California in 1999, we investigated blinding effectiveness by sequential interrogation of participants about their blinded intervention assignment (active or placebo). Irrespective of group, participants showed a strong tendency to believe they had been assigned to the active intervention; this translated into a statistically significant intergroup difference in the correctness of participants\u27 beliefs, even at the start of the trial before unblinding had a chance to occur. In addition, many participants (31%) changed their belief during the trial, suggesting that assessment of belief at a single time does not capture unblinding. Sequential measures based on either two or all eight questionnaires identified significant group-related differences in belief patterns that were not identified by the single, cross-sectional measure. In view of the relative insensitivity of cross-sectional measures, the minimal additional information in more than two assessments of beliefs and the risk of modifying participants\u27 beliefs by repeated questioning, we conclude that the optimal means of assessing unblinding is an intergroup comparison of the change in beliefs (and not their correctness) between the start and end of a randomized controlled trial

Water, Sanitation, and Hygiene Interventions to Reduce Diarrhoea in Less Developed Countries: A Systematic Review and Meta-analysis

The authors developed a comprehensive research strategy designed to identify all peer-reviewed articles, in any language, that presented water, sanitation, or hygiene interventions. Out of 2,120 publications, ultimately 40 studies were judged to contain relevant evidence. Most of the studies confined their study groups to children aged under 5 or 6 years. The identified studies were done in a wide range of settings, in many countries, and over many years. All of the interventions studied were found to reduce significantly the risks of diarrheal illness. The results generally agree with those from previous reviews, but water quality interventions (point-of-use water treatment) were found to be more effective than previously thought, and multiple interventions (consisting of combined water, sanitation, and hygiene measures) were not more effective than interventions with a single focus