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Biomedical subjects

S Cairncross

Publications and source records attributed to S Cairncross.

At least 19 recordsLinked to original sources
PubMed2006

Interventions to improve water quality for preventing diarrhoea.

BACKGROUND: Diarrhoeal diseases are a leading cause of mortality and morbidity, especially among young children in developing countries. While many of the infectious agents associated with diarrhoeal disease are potentially waterborne, the evidence for reducing diarrhoea in settings where it is endemic by improving the microbiological quality of drinking water has been equivocal. OBJECTIVES: To assess the effectiveness of interventions to improve water quality for preventing diarrhoea. SEARCH STRATEGY: We searched the Cochrane Infectious Diseases Group Specialized Register (December 2005), CENTRAL (The Cochrane Library 2005, Issue 4), MEDLINE (December 2005), EMBASE (December 2005), and LILACS (December 2005). We also handsearched relevant conference proceedings, contacted researchers and organizations working in the field, and checked references from identified studies. SELECTION CRITERIA: Randomized and quasi-randomized controlled trials comparing interventions aimed at improving the microbiological quality of drinking water with no intervention in children and adults living in settings where diarrhoeal disease is endemic. DATA COLLECTION AND ANALYSIS: Two authors independently assessed trial quality and extracted data. We used meta-analyses to estimate pooled measures of effect, where appropriate, and investigated potential sources of heterogeneity using subgroup analyses. MAIN RESULTS: Thirty trials (including 38 independent comparisons) covering over 53,000 participants met the inclusion criteria. Differences between the trials limited the comparability of results and pooling by meta-analysis. In general, the evidence suggests that interventions to improve the microbiological quality of drinking water are effective in preventing diarrhoea both for populations of all ages and children less than five years old. Subgroup analyses suggest that household interventions are more effective in preventing diarrhoea than interventions at the water source. Effectiveness was positively associated with compliance. Effectiveness was not conditioned on the presence of improved water supplies or sanitation in the study setting, and was not enhanced by combining the intervention to improve water quality with other common environmental interventions intended to prevent diarrhoea. AUTHORS' CONCLUSIONS: Interventions to improve water quality are generally effective in preventing diarrhoea, and interventions to improve water quality at the household level are more effective than those at the source. Significant heterogeneity among the trials suggests that the actual level of effectiveness may depend on a variety of conditions that research to date cannot fully explain. Rigorous, blinded, multi-arm randomized controlled trials conducted over a longer duration in a variety if settings may help clarify the potential effectiveness.

Adult↗
PubMed2005

Asymptomatic giardiasis and growth in young children; a longitudinal study in Salvador, Brazil.

This study sought to assess the effect of giardiasis on growth of young children. In Salvador, northeast Brazil, 597 children initially aged 6 to 45 months were followed for a year in 1998/9, measured anthropometrically thrice, every 6 months, and monitored for diarrhoea prevalence twice weekly. Stool samples were collected and examined during the second round of anthropometry, and infected children were treated 39 days later, on average (S.D. 20 days). For each 6-month interval, the gains in z-scores of infected and uninfected children were compared, after adjustment for potential confounding factors, including longitudinal prevalence of diarrhoea. No significant difference was found for the first interval but in the second, the gain in adjusted height-for-age z-score was 0.09 less in infected than uninfected children, equivalent to a difference in height gain of 0.5 cm. The shortfall in growth was greater in children who remained free of diarrhoea, and was significantly correlated with the proportion of the second interval during which the child had remained untreated. We conclude that Giardia can impede child growth even when asymptomatic, presumably through malabsorption. This finding challenges the view that young children found to have asymptomatic giardiasis in developing countries should not be treated.

Body Height↗
PubMed2004

Environmental interventions and the pattern of geohelminth infections in Salvador, Brazil.

This paper reports a longitudinal study, conducted in 1989/90, of 1893 children aged 5 to 14 years in 9 poor urban areas of the city of Salvador (population 2.44 million), capital of Bahia State in northeast Brazil. Stool examinations were performed to measure nematode infection and reinfection 9 months after treatment, and an extensive questionnaire was applied to collect information on each child and on the conditions of the household. Comparison of areas with different levels of infrastructure showed the following trends as the level of community sanitation improved: clustering of cases by household became more significant, predisposition of individuals to reinfection and to heavy infection became more marked, and infections with different species were increasingly aggregated in the same individuals. These results suggest that sewerage and drainage can significantly reduce transmission of intestinal nematode infections in the public domain, but that other measures are required to control transmission within the household.

Adolescent↗
PubMed2004

Is there an association between bacteriological drinking water quality and childhood diarrhoea in developing countries?

To investigate the association between bacteriological drinking water quality and incidence of diarrhoea, we conducted a 1-year prospective study in the southern Punjab, Pakistan. Diarrhoea episodes, drinking water sources and drinking water quality were monitored weekly among children younger than 5 years in 200 households. We found no association between the incidence of childhood diarrhoea and the number of Escherichia coli in the drinking water sources (the public domain). A possible trend was seen relating the number of E. coli in the household storage containers (the domestic domain) and diarrhoea incidence, but this did not reach statistical significance. Faecal contamination levels in household water containers were generally high even when the source water was of good quality. Under conditions such as this, it is questionable whether public water treatment will have a significant impact on the incidence of endemic childhood diarrhoea.

Child, Preschool↗
PubMed2003

Childhood diarrhea and observed hygiene behavior in Salvador, Brazil.

Brief biweekly home visits, made as part of a cohort study of diarrhea in young children under age 5 years that was carried out in Salvador, Brazil, in 1998-1999, were used as a low-cost way to collect structured observation data on domestic hygiene behavior. Field-workers were trained to check a list of 23 forms of hygienic or unhygienic behavior by the child or the child's caretaker, if any behaviors were seen during the visit. Children were grouped according to whether mainly unhygienic behavior or mainly hygienic behavior had been recorded. This permitted study of the determinants of hygiene behavior and of its role in the transmission or prevention of diarrheal disease. Observations were recorded on roughly one visit in 20. Households with adequate excreta disposal were significantly more likely to be in the "mainly hygienic" group. The prevalence of diarrhea among children for whom mainly unhygienic behavior was recorded was 2.2 times that among children in the "mainly hygienic" group. The relative risk for prevalence was 2.2 (95% confidence interval: 1.7, 2.8). The relative risk fell to 1.9 (95% confidence interval: 1.5, 2.5) after data were controlled for confounding, but the difference was still highly significant.

Brazil↗
PubMed2003

Risk factors for infection with Giardia duodenalis in pre-school children in the city of Salvador, Brazil.

A cross-sectional study of 694 children aged 2 to 45 months selected from 30 clusters throughout the city of Salvador, Bahia (pop. 2.3 million) was carried out as part of a longitudinal study of diarrhoea in order to identify risk factors for infection with Giardia duodenalis. Variables studied included three social and demographic factors (such as mother's education and marital status), five relating to the peri-domestic environment (rubbish disposal, open sewers, paving of the street), seven relating to the home itself (house construction, susceptibility to flooding, water supply and sanitation) as well as a score for hygiene behaviour based on structured observation. After multivariate analysis using a hierarchical model, only four significant risk factors were found: (a) number of children in the household under five years (b) rubbish not collected from the house (c) presence of visible sewage nearby, and (d) absence of a toilet. All four were significant at the 1% level.

Animals↗
PubMed2003

Sanitation in the developing world: current status and future solutions.

More than a third of the world's population (2.4 billion people) lacks access to adequate excreta disposal. Four in five of these unserved people are in Asia, with approximately one in five in both India and China, respectively. Even in large Asian cities, less than half of those served are using sewerage systems; the others use on-site systems, from pit latrines to septic tanks. Most have been installed by householders or builders employed by them, rather than by government or municipal agencies. Governments, international agencies and municipalities can never hope to meet the immense gap in provision unless they promote sanitation with a marketing approach. A latrine is a consumer durable which must be sold. It is often considered that the constraint to increasing sanitation coverage is a lack of demand, but there is often a lack of supply of appropriate products, and latrine designs are often too expensive for the poor, requiring subsidies which are captured by the better-off. More market research is needed to define the right product and how best to stimulate demand. Where subsidies are used, the promotion, not the production of the latrines must be subsidised to prevent middle-class capture of the subsidy. Promotion is probably best performed by different agencies from those that build latrines. The expertise and marketing capacity of the private sector needs to be brought into play, and public bodies must learn to assist it effectively in bringing sanitation to all.

Communicable Disease Control↗
PubMed2001

The epidemiology of hepatitis A in Rio de Janeiro: environmental and domestic risk factors.

A serological study of hepatitis A was carried out in low-income areas scheduled for a major sanitation programme in Rio de Janeiro, Brazil. Blood spots were collected by finger puncture and transported on filter paper, and total antibodies to hepatitis A virus were detected by ELISA. Households were also interviewed to collect information on their environmental conditions and socio-economic status. A generalized linear model using a complementary log-log function was fitted to the data, using the logarithm of age as an explanatory variable to derive adjusted rate ratios (RR). The risk of infection was greater among households with 2-3 members per room (RR = 1.4; 95% CI = 1.04-1.8) or more than three per room (RR = 1.5; 95% CI = 1.2-2.0). People living on hilltops (RR = 1.5; 95% CI = 1.02-2.2), near to open sewers (RR = 1.2; 95% CI = 1.03-1.5) or lacking a kitchen (RR = 1.4; 95% CI = 1.08-1.9) were also at greater risk than others. The number of taps and water-using fittings in the house was associated with a protective effect (RR = 0.9 for each tap; 95% CI = 0.9-0.98). A significant protective association was found with maternal education but not with gender or household income. The results do not suggest a strong association with water quality. Ownership of a ceramic water filter was associated with a protective effect on the margin of significance, but the practice of boiling drinking-water was not, nor was the type of water source used. The results suggest that that the risk of infection with hepatitis A is determined by environmental variables in the domestic and public domains.

Adolescent↗
PubMed2000

Domestic hygiene and diarrhoea - pinpointing the problem.

Improving domestic hygiene practices is potentially one of the most effective means of reducing the global burden of diarrhoeal diseases in children. However, encouraging behaviour change is a complex and uncertain business. If hygiene promotion is to succeed, it needs to identify and target only those few hygiene practices which are the major source of risk in any setting. Using biological reasoning, we hypothesize that any behaviours which prevent stools from getting into the domestic arena, the child's main habitat, are likely to have a greater impact on health than those practices which prevent pathogens in the environment from being ingested. Hence safe stool disposal, a primary barrier to transmission, may be more important than hand-washing before eating, which constitutes a secondary barrier, for example. We review the epidemiological evidence for the effect of primary and secondary barrier behaviours and suggest that it supports this conclusion. In the absence of local evidence to the contrary, hygiene promotion programmes should give priority to the safe disposal of faecal material and the adequate washing of hands after contact with adult and child stools.

Animals↗
PubMed2000

Review of the evidence base for the 'F' and 'E' components of the SAFE strategy for trachoma control.

Community control of trachoma as a blinding disease is based on the SAFE strategy of Surgery, Antibiotic therapy, Facial cleanliness and Environmental improvement. Surgery and antibiotic therapy currently dominate most programmes. Blindness from trachoma results from frequent infections repeated over many years, so ultimate success requires the reduction of transmission. This is only likely to be sustainable through the F and E components of SAFE. Environmental improvement with access to water, enhanced hygiene and better sanitation reduces trachoma transmission and the blinding sequelae eventually disappear. Transmission routes and factors that cause this are not known and consequently no single specific tool for F and E is in place. Evidence from intervention studies shows that the promotion of face-washing gave modest gains for intense effort and a pilot study showed that trachoma transmission was reduced in the absence of eye-seeking flies. Other studies have shown that latrines and improved access to water are associated with a lower prevalence of active trachoma. There is likely to be a long-term beneficial effect of a combination of improved water supplies, provision of latrines, facial hygiene promotion through established infrastructure and control of eye-seeking flies. Each of these interventions offers additional public health and other benefits in its own right. Further research on the routes of transmission, the role of hygiene and means of sustainable fly control should be a priority.

Animals↗
PubMed1997

Global eradication of Guinea worm.

Little more than a decade ago, it was estimated that over three million cases of dracunculiasis occurred worldwide. Since then, the numbers have fallen dramatically, thanks to the water supply initiatives of the 1980s and, more recently, the national guinea worm eradication programmes implemented in a score of endemic countries. Hervé Periès and Sandy Cairncross discuss how eradication will require the containment of cases in the remaining endemic areas, together with the simultaneous strengthening of surveillance to permit the certification of eradication. This aim requires existing strategies to be adapted to maintain their efficacy and also to improve their sustainability and cost-effectiveness. Sudan with its civil war, and more than a hundred thousand reported cases, remains a major obstacle to rapid achievement of the goal.

Journal Article↗
PubMed1996

Community participation in the eradication of guinea worm disease.

As Guinea worm eradication programmes have got under way in endemic countries over the last decade, there has been a shift towards more participatory methods. The approach to surveillance has changed from periodic cross-sectional surveys to monthly village-based reporting of cases by a volunteer village health worker. At the same time, the emphasis regarding control interventions has moved from the provision of safe water supplies to health education. The new approach has proved very effective. The village health volunteers who carry out both surveillance and health education seem to be motivated largely by the social status of their role; still more commitment will be required of them in the final stages of eradication. It is to be hoped that the networks of village health workers established for Guinea worm eradication will find a useful role in health promotion after the worms have gone.

Africa↗
PubMed1996

The impact of health education to promote cloth filters on dracunculiasis prevalence in the northern region, Ghana.

This paper describes a health education intervention which was conducted during the 1990 dry season in 3 study villages in the Northern Region of Ghana, to reduce dracunculiasis prevalence in that area by promoting the use of cloth filters for drinking water and avoidance of water contact by sufferers. The impact of the intervention in reducing dracunculiasis prevalence was examined by comparing the period prevalence of infection in 1990 and 1991. The findings demonstrate that the intervention had a measurable but limited impact on dracunculiasis prevalence. Face-to-face health education was successful in persuading 56% of households to buy filters. Ownership of at least one filter for every 10 people in the household was associated with a reduction of at least 20% in the risk of dracunculiasis.

Adult↗
PubMed1996

The public and domestic domains in the transmission of disease.

This paper discusses the distinction between the transmission of infectious diseases within the domestic domain (the area normally occupied by and under the control of a household) and that in the public domain, which includes public places of work, schooling, commerce and recreation as well as the streets and fields. Whereas transmission in the public domain can allow a single case to cause a large epidemic, transmission in the domestic domain is less dramatic and often ignored, although it may account for a substantial number of cases. Statistical methods are available to estimate the relative importance of the two. To control transmission in the public domain, intervention by public authorities is likely to be required. Two examples show how environmental interventions for disease control tend to address transmission in one or the other domain; interventions are needed in both domains in order to interrupt transmission.

Adolescent↗