Failure of sanitary wells to protect against cholera and other diarrhoeas in Bangladesh

Broad approaches to cholera control in Asia: Water, sanitation and handwashing

Cholera has been eliminated as a public health problem in high-income countries that have implemented sanitation system separating the community's fecal waste from their drinking water and food supply. These expensive, highly-engineered systems, first developed in London over 150 years ago, have not reached low-income high-risk communities across Asia. Barriers to their implementation in communities at highest risk for cholera include the high capital and operating costs for this technological approach, limited capacity and perverse incentives of local governments, and a decreasing availability of water. Interim solutions including household level water treatment, constructing latrines and handwashing promotion have only marginally reduced the risk of cholera and other fecally transmitted diseases. Increased research to develop and policy flexibility to implement a new generation of solutions that are designed specifically to address the physical, financial and political constraints of low-income communities offers the best prospect for reducing the burden of cholera across Asia.

Relation of childhood diarrheal morbidity with the type of tube well used and associated factors of Shigella sonnei diarrhea in rural Bangladesh site of the Global Enteric Multicenter Study

Background

Diarrheal disease still remains a major public health threat and is often associated with fatal outcome especially in children with shigellosis mostly in developing countries. This study aimed to determine the presence of any associations between drinking shallow tube well (STW) water and childhood shigellosis. A total of 1394 children aged 0–59 months who presented with moderate-to-severe diarrhea (MSD) in Kumudini Women’s Medical College and Hospital, Bangladesh, from December 2007 to March 2011 were enrolled into the study.

Results

Among the study children, STW users often represented poor families (44% vs. 37%, p = 0.010); less often had household electricity (60% vs. 68%, p = 0.001) and cemented floor material (12% vs. 21%, p < 0.001); washed hand before eating (79% vs. 84%, p = 0.020); and had Shigella sonnei infections (7.8% vs. 13.1, p = 0.002) compared to deep tube well (DTW) water families (in bivariate analysis). After adjusting for covariates, a significant negative association was observed between childhood MSD episodes due to Shigella sonnei infections and the use of STW water (aOR 0.53, 95% CI 0.36, 0.79).

Conclusions

An emergence of less severe Shigella sonnei has replaced relatively more severe Shigella flexneri among the MSD children from DTW-user families. However, more monitoring in terms of disease surveillance for changes in the distribution of Shigella serogroups and serotypes and its upsurges and antimicrobial susceptibility is essential.

Effects of source- versus household contamination of tubewell water on child diarrhea in rural Bangladesh: a randomized controlled trial

BACKGROUND

Shallow tubewells are the primary drinking water source for most rural Bangladeshis. Fecal contamination has been detected in tubewells, at low concentrations at the source and at higher levels at the point of use. We conducted a randomized controlled trial to assess whether improving the microbiological quality of tubewell drinking water by household water treatment and safe storage would reduce diarrhea in children <2 years in rural Bangladesh.

METHODS

We randomly assigned 1800 households with a child aged 6-18 months (index child) into one of three arms: chlorine plus safe storage, safe storage and control. We followed households with monthly visits for one year to promote the interventions, track their uptake, test participants' source and stored water for fecal contamination, and record caregiver-reported child diarrhea prevalence (primary outcome). To assess reporting bias, we also collected data on health outcomes that are not expected to be impacted by our interventions.

FINDINGS

Both interventions had high uptake. Safe storage, alone or combined with chlorination, reduced heavy contamination of stored water. Compared to controls, diarrhea in index children was reduced by 36% in the chlorine plus safe storage arm (prevalence ratio, PR = 0.64, 0.55-0.73) and 31% in the safe storage arm (PR = 0.69, 0.60-0.80), with no difference between the two intervention arms. One limitation of the study was the non-blinded design with self-reported outcomes. However, the prevalence of health outcomes not expected to be impacted by water interventions did not differ between study arms, suggesting minimal reporting bias.

CONCLUSIONS

Safe storage significantly improved drinking water quality at the point of use and reduced child diarrhea in rural Bangladesh. There was no added benefit from combining safe storage with chlorination. Efforts should be undertaken to implement and evaluate long-term efforts for safe water storage in Bangladesh.

TRIAL REGISTRATION

ClinicalTrials.gov NCT01350063.

Risk factors for severe cholera among children under five in rural and urban Bangladesh, 2000-2008: a hospital-based surveillance study

Background

Children under five bear the largest cholera burden. We therefore sought to identify modifiable risk factors among Bangladeshi children.

Methodology/Principal Findings

We used multivariate Poisson regression to assess risk factors for severe cholera among diarrheal patients presenting at hospitals in Matlab (rural) and Dhaka (urban), Bangladesh. Risk increased with age. Compared to those under one, rural and urban four-year-olds had adjusted risk ratios (aRR) of 4.17 (95% confidence interval (CI) 2.43–7.15) and 6.32 (95% CI: 4.63–8.63), respectively. Breastfeeding halved the risk in both rural (aRR = 0.49, 95% CI: 0.35–0.67) and urban (aRR = 0.51, 95% CI: 0.41–0.62) settings. Rural children’s risk decreased with maternal education (P-trend: <0.001) and increased among those with a family member with diarrhea in the past week (aRR = 1.61, 95% CI: 1.22–2.14) and those with prior vitamin A supplementation (aRR = 1.65, 95% CI: 1.12–2.43). Urban children whose mothers daily (aRR = 0.41, 95% CI: 0.21–0.79) or occasionally (aRR = 0.55, 95% CI: 0.36–0.84) read a newspaper experienced reduced risk. Urban children from households with incomes between 34–84 USD/month had a 30% increased risk compared to those from households with incomes >84 USD/month.

Conclusion/Significance

Increasing age, lower socioeconomic status, and lack of breastfeeding are key correlates of increased risk for cholera hospitalization among those under five in rural and urban Bangladesh. In addition, having a family member with diarrhea in the past week was associated with increased risk among rural children. Continued attention should be directed to the promotion of breastfeeding. Further research is needed to elucidate the relationship between maternal education and cholera risk. Renewed research regarding the use of chemoprophylaxis among family members of cholera cases may be warranted in rural endemic settings.

Assessment of the effects of teaching germ theory on changes in hygiene behaviors, cleanliness, and diarrheal incidence in rural bangladesh

Germ theory was taught as part of a hygiene intervention in five villages in Bangladesh in which 87 percent of mothers were illiterate. Volunteer mothers taught other community mothers interactively in small groups using demonstration and teaching aids developed by a community working group. At final measurement 91 percent of mothers could explain five simple messages defining germ theory. Using germ theory in groups they identified forty high risk day-to-day practices and modified them to reduce diarrheal transmission. They adopted these new hygiene practices at rates ranging from 65 percent to 100 percent. Regression analysis suggests that understanding of germ theory was an important determinant of hygiene practices, cleanliness, and reduction in diarrheal incidence. Understanding of germ theory appeared to reduce diarrheal incidence not only through the interventions designed by the project but also changing perceptions of risk in the environment which led to spontaneous improvement in hygiene behaviors. We believe that accurate understanding of causes, transmission, and prevention of disease can 1) empower community and individual actions; and 2) contribute significantly to the impact of hygiene interventions. Therefore, it may be imperative to integrate teaching germ theory into community health education.

Increase in diarrheal disease associated with arsenic mitigation in Bangladesh

BACKGROUND

Millions of households throughout Bangladesh have been exposed to high levels of arsenic (As) causing various deadly diseases by drinking groundwater from shallow tubewells for the past 30 years. Well testing has been the most effective form of mitigation because it has induced massive switching from tubewells that are high (>50 µg/L) in As to neighboring wells that are low in As. A recent study has shown, however, that shallow low-As wells are more likely to be contaminated with the fecal indicator E. coli than shallow high-As wells, suggesting that well switching might lead to an increase in diarrheal disease.

METHODS

Approximately 60,000 episodes of childhood diarrhea were collected monthly by community health workers between 2000 and 2006 in 142 villages of Matlab, Bangladesh. In this cross-sectional study, associations between childhood diarrhea and As levels in tubewell water were evaluated using logistic regression models.

RESULTS

Adjusting for wealth, population density, and flood control by multivariate logistic regression, the model indicates an 11% (95% confidence intervals (CIs) of 4-19%) increase in the likelihood of diarrhea in children drinking from shallow wells with 10-50 µg/L As compared to shallow wells with >50 µg/L As. The same model indicates a 26% (95%CI: 9-42%) increase in diarrhea for children drinking from shallow wells with ≤10 µg/L As compared to shallow wells with >50 µg/L As.

CONCLUSION

Children drinking water from shallow low As wells had a higher prevalence of diarrhea than children drinking water from high As wells. This suggests that the health benefits of reducing As exposure may to some extent be countered by an increase in childhood diarrhea.

Impact of tubewell access and tubewell depth on childhood diarrhea in Matlab, Bangladesh

BACKGROUND

During the past three decades in Bangladesh, millions of tubewells have been installed to reduce the prevalence of diarrheal disease. This study evaluates the impacts of tubewell access and tubewell depth on childhood diarrhea in rural Bangladesh.

METHODS

A total of 59,796 cases of diarrhea in children under 5 were recorded in 142 villages of Matlab, Bangladesh during monthly community health surveys between 2000 and 2006. The location and depth of 12,018 tubewells were surveyed in 2002-04 and integrated with diarrhea and other data in a geographic information system. A proxy for tubewell access was developed by calculating the local density of tubewells around households. Logistic regression models were built to examine the relationship between childhood diarrhea, tubewell density and tubewell depth. Wealth, adult female education, flood control, population density and the child's age were considered as potential confounders.

RESULTS

Baris (patrilineally-related clusters of households) with greater tubewell density were associated with significantly less diarrhea (OR (odds ratio) = 0.87, 95% confidence interval (CI): 0.85-0.89). Tubewell density had a greater influence on childhood diarrhea in areas that were not protected from flooding. Baris using intermediate depth tubewells (140-300 feet) were associated with more childhood diarrhea (OR = 1.24, 95% CI: 1.19-1.29) than those using shallow wells (10-140 feet). Baris using deep wells (300-990 feet) had less diarrheal disease than those using shallow wells, however, the difference was significant only when population density was low (< 1000 person/km(2)) or children were at the age of 13-24 months.

CONCLUSIONS

Increased access to tubewells is associated with a lower risk of childhood diarrhea. Intermediate- depth wells are associated with more childhood diarrhea compared to shallower or deeper wells. These findings may have implications for on-going efforts to reduce exposure to elevated levels of arsenic contained in groundwater that is pumped in this study area primarily from shallow tubewells.

Contrasting influence of geology on E. coli and arsenic in aquifers of Bangladesh

Arsenic in groundwater has been a concern in South and Southeast Asia for more than a decade. We explore here the possibility that hydrogeologic factors recently shown to influence the distribution of arsenic might also affect the level of contamination of shallow (<20 m) wells with microbial pathogens. A total of 96 shallow tube wells in two nearby villages of Bangladesh were surveyed during the wet and dry seasons, along with 55 deeper wells in neighboring villages. One of the two villages is located in a particularly sandy environment where recharge is rapid and shallow wells contain little arsenic. Shallow aquifers in the other village are capped with an impermeable clay layer, recharge is an order of magnitude slower, and arsenic levels are high. The fecal indicator E. coli was detected in 43% of shallow wells, compared with 12% of deeper wells. More shallow wells contained E. coli during the wet season (61%) than during the dry season (9%). In the wet season, a higher proportion of shallow wells in the village with low arsenic levels (72%) contained E. coli compared with the village having high arsenic levels (43%). Differences in arsenic and E. coli distributions between the two sites are likely due to the differences in permeability of near-surface sediments although differences in average well-depth between the two villages (9 ± 4 vs. 15 ± 3 m) may play a role as well. Hydrogeologic conditions that favor high levels of fecal contamination but low levels of arsenic in shallow groundwater should be taken into account during arsenic mitigation throughout South and Southeast Asia.

Tubewell water quality and predictors of contamination in three flood-prone areas in Bangladesh

AIMS

To measure enteric bacterial contamination of tubewells in three flood prone areas in Bangladesh and the relationship of bacteriological contamination with tubewell sanitary inspection scores.

METHODS AND RESULTS

Microbiologists selected 207 tubewells in three flood prone districts, assessed physical characteristics of the tubewells and collected a single water sample from each tubewell. Tubewell water samples were contaminated with total coliforms (41%, n = 85), thermotolerant coliforms (29%, n = 60) and Escherichia coli (13%, n = 27). Among contaminated wells, the median CFU of contamination per 100 ml was 8 (interquartile range, 2-30) total coliforms, 5 (interquartile range, 2-23) thermotolerant coliforms and 6 (interquartile range, 1-30) E. coli. There was no significant association between tubewell contamination with E. coli, thermotolerant coliforms or total coliforms and a poor sanitary inspection score, though a history of inundation was associated with contamination with both E. coli and thermotolerant coliforms.

CONCLUSIONS

Tubewells in flood-prone regions of Bangladesh were commonly contaminated with low levels of faecal organisms, contamination that could not be predicted by examining the tubewell's external characteristics.

SIGNIFICANCE AND IMPACT OF THE STUDY

The forms currently used for sanitary inspection do not identify the most important causes of drinking water contamination in these communities.

Searching for an optimum solution to the Bangladesh arsenic crisis

Searching for an optimum solution to the Bangladesh arsenic crisis: Thirty years ago Bangladesh experienced very high levels of infant and child mortality, much of it due to water-borne disease in deltaic conditions where surface water was highly polluted. In what appeared to be one of the great public health achievements, 95% of the population were converted to drinking bacteria-free tubewell water from underground aquifers. Recently, it has been shown that perhaps 20% of this water is arsenic contaminated and alternatives to tubewell water have been sought. This paper reports on two national surveys collaboratively carried out in 2000 by the Health Transition Centre, Australian National University and Mitra and Associates, Dhaka: A census of tubewells and a household survey of tubewell use and arseniosis. The study found that the tubewell revolution has been promoted not only by health considerations but also by the demand for a household water facility and the desire by women to reduce workloads associated with using surface water. Because of this, and because the population had absorbed the message about safe tubewell water, it is argued that the movement away from the use of tubewell water should be as limited as possible, even if this means using safe tubewells which are often found in the neighbourhood. To enable such a move the most urgent need is not changing the source of water but comprehensive national water testing providing essential information to households about which wells are safe and which are not.

Microbiological analysis of tube-well water in a rural area of Bangladesh

Five tube-wells in Matlab, Bangladesh, were selected for analysis of selected biophysicochemical parameters. The results showed that all tube-well water samples contained zooplankton and bacteria. Results for some of the parameters were outside the accepted limits recommended by the World Health Organization for drinking water. It is concluded that water from tube-wells should be treated if used as drinking water.

Water quality and public health in northern Sudan: a study of rural and peri-urban communities

Access to adequate supplies of good quality drinking water continues to be limited among many rural and peri-urban communities in Africa, despite several decades of water improvement programmes. The present study investigated water quality at the source and point of consumption among rural and peri-urban communities in northern Sudan. Faecal coliform counts were determined by the membrane filtration technique and geometric mean counts compared in different seasons and among the different communities. Among nomadic pastoralists and riverine villages, both water sources and water stored for consumption had faecal coliform counts grossly in excess of WHO standards, with higher counts at the end of the rainy season. In the peri-urban community on the outskirts of Omdurman, while water quality from the distribution system had faecal coliform counts generally below 10 dl - 1, after storage, water was of considerably lower quality, with faecal coliform counts up to 1000 d1 - 1. The highest counts again occurred in the rainy season. Rates of diarrhoeal disease for Khartoum province were also greatest towards the end of the rainy season. The study has shown that poor quality water continues to be a major risk factor for public health in these communities.

Shigella infections

Shigella dysentery is a major public-health problem in many tropical areas. Despite improvements in water supplies and sanitation, it continues to be a disease of poor rural and urban communities and in populations affected by migration and crowding following disasters. Pathogenesis is due to colonic invasion, endotoxin, and, in Shigella dysenteriae 1, shiga toxin. As well as the local manifestations of dysentery, systemic complications include convulsions, haemolytic-uraemic syndrome, hyponatraemia and hypoglycaemia. The spread of shigella infection is most commonly person-person, although water and food-borne outbreaks have been reported. Since 1970, multiple antimicrobial resistance, particularly in Sh. dysenteriae 1, has complicated strategies for management. Multiply resistant strains have occurred in Latin America, Central Africa and southern and south-eastern Asia. No vaccines are currently available, and prevention and control will depend on public-health improvements and improved case management.

Water sources and environmental transmission of multiply resistant enteric bacteria in rural Bangladesh

The role of different water sources in the spread of multiply resistant enteric bacteria was investigated in rural Bangladesh. The prevalence of resistance to commonly used antimicrobial agents in the faecal flora of village children and the water quality and prevalence of resistance in village water sources were studied. Most of the children studied (81%) had multiply resistant faecal coliform bacteria, i.e. bacteria resistant to at least three antimicrobials. Although tubewells provided water with low faecal coliform counts, 62% of household storage pots contained water with moderate to high counts. Most of the storage pots (76%) and each of the river and pond sites tested contained multiply resistant isolates. Contamination of water within the household, and the widespread distribution of resistant coliforms in the environment, contribute to the high prevalence of multiply resistant enteric flora in the community. These findings are of importance in understanding the spread of multiply resistant enteric pathogens.

Cholera

Although it is more than a century since the discovery of the vibrio bacillus, cholera remains one of the great epidemic diseases of the tropical world. The epidemiology of cholera is an interaction between the biological and ecological properties of Vibrio cholerae and the complex patterns of human behaviour in tropical environments. The seventh pandemic has spread through all areas of the tropics, and cholera has become endemic in many new areas. The view that cholera was primarily water borne and that humans were the only long-term reservoir has been challenged by the discovery that V. cholerae can survive, often in a dormant state, in aquatic environments. The recent appearance of V. cholerae 0139, a new serotype that causes a disease clinically and epidemiologically indistinct from cholera, has further complicated our understanding of this ancient disease. Developments in the molecular characterization of V. cholerae are providing new information to explain the genetic and epidemiological variations.

Epidemiology and infection in famine and disasters

Despite advances in health care in the tropics, and the inputs of international and voluntary organisations, famine and disaster continue to cause major devastation in many developing countries. In the aftermath of acute disasters such as earthquakes or cyclones and in chronic post-famine relief camps, mortality rates may be 20–30 times greater than those in ‘normal’ years [1]. The interaction of malnutrition, crowding, poor environmental sanitation, and changes in host parasite relationships due to migration or environmental change, result in communicable diseases playing a major role in excess morbidity and mortality.

Waterborne transmission and the evolution of virulence among gastrointestinal bacteria

Diarrhoeal diseases are primary contributors to millions of deaths annually. Yet, little is known about the evolutionary reasons for the differences in virulence among gastrointestinal pathogens. Applying the comparative, cost/benefit approach of evolutionary biology this paper proposes that waterborne transmission should favour evolution towards high virulence. This hypothesis is supported by a cross-specific test, which shows that waterborne transmission is strongly correlated with the virulence of bacterial gastrointestinal pathogens of humans. Alternative explanations of this correlation are not supported by available data. These findings bear on public health policy because they draw attention to a previously unrecognized long-range benefit gained from purification of water supplies; diarrhoeal pathogens may evolve to lower levels of virulence.

Analysing morbidity determination with flawed data: the case of dysentery in regional India

A method is suggested for removing measurement error from morbidity data collected in Third World countries. The method assumes the existence of diseases which are independent of socio-economic factors and exploits observed correlations between these disease and these factors to construct an index of measurement error. This index may be used as an explanatory variable in the analysis of other diseases which are hypothesised to have socio-economic causes which are the object of research. The method is applied to statewide data for India where the index of measurement error is based on influenza data which is then used to isolate the socio-economic factors that influenced dysentery.

Jakarta kampung morbidity variations: some policy implications

Urban growth in the developing world is likely to be accompanied by health problems in crowded zones where services are not available. Geographical analyses of aggregated data may prove interesting, but reliability and utility of spatial correlations are greater when microscale data are acquired. In this study data for households in 11 Jakarta neighborhoods were collected in interviews. Malaria and diarrheal disease patterns have been correlated with environmental and socioeconomic variables at the household level. Several environmental characteristics seem to be closely associated with the incidence of malaria and diarrheal diseases.

Enumeration of Vibrio cholerae O1 in Bangladesh waters by fluorescent-antibody direct viable count

A field trial to enumerate Vibrio cholerae O1 in aquatic environments in Bangladesh was conducted, comparing fluorescent-antibody direct viable count with culture detection by the most-probable-number index. Specificity of a monoclonal antibody prepared against the O1 antigen was assessed and incorporated into the fluorescence staining method. All pond and water samples yielded higher counts of viable V. cholerae O1 by fluorescent-antibody direct viable count than by the most-probable-number index. Fluorescence microscopy is a more sensitive detection system than culture methods because it allows the enumeration of both culturable and nonculturable cells and therefore provides more precise monitoring of microbiological water quality.

Epidemiological assessment of the health and nutrition of Ethiopian refugees in emergency camps in Sudan, 1985

The findings from epidemiological data that were collected from emergency camps for Ethiopian refugees during a mass influx of refugees into Eastern Sudan in 1985 are presented. An overall mortality of 8.9 per 10,000 a day was recorded during February 1985, and in children under 5 years of age the rate was 22 per 10,000 a day. The estimated prevalence of malnutrition (calculated as less than 80% of the reference weight for height) ranged from 32% to 52% among children of preschool age. The principal causes of morbidity and mortality were measles, diarrhoea and dysentery, respiratory infections, and malaria. The findings suggest that malnutrition and disease increased in these refugees after they arrived in the camps. Epidemiological assessment is essential to help to maintain the health and nutrition of refugees in emergency camps.

Cryopreservation of semen in men with testicular tumour or Hodgkin's disease: results of artificial insemination of their partners

After cryopreservation of semen from men with testicular tumours or Hodgkin's disease the success rate of artificial insemination of their partners was analysed. The cumulative probability of pregnancy at 6 months was 45%. The chance of pregnancy was greater when timing of ovulation was predicted with measurements of urinary luteinising hormone. Sperm density and sperm motility were also important in predicting the likelihood of pregnancy.

Studies of diarrhoea in Quindio (Colombia): problems related to water treatment

This paper studies the association between fluctuations in rates of diarrhoea among children less than 5 years old in Armenia (Quindio) and variations in the application of chlorine in the aqueduct of the city. The study shows that to a great extent diarrhoea morbidity can be explained by the application of chlorine which does not reach useful levels of concentration during the required time. The article concluded by recommending the improvement of existing treatment plants and investing the necessary resources in new plants to insure the quality of water.

Social and environmental factors associated with diarrhoea and growth in young children: child health in urban Africa

This study investigates the relationship between social and environmental variables and diarrhoea and growth in children aged between 6 and 36 months in an urban area of The Gambia, West Africa. The social and environmental conditions of 493 children were observed and recorded over a period of 12 months. Two hundred and seventy-seven children were under weekly diarrhoea surveillance for a 15 week period during the wet season and 322 children had anthropometric measurements taken in May and September. Computer analysis was used to determine association between single and multiple environmental and social factors and diarrhoea prevalence and growth. The results of the diarrhoea surveillance showed that there was considerable variation between individual children. Thirty children had no diarrhoea during the period of surveillance and 30 had diarrhoea for over 24% of the time, with 2 children having diarrhoea for more than 50 days out of a total of 105. None of the social and environmental variables recorded showed a significant relationship with diarrhoea prevalence. The anthropometric measurements showed that at the end of the wet season, in September, 23% of children in this age group were less than 90% of the National Centre for Health Statistics standards of height for age and several of the variables recorded showed a statistically significant association with this measurement.

Interruption of shigellosis by hand washing

High attack rates, increasing resistance to antibiotics and high mortality make shigellosis a serious problem. As Shigella is associated with poor hygiene we examined the effectiveness of a simple intervention, washing hands with soap and water, in checking the spread of the disease. The study population was comprised of confirmed cases of shigellosis. These and matched controls were followed up for 10 days. Several pieces of soap and earthenware pitchers for storing water were provided to the study families and they were advised to wash their hands with soap and water after defaecation and before meals. Compliance was monitored daily by observing the size of the soap and residual water. Rectal swabs of contacts of both the groups were obtained for culture. The secondary infection rate was 10.1% in the study group and 32.4% in the control group. The secondary case (symptomatic) rate was 2.2% in the study group and 14.2% in the control group. These results suggest that hand-washing has a positive interrupting effect, even in unsanitary environments.

Role of water and sanitation in the incidence of cholera in refugee camps

The purpose of this study was to determine the prevalence of cholera in two groups: (i) people using covered latrine and piped water; (ii) people using uncovered surface latrine and pond and tubewell water. The study population consisted of cholera cases admitted to the ICDDR, B hospital from three refugee camps. In the one camp with sanitation facilities, the cholera rate was 1.6 per 1,000, whereas in the two camps without facilities the rates were 4.0 and 4.3 per 1,000. Following demolition of the camps, the cholera rates decreased significantly in the camps geographical zones. Cholera was not totally eliminated, even in the one camp with sanitation facilities, suggesting that health education, as well as proper sanitation, is necessary to eradicate cholera.

Selective primary health care: an interim strategy for disease control in developing countries

Priorities among the infectious diseases affecting the three billion people in the less developed world have been based on prevalence, morbidity, mortality and feasibility of control. With these priorities in mind a program of selective primary health care is compared with other approaches and suggested as the most cost-effective form of medical intervention in the least developed countries. A flexible program delivered by either fixed or mobile units might include measles and diphtheria-pertussis-tetanus vaccination, treatment for febrile malaria and oral rehydration for diarrhea in children, and tetanus toxoid and encouragement of breast feeding in mothers. Other interventions might be added on the basis of regional needs and new developments. For major diseases for which control measures are inadequate, research is an inexpensive approach on the basis of cost per infected person per year.