Excreta Disposal Research Articles

Family latrines and paediatric shigellosis in rural Bangladesh: benefit or risk?

The potential benefits of installing excreta disposal facilities on the burden of paediatric diarrhoea in less-developed settings remain controversial. We conducted a longitudinal study to evaluate whether family latrines are associated with interruption of the transmission of shigellosis to younger children in rural Bangladesh. We prospectively studied 1529 children under 5 years of age exposed to index cases of Shigella dysentery. In all 219 children with culture-proven shigellosis detected during 1 month of follow-up were compared with 1310 control children who did not develop shigellosis or Shigella-negative dysentery. Overall, the presence of a family latrine appeared to be associated with a higher, not a lower, risk of paediatric shigellosis (adjusted odds ratio (ORa) = 1.37, 95% confidence interval (CI): 0.99-1.89). While use of a pit or sanitary latrine revealed no evidence of a protective association (ORa = 0.96, 95% CI: 0.43-2.15), use of a hanging latrine in which faeces were discharged directly onto the ground or into a body of water was associated with a notable increase of risk (ORa = 1.42, 95% CI: 1.02-1.98, P < 0.05). While cautioning that installation of sanitary latrines may not be sufficient to reduce the burden of paediatric shigellosis in less-developed settings, these data suggest that eliminating unsanitary latrines constitutes a potentially important intervention in its own right in these settings.

Patterns of Water Quality in Rural Areas of Assyut Governorate, Egypt

In 1990-1991 an action-research programme in the field of rural water supply and sanitation was implemented with the objective “To assess to what extent childhood diarrhoea is reduced by the delivery of hardware facilities which improve water quality, water availability and excreta disposal, and also including an intensive educational package directed toward improving behaviours concerning water use and personal and domestic hygiene”. The intervention in Assyut Governorate comprising the construction of handpumps and latrines and a health education programme, was implemented during the second half of 1990. The data collection and data evaluation have been carried out during the period 1990-1991. Data were collected from the villages served with a complete intervention package as well as in control villages. This paper deals mainly with the water quality issues which were part of the research programme. A comparison is presented for the water quality from both traditional and new handpumps. This comparison is supported by data collection throughout the research period within certain intervals, and by data collected from other handpumps installed at earlier times in areas within Upper Egypt. Findings concerning the actual drinking water quality, and the quality control of intervention and monitoring procedures are also discussed. Major conclusions drawn from the results of the monitoring programme are:–The design, the drilling method and a proper development of handpump wells play an important role in the quality control of its water.–The bacteriological water quality improves only gradually after construction and eventually reaches acceptable levels. However, deep groundwater is thought to be of bacteriologically excellent quality. The most probable explanation for this gradual improvement is therefore the relatively long survival times of bacteria that entered the wells during construction.–Although it is not the intention of this paper to discuss the behavioural changes in the village communities during the research period, it was observed that, while water quality from handpumps is improving with time, the water quality from in-house zirs (storage reservoirs for drinking water) remained poor.

Factores de riesgo en la transmisión del Cólera en Salahonda (Nariño)

In the Department of Nariño on the Pacific colombian coast, a case-control study was performed in Salahonda village. The main purpose of this study was to fin out the risk factors concerning the transmission of cholera. People living in stilt huts and deficient aqueduct water supply constituted the highest risk: OR:23 and OR:19, respectivly. Drinking unboiled milk or eating inadequately washed vegetables and unapproprieted human disposal of human excreta also increased the risk of developing the disease. Improvement of sanitary education, the supply of purified water and the adequate disposal of human excreta would constitute the best strategies for the control of this illness in theses underverloped communities.

Day Care Center Attendance and Diarrheal Morbidity in Colombia

This study was designed to determine whether day care center attendance was associated with increased risk of diarrheal disease among poor children in an urban, developing country setting. From July 17 to December 18, 1988, mothers of 493 Colombian children less than 5 years old (241 attendees and 252 nonattendees) were interviewed weekly about diarrheal events during the previous week. The incidence of diarrhea was greater for day care center attendees than for nonattendees (3.2 vs 2.0 episodes per child-year, P < .0005). For children less than 2 years of age, attendees experienced 7.2 episodes/child-year vs 3.5 episodes per child-year for nonattendees (P < .0005). Analyses controlling for water source and availability, excreta disposal, socioeconomic status, and duration of follow-up showed that the increased diarrheal risk was limited to children younger than 3 years of age spending more than 30 hours per week in the centers. In addition, although the risk among attendees of suffering diarrheal episodes of longer duration was fairly constant across levels of socioeconomic status, this risk was inversely proportional to socioeconomic status for nonattendees. In summary, the increase in risk of diarrhea among young, full-time day care attendees was modest, yet important, because diarrhea continues to be a major cause of morbidity and mortality in Colombian children.

Excreta Disposal Behaviour and Latrine Ownership in Relation to the Risk of Childhood Diarrhoea in Sri Lanka

A case-control study of environmental and behavioural risk factors for childhood diarrhoea was conducted in Kurunegala district, Sri Lanka. From five hospitals, 2458 children aged less than 5 years and suffering from diarrhoea were recruited as clinic cases, and a further 4140 reporting with complaints other than diarrhoea were recruited as clinic controls. Community-based cross-sectional surveys were also conducted in three of the five areas served by these hospitals, and from these a further 1659 children were recruited as community controls. Children from households where excreta were reported to be disposed of in a latrine were less likely to have diarrhoea than children whose families improperly disposed of excreta. The results obtained from comparisons of cases with clinic controls (adjusted odds ratio [OR] 1.42, 95% confidence interval [CI] : 1.01-1.98), and of cases with community controls (OR 1.35, 95% CI : 0.85-2.13) were in agreement, suggesting that no important selection bias operated on this association. If the observed proportion (91%) of improper excreta disposal among the population could be reduced to 50%, 12% of childhood diarrhoea episodes would be prevented. Although latrine ownership may be a necessary condition for safe excreta disposal behaviour, diarrhoeal morbidity may only be reduced in Sri Lanka if behavioural changes take place concomitant with the construction of sanitation facilities.

Environmental Health Conditions and Cholera Vulnerability in Latin America and the Caribbean

Epidemic cholera reached South America in January 1991 and later spread to Central America and the United States. It afflicted 312000 people and claimed 3200 lives. Since cholera had not been in Latin America for almost 70 years health authorities allowed environmental health barriers to cholera collapse. For example the Governments of the Region agreed in 1961 to abide by the Charter of Punta del Este to provide water and sewerage to 70% of the urban population and 50% f the rural population by 1971. They did not achieve their goals for the rural population. In fact at the end of 1988 water was piped to 79% of the urban households and an additional 11% of the urban population had access to a public water source. Sewerage services served 49% of the urban population and with other methods of excreta disposal 80% of the population had adequate excreta disposal. On the other hand only 55% of rural inhabitants had access to either piped water or public standpipes. Further sanitary excreta disposal services only covered 32%. Besides the water quality of existing water supply systems was poor. Since feces of infected people have as many as 1 billion Vibrio cholerae and in some of Vibrio up to 80% of carriers exhibit only mild symptoms or no symptoms at all it is easy to understand how cholera took hold in Latin America. Researchers identified the points of contamination responsible for the cholera outbreak in Piura and Trujillo Peru to be wells distribution systems and house. Annual population growth in Latin America at 2.6% poses specific problems to providing enough water and sanitation services to all in need especially those in marginal areas around the cities (who will make up 40% of the population by 2000).

Groundwater Quality Monitoring in Relation to On‐site Sanitation in Developing Countries

ABSTRACTGroundwater quality monitoring is considered to be an essential component of any sanitation programme where simultaneous groundwater abstraction and on‐site waste disposal are proposed. The low priority currently accorded to monitoring programmes reflects inexperience of monitoring in general and consequent misconceptions about the content and benefits of groundwater quality monitoring.The purpose of this paper is two‐fold. Firstly to explain why groundwater quality monitoring is a requisite component of all pilot sanitation projects which involve on‐site disposal of human excreta. Secondly, to demonstrate that it is not unrealistic to expect groundwater quality monitoring to be carried out in relation to all such pilot projects.The resource constraints inherent in developing countries need not prohibit routine monitoring. However, it is important to define clearly the specific objectives of any monitoring programme and to design a sampling network appropriate to both these objectives and the site conditions. Monitoring must not be confused with initial assessment of prevailing conditions, nor with research studies, for which the aims, duration, technical complexity, and hence investment, are quite different.Monitoring is a process which can evolve with increased investment to address various questions regarding the causes, nature and processes of groundwater contamination.

The impact of improvement of water supply and sanitation facilities on diarrhea and intestinal parasites: a Brazilian experience with children in two low-income urban communities.

During the second half of 1986 the impact of the improvement of water supply and excreta disposal facilities on diarrheal diseases and intestinal parasitosis was studied in 254 children up to six years of age from two favelas (shanty towns) of Belo Horizonte, Brazil. The estimated incidence of diarrhea was 6.2 episodes/child year and the estimated period prevalence reached 31.0 episode days/child/year. The point prevalence of parasitosis was 70.7% (Ascaris lumbricoides: 55.4%, Trichuris trichiura: 19.6%, Giardia lamblia: 17.9%). The estimated prevalence of diarrhea decreased with improvement of water supply and sanitation facilities to 45% and 44% respectively, but no statistically significant impact was observed in the case of parasitosis. School education and weaning practice were found to be other important determinants of diarrhea.

Non-A, non-B hepatitis

Diagnosis of non-A, non-B hepatitis (NANB) is made after exclusion of other known causes of hepatitis. Parenterally spread non-a, non-B hepatitis (PNANB) and enterally transmitted non-A, non-B hepatitis (ENANB) almost certainly appear to be two different diseases. The definite causative agents have not hitherto been identified. Much of our knowledge of NANB is based on (i) experimental studies on chimpanzees; and (ii) epidemiological studies. Parenterally spread non-A non-B hepatitis caused by whole blood transfusion and blood-product infusion has different incubation periods and may be caused by different agents. It is a mild disease clinically, and the majority of the patients are asymptomatic. It can be prevented only by judicious use of blood transfusion. Whenever possible, blood/blood products should be derived from individual volunteer donors who are anti-HB ε sero-negative and have serum alanine transaminase of under 45IU/1. Enterally-transmitted non-A non-B hepatitis is endemic in the Indian subcontinent, South-East Asia, North and East Africa and Latin America. Epidemic NANB is usually transmitted by water supply contaminated with feces. ENANB has a predilection for young adults. The disease is usually mild, except in pregnant women, who have a high case-fatality rate from fulminant hepatic failure. Control measures include provision of clean water supplies, safe disposal of human excreta and sound personal and food hygiene practices. non-A, non-B hepatitis/causative agents/control measures

Cultural ecology of prehistoric parasitism on the Colorado Plateau as evidenced by coprology.

The study of coprolites (desiccated feces) is recognized as a viable method for analyzing parasitism of prehistoric peoples. Eight species of helminth parasites, including nematodes, cestodes, and acanthcephalans, have been recovered from archaeological sites on the Colorado Plateau. The comparative analysis of parasitological findings illustrates the effects of changing subsistence strategies and varying life-style on prehistoric human parasitism. This comparative study is based on the analysis of coprolites recovered from one Archaic hunter-gatherer site and two Anasazi agricultural villages. Hunter-gatherers are represented by coprolites from Dust Devil Cave in south-eastern Utah. Coprolites of prehistoric agriculturalists from Antelope House in Canyon de Chelly, Arizona, and from Salmon Ruin in northwestern New Mexico were studied. The results demonstrate that helminth parasitism increased with the advent of agriculture. Between the agricultural sites, differences in patterns of excreta disposal, foraging behavior, and local ecology resulted in pronounced variations in both percentage of coprolites containing parasite remains and the number of parasite species represented.

WATERBORNE NON-A, NON-B HEPATITIS

Waterborne non-A, non-B hepatitis (NANB) is responsible for outbreaks of hepatitis with a predilection for young adults. The disease is usually mild, except in pregnant women, who have a high case-fatality rate from fulminant hepatic failure. Diagnosis is largely based on the epidemiological findings of faecal contamination of drinking water and serological exclusion of hepatitis A and B virus infection. Histological features of liver biopsy specimens are characteristic and virus-like particles in the stool are aggregated by antibody present in acute and convalescent phase sera of the test subject. NANB is widespread in India and several countries of South-East Asia; it is increasingly recognised in Africa and may occur in Latin America. Control measures include provision of clean water supplies, safe disposal of human excreta, and sound personal and food hygiene practices. Passive immunisation with immunoglobulin derived from healthy donors resident in the countries affected by the disease may protect vulnerable groups.

Serological and demographic survey of Epstein-Barr virus infection in Ethiopia

A demographic and serological survey of Epstein-Barr virus infection was carried out in 5 geographically representative regions of Ethiopia. 80% of the 500 people studied were under 15 years of age. 82% of children under 5 years of age and 94% under 10 years of age were positive for IgG anti-viral capsid antigen (VCA) antibody. 51 of 100 children under 12 months of age and from 5 different provinces were positive for anti-VCA antibody. Of these, 23 were under 6 months. The distribution of anti-VCA antibody positivity was comparable in both sexes, in each age group and in the different provinces at different altitudes. Economic status, expressed in terms of estimated income, type of water supply, mode of excreta disposal and family size, did not significantly influence the distribution of anti-VCA antibody. Thus, early exposure to Epstein-Barr virus, with asymptomatic or subclinical presentation, probably accounts for the rarity of typical infectious mononucleosis in young adult Ethiopians. The lack of a relationship between Epstein-Barr virus infection and Burkitt's lymphoma, nasopharyngeal carcinoma, malaria as well as liver diseases is briefly discussed.

Limitation of communal latrines in changing the prevalence of parasites and diarrhoeal attack rate in Dhaka Peri-urban slums

A study of the effects of communal latrines on diarrhoeal incidence and parasite prevalence rates was conducted in 1983 at Tongi, which had five communal Oxfam latrines with a manual flushing system for 924 people; and at Kalsi, which had 39 open fit latrines for 823 people. Inhabitants' stool samples were tested initially and also after twelve months to see the reinfection rates. All inhabitants were dewormed with pyrantel, and were visited weekly to obtain diarrhoea histories. In both communities, there were high prevalence rates of roundworm, hookworm, Trichuris trichiura, Entamoeba histolytica, Giardia lambia and Strongyloides stercoralis. Following the dewormings, the prevalence rates of roundworm, hookworm and Trichuris infection came down significantly, in both areas. The prevalence or reinfection rates remained identical in both communities. There was also no difference in diarrhoea incidence rate for the two areas. It is found that keeping all other variables unchanged, use of communal latrines, without strict disposal of everyone's excreta, does not affect parasite prevalence and diarrhoea rates. People must be educated about the use of communal latrines and the safe disposal of all excreta, including that of children.

A note on survival of salmonellas during anaerobic digestion of cattle dung.

Anaerobic digestion of night soil with cattle dung slurry in biogas plants is advocated in Indian villages as a means of disposal of human excreta in the absence of conventional sanitary systems. Although intestinal pathogens are likely to be eliminated during anaerobic digestion, there is no conclusive evidence that this is so. Large numbers of saprophytic organisms in the fermenting mass make it impossible to detect the residual pathogens. Use of an antibiotic-resistant strain of Salmonella typhimurium as a test organism to study its survival during anaerobic digestion showed that the organism is totally eliminated in nine days.

Hepatitis A, B, and delta infection in Ethiopia: a serologic survey with demographic data.

A total of 500 individuals from five different regions of Ethiopia were studied. Demographic and clinical data were recorded and serologic tests were carried out to detect antigen and antibody markers of hepatitis B virus, hepatitis A virus, and the delta agent. Data on the economic status, number of rooms per household, number of persons per household, type of water supply, and mode of excreta disposal revealed that the majority of the population surveyed lived with economic hardship, overcrowding and poor hygiene. Only 36 persons gave a past history of jaundice. The mean carrier rate of hepatitis B surface antigen (HBsAg) was 6.2%, the mean overall hepatitis B virus marker prevalence was 42%, and in those over 14 years of age it was 76%. Among those who were positive for HBsAg, there was a tendency for hepatitis B e antigen (HBeAg) to decrease and the corresponding antibody (anti-HBe) to increase with advancing age. No woman more than 15 years of age had demonstrable hepatitis B e antigen in serum. Antibody to hepatitis A virus was detected in 84%. Three positive individuals were found to have antibody to the delta agent.

Potable Groundwater Supplies and Low‐cost Sanitary Engineering — How Compatible?

Many developing countries are counting on groundwater to supply an increasing proportion of their demand for drinking. There is currently a drive, in many of these same countries, for major improvements in excreta disposal, involving the intensive use of unsewered sanitation or sewage treatment in stabilization ponds with effluent reuse. Under certain hydrogeological conditions these low‐cost technologies may be in conflict with the use of groundwater for potable supplies. The principal potential hazards are identified, discussed and illustrated. A more detailed understanding of these problems, coupled with improved design, careful siting and integrated planning of the installations involved, is required to reduce the groundwater pollution hazard.

Human rotavirus infection in Malaysia. II. A study on the influence of living standard on the prevalence of rotavirus-associated gastroenteritis in children hospitalized with diarrhoea.

The association between different living standards and the prevalence of rotavirus gastroenteritis in children and infants up to 6 years of age who were admitted to the gastroenteritis ward of the Kuala Lumpur General Hospital from December 1981 to November 1982 was studied. Rotavirus gastroenteritis was determined by the detection of rotavirus in the feces of the patients using an enzyme-linked immunosorbent assay. The results of this survey indicate higher prevalence of rotavirus-associated gastroenteritis in children from lower socioeconomic classes. The prevalence of the disease is higher in large families. Hygienic home circumstances reduced the risk of rotavirus diarrhea but the source of water supply used for drinking and washing and methods of human excreta disposal seem not be important factors in influencing the prevalence of the disease. (authors modified)

Selective primary health care: strategies for control of disease in the developing world. XII. Ascariasis and trichuriasis.

Ascariasis and trichuriasis are the most prevalent and widespread intestinal helminthiases. Transmission of disease occurs by ingestion or inhalation of Ascaris and Trichuris eggs embryonated in the soil. During the migration of Ascaris to the lungs, pneumonic symptoms may develop. The intestinal stage of the parasite can cause severe symptoms and complications when the worm burden is high. High numbers of Trichuris may cause diarrhea. The poor standard of hygiene, the biology of the parasite (which is such that a high number of very resistant eggs are produced), and the habits of the host (such as the use of night soil) are factors causing a high prevalence of infection in many countries in Asia, Africa, South America, and Europe. The mechanism of the transmission of Ascaris varies in different communities. The peak of infection is among children aged four to 14 years. Worm burden is normally low, and only a small segment of the population harbors a high proportion of the worms present in a community. Control of infections due to Ascaris and Trichuris is feasible by a combination of mass chemotherapy with the effective drugs now available, safe disposal of excreta, destruction of the eggs, and health education.

Water Supply and Sanitation in Developing Countries

Multi-authored books often have problems of uneven presentation, and this one is no exception. However, there are several chapters that stand out as extremely valuable contributions to the understanding of water supply and sanitation technologies for developing countries. The contributors to a person have had long years of experience in developing countries. They addressed current problems with apt examples taken from these countries. The presentation is practically oriented. It is a “how-to” book that will be useful to those who deal with tropical environmental health problems. The chapter on Simple Water Treatment Method is practical and extremely well written. Sewerage: The Developing Country Dilemma points to the problem in planning when sanitation is made the weak step-sister to water supply as is often the case. The stereotype of the “foreign consultant” by the authors of this chapter, however, is patently unfair to many workers who labor at appropriate technology.The chapter on Low-Cost Alternatives to Sewerage provides various methods for excreta disposal, but also raises important questions.

Excreta disposal facilities and intestinal parasitism in urban Africa: preliminary studies in Botswana, Ghana and Zambia

The relationships between intestinal parasitism and excreta disposal technologies in Gaborone (Botswana), Ndola (Zambia) and Kumasi (Ghana) were investigated. Parasitic prevalence and intensity rates amongst groups of urban residents having similar socio-economic status and housing, but different excreta disposal technologies, were compared. In Gaborone, there was no evidence of a difference in intestinal parasitism between those using aqua privies and having access to public taps and those in identical houses enjoying flush toilets, in-house water connections and showers. In Ndola, the group with sewered aqua privies had larger houses, cleaner toilets, better water supplies, longer residence and more people in paid employment than the groups using pit latrines or communal flush toilets. Despite this, the sewered aqua privy users were not found to be different from the other groups with regard to hookworm and protozoal infection but had significantly higher Ascaris infection rates. In Kumasi, despite the differences in toilet type—from squalid communal aqua privies, through often fouled bucket latrines to well-maintained flush toilet systems—and despite also the differences in water provision, no evidence was obtained of any differences in intestinal parasitism between the groups studied. These findings suggest that the provision of superior water and sanitation facilities to a small cluster of houses, or to houses scattered through an area, may not protect those families from infection if the over-all level of faecal contamination of the environment is high. The sample sizes and response rates achieved in this study were low and follow-up studies, employing the same methodology but with larger samples, are recommended.