Measurement issues in trials of pediatric acute diarrheal diseases: a systematic review

BACKGROUND: Worldwide, diarrheal diseases rank second among conditions that afflict children. Despite the disease burden, there is limited consensus on how to define and measure pediatric acute diarrhea in trials. OBJECTIVES: In RCTs of children involving acute diarrhea as the primary outcome, we documented (1) how acute diarrhea and its resolution were defined, (2) all primary outcomes, (3) the psychometric properties of instruments used to measure acute diarrhea and (4) the methodologic quality of included trials, as reported. METHODS: We searched CENTRAL, Embase, Global Health, and Medline from inception to February 2009. English-language RCTs of children younger than 19 years that measured acute diarrhea as a primary outcome were chosen. RESULTS: We identified 138 RCTs reporting on 1 or more primary outcomes related to pediatric acute diarrhea/diseases. Included trials used 64 unique definitions of diarrhea, 69 unique definitions of diarrhea resolution, and 46 unique primary outcomes. The majority of included trials evaluated short-term clinical disease activity (incidence and duration of diarrhea), laboratory outcomes, or a composite of these end points. Thirty-two trials used instruments (eg, single and multidomain scoring systems) to support assessment of disease activity. Of these, 3 trials stated that their instrument was valid; however, none of the trials (or their citations) reported evidence of this validity. The overall methodologic quality of included trials was good. CONCLUSIONS: Even in what would be considered methodologically sound clinical trials, definitions of diarrhea, primary outcomes, and instruments employed in RCTs of pediatric acute diarrhea are heterogeneous, lack evidence of validity, and focus on indices that may not be important to participants.

Impact of Water Supply and Sanitation on Diarrheal Morbidity among Young Children in the Socioeconomic and Cultural Context of Rwanda (Africa)

This project studied the frequency and of water contamination at the source, during transportation, and at home to determine the causes of contamination and its impact on the health of children aged 0 to 5 years. The methods used were construction of the infrastructure for three sources of potable water, administration of a questionnaire about socioeconomic status and sanitation behavior, anthropometric measurement of children, and analysis of water and feces. The contamination, first thought to be only a function of rainfall, turned out to be a very complex phenomenon. Water in homes was contaminated (43.4%) with more than 1100 total coliforms/100 ml due to the use of unclean utensils to transport and store water. This socio-economic and cultural problem should be ad- dressed with health education about sanitation, The latrines (found in 43.8% of families) presented a double-edged problem. The extremely high population density reduced the surface area of land per family, which resulted in a severe nutritional deficit (15% of the children) affecting mainly young children, rendering them more susceptible to diarrhea (three episodes/child/year).

Acute infectious diarrhea lessons learned from the past?

The Journal of Pediatric Gastroenterology and Nutrition (JPGN) has been at the forefront of many of the seminal advances into research on infectious diarrhea. In 1982, the first article of the JPGN was entitled “Oral Therapy for Dehydration in Diarrheal Diseases as a Global Problem” and has set the scene for several thousand subsequent articles. In his initial editorial, Finberg (1) posed several questions, which still have relevance 30 years later: 1. When is oral rehydration not appropriate, if ever? 2. What should be the composition of the oral solution and should there be more than one? 3. Should recommended practice be different in lesser-developed countries from those in developed countries? 4. Should the salts and glucose be prepackaged or should home supplies be used by instructed mothers? 5. When should standard feedings be resumed?

The Health Impacts of Climate Change: A Study of Cholera in Tanzania

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Habitat for Humanity: Calibrating Best Practice Against the MDGs

Poverty alleviation lies at the heart of contemporary international initiatives on development. The key to development is the creation of an environment in which people can develop their potential, leading productive, creative lives in accordance with their needs, interests and faith. This entails, on the one hand, protecting the vulnerable from things that threaten their survival, such as inadequate nutrition, disease, conflict, natural disasters and the impact of climate change, thereby enhancing the poor’s capabilities to develop resilience in difficult conditions. On the other hand, it also requires a means of empowering the poor to act on their own behalf, as individuals and communities, to secure access to resources and the basic necessities of life such as water, food, shelter, sanitation, health and education. ‘Development’, from this perspective, seeks to address the sources of human insecurity, working towards ‘freedom from want, freedom from fear’ in ways that empower the vulnerable as agents of development (not passive recipients of benefaction).

Recognition of the magnitude of the problems confronted by the poor and failure of past interventions to tackle basic issues of human security led the United Nations (UN) in September 2000 to set out a range of ambitious, but clearly defined, development goals to be achieved by 2015. These are known as the Millennium Development Goals (MDGs). The intention of the UN was to mobilise multilateral international organisations, non-governmental organisations and the wider international community to focus attention on fulfilling earlier promises to combat global poverty. This international framework for development prioritises: the eradication of extreme poverty and hunger; achieving universal primary education; promoting gender equality and empowering women; reducing child mortality; improving maternal health; combating HIV/AIDS, malaria and other diseases; ensuring environmental sustainability; and developing a global partnership for development. These goals have been mapped onto specific targets (18 in total) against which outcomes of associated development initiatives can be measured and the international community held to account. If the world achieves the MDGs, more than 500 million people will be lifted out of poverty. However, the challenges the goals represent are formidable. Interim reports on the initiative indicate a need to scale-up efforts and accelerate progress.
Only MDG 7, Target 11 explicitly identifies shelter as a priority, identifying the need to secure ‘by 2020 a significant improvement in the lives of at least 100 million slum dwellers’. This raises a question over how Habitat for Humanity’s commitment to tackling poverty housing fits within this broader international framework designed to allievate global poverty. From an analysis of HFH case studies, this report argues that the processes by which Habitat for Humanity tackles poverty housing directly engages with the agenda set by the MDGs. This should not be regarded as a beneficial by-product of the delivery of decent, affordable shelter, but rather understood in terms of the ways in which Habitat for Humanity has translated its mission and values into a participatory model that empowers individuals and communities to address the interdependencies between inadequate shelter and other sources of human insecurity. What housing can deliver is as important as what housing itself is.

Examples of the ways in which Habitat for Humanity projects engage with the MDG framework include the incorporation of sustainable livelihoods strategies, up-grading of basic infrastructure and promotion of models of good governance. This includes housing projects that have also offered training to young people in skills used in the construction industry, microfinanced loans for women to start up their own home-based businesses, and the provision of food gardens. These play an important role in lifting families out of poverty and ensuring the sustainability of HFH projects. Studies of the impact of improved shelter and security of livelihood upon family life and the welfare of children evidence higher rates of participation in education, more time dedicated to study and greater individual achievement. Habitat for Humanity projects also typically incorporate measures to up-grade the provision of basic sanitation facilities and supplies of safe, potable drinking water. These measures not only directly help reduce mortality rates (e.g. diarrheal diseases account for around 2 million deaths annually in children under 5), but also, when delivered through HFH project-related ‘community funds’, empower the poor to mobilise community resources, develop local leadership capacities and even secure de facto security of tenure from government authorities.

In the process of translating its mission and values into practical measures, HFH has developed a range of innovative practices that deliver much more than housing alone. The organisation’s participatory model enables both direct beneficiaries and the wider community to tackle the insecurities they face, unlocking latent skills and enterprise, building sustainable livelihood capabilities. HFH plays an important role as a catalyst for change, delivering through the vehicle of housing the means to address the primary causes of poverty itself. Its contribution to wider development priorities deserves better recognition. In calibrating the success of HFH projects in terms of units completed or renovated alone, the significance of the process by which HFH realises these outcomes is often not sufficiently acknowledged, both within the organisation and externally. As the case studies developed in the report illustrate, the methodologies Habitat for Humanity employs to address the issue of poverty housing within the developing world, place the organisation at the centre of a global strategic agenda to address the root causes of poverty through community empowerment and the transformation of structures of governance.

Given this, the global network of HFH affiliates constitutes a unique organisational framework to faciliate sharing resources, ideas and practical experience across a diverse range of cultural, political and institutional environments. This said, it is apparent that work needs to be done to better to faciliate the pooling of experience and lessons learnt from across its affiliates. Much is to be gained from learning from less successful projects, sharing innovative practices, identifying strategic partnerships with donors, other NGOs and CBOs, and engaging with the international development community on how housing fits within a broader agenda to alleviate poverty and promote good governance.

New scientific paradigms for probiotics and prebiotics

The inaugural meeting of the International Scientific Association for Probiotics and Prebiotics (ISAPP) was held May 3 to May 5 2002 in London, Ontario, Canada. A group of 63 academic and industrial scientists from around the world convened to discuss current issues in the science of probiotics and prebiotics. ISAPP is a non-profit organization comprised of international scientists whose intent is to strongly support and improve the levels of scientific integrity and due diligence associated with the study, use, and application of probiotics and prebiotics. In addition, ISAPP values its role in facilitating communication with the public and healthcare providers and among scientists in related fields on all topics pertinent to probiotics and prebiotics. It is anticipated that such efforts will lead to development of approaches and products that are optimally designed for the improvement of human and animal health and well being. This article is a summary of the discussions, conclusions, and recommendations made by 8 working groups convened during the first ISAPP workshop focusing on the topics of: definitions, intestinal flora, extra-intestinal sites, immune function, intestinal disease, cancer, genetics and genomics, and second generation prebiotics. Humans have evolved in symbiosis with an estimated 1014 resident microorganisms. However, as medicine has widely defined and explored the perpetrators of disease, including those of microbial origin, it has paid relatively little attention to the microbial cells that constitute the most abundant life forms associated with our body. Microbial metabolism in humans and animals constitutes an intense biochemical activity in the body, with profound repercussions for health and disease. As understanding of the human genome constantly expands, an important opportunity will arise to better determine the relationship between microbial populations within the body and host factors (including gender, genetic background, and nutrition) and the concomitant implications for health and improved quality of life. Combined human and microbial genetic studies will determine how such interactions can affect human health and longevity, which communication systems are used, and how they can be influenced to benefit the host. Probiotics are defined as live microorganisms which, when administered in adequate amounts confer a health benefit on the host.1 The probiotic concept dates back over 100 years, but only in recent times have the scientific knowledge and tools become available to properly evaluate their effects on normal health and well being, and their potential in preventing and treating disease. A similar situation exists for prebiotics, defined by this group as non-digestible substances that provide a beneficial physiological effect on the host by selectively stimulating the favorable growth or activity of a limited number of indigenous bacteria. Prebiotics function complementary to, and possibly synergistically with, probiotics. Numerous studies are providing insights into the growth and metabolic influence of these microbial nutrients on health. Today, the science behind the function of probiotics and prebiotics still requires more stringent deciphering both scientifically and mechanistically. The explosion of publications and interest in probiotics and prebiotics has resulted in a body of collective research that points toward great promise. However, this research is spread among such a diversity of organisms, delivery vehicles (foods, pills, and supplements), and potential health targets such that general conclusions cannot easily be made. Nevertheless, this situation is rapidly changing on a number of important fronts. With progress over the past decade on the genetics of lactic acid bacteria and the recent, 2,3 and pending, 4 release of complete genome sequences for major probiotic species, the field is now armed with detailed information and sophisticated microbiological and bioinformatic tools. Similarly, advances in biotechnology could yield new probiotics and prebiotics designed for enhanced or expanded functionality. The incorporation of genetic tools within a multidisciplinary scientific platform is expected to reveal the contributions of commensals, probiotics, and prebiotics to general health and well being and explicitly identify the mechanisms and corresponding host responses that provide the basis for their positive roles and associated claims. In terms of human suffering, the need for effective new approaches to prevent and treat disease is paramount. The need exists not only to alleviate the significant mortality and morbidity caused by intestinal diseases worldwide (especially diarrheal diseases in children), but also for infections at non-intestinal sites. This is especially worthy of pursuit in developing nations where mortality is too often the outcome of food and water borne infection. Inasmuch as probiotics and prebiotics are able to influence the populations or activities of commensal microflora, there is evidence that they can also play a role in mitigating some diseases. 5,6 Preliminary support that probiotics and prebiotics may be useful as intervention in conditions including inflammatory bowel disease, irritable bowel syndrome, allergy, cancer (especially colorectal cancer of which 75% are associated with diet), vaginal and urinary tract infections in women, kidney stone disease, mineral absorption, and infections caused by Helicobacter pylori is emerging. Some metabolites of microbes in the gut may also impact systemic conditions ranging from coronary heart disease to cognitive function, suggesting the possibility that exogenously applied microbes in the form of probiotics, or alteration of gut microecology with prebiotics, may be useful interventions even in these apparently disparate conditions. Beyond these direct intervention targets, probiotic cultures can also serve in expanded roles as live vehicles to deliver biologic agents (vaccines, enzymes, and proteins) to targeted locations within the body. The economic impact of these disease conditions in terms of diagnosis, treatment, doctor and hospital visits, and time off work exceeds several hundred billion dollars. The quality of life impact is also of major concern. Probiotics and prebiotics offer plausible opportunities to reduce the morbidity associated with these conditions. The following addresses issues that emerged from 8 workshops (Definitions, Intestinal Flora, Extra-Intestinal Sites, Immune Function, Intestinal Disease, Cancer, Genomics, and Second Generation Prebiotics), reflecting the current scientific state of probiotics and prebiotics. This is not a comprehensive review, however the study emphasizes pivotal knowledge gaps, and recommendations are made as to the underlying scientific and multidisciplinary studies that will be required to advance our understanding of the roles and impact of prebiotics, probiotics, and the commensal microflora upon health and disease management.

Probiotics for the developing world

Every minute of every day more and more children die of diarrheal diseases and women, and girls become infected by HIV An estimated 7,000 women become infected each day. While many valiant efforts are being made to address these issues, until now they have proved to be markedly ineffective. The notion that lactic acid bacteria, formulated into food or dietary supplements, could have a role to play in slowing the morbidity and mortality associated with HIV/AIDS and gastroenteritis, is built upon sound clinical findings and scientific investigations, yet no international efforts have been placed in this approach, to date. We hereby summarize the reasons why such efforts should be made, provide an example of one model being set up in sub-Saharan Africa, and challenge the international community to consider the potential benefits of probiotics, especially for communities not reached by governmental and nongovernmental agencies.

Mortality rates, prevalence of malnutrition, and prevalence of lost pregnancies among the drought-ravaged population of Tete province Mozambique

Background: Tete Province, Mozambique has experienced chronic food insecurity and a dramatic fall in livestock numbers due to the cyclic problems characterized by the floods in 2000 and severe droughts in 2002 and 2003. The Province has been a beneficiary of emergency relief programs, which have assisted >22% of the population. However, these programs were not based on sound epidemiological data, and they have not established baseline data against which to assess the impact of the programs. Objective: The objective of this study was to document mortality rates, causes of death, the prevalence of malnutrition, and the prevalence of lost pregnancies after 2.5 years of humanitarian response to the crisis. Methods: A two-stage, 30-cluster household survey was conducted in the Cahora Bassa and Changara districts from 22 October to 08 November 2004. A total of 838 households were surveyed, with a population size of 4,688 people. Results: Anthropometric data were collected among children 6-59 months of age. In addition, crude mortality rates (CMRs), under five mortality rates (U5MRs), causes of deaths, and prevalence of lost pregnancies were determined among the sample population. The prevalence of malnutrition was 8.0% (95% confidence interval (CI)=6.2-9.8%) for acute malnutrition, 26.9% (95% CI=24.0-29.9%) for being underweight, and 37.0% (95% CI=33.8-40.2%) for chronic malnutrition. Boys were more likely to be underweight than were girls (odds ratio (OR)=1.34; 95% CI=1.00, 1.82; p<0.05) after controlling for age, household size, and food aid beneficiary status. Similarly, children 30-59 months of age were significantly less likely to suffer from acute malnutrition (OR=0.45; 95% CI=0.26, 0.79; p<0.01) and less likely to be underweight (OR=0.37; 95% CI=0.27, 0.51; p<0.01) than children 6-29 months of age, after adjusting for the other, aforementioned factors. The proportion of lost pregnancies was estimated at 7.7% (95% CI=4.5-11.0%). A total of 215 deaths were reported during the year preceding the survey. Thirty-nine (18.1%) children <5 years of age died. The CMR was 1.23/10 000/day (95% CI=1.08-1.38), and an U5MR was 1.03/10 000/day (95% CI=0.71-1.35). Diarrheal diseases, malaria, tuberculosis, and human immunodeficiency virus/acquired immunodeficiency syndrome (HIV/AIDS) accounted for more than two-thirds of all deaths. Conclusions: The observed CMR in Tete Province, Mozambique is three times higher than the baseline rate for sub-Saharan Africa and 1.4 times higher than the CMR cut-off point used to define excess mortality in emergencies. The current humanitarian response in Tete Province would benefit from an improved alignment of food aid programming in conjunction with diarrheal disease control, HIV/AIDS, and malaria prevention and treatment programs. The impact of the food programs would be improved if mutually acceptable food aid programme objectives, verifiable indicators relevant to each objective, and beneficiary targets and selection criteria are developed. Periodic re-assessments and evaluations of the impact of the program and evidenced-based decision-making urgently are needed to avert a chronic dependency on food aid.

From cholera outbreaks to pandemics : the role of poverty and inequality

Cholera and other diarrheal diseases are the second leading cause of death among the poor globally. The tragedy of this statistic is that it need not be the case. Unlike many afflictions, the impact of cholera can be greatly reduced, if not eliminated, through the provision of clean water services. This begs the question of why such provision is absent in much of the world. It is our contention that the provision of clean water services is an increasing function of both a country's level of income and income equality. We test these hypotheses by analyzing 1,032 annual observations arising from 55 relatively poor countries between the years 1980 and 2002. In the primary part of the analysis, we find that providing clean water is, as predicted, an increasing function of income and equality. Following this, and consistent with the existing epidemiological research on cholera, we find that both the numbers of cases and deaths resulting from a given cholera outbreak are strongly and negatively related to the provision of clean water.

Doenças de Veiculação Hídrica em Trechos da Bacia do Rio Piranhas-Assu: ocorrência de bactérias oportunistas, caracterização epidemiológica e concepções de professores e agentes de saúde

Water is essential to life and all living organisms and their supply is necessary for economic development and quality of life of human populations, but their quality has been altered by human actions. In semi-arid northeast, the water is an issue of concern, especially its quality. This region is common to the construction of reservoirs that capture rain water, streams and temporary rivers in search of ease this situation, being intended for various purposes. Water scarcity is a limiting factor for the economic and social development of the region and contributes to the maintenance of waterborne diseases. About 80% of diseases that occur in developing countries are infected by waterborne pathogens. Therefore, this study aimed to determine in two environments that are part of semilênticos Armando Ribeiro Gonçalves reservoir, and a stretch of the river Assu, all located in the semiarid RN, the occurrence of opportunistic pathogenic bacteria; check the conceptions of teachers and health workers about the issues "waterborne diseases" and "bacteria" and a diagnosis of diarrheal diseases that affect the population in some municipalities of the semi-arid region of RN from a survey of epidemiological data. For identification of bacteria using commercial kits and the diagnosis of diarrheal disease was based on information from databases. The previous conceptions of teachers and health workers were obtained through questionnaires. The results confirmed the presence of opportunistic bacteria in the studied area, showing the importance of monitoring water quality. There was an under-reporting of cases of diarrhea pointing out flaws in the monitoring of Diarrheal Diseases and indicating the need to improve it. It was felt also the need to implement educational activities on topics dealt with both with teachers and health workers, since they were identified misconceptions on the subject

Water and sanitation accessibility and the health of rural Ugandans

The lack of access to sufficient water and sanitation facilities is one of the largest hindrances towards the sustainable development of the poorest 2.2 billion people in the world. Rural Uganda is one of the areas where such inaccessibility is seriously hampering their efforts at development. Many rural Ugandans must travel several kilometers to fetch adequate water and many still do not have adequate sanitation facilities. Such poor access to clean water forces Ugandans to spend an inordinate amount of time and energy collecting water - time and energy that could be used for more useful endeavors. Furthermore, the difficulty in getting water means that people use less water than they need to for optimal health and well-being. Access to other sanitation facilities can also have a large impact, particularly on the health of young children and the elderly whose immune systems are less than optimal. Hand-washing, presence of a sanitary latrine, general household cleanliness, maintenance of the safe water chain and the households’ knowledge about and adherence to sound sanitation practices may be as important as access to clean water sources. This report investigates these problems using the results from two different studies. It first looks into how access to water affects peoples’ use of it. In particular it investigates how much water households use as a function of perceived effort to fetch it. Operationally, this was accomplished by surveying nearly 1,500 residents in three different districts around Uganda about their water usage and the time and distance they must travel to fetch it. The study found that there is no statistically significant correlation between a family’s water usage and the perceived effort they must put forth to have to fetch it. On average, people use around 15 liters per person per day. Rural Ugandan residents apparently require a certain amount of water and will travel as far or as long as necessary to collect it. Secondly, a study entitled “What Works Best in Diarrheal Disease Prevention?” was carried out to study the effectiveness of five different water and sanitation facilities in reducing diarrheal disease incidences amongst children under five. It did this by surveying five different communities before and after the implementation of improvements to find changes in diarrheal disease incidences amongst children under five years of age. It found that household water treatment devices provide the best means of preventing diarrheal diseases. This is likely because water often becomes contaminated before it is consumed even if it was collected from a protected source.

Study of water use and supply in the district of Independencia, Peru

Peru is a developing country with abundant fresh water resources, yet the lack of infrastructure leaves much of the population without access to safe water for domestic uses. The author of this report was a Peace Corps Volunteer in the sector of water & sanitation in the district of Independencia, Ica, Peru. Independencia is located in the arid coastal region of the country, receiving on average 15 mm of rain annually. The water source for this district comes from the Pisco River, originating in the Andean highlands and outflowing into the Pacific Ocean near the town of Pisco, Peru. The objectives of this report are to assess the water supply and sanitation practices, model the existing water distribution system, and make recommendations for future expansion of the distribution system in the district of Independencia, Peru. The assessment of water supply will be based on the results from community surveys done in the district of Independencia, water quality testing done by a detachment of the U.S. Navy, as well as on the results of a hydraulic model built in EPANET 2.0 to represent the distribution system. Sanitation practice assessments will be based on the surveys as well as observations from the author while living in Peru. Recommendations for system expansions will be made based on results from the EPANET model and the municipality’s technical report for the existing distribution system. Household water use and sanitation surveys were conducted with 84 families in the district revealing that upwards of 85% store their domestic water in regularly washed containers with lids. Over 80% of those surveyed are drinking water that is treated, mostly boiled. Of those surveyed, over 95% reported washing their hands and over 60% mentioned at least one critical time for hand washing when asked for specific instances. From the surveys, it was also discovered that over 80% of houses are properly disposing of excrement, in either latrines or septic tanks. There were 43 families interviewed with children five years of age or under, and just over 18% reported the child had a case of diarrhea within the last month at the time of the interview. Finally, from the surveys it was calculated that the average water use per person per day is about 22 liters. Water quality testing carried out by a detachment of the U.S. Navy revealed that the water intended for consumption in the houses surveyed was not suitable for consumption, with a median E. coli most probable number of 47/100 ml for the 61 houses sampled. The median total coliforms was 3,000 colony forming units per 100 ml. EPANET was used to simulate the water delivery system and evaluate its performance. EPANET is designed for continuous water delivery systems, assuming all pipes are always flowing full. To account for the intermittent nature of the system, multiple EPANET network models were created to simulate how water is routed to the different parts of the system throughout the day. The models were created from interviews with the water technicians and a map of the system created using handheld GPS units. The purpose is to analyze the performance of the water system that services approximately 13,276 people in the district of Independencia, Peru, as well as provide recommendations for future growth and improvement of the service level. Performance evaluation of the existing system is based on meeting 25 liters per person per day while maintaining positive pressure at all nodes in the network. The future performance is based on meeting a minimum pressure of 20 psi in the main line, as proposed by Chase (2000). The EPANET model results yield an average nodal pressure for all communities of 71 psi, with a range from 1.3 – 160 psi. Thus, if the current water delivery schedule obtained from the local municipality is followed, all communities should have sufficient pressure to deliver 25 l/p/d, with the exception of Los Rosales, which can only supply 3.25 l/p/d. However, if the line to Los Rosales were increased from one to four inches, the system could supply this community with 25 l/p/d. The district of Independencia could greatly benefit from increasing the service level to 24-hour water delivery and a minimum of 50 l/p/d, so that communities without reliable access due to insufficient pressure would become equal beneficiaries of this invaluable resource. To evaluate the feasibility of this, EPANET was used to model the system with a range of population growth rates, system lifetimes, and demands. In order to meet a minimum pressure of 20 psi in the main line, the 6-inch diameter main line must be increased and approximately two miles of trench must be excavated up to 30 feet deep. The sections of the main line that must be excavated are mile 0-1 and 1.5-2.5, and the first 3.4 miles of the main line must be increased from 6 to 16 inches, contracting to 10 inches for the remaining 5.8 miles. Doing this would allow 24-hour water delivery and provide 50 l/p/d for a range of population growth rates and system lifetimes. It is expected that improving the water delivery service would reduce the morbidity and mortality from diarrheal diseases by decreasing the recontamination of the water due to transport and household storage, as well as by maintaining continuous pressure in the system to prevent infiltration of contaminated groundwater. However, this expansion must be carefully planned so as not to affect aquatic ecosystems or other districts utilizing water from the Pisco River. It is recommended that stream gaging of the Pisco River and precipitation monitoring of the surrounding watershed is initiated in order to begin a hydrological study that would be integrated into the district’s water resource planning. It is also recommended that the district begin routine water quality testing, with the results available to the public.

CHARACTERIZATION OF THE COLONIZATION FACTOR ANTIGEN II PLASMID (CFA/II) FROM ENTEROTOXIGENIC ESCHERICHIA COLI

The etiological role of enterotoxigenic E. coli (ETEC) in diarrheal diseases of man and domestic animals is firmly established. Besides the production of enterotoxins (ST and LT), ETEC produces other important virulence factors; the colonization factor antigens (CFAs). CFAs mediate the attachment of ETEC to the epithelial cells of the small intestine, and this favors colonization by the bacteria and facilitates delivery of the enterotoxins to the intestinal cells.^ The production of enterotoxin and CFA is determined by plasmids and has been found to be restricted to a select number of E. coli serotypes.^ In this work, plasmid DNA analysis was performed in twenty-three CFA/II-producing enterotoxigenic Escherichia coli strains and their spontaneous CFA/II-negative derivatives. In some cases, strains lost the high molecular weight plasmid and also the ability to produce CFA/II, ST and LT. In other cases there was a deletion of the plasmid, which produced strains that were CFA/II('-), ST('-), LT('-) or CFA/II('-), ST('+), LT('+).^ The CFA/II plasmid from strain PB-176 (06:H16:CFA/II('+), ST('+), LT('+)) was transferred by transformation into E. coli K12 with concomitant transfer of the three characteristics: CFA/II, ST and LT.^ A physical map of the prototype CFA/II:ST:LT (pMEP60) plasmid was constructed by restriction endonuclease analysis and compared to plasmids from three other CFA/II-producing strains. A CFA/II-negative (but ST and LT positive) deletion derivative of pMEP60 (pMEP30) was also included in the map. The four CFA/II plasmids analyzed had a common region of approximately 30 kilobase pairs. The toxin genes were approximately 5 kbp apart and about 20 kbp from the common region. The information given by this physical map could be of great value when constructing a clone that will express the CFA/II genes but not the toxin genes. ^

Variation of genotype and prevalence of Noro virus in U.S. students in Mexico with Traveler's Diarrhea, summer of 2004 and 2005

Noro virus, a positive single stranded RNA virus has been identified as a major etiologic agent in food borne gastroenteritis and diarrheal diseases. The emergence of this organism as a major non-bacterial cause in such outbreaks is partly due to the improved diagnostic tools like Reverse Transcription Polymerase chain reaction (RTPCR) that enable its detection. Noro virus accounts for nearly 96% of non-bacterial gastroenteritis outbreaks in US (1). Travelers' Diarrhea (TD) has remained a constant public health risk in the developed nations for decades and bacteria like Entero toxigenic Escherichia coli, Entero aggregative Escherichia coli have been described as the main etiologic agents for TD (2-4). A possible viral contribution to TD has been discovered in two studies (5, 6). The current study was designed to determine the prevalence of Noro virus in a population of 107 US students with TD acquired in Mexico in 2005 and to compare the prevalence to the prevalence of Noro virus in a similar study done in 2004. This study involved the testing of clinical stool specimens from 107 subjects in 2005 for the presence of Noro virus using RTPCR. The prevalence of Noro virus in 2004 used for comparison to 2005 data was obtained from published data (5). All subjects were recruited as TD subjects in a randomized, double-blinded clinical trial comparing a standard three day dosing of Rifaximin with and without an anti motility drug Loperamide. The prevalence of Noro virus geno group I was similar in both years, but geno group II prevalence differed across the two years (p = 0.003). This study finding suggests that the prevalence of Noro virus geno groups varies with time even within a specific geographic location. This study emphasizes the need for further systematic epidemiologic studies to determine the molecular epidemiology and the prevalence patterns of different geno groups of this virus. These are essential to planning and implementation of public health measures to lessen the burden of TD due to Noro virus infection among US travelers. ^

Facteurs de risque pour les maladies diarrhéiques chez les enfants à Dakar : une analyse multi-niveaux avec variables latentes

Au Sénégal, les maladies diarrhéiques constituent un fardeau important, qui pèse encore lourdement sur la santé des enfants. Ces maladies sont influencées par un large éventail de facteurs, appartenant à différents niveaux et sphères d'analyse. Cet article analyse ces facteurs de risque et leur rôle relatif dans les maladies diarrhéiques de l'enfant à Dakar. Ce faisant, elle illustre une nouvelle approche pour synthétiser le réseau de ces déterminants. Une analyse en classes latentes (LCA) est d’abord menée, puis les variables latentes ainsi construites sont utilisées comme variables explicatives dans une régression logistique sur trois niveaux. Les résultats confirment que les déterminants des diarrhées chez l'enfant appartiennent aux trois niveaux d'analyse et que les facteurs comportementaux et l'assainissement du quartier jouent un rôle prépondérant. Les résultats illustrent aussi l'utilité des LCA pour synthétiser plusieurs indicateurs, afin de créer une image causale intégrée, tout en utilisant des modèles statistiques parcimonieux.