A cohort of 321 children was followed from birth up to 2 years of age to determine the incidence of enterotoxigenic Escherichia coli (ETEC) in Bangladesh. The average number of diarrheal days and incidence rates were 6.6 and 2.3/child/year, respectively. ETEC was the most common pathogen and was isolated in 19.5% cases, with an incidence of 0.5 episode/child/year. The prevalence of rotavirus diarrhea was lower (10%). ETEC expressing the heat-stable enterotoxin (ST) was predominant. Strains isolated from diarrheal cases were positive for colonization factors (CFs) in higher frequency (66%) than from healthy children (33%) (P < 0.001). The heat-labile toxin (LT)-positive strains from healthy children were more often CF negative (92%) than those isolated from children with diarrhea (73%) (P < 0.001). In children with symptomatic or asymptomatic infections by CFA/I, CS1 plus CS3, CS2 plus CS3, or CS5 plus CS6 strains, a repeat episode of diarrhea or infection by the homologous CF type was uncommon. Repeat symptomatic infections were noted mostly for LTand ST-expressing ETEC. ETEC diarrhea was more prevalent in children in the A and AB groups than in those in the O blood group (P ‫؍‬ 0.032 to 0.023). Children with ETEC diarrhea were underweight and growth stunted at the 2-year follow-up period, showing the importance of strategies to prevent and decrease ETEC diarrheal morbidity in children.Enterotoxigenic Escherichia coli (ETEC) is a common cause of acute watery diarrhea in children in developing countries (25). ETEC is a multivalent pathogen producing the heatstable (ST) and/or heat-labile toxin (LT) as well as over 25 colonization factors (CFs). The ST phenotype of ETEC has been shown to be predominant (23,25), while the most common of the CFs are CFA/I and CS1 to CS6 (14,23,25,37). Studies in animals and in humans suggest that immunity against both LT and CFs may be important for protection against ETEC. However, results from different studies are conflicting regarding the relative importance of different toxin types and/or CFs on protection from further disease and infection (11,18,27,32), and data from different settings are needed to elucidate whether ETEC strains expressing these different virulence factors may prevent against repeated episodes of diarrhea. The first longitudinal study to determine the relationship between ETEC and other enteric pathogens and the incidence of diarrhea of children in a birth cohort was carried out in Mexico (10). In the present study, we have evaluated the natural history of ETEC infections, with emphasis on the different phenotypes, during the first 2 years of life in a birth cohort of 321 children in an urban slum area in Dhaka, Bangladesh. This included evaluation of the incidence, seasonality, and occurrence of symptomatic and asymptomatic ETEC infections. We have also evaluated whether blood group and nutritional factors may predispose to ETEC diarrhea. For comparison, we have also studied the incidence of other common enteric infections. MATERIALS AND METHODS Study popul...

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A single dose of the oral cholera vaccine was efficacious in older children (≥5 years of age) and in adults in a setting with a high level of cholera endemicity. (Funded by the Bill and Melinda Gates Foundation and others; ClinicalTrials.gov number, NCT02027207.).

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Background Diarrheal illnesses remain a leading cause of morbidity and mortality globally, with increasing recognition of long-term sequelae, including postinfectious irritable bowel syndrome and growth faltering, as well as cognitive deficits in children. Identification of specific etiologic agents is often lacking. In vitro and in vivo data suggest that enterotoxigenic Bacteroides fragilis (ETBF) may contribute to the burden of colonic inflammatory diarrheal disease. The study goal was to investigate the pathogenesis of ETBF diarrheal illnesses. Methods We performed an observational study of children and adults with acute diarrheal illnesses in Dhaka, Bangladesh, from January 2004 through November 2005, to define the clinical presentation, intestinal inflammatory responses, and systemic and intestinal antibody responses to ETBF. Other enteric pathogens were also evaluated. Results ETBF was identified to cause a clinical syndrome with marked abdominal pain and nonfebrile inflammatory diarrhea in both children (age, >1 year) and adults. Fecal leukocytes, lactoferrin, and proinflammatory cytokines (interleukin 8, tumor necrosis factor–α)—as well as B. fragilis toxin systemic antitoxin responses—increased rapidly in ETBF-infected patients. Evidence of intestinal inflammation often persisted for at least 3 weeks, despite antibiotic therapy. Conclusions ETBF infection is a newly recognized cause of inflammatory diarrhea in children and adults. Future studies are needed to evaluate the role of ETBF in persistent colonic inflammation and other morbid sequelae of acute diarrheal disease.

Many currently available diagnostic tests for typhoid fever lack sensitivity and/or specificity, especially in areas of the world where the disease is endemic. In order to identify a diagnostic test that better correlates with typhoid fever, we evaluated immune responses to Salmonella enterica serovar Typhi (serovar Typhi) in individuals with suspected typhoid fever in Dhaka, Bangladesh. We enrolled 112 individuals with suspected typhoid fever, cultured day 0 blood for serovar Typhi organisms, and performed Widal assays on days 0, 5, and 20. We harvested peripheral blood lymphocytes and analyzed antibody levels in supernatants collected on days 0, 5, and 20 (using an antibody-in-lymphocyte-supernatant [ALS] assay), as well as in plasma on these days. We measured ALS reactivity to a serovar Typhi membrane preparation (MP), a formalin-inactivated whole-cell preparation, and serovar Typhi lipopolysaccharide. We measured responses in healthy Bangladeshi, as well as in Bangladeshi febrile patients with confirmed dengue fever or leptospirosis. We categorized suspected typhoid fever individuals into different groups (groups I to V) based on blood culture results, Widal titer, and clinical features. Responses to MP antigen in the immunoglobulin A isotype were detectable at the time of presentation in the plasma of 81% of patients. The ALS assay, however, tested positive in all patients with documented or highly suspicious typhoid, suggesting that such a response could be the basis of improved diagnostic pointof-care-assay for serovar Typhi infection. It can be important for use in epidemiological studies, as well as in difficult cases involving fevers of unknown origin.Salmonella enterica serovar Typhi (serovar Typhi) is the cause of typhoid fever, an illness that affects over 20,000,000 individuals worldwide each year, killing over 200, 000 (5, 8, 16). The largest burden of typhoid fever is borne by impoverished individuals in resource-poor areas of the world. Serovar Typhi is a human-restricted invasive enteric pathogen which, after ingestion, crosses the intestinal mucosa, is taken up by gutassociated lymphoreticular tissues, and enters the systemic circulation. Both mucosal and systemic host immune responses are stimulated after infection. Serovar Typhi is an intracellular pathogen, and antibody and cell-mediated immune responses occur after infection or immunization with live oral attenuated typhoid vaccines (10,25,34).Diagnostic tests for typhoid fever often lack sensitivity and/or specificity, especially in areas of the world that are endemic for typhoid fever, where clinically distinguishing typhoid fever from other febrile illnesses is difficult (5, 17, 39). Microbiologic culturing of blood is approximately 30 to 70% sensitive, with the highest sensitivity being associated with an absence of prior use of antibiotics and the culturing of larger volumes of blood, features that complicate this mode of diagnosis in young children (5,6,8,36). Microbiologic culturing of bone marrow aspirates is more sensitive than bl...

BackgroundIn endemic countries such as Bangladesh, consequences of cholera place an enormous financial and social burden on patients and their families. Cholera vaccines not only provide health benefits to susceptible populations but also have effects on the earning capabilities and financial stability of the family. Community-based research and evaluations are necessary to understand perceptions about and practices of the community relating to cholera and oral cholera vaccines. This may help identify the ways in which such vaccines may be successfully introduced, and other preventive measures can be implemented. The present study assessed the knowledge of, attitudes toward, and preventive practices relating to cholera and oral cholera vaccine among an urban population residing in a high cholera-prone setting in Dhaka, Bangladesh.MethodsThis cross-sectional study was conducted in an area of high cholera prevalence in 15 randomly-selected clusters in Mirpur, Dhaka city. A study team collected data through a survey and in-depth interviews during December 2010–February 2011.ResultsOf 2,830 families included in the final analysis, 23% could recognize cholera as acute watery diarrhea and 16% had ever heard of oral cholera vaccine. About 54% of the respondents had poor knowledge about cholera-related issues while 97% had a positive attitude toward cholera and oral cholera vaccine. One-third showed poor practice relating to the prevention of cholera.The findings showed a significant (p < 0.05) association between the respondents’ knowledge and sex, education, occupation, monthly overall household expenditure, attitudes and practice. In the adjusted model, male sex, having a lower monthly overall household expenditure, and having a less positive attitude toward cholera were the significant predictors to having poor knowledge.ConclusionsThe findings suggest the strengthening of health education activities to improve knowledge on cholera, its prevention and treatment and information on cholera vaccination among high-risk populations. The data also underscore the potential of mass cholera vaccination to prevent and control cholera.

A feasibility study of an oral cholera vaccine was carried out to test strategies to reach high-risk populations in urban Mirpur, Dhaka, Bangladesh. The study was cluster randomized, with three arms: vaccine, vaccine plus safe water and hand washing practice, and no intervention. High risk people of age one year and above (except pregnant woman) from the two intervention arms received two doses of the oral cholera vaccine, Shanchol™. Vaccination was conducted between 17th February and 16th April 2011, with a minimum interval of fourteen days between two doses. Interpersonal communication preceded vaccination to raise awareness amongst the target population. The number of vaccine doses used, the population vaccinated, left-out, drop out, vaccine wastage and resources required were documented. Fixed outreach site vaccination strategy was adopted as the mode of vaccine delivery. Additionally, mobile vaccination sites and mop-up activities were carried out to reach the target communities. Of the 172,754 target population, 141,839 (82%) and 123,666 (72%) received complete first and second doses of the vaccine, respectively. Dropout rate from the first to the second dose was 13%. Two complete doses were received by 123,661 participants. Vaccine coverage in children was 81%. Coverage was significantly higher in females than in males (77% vs. 66%, P<0.001). Vaccine wastage for delivering the complete doses was 1.2%. The government provided cold-chain related support at no cost to the project. Costs for two doses of vaccine per-person were US$3.93, of which US$1.63 was spent on delivery. Cost for delivering a single dose was US$0.76. We observed no serious adverse events. Mass vaccination with oral cholera vaccine is feasible for reaching high risk endemic population through the existing national immunization delivery system employed by the government.