Showing papers by "International Centre for Diarrhoeal Disease Research, Bangladesh published in 1995"

Rapid diagnosis of Entamoeba infection by using Entamoeba and Entamoeba histolytica stool antigen detection kits.

Abstract: Humans are infected by two morphologically identical species of Entamoeba: Entamoeba histolytica causes amebic colitis and liver abscess, and Entamoeba dispar is noninvasive. Several weeks of culture and isoenzyme (zymodeme) analysis are required to differentiate E. histolytica from E. dispar. Here we report a field trial of commercial antigen detection kits designed to rapidly detect and differentiate E. histolytica from E. dispar in stool specimens. Stool specimens from 202 patients with diarrhea were examined for E. histolytica and E. dispar by microscopy, culture, and antigen detection. Compared with culture, microscopic identification of the E. histolytica-E. dispar complex was 60% sensitive and 79% specific, while the screening antigen detection test for the E. histolytica-E. dispar complex was 80% sensitive and 99% specific. Differentiation of E. dispar from E. histolytica by the E. histolytica-specific test was 95% sensitive and 93% specific compared with zymodeme analysis. We conclude that the antigen detection test for the E. histolytica-E. dispar complex is more sensitive and specific than microscopy and that the E. histolytica-specific antigen detection test is as reliable and much more rapid than zymodeme analysis for the differentiation of E. histolytica from E. dispar.

Controlled study of Escherichia coli diarrheal infections in Bangladeshi children.

Abstract: Diarrheal diseases are highly prevalent in Bangladesh. However, the relative contribution of diarrheagenic Escherichia coli organisms--those that are enterotoxigenic (ETEC), enteropathogenic (EPEC), enteroinvasive, enterohemorrhagic, enteroaggregative, and diffuse adherent--to diarrhea in Bangladeshi populations is not known. With DNA probes specific for these diarrheagenic E. coli strains, we analyzed fecal E. coli from 451 children up to 5 years of age with acute diarrhea seeking treatment at a Dhaka hospital and from 602 matched control children without diarrhea from July 1991 to May 1992. Enteroinvasive E. coli was not isolated from any children; enterohemorrhagic E. coli was not isolated from any diarrheal children but was isolated from five control children; enteroaggregative and diffuse adherent E. coli strains were isolated with similar frequencies from children with and without diarrhea, thereby showing no association with diarrhea; ETEC was significantly associated with diarrhea in the diarrheal children as a whole and especially in the age groups of 0 to 24 months and 37 to 48 months (further analysis suggests an association with diarrhea for the heat-stable toxin only and for both heat-labile- and heat-stable-toxin-producing ETEC only); and EPEC was significantly associated with diarrhea in the diarrhea group as a whole and particularly in infants up to 1 year of age. Further analysis suggested that EPEC strains of only the traditional serogroups were significantly associated with diarrhea. ETEC and EPEC infections peaked during warm months. Our data thus suggest that EPEC and ETEC are important causes of acute diarrhea in children in this setting.

Genetic rearrangements in the rfb regions of Vibrio cholerae O1 and O139.

Abstract: The recent emergence of a pathogenic new non-O1 serotype (O139) of Vibrio cholerae has led to numerous studies in an attempt to identify the origins of this new strain. Our studies indicate that O139 strains have clear differences in the surface polysaccharides when compared with O1 strains: the lipopolysaccharide can be described as semi-rough. Southern hybridization with the O1 rfb region demonstrates that O139 strains no longer contain any of the rfb genes required for the synthesis of the O1 O-antigen or its modification and also lack at least 6 kb of additional contiguous DNA. However, O139 strains have retained rfaD and have a single open reading frame closely related to three small open reading frames of the O1 rfb region. This region is closely related to the H-repeat of Escherichia coli and to the transposases of a number of insertion sequence elements and has all the features of an insertion sequence element that has been designated VcIS1. Transposon insertion mutants defective in O139 O-antigen (and capsule) biosynthesis map to the same fragment as VcIS1. Preliminary sequence data of complementing clones indicate that this DNA encodes a galactosyl-transferase and other enzymes for the utilization of galactose in polysaccharide biosynthesis. We propose a mechanism by which both the Ogawa serotype of O1 strains and the O139 serotype strains may have evolved.

Comparison of the vibriocidal antibody response in cholera due to Vibrio cholerae O139 Bengal with the response in cholera due to Vibrio cholerae O1.

Abstract: Vibrio cholerae serogroup O139, now considered to be the second organism capable of causing epidemic severe dehydrating cholera, contains a capsular polysaccharide which makes it difficult for it to be used in the conventional vibriocidal antibody assay optimized for V. cholerae O1. After modification of the procedure, which involved the use of specific bacterial strains, a lower bacterial inoculum, and increased amounts of complement, the vibriocidal antibody responses to V. cholerae O139 were measured in acute- and convalescent-phase sera from 33 V. cholerae O139-infected and 18 V. cholerae O1-infected patients and in single serum samples from 20 healthy control subjects. The responses in these individuals to V. cholerae O1 strains were also determined. Significant elevations in the homologous antibody response were found only in the convalescent-phase sera from both groups of patients with cholera. These findings may explain the basis for the lack of heterologous protection between the two serogroups of V. cholerae. Healthy controls had higher background levels of vibriocidal antibody to V. cholerae O1 than to V. cholerae O139.

Structure of the Capsular Polysaccharide of Vibrio cholerae O139 Synonym Bengal Containing D-galactose 4,6-Cyclophosphate

Abstract: The capsular polysaccharide (CPS) of Vibrio cholerae O139 synonym Bengal, which is thought to carry determinants of O-specificity, was isolated by phenol/water extraction followed by delipidation of the contaminating lipopolysaccharide at pH 4.2 and gel-permeation chromatography. The CPS contained D-galactose, 3,6-dideoxy-L-xylo-hexose (colitose, Col), 2-acetamido-2-deoxy-D-glucose, 2-acetamido-2,6-dideoxy-D-glucose (N-acetyl-D-quinovosamine, D-QuiNAc), D-galacturonic acid (D-GalA), and phosphate. The CPS was studied by NMR spectroscopy, methylation analysis, and selective degradations, including partial acid hydrolysis at pH 3.1 and dephosphorylation with aqueous 48% hydrofluoric acid, which both resulted in complete cleavage of Col. It was concluded that the CPS is built up of hexasaccharide repeating units containing inter alia D-galactose 4,6-cyclophosphate and having the following structure [structure: see text] These data basically confirm the structure of the V. cholerae CPS proposed on the basis of an NMR study [L. M. Preston et al. (1995) J. Bacteriol. 177, 835-838] and specify exactly the absolute configurations of the constituent monosaccharides and the position of the cyclic phosphate.

Factors affecting acceptance of immunization among children in rural Bangladesh

Abstract: This paper uses the Bangladesh Fertility Survey 1989 data to identify the factors affecting acceptance of immunization among children in rural Bangladesh. Acceptance of DPT, measles and BCG vaccinations were the dependent variables. The independent variables included proximity to health facilities, frequency of visit by health worker, respondent's mobility, media exposure, education, age, economic status of household, region of residence, and gender of child. Logistic regression analysis was performed to assess the net effects of the variables in addition to univariate analysis. Among the independent variables, proximity to health facility, frequency of health worker's visit, mother's mobility, education, age, gender of child, ownership of radio, economic condition of household, and region of residence showed statistically significant association with acceptance of immunization. The effect of frequency of health worker's visit was dependent on region of residence, possession of radio, and mother's education. The effect of mother's ability to visit health centre alone was also dependent on ownership of radio, economic condition of household, and mother's education.

Mothers' knowledge about vaccine preventable diseases and immunization coverage of a population with high rate of illiteracy

Abstract: In a case-control analysis of cross-sectional data, 328 children aged 12-35 months and their mothers were studied to identify the factors associated with delayed or non-immunization of their children. Delayed or non-immunization was associated with low socio-economic status, maternal illiteracy, and lack of mothers' knowledge on vaccine preventable diseases as recommended by the Expanded Programme on Immunization (EPI). The association of this lack of mother's knowledge with no or delayed immunisation persisted after adjusting the effects of others in logistic regression analysis (Odds Ratio 16.7; 95 per cent confidence interval: 15.65-17.8; P < 0.0001). The results indicate that even in the presence of maternal illiteracy, educating mothers about the vaccines and vaccine preventable diseases may be highly effective in increasing the immunization coverage.

Evaluation of the monoclonal antibody-based kit Bengal SMART for rapid detection of Vibrio cholerae O139 synonym Bengal in stool samples.

Abstract: A monoclonal antibody-based test, Bengal SMART, was developed for rapid detection of Vibrio cholerae O139 synonym Bengal directly from stool specimens. The test, which takes about 15 min to complete, was used to screen 189 diarrheal stool specimens. The results were compared with those of a monoclonal antibody-based coagglutination test (COAT) and the conventional culture methods used as the "gold standard" for detection of V. cholerae O139. The Bengal SMART test showed a sensitivity of 100% and a specificity of 97% in comparison with the gold standard. It also fared better than COAT, which had a sensitivity of 96% for rapid detection of V. cholerae O139 synonym Bengal. These results show that Bengal SMART is suitable for use in field settings for rapid diagnosis of cholera caused by V. cholerae O139.

Prevalence of Helicobacter pylori infection in infants and family contacts in a poor Bangladesh community.

Abstract: AlthoughH. pylori is well established as an etiological agent of type B gastritis and a predisposing factor for peptic ulcer, knowledge about its transmission is unclear. In this study we examined the prevalence ofH. pylori infection in the family members of index infants infected with this organism as indicated by positive [13C]-urea breath test (UBT). We performed UBT among family members of 15 predominantly breastfed infants, eight with and seven withoutH. pylori infection. Infection rates were 82% and 91% in family contacts of the infected and noninfected infants respectively, the average infection rate being 85%, which is rated to be high. There was no difference in infection rates among the parents of the infected and noninfected infants. Fifty percent and 70% families belonging to infected and noninfected infants, respectively, were found to have all members infected withH. pylori. No evidence of sex predilection of infection was found. We conclude that in communities with high prevalence ofH. pylori infection, there is almost an equal infection rate among the family contacts of infected and noninfected infants, suggesting that environmental factors may be more important than intrafamilial transmission.

The sisterhood method of estimating maternal mortality: the Matlab experience

Abstract: This study reports the results of a test of validation of the sisterhood method of measuring the level of maternal mortality using data from a Demographic Surveillance System (DSS) operating since 1966 in Matlab, Bangladesh The records of maternal deaths that occurred during 1976-90 in the Matlab DSS area were used One of the deceased woman's surviving brothers or sisters, aged 15 or older and born to the same mother, was asked if the deceased sister had died of maternity-related causes Of the 384 maternal deaths for which siblings were interviewed, 305 deaths were correctly reported, 16 deaths were underreported, and the remaining 63 were misreported as nonmaternal deaths Information on maternity-related deaths obtained in a sisterhood survey conducted in the Matlab DSS area was compared with the information recorded in the DSS Results suggest that in places similar to Matlab, the sisterhood method can be used to provide an indication of the level of maternal mortality if no other data exist, though the method will produce negative bias in maternal mortality estimates

Molecular epidemiology of toxigenic Vibrio cholerae in Bangladesh studied by numerical analysis of rRNA gene restriction patterns.

Abstract: Cholera is endemic in Bangladesh, and a regular seasonal pattern of cholera epidemics occurs. We examined the clonal relationships among 103 clinical and environmental Vibrio cholerae isolates belonging to O1, O139, or non-O1 non-O139 serogroups isolated during epidemic and interepidemic periods in Bangladesh and compared them with those of 51 V. cholerae isolates from four countries in Asia and Africa. These studies were done by a computer-assisted numerical analysis of the restriction endonuclease cleavage patterns of rRNA genes (ribotypes). Unweighed pair-group cluster analysis of BglI- and HindIII-generated band patterns revealed 16 clusters. Ribotypes were defined as clusters of strains possessing > 98% similarity. The results showed that 154 isolates could be differentiated into 15 different ribotypes, and strains belonging to 3 of these ribotypes (ribotypes I, V, and VIIIA and VIIIB) were isolated more frequently during the epidemic periods than during interepidemic periods in Bangladesh. Classical vibrios belonged to six different ribotypes (ribotypes I to VI), with a mean similarity coefficient of 0.84, and the El Tor vibrios belonged to five different ribotypes (ribotypes VIIIA and IX to XII), with a mean similarity coefficient of 0.82. A single clone of El Tor vibrios (ribotype XII) was resident in Tanzania, whereas Nigeria, Syria, and India shared toxigenic El Tor strains with Bangladesh. Cholera toxin (CT)-positive O139 vibrios isolated from Bangladesh and India belonged to a single ribotype (ribotype VIIIB) and were > 98% similar to one of the ribotypes of El Tor vibrios (ribotype VIIIA), but a CT-negative O139 vibrio from Argentina (ribotype XIII) was < 75% similar to the same cluster of El Tor vibrios, thus suggesting more than one possible origin for O139 vibrios. Strains belonging to the same ribotypes (ribotypes VIII to X) were isolated from both patients and surface water in Bangladesh, indicating possible transmission through surface water. A clone of a CT-positive environmental isolate of non-O1 V. cholerae (ribotype VII) was found to be closely related (76.3% similarity) to a clone of classical vibrios (ribotype I) and was only between 27.2 and 56.1% similar to clusters of El Tor, O139, and two other non-O1 nontoxigenic clones.

Bulging fontanelle after supplementation with 25 000 IU of vitamin A in infancy using immunization contacts

Abstract: To evaluate the safety of vitamin A supplementation in early infancy using DPT/OPV immunization contracts, a double-blind, randomized, placebo-controlled trial was conducted in Bangladesh. One hundred and sixty-seven infants received three doses of either 25 000 IU of vitamin A or a placebo at about 6.5, 11.8 and 17.0 weeks of age. Trained physicians examined each of the infants on days 1, 2, 3 and 8 after supplementation. Nine infants (10.5%) supplemented with vitamin A had episodes of bulging of the fontanelle compared with two infants (2.5%) in the placebo group (p < 0.05). Twelve of the 14 episodes occurred in infants supplemented with vitamin A. Of these 12 episodes, none occurred with the first dose, 3 occurred with the second and 9 with the third dose. The higher incidence of bulging of the fontanelle in the vitamin A group relative to the placebo group and its temporal association with the vitamin A doses are suggestive of a causal association. The finding that increased numbers of vitamin A doses were associated with a higher probability of bulging of the fontanelle suggests a cumulative effect.Bulging fontanelle, clinical trial, safety, toxicity, vitamin A AH Baqui, Urban MCH-FP Extension Project, ICDDR.B, GPO Box 128, Dhaka 1000, Bangladesh

Administration of 25,000 IU vitamin A doses at routine immunisation in young infants.

Abstract: OBJECTIVE: To investigate whether monthly administration of vitamin A at routine immunisation produces any side-effects, and to examine the effect of this supplementation on the vitamin A nutrition status of infants. DESIGN: A double-blind randomised placebo-controlled clinical trial. SETTING: Immunisation clinic of a large diarrhoea treatment centre. SUBJECTS: Infants aged 6-17 weeks who will receive their first diphtheria-pertussis-tetanus/oral polio vaccine (DPT/OPV) dose. METHODS: Infants were randomly assigned to receive either 25,000 IU vitamin A or placebo. Three such doses were given with each immunisation dose at monthly intervals. Infants were examined by a physician before and during 24 h after the doses and any signs of toxicity were recorded. Venous blood was drawn at entry and 1 month after the 3rd dose for retinol assay. RESULTS: One hundred and one infants received vitamin A and 98 received placebo. Decreased feeding, irritability, diarrhoea, and vomiting were comparable between the two groups. In the vitamin A group five infants developed bulging fontanelle; three of them developed it once (after 1st, 2nd and 3rd dose respectively), one developed it twice (after both the 2nd and 3rd dose), and the other infant after all three doses. In the placebo group a single child developed bulging fontanelle after the 3rd dose. In all the cases the bulging disappeared within 48 h of onset except in one infant, in whom it subsided at 60 h. The total bulging episodes in the vitamin A and placebo groups were 8 and 1 respectively (RR = 7.7; P < 0.04). However, none of these infants had irritability. At entry fasting retinol level was < 10 micrograms/dl in 35% infants and in 87% infants it was < 20 micrograms/dl. After the third dose fasting retinol level was marginally better in the vitamin A group (mean +/- s.d.: 21.9 +/- 8.2 vs 19.2 +/- 7.8; P = 0.05). However, 47% infants receiving supplementation still had serum retinol level <20 micrograms/dl. CONCLUSION: The results suggest that administration of 25,000 IU of vitamin A in young infants along with routine immunisations, though associated with increased incidence of transient bulging fontanelle without any associated adverse signs or symptoms, may still be inadequate to prevent deficiency in this population. SPONSORSHIP: This study was funded by the United States Agency for International Development (USAID) under grant no. DPE-5986-A-1009-00 with the International Centre for Diarrhoeal Disease Research, Bangladesh (ICDDR,B). The ICDDR,B is supported by countries and agencies which share its concern for the health problems of developing countries.

Antibody isotype responses to antigens of Ascaris lumbricoides in a case-control study of persistently heavily infected Bangladeshi children

Abstract: Antibody responses to Ascaris lumbricoides worm antigens were examined by ELISA in a case-control study of 2 groups of Bangladeshi children, one of which had been shown over a period of 12 months to be consistently lightly infected (controls) and the other consistently heavily infected (cases). The children showed a wide range in intensity of infection; children identified as cases were on average 4 times more heavily infected than the controls. There were no significant differences in weight, height, mid-upper arm circumference and skinfold thickness between the case or control subjects at the time blood samples for analyses by ELISA were collected. Children with repeatedly heavy infections with A. lumbricoides had higher concentrations of antibody isotypes to the antigens of A. lumbricoides than children who are repeatedly lightly infected. IgG1, IgG4 and IgE to worm antigens occurred in significantly higher concentrations in heavily infected subjects. This suggests that these antibody responses simply reflect the intensity of infection and may not play a significant role in protecting against heavy infections.

Development of an improved animal model of shigellosis in the adult rabbit by colonic infection with Shigella flexneri 2a.

Abstract: Rabbits are not usually susceptible to intestinal Shigella infection without extensive pretreatment, including starvation and administration of antimicrobial, antimotility, and toxic agents (carbon tetrachloride). Most animals infected this way die rapidly and do not always develop colonic lesions and signs of dysentery. We describe here a successful experimental infection in the adult rabbit which does not require preparatory treatment and which reproduced characteristic features of human shigellosis. Unstarved, untreated adult rabbits were infected by direct inoculation of virulent Shigella flexneri 2a (10 ml of 10(7) bacteria per ml) into the proximal colon after ligation of the distal cecum (cecal bypass). Within 24 h of infection, most inoculated animals consistently developed clinical dysentery, characterized by liquid stool mixed with mucus and blood, leukocytosis, anorexia, and weight loss. Histologically, there were edema, exudation, superficial ulceration, and polymorphonuclear infiltrations in the lamina propria; crypt abscess formation; focal hemorrhages; and the presence of immunohistochemically stained S. flexneri in the colonic mucosa. Successful bacterial colonization was indicated by the isolation of the challenge strain of S. flexneri 2a from the colonic contents. None of the control rabbits challenged with nonvirulent S. flexneri or without cecal bypass developed dysentery or colitis. We conclude that successful Shigella infection can be induced by direct colonic inoculation with virulent S. flexneri 2a in adult rabbits without starvation and pretreatment. The colitis is dependent on the virulence of the bacteria and on the cecal bypass. This model should be useful in studies of the immunopathogenesis of Shigella infection.

Diffusion of the culture of contraception: program effects on young women in rural Bangladesh.

Abstract: During a focus group study examining the relationship between womens status and family planning in Matlab Bangladesh researchers learned that a group facilitator had clearly remembered the arrival of the community family planning worker in her village 10 years earlier when she was not yet married and the effect her arrival had on the facilitator and her friends. Four more focus group sessions with 15 young recently married women (mean age = 16.7 years) and questions about young women were added to the study and session guidelines. The study revealed that the media was an important influence. These focus group discussions indicated that the family planning worker contributed greatly to the diffusion of information and ideas in the late 1970s when the Matlab family planning/maternal and child health project began and during the 1980s. The media the rise of a culture of contraception and the influence of modernization facilitated the family planning workers role. Her presence in the community and the information disseminated through the media stimulated conversations. The interaction of peers and family members processed new knowledge and ideas. The Matlab project through its community workers introduced the idea that women can control their reproductive lives and consciously determine their family size. These findings emphasize the significant role of the female outreach worker in rural Bangladesh. They suggest that employment of women as community family planning workers may have had benefits other than those expected. The findings show the need for family planning programs to address the contraceptive needs of young married women.

Comparative trial of five antimicrobial compounds in the treatment of cholera in adults

Abstract: To compare the efficacy of ciprofloxacin, erythromycin, nalidixic acid and pivmecillinam in the treatment of tetracycline-resistant strains of Vibrio cholerae O1 in adults, a randomized, open, clinical trial was conducted. A tetracycline group was used for comparison. Seventy-five adult men infected with V. cholerae O1 were randomly assigned to receive either 400 mg pivmecillinam or 500 mg of one of each of the other drugs. Ciprofloxacin was given every 12 h and the others every 6 h for 3 d. The mean total stool volume per kg was 155 mL for the ciprofloxacin group, 212 mL for the erythromycin and pivmecillinam groups, 246 mL for nalidixic acid, and 293 mL for tetracycline. The difference between ciprofloxacin and tetracycline was significant (P = 0.045). After 72 h, diarrhoea had stopped in 14 patients (93%) in the ciprofloxacin group and 12 (80%) in the erythromycin group, compared to 5 (42%) of those receiving tetracycline (P = 0.006 and 0.049, respectively). Bacteriological clearance was 100% at 24 h in patients treated with ciprofloxacin compared to 20% and 8.3% (P < 0.001 for both comparisons) in the erythromycin and tetracycline groups. Ciprofloxacin in conjunction with appropriate fluid therapy was the most effective treatment for cholera in adults; erythromycin was the next best.

Treatment of shigellosis: IV. Cefixime is ineffective in shigellosis in adults.

Abstract: Objective: To compare the efficacy of cefixime with that of pivamdinocillin in the treatment of adults with acute dysentery caused by Shigella infection. Design: Randomized, double-blind clinical t...

Household aggregation of Strongyloides stercoralis infection in Bangladesh.

Abstract: Strongyloides stercoralis infections were shown to be aggregated in households in an urban slum community in Dhaka, Bangladesh. Parasitological data on 880 residents living in 280 households were analysed statistically using 3 different tests, each of which yielded significant evidence of household aggregation of S. stercoralis infection. One test was applied to the data after stratification for 4 variables which were previously shown to be independently associated with infection. Evidence of household aggregation of infection remained after stratification, suggesting that aggregation is due not only to shared risk factors, but also to either familial genetic predisposition to infection or close contact person to person transmission of infection within households.

Research methodology for developing efficient handwashing options: an example from Bangladesh.

Abstract: Handwashing has been universally promoted for health interventions, but it is essential that the factors related to behaviour are understood in order to develop appropriate handwashing messages. We found the study of behaviour complex and had to combine several methods: in-depth interviewing, questionnaire; observational and bacteriological. Here we present our experiences in developing efficient handwashing options for rural Bangladesh. The components of handwashing practices after defecation of 90 rural women were studied (phase 1). During phase 1 an in-depth interview was used to design the observational and questionnaire surveys. Behaviour was observed using a semi-structured record form and the effectiveness of the acts was measured by means of bacteriological tests. A questionnaire survey was undertaken on socioeconomic and water sanitation-related variables since they influence behaviour. Then, to develop efficient handwashing options, an experimental phase (phase 2) tested the bacteriological efficacy of the components found appropriate in phase 1. The effectiveness of the handwashing practices is believed to be poor since the bacteriological counts were found to be high (faecal coliform count of the left hand 1995, and of the right hand 1318 colony forming units/hand). The practice comprised several components: use of an agent, handedness, frequency of rubbing, source and volume of rinsing water, and drying of the hands. Seventy-five per cent of the women reported that they could not afford soap. The experimental trials showed that soap, ash and soil give similar results under similar conditions of handwashing (faecal coliform counts of left hands: 195 (soap), 98 (ash), 129 (soil) and of right: 112 (soap), 54 (ash) and 89 (soil) cfu/hand). The use of multi-method techniques in the study helped to understand and develop efficient handwashing options.

The Importance of Breastfeeding in Minimizing Mortality and Morbidity from Diarrhoeal Diseases: the Bangladesh Perspective

Abstract: Despite world-wide promotion of breastfeeding, there is a declining trend in breastfeeding practice in many developed as well as developing countries. In these countries, health planners are faced with the difficult task of re-educating women on the value of breastfeeding. In this context, it is useful to review the role of breastfeeding in combating infectious diseases, especially childhood diarrhoea, and in preventing deaths. Studies have shown that the duration of benefits of breastfeeding in diarrhoea can range from a few months to several years. However, breastfeeding is not consistently protective in all types of diarrhoea. For example, there is evidence of increased risk of rotavirus diarrhoea in breastfed children compared to non-breastfed children after certain age. Impairment of child growth is another controversial issue associated with prolonged breastfeeding. Is this growth-faltering, or do breastfed children follow a normal growth pattern which is below the reference growth curve? How long should mothers be advised to continue breastfeeding? This review focuses on answers to these questions and discusses benefits of breastfeeding and its controversial issues. The reasons for choosing the case study in Bangladesh are: (i) the prevalence of breastfeeding in Bangladesh is often cited as one of the highest in the world, (ii) diarrhoeal diseases are hyper endemic in this country; and (iii) issues of breastfeeding in several diarrhoeal diseases have been well documented here.

Hypotonic oral rehydration solution in acute diarrhoea: a controlled clinical trial

Abstract: To evaluate the assumption that an oral rehydration salt (ORS) solution made hypotonic by reducing the glucose and sodium concentrations enhances water absorption this regimen was administered to 30 children 5-24 months of age admitted to the International Centre for Diarrheal Disease Research Bangladeshs short-stay unit; 30 matched controls also admitted to the unit received the standard ORS solution. All children had a history of acute watery diarrhea of no more than 3 days duration and mild to moderate dehydration with no other illness or complications. The hypotonic solution contained 2.7 g of sodium chloride 1.5 g of potassium chloride 2.0 g of trisodium citrate dihydrate and 16 g of glucose dissolved in 1 l of water. Compared with the standard ORS the hypotonic solution achieved better clinical results in the 24-48 hours after administration. In the hypotonic ORS group stool frequency was reduced by 33% vomiting by 30% ORS requirements by 21% and the purging rate by 21%. After 48 hours serum electrolytes were comparable in both groups. These beneficial effects were limited however to children negative for rotavirus suggesting a need for etiology-specific diarrhea control strategies.

Characteristics of invasion of HEp-2 cells by Providencia alcalifaciens.

Abstract: Surmmary Previous studies with three isolates from diarrhoeal stools suggested that Providencia alcalifaciens is an invasive enteric pathogen that also causes actin condensation in infected cells. These findings were extended in the present study with a further 14 diarrhoeal stool isolates of P. alcalifaciens and HEp-2 cell monolayers for invasion assays. Studies on invasion characteristics with two selected isolates suggested that P. alcalifaciens required prior growth at 37°C for better invasion. Invasion and actin condensation were inhibited by an agent that inhibits microfilament formation, but not by agents that inhibit receptormediated endocytosis, microtubule formation, endosome acidification or receptor recycling. In time-course assays with HEp-2 cell monolayers maintained in medium containing gentamicin, P. alcalifaciens showed a small degree of multiplication after invasion of the cells, but viable bacteria could not be recovered over a 24-h period although the integrity of the cell monolayer was preserved during this period.

Working women, maternity entitlements, and breastfeeding: a report from Bangladesh

Abstract: Early infant feeding practices and facilities available for supporting breastfeeding in workplaces in Dhaka, Bangladesh were studied through interviews with working women (n = 238) with children younger than 30 months of age. Of the women interviewed, 20 percent were aware of the benefits of, and had exclusively breastfed in the first month, 13 percent in the second month, and two percent in the fifth month of employment. The median age of starting complementary feeds was 41 days (range, 1-210) preparatory to resuming work. Total duration of breastfeeding was significantly shorter in mothers who had started these feeds before 41 days of age as compared to those who started later (mean +/- SD) 275 +/- 216 days versus 361 +/- 223 days (p = 0.003). Ninety-nine percent of the mothers were unaware of their maternity entitlements, and only 20 percent had taken breaks for breastfeeding, those breaks being treated as "unofficial." Working women should be informed through health personnel and communication media, about the benefits of exclusive breastfeeding and about maternity entitlements. Provision of facilities to support breastfeeding in the workplace must also be encouraged so that maternal employment does not hamper breastfeeding.

Occurrence and distribution of culturable vibrio cholerae 01 in aquatic environments of Bangladesh

Abstract: Cholera epidemics occur twice a year in Bangladesh during which Vibrio cholerae 01 can be isolated from the aquatic environment. The reservoirs or sites of survival and multiplication of the bacteria between epidemics remain obscure. An investigation was carried out over 12 months to investigate the occurrence and distribution of Vibrio cholerae 01 in various components of 5 ponds in Dhaka. Samples were collected bimonthly with a total of 600 samples which included surface water, plants, phytoplankton, zooplankton and sediment and cultured for Vibrio cholerae 01 following an enrichment technique. Identification was carried out by following standard procedures. The highest isolation was from water (2.5%), followed by plants (1.67%) and phytoplankton (1.67%). The lowest and highest pH and salinity were recorded in pond 1 and 5, respectively. A total of 9 V. cholerae 01 biotype E1 Tor and serotype Inaba were isolated from water, plants, phytoplankton, zooplankton and sediment samples. This study demonstrated...

Structural elucidation of the O-antigen lipopolysaccharide from two strains of Plesiomonas shigelloides that share a type-specific antigen with Shigella flexneri 6, and the common group 1 antigen with Shigella flexneri spp and Shigella dysenteriae 1.

Abstract: Sugar and methylation analyses of native polysaccharides together with one-dimensional 1H- and 13C-NMR spectroscopy revealed that the two polysaccharides from strains 22074 and 12254 of Plesiomonas shigelloides are identical. The structure of the polysaccharide from strain 22074 was deduced from a uronic acid degradation and by NMR spectroscopy where heteronuclear multiple bond connectivitiy and two-dimensional nuclear Overhauser effect spectroscopy experiments established the pentasaccharide repeating unit as 4)-α-D-Galp A-(13)-α-D-Glcp NAc-(13)-α-L-Rhap -(12)-α-L-Rhap -(12)-α-L-Rhap -(1.