Showing papers by "International Centre for Diarrhoeal Disease Research, Bangladesh published in 1997"

Epidemiological Features of Helicobacter pylori Infection in Developing Countries

Abstract: Helicobacter pylori infection has a worldwide distribution, and it has distinct epidemiological features in developing countries. In contrast to that in developed countries, H. pylori infection in developing countries seems to be nearly universal, beginning in early childhood. Children become infected in the first few months of life; in some communities as many as 50% of the children are infected by the age of 5 years, and up to 90% are infected by the time they reach adulthood. In some developing countries with improvements in industrialization, socioeconomic conditions, and hygiene, infection rates are lower. The incidence of H. pylori infection, determined indirectly, also suggests a rate several times higher than that in developed countries. Marked differences in H. pylori seroprevalence have been observed between various ethnic and racial groups. Although the mode of transmission of H. pylori remains uncertain, evidence suggests person-to-person transmission occurs.

Antimicrobial Resistance in Organisms Causing Diarrheal Disease

Abstract: Antimicrobial resistance is becoming increasingly important in the treatment of enteric infections, particularly those due to Shigella, Vibrio cholerae, enterotoxigenic Escherichia coli (associated with traveler's diarrhea), and Salmonella typhi. The rate of antimicrobial resistance is highest in the developing world, where the use of antimicrobial drugs is relatively unrestricted. Of greatest immediate concern is the need for an effective, inexpensive antimicrobial that can be used safely as treatment for small children with dysentery due to Shigella, primarily Shigella dysenteriae type 1.

Treatment of shigellosis: V. Comparison of azithromycin and ciprofloxacin. A double-blind, randomized, controlled trial.

Abstract: Background: Treatment of shigellosis is currently limited by the high prevalence of multidrug-resistant strains of Shigella. Objective: To determine the efficacy of azithromycin in the treatment of...

Entamoeba histolytica and Entamoeba dispar Infection in Children in Bangladesh

Abstract: The prevalence of infection by the invasive parasite Entamoeba histolytica and the noninvasive parasite Entamoeba dispar was determined in 2000 children in Bangladesh. Antigen detection identified more cases of E. histolytica-E. dispar infection than did culture or microscopy. Microscopic identification of E. histolytica-E. dispar complex infection in stool did not equate with the diagnosis of amebic dysentery because most amebic infections in this population were due to E. dispar: Urban children with diarrhea had a 4.2% prevalence of E. histolytica infection and a 6.5% prevalence of E. dispar infection; rural asymptomatic children had a 1.0% prevalence of E. histolytica infection and a 7.0% prevalence of E. dispar infection. Shigella dysenteriae and Shigella flexneri infections were more frequent in children who also had Entamoeba infection, a potentially important consideration for the empiric treatment of dysentery in this population.

Comparison of immune responses in patients infected with Vibrio cholerae O139 and O1.

Abstract: Vibrio cholerae O139 has recently emerged as the second etiologic agent of cholera in Asia. A study was carried out to evaluate the induction of specific immune responses to the organism in V. cholerae O139-infected patients. The immune responses to V. cholerae O139 Bengal were studied in patients by measuring antibody-secreting cells (ASC), as well as vibriocidal and antitoxic antibodies in the circulation. These responses were compared with those in patients with V. cholerae O1 disease. Strong immunoglobulin A (IgA) and IgM ASC responses were seen against the homologous lipopolysaccharide or serogroup of V. cholerae. The magnitude and isotype of the responses were similar in O139- and O1-infected patients. Vibriocidal antibody responses were seen against bacteria of the homologous but not heterologous serogroup, and these responses reflect the lack of cross-protection between the infections caused by the two serogroups. The two groups of patients showed comparable cholera toxin-specific ASC responses, with the IgG isotype dominating over the IgA isotype, as well as comparable antitoxic immune responses in plasma. These results suggest that despite having a polysaccharide capsule, V. cholerae O139 induces systemic and intestine-derived ASC responses in peripheral blood comparable to those seen in patients with V. cholerae O1 disease.

Acute respiratory infections in children: a community-based longitudinal study in rural Bangladesh.

Abstract: A community-based logitudinal study conducted in Matlab, a rural area in Bangladesh, investigated acute respiratory infections (ARI) among children. A cohort of 696 children under 5 years of age was followed for 1 year yielding 183,865 child-days of observation. Trained field workers visited the study children every fourth day. Data on symptoms suggesting ARI, such as fever, cough, and nasal discharge, were collected for the preceding 3 days by recall. To determine the type and severity of ARI, the field workers conducted physical examinations (temperature, rate of respiration, and chest indrawing) of children reporting cough and/or fever. The overall incidence of ARI was 5.5 episodes per child-year observed; the prevalence was 35.4 per hundred days observed. Most of the episodes (96 per cent) were upper respiratory infections (URI). The incidence of acute lower respiratory infections (ALRI) was 0.23 per child per year. The incidence of URI was highest in 18-23-month-old children, followed by infants 6-11 months old. The highest incidence of ALRI was observed in 0-5-month-old infants followed by 12-17-month-old children. Among 559 children who were followed for 6 months or longer, about 9 per cent did not suffer any URI episode and about 16 per cent suffered one or more ALRI episodes. About 46 per cent of URI and 65 per cent of ALRI episodes lasted 15 days or more. The incidence rates of URI were higher during the monsoon and pre-winter periods, and that of ALRI at the end of the monsoon and during the pre-winter periods. Sociodemographic variables were not associated with the incidence of URI or ALRI. The study documents ARI to be a major cause of morbidity among rural Bangladeshi children.

Impact of a single megadose of vitamin A at delivery on breastmilk of mothers and morbidity of their infants

Abstract: Objectives: To evaluate the effect of vitamin A supplementation 24 h after delivery on breastmilk retinol concentration. Methods: Fifty low income women were randomly assigned to a single oral dose of 209 μmol of Vitamin A or none at delivery. Maternal serum and breastmilk retinol levels and infant morbidity and anthropometry were serially assessed. Results: Mean (95% CI) serum retinol levels increased in the supplemented mothers at 2.77 (2.3, 3.2) compared to 1.15 (0.9, 1.4) μmol/l in controls (P<0.05) and remained at a significantly higher level of 1.59 (1.4, 1.8) μmul/l compared to 1.33 (1.8, 1.5) μmol/l in the control group (P<0.001) up to a period of three months. Breastmilk retinol concentration was also greater at 24 h after supplementation, mean (CI) 11.34 (9.0, 13.7) μmol/l, compared to 2.95 (2.3, 3.6) μmol/l in the control group (P<0.0001), and remained higher for the next six months at 1.06 (0.9, ,1.3) μmol/l compared to 0.73 (0.6, 0.8) μmol/l in the control group (P<0.02). Infants of the supplemented mothers had reduced mean duration of respiratory tract infection of 3.1 (2.7, 3.5) days compared to 3.7 (3.3, 4.2) days (P<0.03) and mean incidence of febrile illness 0.1 (0.1, 0.1) compared to control infants 0.3 (0.3, 0.3) days, (P<0.002). Conclusion: Vitamin A supplementation of malnourished mothers maintains higher breastmilk retinol concentration for at least six months and reduces the duration of respiratory tract infection and febrile illness in their breastfed infants. Sponsorship: The study was supported by the International Centre for Diarrhoeal Disease Research and the United States Agency for International Development.

Emergence of a new clone of toxigenic Vibrio cholerae O1 biotype El Tor displacing V. cholerae O139 Bengal in Bangladesh.

Abstract: The emergence of Vibrio cholerae O139 Bengal in 1993, its rapid spread in an epidemic form, in which it replaced existing strains of V. cholerae O1 during 1992 and 1993, and the subsequent reemergence of V. cholerae O1 of the El Tor biotype in Bangladesh since 1994 have raised questions regarding the origin of the reemerged El Tor vibrios. We studied 50 El Tor vibrio strains isolated in Bangladesh and four other countries in Asia and Africa before the emergence of V. cholerae O139 and 32 strains isolated in Bangladesh during and after the epidemic caused by V. cholerae O139 and 32 strains isolated in Bangladesh during and after the epidemic caused by V. cholerae O139 to determine whether the reemerged El Tor vibrios were genetically different from the El Tor vibrios which existed before the emergence of V. cholerae O139. Analysis of restriction fragment length polymorphisms in genes for conserved rRNA, cholera toxin (ctxA), and zonula occludens toxin (zot) or in DNA sequences flanking the genes showed that the El Tor strains isolated before the emergence of V. cholerae O139 belonged to four different ribotypes and four different ctx genotypes. Of 32 El Tor strains isolated after the emergence of O139 vibrios, 30 strains (93.7%) including all the clinical isolates belonged to a single new ribotype and a distinctly different ctx genotype. These results provide evidence that the reemerged El Tor strains represent a new clone of El Tor vibrios distinctly different from the earlier clones of El Tor vibrios which were replaced by the O139 vibrios. Further analysis showed that all the strains carried the structural and regulatory genes for toxin-coregulated pilus (tcpA, tcpI, and toxR). All strains of the new clone produced cholera toxin (CT) in vitro, as assayed by the GM1-dependent enzyme-linked immunosorbent assay, and the level of CT production was comparable to that of previous epidemic isolates of El Tor vibrios. Further studies are required to assess the epidemic potential of the newly emerged clone of V. cholerae O1 and to understand the mechanism of emergence of new clones of toxigenic V. cholerae.

Anticipating rotavirus vaccines: hospital-based surveillance for rotavirus diarrhea and estimates of disease burden in Bangladesh.

Abstract: Objectives. Rotavirus is the most common cause of severe diarrhea in children worldwide, and a vaccine may soon be licensed and available for use in immunization programs. To assess the need for a rotavirus vaccine in Bangladesh, we estimated the disease burden of rotavirus diarrhea from national vital statistics for births and diarrheal deaths, together with hospital surveillance data on the proportion of severe childhood diarrhea attributed to rotavirus. Methods. From 1990 through 1993, hospital surveillance was conducted of a systematic, random 4% sample of >80 000 patients with diarrhea who sought care each year at the International Centre for Diarrhoeal Disease Research, Bangladesh (ICDDR,B). Results. Rotavirus was detected in 20% (1561 of 7709) of fecal specimens from children with diarrhea <5 years of age; 92% of all cases (1436) occurred in children <2 years of age, but only 3% (50) of cases occurred in infants <3 months of age. Children infected with rotavirus were more likely to have watery stools (P < 0.001), severe vomiting (P < 0.001) but less severe dehydration (P = 0.007) than children infected with other enteropathogens. Conclusions. We estimate that in this setting, where 18% of children die by age 5 and about 25% of these succumb to diarrhea, between 14 850 and 27 000 of the 3 million Bangladeshi children born in 1994 will die of rotavirus by the age of 5 years, equivalent to 1 rotavirus death per 111 to 203 children. The estimated burden of rotavirus diarrhea in Bangladesh is sufficiently great to warrant field testing of rotavirus vaccines for possible inclusion in the current immunization program.

Molecular analysis of toxigenic Vibrio cholerae O139 Bengal strains isolated in Bangladesh between 1993 and 1996: evidence for emergence of a new clone of the Bengal vibrios.

Abstract: Vibrio cholerae O139 Bengal emerged in 1992 and rapidly spread in an epidemic form, in which it replaced existing strains of V. cholerae O1 in Bangladesh during 1992 and 1993. The subsequent emergence of a new clone of V. cholerae O1 of the El Tor biotype that transiently displaced the O139 vibrios during 1994 to 1995 and the recent reemergence of V. cholerae O139 and its coexistence with the El Tor vibrios demonstrated temporal changes in the epidemiology of cholera in Bangladesh. We studied clonal diversity among V. cholerae O139 strains isolated from cholera patients and environmental surface water since their first appearance until their transient disappearance in 1994 as well as the O139 strains that reemerged during 1995 to 1996 and were isolated in the capital Dhaka and four rural districts of Bangladesh to investigate the origin of the reemerged strains. Analysis of restriction fragment length polymorphisms in genes for conserved rRNA and cholera toxin (CT) (ctxA) or in DNA sequences flanking these genes revealed four different ribotypes and four different ctx genotypes among the 93 strains of V. cholerae O139 studied. Ribotypes I and II and ctx genotypes A through C were shared by strains isolated from the epidemic outbreak during 1992 and 1993 in Bangladesh and India, ribotype III was represented by a single CT-negative O139 strain from Argentina, and 16 of 27 (59.2%) of the reemerged strains isolated during 1995 and 1996 belonged to a new ribotype of O139 vibrios designated ribotype IV. All 16 strains belonging to ribotype IV also belonged to a new ctx genotype (genotype 4). These results provide evidence for the emergence of a new clone of toxigenic V. cholerae O139 in Bangladesh. Further analysis of the rfb gene cluster by PCR revealed the absence of a large region of the O1-specific rfb operon and the presence of an O139-specific genomic region in all O139 strains. The PCR amplicon corresponding to the rfaD gene of a CT-negative O139 strain from Argentina was smaller in length than those of the toxigenic O139 strains but was identical to those of seven non-O1 and non-O139 strains. All O139 strains except the CT-negative strain carried structural and regulatory genes for CT and toxin-coregulated pili (ctxA, tcpA, tcpI, and toxR). These results suggest that the O139 Bengal strains possibly emerged from an El Tor strain but that the CT-negative non-Bengal O139 strain might have emerged from a non-O1, non-O139 strain. Thus, strains belonging to the O139 serogroup may have emerged from similar serotype-specific genetic changes in more than one progenitor strain of V. cholerae.

Helicobacter pylori: Prevalence, Transmission, and Serum Pepsinogen II Concentrations in Children of a Poor Periurban Community in Bangladesh

Abstract: The aim of this study was to determine the age-specific prevalence of Helicobacter pylori infection in infants and children aged 1-99 months from a poor periurban community in Bangladesh. We also examined the frequency of infection among infants and their 53 immediate family members and evaluated the relationship between infection and fasting serum group II pepsinogen (pepsinogen II) concentration in 76 children. Sixty-one percent of 1-3 month-old infants tested positive for H. pylori; this rate declined steadily to 33% in children aged 10-15 months and then increased to 84% in children aged 5-8 years. The H. pylori infection rate was 2.5 times higher in children with illiterate mothers. No difference in infection rate was detected among the family contacts of infected vs. noninfected infants. H. pylori-infected children had significantly higher serum pepsinogen II concentrations than did noninfected children (P < .001). We conclude that infection with H. pylori is highly prevalent and occurs at an early age. An environmental factor or factors, rather than or in addition to intrafamilial spread of this infection, are important in poor communities of Bangladesh. The higher levels of serum pepsinogen II in H. pylori-positive children might indicate the presence of gastritis in such asymptomatic children.

Cryptosporidium infection in children in urban Bangladesh

Abstract: We reviewed data during 1991-94 from a systematic 4 per cent subsample of all patients who presented with diarrhoea to our facility, in which there were 1949 cases of acute diarrhoea in children between the ages of birth to 59 months. Cryptosporidia oocysts were detected in the stools of 68 (3.5 per cent) of these children. A case-control study was designed using surveillance data which included the 68 children with stool positive for Cryptosporidium as cases. Two hundred and four children who did not have Cryptosporidium were randomly selected to serve as controls. The most common presentations were watery diarrhoea (91 per cent), dehydration (81 per cent), and vomiting (71 per cent), and Cryptosporidium was detected throughout the year, but was most frequently isolated during April to October. Lowest rates of detection were observed in the months of November, December, and January. Age below 2 years, non-breastfeeding, and stunting were significantly associated with Cryptosporidium infection. In multivariate analysis of our study we found that only stunted (P = 0.031) and non-breastfed children (P = 0.022) had a greater risk of having Cryptosporidium infection.

Awareness of sexually transmitted disease among women and service providers in rural Bangladesh.

Abstract: Sexually transmitted disease (STD) in rural Bangladesh is currently a topic of great concern. To date, little information is available in the literature regarding its prevalence. It is now known, however, that the current level of STD awareness among the rural population with regard to modes of transmission and means of prevention is inadequate. In 1994, the MCH-FP Extension Project (Rural) of ICDDR, B surveyed 8674 married women of reproductive age (MWRA) in 4 rural thanas to examine their awareness of STDs. The association between socio-demographic and programmatic factors (variables which affect STD information availability) and awareness of STDs was examined by both bivariate and multivariate analyses. Seven focus group discussions were conducted among groups of government health and family planning workers and paramedics to assess their knowledge of STDs and attitudes about their prevention. Only 12% of the original group had even a basic understanding about STDs and how to protect themselves from them. Twenty-five per cent of the women surveyed had ever heard of either syphilis or gonorrhoea. Of these women, less than half could mention specific mechanisms involved in the transmission of these diseases. Seven per cent reported that syphilis and gonorrhoea are transmitted through sexual intercourse. Thirteen per cent reported that the infections are transmitted from spouses to their partners. Four per cent reported that STDs can be spread by having multiple sexual partners. The results of logistic regression analysis indicate that awareness of STDs was higher among relatively older women than among younger women. Awareness of STDs was most strongly and positively associated with the education of both the women and their husbands. Awareness of STDs was also found to be higher among women who were more socially mobile (e.g. those who frequent cinemas or mothers' clubs). The findings of focus group discussions indicate that family planning and health care service providers have a moderate level of STD awareness. Modes of transmission and means of prevention, however, were areas of weakness. It will, therefore, be necessary, whether to prevent a potential STD epidemic or to combat current STD prevalence, to implement culturally acceptable and affordable means of disseminating knowledge in rural areas of Bangladesh. Training of health care providers will be an essential first step.

Long-Term Oral Supplementation with Iron Is Not Harmful for Young Children in a Poor Community of Bangladesh

Abstract: The effect of long-term oral iron supplementation on morbidity due to diarrhea, dysentery and respiratory infections in 349 children, aged 2-48 mo, living in a poor community of Bangladesh, was evaluated in this double-blind study. The treatment group received 125 mg of ferrous gluconate (15 mg elemental iron) plus multivitamins and the controls received only multivitamins, daily for 15 mo. House-to-house visits were made on alternate days by trained community health workers for recording symptoms and duration of illnesses and for monitoring medicine intake. Seventy-six percent of the children continued the syrup for over 1 y. No untoward effects were noticed in either treatment group. The attack rates for diarrhea, dysentery and acute respiratory tract infections (ARI) were 3, 3 and 5 episodes per child per year, respectively. Each episode of diarrhea lasted a mean of 3 d, and those of dysentery and ARI, 5 d. The two treatment groups did not differ in the number of episodes, mean duration of each episode, or total days of illnesses due to diarrhea, dysentery and ARI. However, a 49% greater number of episodes of dysentery was observed with iron supplementation in a subset of the study children who were less than 12 mo old (P = 0.03). The results of this study suggest that long-term oral iron supplementation is not harmful for older children in a poor community. Further studies are needed to demonstrate the safety and efficacy of iron administration in young infants.

Malnutrition, cell-mediated immune deficiency and acute upper respiratory infections in rural Bangladeshi children.

Abstract: A community-based longitudinal study conducted in rural Bangladesh investigated the association between nutritional status, cell-mediated immune status and acute upper respiratory infections (URI). A total of 696 children aged 0-59 months was followed prospectively for 1 y yielding 183,865 child-days' observation. Trained field workers visited each child every 4th d and collected morbidity data on symptoms suggesting URI (cough, fever, nasal discharge) for the preceding 3 d by recall. On the day of visit they examined each child reporting cough and/or fever to record the temperature, presence of nasal discharge, rate of respiration and presence of chest indrawing. Anthropometry for all children was conducted monthly. Cell-mediated immune competence was assessed by a multiple antigen skin test at baseline and thereafter every 3 months. The incidence of URI was 5.3 episodes per child-year observed. Approximately three-quarters of the study children were below -2 Z-score weight for age and height for age, and a quarter below -2 Z-score weight for height. During different test periods 9-21% of the study children did not respond to any of the test antigens. In a regression model children < -2 Z-score for weight for height had 16% [odds ratio (OR) 1.16, 95% confidence interval (CI) 1.03-1.31, p = 0.01] higher risk of developing URI. Anergic children had 20% higher risk (OR 1.20, CI 1.05-1.38, p = 0.009) of URI than immunocompetent children. The study demonstrated that wasting and depressed cell-mediated immunity (CMI), but not stunting, were associated with the incidence of URI among rural Bangladeshi children.

Immune response to the mannose-sensitive hemagglutinin in patients with cholera due to Vibrio cholerae O1 and O0139.

Abstract: The mannose-sensitive hemagglutinin (MSHA) is a type 4 pilus present in Vibrio cholerae O1 strains of the El Tor biotype, as well as in strains of serogroup O139. It has been shown to be a colonization antigen in animal models. The aim of this study was to investigate systemic and local antibody responses to MSHA in adult patients with cholera due to V. cholerae O1 and O139. Twenty-four of 28 (86%) patients with O1 cholera and 11 of 17 (65%) patients with O139 cholera showed significant increases in MSHA-specific immunoglobulin A (IgA) and IgM antibody-secreting cells (ASCs) 7 days after the onset of disease. However, the magnitude of the ASC response in O1 cholera patients was significantly higher than that in the O139 cholera patients in both IgA-producing (P = 0.015) and IgM-producing (P = 0.029) cells. Both groups of patients responded with antibody responses to MSHA in plasma, seroconverting with both IgA (63 to 70% of patients) and IgG (43 to 59% of patients) antibodies. Compared to the MSHA-specific antibody levels determined in healthy controls (n = 10), more than 90% of O1 and O139 cholera patients showed responses to MSHA of both the IgA and the IgG isotypes. About 70% of the patients in both groups also had antibody responses to MSHA in their feces. In summary, we demonstrated that MSHA is immunogenic, giving rise to both systemic and local antibodies in patients with cholera due to both O1 and O139 serogroups.

Phenotypic and genotypic changes in Vibrio cholerae O139 Bengal.

Abstract: To find reasons for the recent decline of Vibrio cholerae O139 Bengal cholera in Bangladesh, phenotypic and genotypic changes in O139 isolates obtained from patients with cholera from 1993 to 1996 were studied. The isolates were tested for the presence of ctx and tcpA genes, hemagglutinin/protease (HA/P), capsule, D-mannose-sensitive hemagglutinin (MSHA), L-fucose-sensitive hemagglutinin (FSHA), tube test (tube) and CAMP test (CAMP) hemolytic activities, resistance to 2,4-diamino-6,7-diisopropyl pteridine (O/129) and trimethoprim-sulfamethoxazole (TMP-SMX), and genotype by pulsed-field gel electrophoresis (PFGE). All isolates possessed ctx and tcpA genes, HA/P, and a capsule. Most isolates were negative for FSHA, but although the majority of the isolates were positive for MSHA, no discernible trend in the activity was found during the study period. All early isolates were CAMP hemolysin positive and resistant to the vibriostatic compound O/129 and TMP-SMX, the two properties that could be used for the presumptive diagnosis of O139 cholera. However, subsequently, isolates that were CAMP hemolysin negative and susceptible to TMP-SMX and O/129 were increasingly encountered, with all the 1996 isolates being so, which suggested that these properties can no longer be used for the presumptive diagnosis of O139 cholera. V. cholerae O139 isolates that were CAMP hemolysin positive and resistant to O/129 and TMP-SMX produced a disease of greater severity than that caused by the CAMP hemolysin-negative and susceptible isolates on the basis of the lengths of stay of the hospitalized patients. The study period witnessed the evolution of four different genotypes by PFGE. All of these data suggested that the V. cholerae O139 isolates have undergone changes in some properties. However, how these changes influenced their prevalence relative to that of V. cholerae O1 in human infection is not clear. Studies of the environmental factors will provide the key for an understanding of the relative abundance of these vibrios.

Breastfeeding and the risk of life-threatening enterotoxigenic Escherichia coli diarrhea in Bangladeshi infants and children

Abstract: Objective. To assess the relationship between breastfeeding and the risk of life-threatening enterotoxigenic Escherichia coli (ETEC) diarrhea among Bangladeshi infants and young children Design. Case–control study. Setting. A rural Bangladesh community. Participants. A total of 168 cases with clinically severe ETEC diarrhea detected in a treatment center-based surveillance system during 1985 to 1986 and 3679 controls selected in three surveys of the same community during the same calendar interval. Outcomes. Cases and controls were compared for the frequency of antecedent breastfeeding patterns. Results. Compared with other feeding modes, exclusive breastfeeding of infants was associated with significant protection against severe ETEC diarrhea (relative risk [RR] = 0.51; 95% confidence interval [CI]: 0.28,0.96). However, during the second and third years of life, the risk of this outcome was similar in both breastfed and nonbreastfed children (RR = 0.98; 95% CI: 0.45,2.12), and no significant overall protective association between breastfeeding and severe ETEC diarrhea was evident during the first 3 years of life (RR = 0.86; 95% CI: 0.43,1.74). Conclusions. Exclusive breastfeeding appeared to protect infants against severe ETEC diarrhea, but breastfeeding was not associated with protection after infancy, nor was it associated with a major overall reduction of severe ETEC disease during the first 3 years of life. Although not diminishing the importance of breastfeeding, our findings suggest that other interventions, such as immunization and education about proper food hygiene, may also be required in efforts to prevent this major pediatric disease.

Rapid detection of Vibrio cholerae O139 Bengal from stool specimens by PCR.

Abstract: In a previous study using pure bacterial cultures in a PCR assay, a primer pair corresponding to a unique chromosomal region of Vibrio cholerae O139 Bengal generated an amplicon from only V. cholerae O139 Bengal. PCR with the same primer pair was used to screen 180 diarrheal stool specimens. All the 67 V. cholerae O139 culture-positive stool specimens were positive by PCR, and the remaining specimens, which contained either other recognized enteric pathogens or no pathogens, were all negative by PCR.

Characterization of filamentous phages of Vibrio cholerae O139 and O1

Abstract: We have analyzed our collection of Vibrio cholerae O139 strains to determine whether filamentous phages are produced in their culture supernatants, and whether any replicative form of DNA is detectable in cell lysates. Two types of filamentous phage, designated fs1 (6.4 kb) and fs2 (8.5 kb), were found in strains of Vibrio cholerae O139, fs1 was commonly produced from clinical isolates of Vibrio cholerae O1. Infectious particles (filamentous phages) were inducible by subculture, mitomycin C, and cultivation in a ligated ileal loop of a rabbit. Type 4 fimbriae of Vibrio cholerae O1 sensitive to d-glucose and d-mannose were suggested to be receptors for fs1 and fs2. The genome of fs1 was revealed to encode a potential new enterotoxin homologous to zonula occludens toxin. Clarification of the relation of type 4 fimbriae and these filamentous phages will provide a new understanding of the colonization of Vibrio cholerae O1 and O139. Thus the presence of a new enterotoxin encoded by the genome of filamentous phage like fs1 may clarify the pathogenesis of cholera toxin negative clinical isolates of Vibrio cholerae O1 and non-O1. Our findings combined with the earlier report by Ehara et al. [Microbio. Immunol. 37 (1993) 679–688] suggest that type 4 fimbriae of Vibrio cholerae O1 are important for the development of an effective vaccine against cholera.

Reasons for Failure of Breast-Feeding Counselling: Mothers' Perspectives in Bangladesh

Abstract: During the hospitalization in the Dhaka hospital of the international Centre for Diarrhoeal Disease Research, Bangladesh, of a group of partially breast-fed infants aged 1-12 weeks who had been admitted with acute diarrhoea, their mothers were individually counselled by breast-feeding counsellors to start exclusive breast-feeding. The counselling was repeated 1 week later at home, and the women's infant-feeding practices were evaluated 2 weeks after their infants had been discharged from hospital. A total of 25% of the mothers failed to breast-feed exclusively despite having been counselled. The case studies of these mothers illustrate that although they generally complained about having "insufficient breast milk" various factors such as domineering grandmothers, lack of financial support by their husbands, too much housework, or disinterest contributed to their failure to breast-feed exclusively. While family support is essential for all lactating mothers, women with familial or financial problems require special attention and extra counselling sessions so that they can be helped to identify how to achieve and sustain exclusive breast-feeding.

Epidemiology of shigellosis among children exposed to cases of Shigella dysentery: a multivariate assessment.

Abstract: We followed 1,756 young, rural Bangladeshi children less than five years of age for one month after identification of sentinel Shigella patients in their neighborhoods. Two hundred nineteen (12%) children developed Shigella diarrhea (shigellosis) and 227 (13%) developed culture-negative dysentery. Shigella flexneri (60%) and S. dysenteriae, type 1 (15%) were the most common isolates among shigellosis cases. Within individual neighborhoods, there was poor agreement (Kappa = 0.21) between Shigella species isolated from sentinel patients and from additional cases detected during surveillance. The risk of shigellosis increased substantially after infancy and peaked in the second year of life. Severe stunting, as assessed by height-for-age, was associated with an increased risk of shigellosis (adjusted odds ratio [ORa] = 1.67, 95% confidence interval [CI] = 1.09-2.57, P < 0.05), while breast-feeding was protectively associated (ORa = 0.40, 95% CI = 0.24-0.69, P < 0.001). Only 43% of the shigellosis cases reported bloody stools; frank dysentery occurred more frequently in S. dysenteriae 1 infections than in S. flexneri infections (ORa = 5.04, 95% CI = 1.76-14.48, P < 0.01), and was also associated with severe stunting (ORa = 2.16, 95% CI = 1.01-4.58, P < 0.05). Our findings show that the high risk of shigellosis in residentially exposed Bangladeshi children results from multiple Shigella strains circulating concurrently within the same neighborhood; demonstrate that the risk is notably modified by host age, nutritional status, and dietary patterns; and illustrate that the classic picture of dysentery is relatively infrequent and is correlated with the infecting species and with host nutritional status.

Impact of national immunization days on polio-related knowledge and practice of urban women in Bangladesh.

Abstract: Bangladesh began to hold National Immunization Days (NIDs) from 1995 as part of the country's goal to eradicate poliomyelitis by the turn of the century. The NIDs brought together government agencies, the media, voluntary organisations and individual volunteers in social mobilization and service delivery activities. This paper assesses the impact of the first two polio NIDs in terms of the immunization coverage and change in knowledge about the disease among women living in Dhaka city, the capital of the country. Data were collected through pre- and post-NID cross-sectional surveys in a sample of one area of Dhaka city which included slum and non-slum households. Knowledge data were collected from 525 women with at least one child aged less than five years. The oral polio vaccine (OPV) coverage during NIDs was obtained from 720 children. Knowledge of polio as a vaccine preventable disease increased after NIDs among both slum and non-slum women. The knowledge gap between the two groups was significantly reduced. Field workers, who regularly visit women at their homes to promote health and family planning services, were the main source of information for the slum women while television was cited as the most important source of information by non-slum women. The study revealed that 88% of children under five years received at least one dose of oral polio vaccine (OPV) during NIDs, and 67% received two stipulated doses with no significant differences between slum (65%) and non-slum (69%) groups. In addition, 68% of the children contacted during the NIDs were given vitamin A supplementation. The study suggests that strategies like NID can be effectively used to tap into community resources and to generate political commitments for health programmes.

Higher proportion of CD8+ T cells in the blood in healthy adults from Ethiopia and Bangladesh compared with Sweden

Abstract: The phenotypic composition of peripheral blood lymphocytes in 45 healthy adults (15 each from Bangladesh, Ethiopia and Sweden) was analysed as an indicator of the influence of environment and/or ethnic background on the human immune response. The possible interference of technical factors was minimized by highly standardized handling of samples and by use of a similar simultaneous 3-colour flow cytometry analysis technique for all samples. The percentage of CD4+ cells was lower, and the percentage of CD8+ cells was higher, in Bangladeshi and Ethiopian subjects than in those from Sweden. A higher percentage of CD57+/CD8+ T cells was also found in these 2 groups than in Swedish subjects. The percentage of gamma delta T cells was higher in Bangladeshi subjects and a difference in T cell receptor V beta expression was also noted between Bangladeshi and Swedish subjects. The data suggest that environmental or genetic factors are important bias factors to be considered in immunophenotyping studies. Possibly differences in the pattern or level of microbial challenge, as well as nutritional factors, may lead to different adaptive changes in the immune response. The potential influence of such immune adaptation on the response to vaccination or pharmaceutical therapy may be important in the development of new strategies of medical intervention in different geographical regions or ethnic groups.

Determinants of infant and child mortality in rural Bangladesh.

Abstract: This paper examines the trends and covariates of infant and child mortality in rural areas of Bangladesh Data on a cohort of 21268 children born during 1983-91 in three rural Project sites were obtained from the longitudinal Sample Registration System (SRS) of the Maternal-Child Health-Family Planning (MCH-FP) Extension Project (Rural) of the International Center for Diarrheal Disease Research Bangladesh The analysis follows the model specified in the extended analysis of the Bangladesh Demographic and Health Survey 1993-94 and is divided into three components: neonatal mortality post-neonatal mortality and mortality between 12 and 23 months Estimates of mortality differentials by socio-demographic characteristics were derived using a life-table technique Multivariate logistic regression procedures were applied separately to include fixed and temporal characteristics of the cohort Mortality estimates were compared with those of the national-level extended analysis Childhood mortality has been declining in the MCH-FP Extension Project areas since 1983 as it has been nationally Reductions in the rates of mortality among infants and children aged < 5 years were less pronounced at the Extension Project sites than it was in the national study The findings of the study confirm the findings of other research which show that longer preceding birth intervals play a significant role in reducing child mortality Of course provision of primary healthcare services is as well associated with reduced risk The data from the SRS in the MCH-FP Extension Project sites suggest that there is a significant relationship between childhood immunization and reduced child mortality Access to tubewell water was also associated with a reduced risk of mortality for young children These findings have strong policy implications Goals and objectives of the family planning program and those of the Expanded Programme on Immunization do not compete rather they complement each other Each of them plays a unique role in improving child survival (authors)

Flood control embankments contribute to the improvement of the health status of children in rural Bangladesh.

Abstract: Every year, Bangladesh experiences major floods that inundate about one-third of the country. Therefore, flood control projects that comprise earthen dikes and irrigation/drainage systems are built along the major rivers to protect the people living in low-lying areas, stabilize the river banks and improve agricultural productivity. However, the adverse effects of these projects are regularly emphasized, such as environmental degradation and reduction of fishing supplies. The Demographic Surveillance System of the International Centre for Diarrhoeal Diseases Research, Bangladesh (ICDDR,B) was used to assess the effect of a flood control programme on the mortality of 0-4-year-old children residing in the Matlab study area. Adjusted mortality rates were used in comparing four adjacent child populations residing either inside or outside a flood-control embankment and according to the type of health services provided in this area. Between the periods 1983-86 and 1989-92, the crude child mortality in the total study area decreased by 37%, from 185.9 per 1000 live births to 117.9 per 1000 live births. Following the construction of the embankment, death rates outside were up to 29% higher in 1-4-year-old children and 9% higher for 0-4-year age group compared to the flood-protected area (P < 0.001). Simultaneously, in the same study area, health interventions contributed to a 40% reduction in mortality among children less than 5 years of age in all causes of deaths (P < 0.001). Migration patterns and the effect of distances to the hospital are discussed.