Showing papers by "International Centre for Diarrhoeal Disease Research, Bangladesh published in 2004"
TL;DR: Two Nipah virus encephalitis outbreaks in Bangladesh may be associated with person-to-person transmission.
Abstract: We retrospectively investigated two outbreaks of encephalitis in Meherpur and Naogaon, Bangladesh, which occurred in 2001 and 2003. We collected serum samples from persons who were ill, their household contacts, randomly selected residents, hospital workers, and various animals. Cases were classified as laboratory confirmed or probable. We identified 13 cases (4 confirmed, 9 probable) in Meherpur; 7 were in persons in two households. Patients were more likely than nonpatients to have close contact with other patients or have contact with a sick cow. In Naogaon, we identified 12 cases (4 confirmed, 8 probable); 7 were in persons clustered in 2 households. Two Pteropus bats had antibodies for Nipah virus. Samples from hospital workers were negative for Nipah virus antibodies. These outbreaks, the first since 1999, suggest that transmission may occur through close contact with other patients or from exposure to a common source. Surveillance and enhancement of diagnostic capacity to detect Nipah virus infection are recommended.
493 citations
TL;DR: Results indicate that arsenic contaminates some food items in Bangladesh, and further studies are needed to demonstrate the extent of arsenic contamination of food in Bangladesh.
413 citations
TL;DR: There are many promising measures that might be pursued: establishment of goals for improved coverage in the poor, rather than in entire populations, and use of those goals to direct planning toward the needs of the disadvantaged.
407 citations
TL;DR: The beneficial effects of weekly iron and zinc supplementation on motor development and orientation-engagement suggest that infants benefit from these minerals when administered together.
240 citations
TL;DR: Four T4-like coliphages with broad host ranges for diarrhea-associated Escherichia coli serotypes showed a highly efficient gastrointestinal passage in adult mice when added to drinking water, apparently indicating that the resident E. coli gut flora is physically or physiologically protected against phage infection.
Abstract: Four T4-like coliphages with broad host ranges for diarrhea-associated Escherichia coli serotypes were isolated from stool specimens from pediatric diarrhea patients and from environmental water samples. All four phages showed a highly efficient gastrointestinal passage in adult mice when added to drinking water. Viable phages were recovered from the feces in a dose-dependent way. The minimal oral dose for consistent fecal recovery was as low as 103 PFU of phage per ml of drinking water. In conventional mice, the orally applied phage remained restricted to the gut lumen, and as expected for a noninvasive phage, no histopathological changes of the gut mucosa were detected in the phage-exposed animals. E. coli strains recently introduced into the intestines of conventional mice and traced as ampicillin-resistant colonies were efficiently lysed in vivo by phage added to the drinking water. Likewise, an in vitro phage-susceptible E. coli strain freshly inoculated into axenic mice was lysed in vivo by an orally applied phage, while an in vitro-resistant E. coli strain was not lysed. In contrast, the normal E. coli gut flora of conventional mice was only minimally affected by oral phage application despite the fact that in vitro the majority of the murine intestinal E. coli colonies were susceptible to the given phage cocktail. Apparently, the resident E. coli gut flora is physically or physiologically protected against phage infection.
232 citations
TL;DR: Daily consumption of cooked, puréed green leafy vegetables or sweet potatoes has a positive effect on vitamin A stores in populations at risk of vitamin A deficiency, as assessed in Bangladeshi men.
222 citations
TL;DR: Adjuvant treatment with 20 mg zinc per day accelerates recovery from severe pneumonia in children, and could help reduce antimicrobial resistance by decreasing multiple antibiotic exposures, and lessen complications and deaths where second line drugs are unavailable.
210 citations
TL;DR: 2 years into the assessment, the results show improvements in the quality of care in health facilities, increases in use of facilities, and gains in the proportion of sick children taken to an appropriate health care provider.
198 citations
TL;DR: Results of this study suggest that the environmental V. cholerae population in a cholera-endemic area is highly heterogeneous, and selection in the mammalian intestine can cause enrichment of environmental strains with virulence potential, which involves more virulence genes than currently appreciated.
Abstract: To understand the evolutionary events and possible selection mechanisms involved in the emergence of pathogenic Vibrio cholerae, we analyzed diverse strains of V. cholerae isolated from environmental waters in Bangladesh by direct enrichment in the intestines of adult rabbits and by conventional laboratory culture. Strains isolated by conventional culture were mostly (99.2%) negative for the major virulence gene clusters encoding toxin-coregulated pilus (TCP) and cholera toxin (CT) and were nonpathogenic in animal models. In contrast, all strains selected in rabbits were competent for colonizing infant mice, and 56.8% of these strains carried genes encoding TCP alone or both TCP and CT. Ribotypes of toxigenic O1 and O139 strains from the environment were similar to pandemic strains, whereas ribotypes of non-O1 non-O139 strains and TCP- nontoxigenic O1 strains diverged widely from the seventh pandemic O1 and the O139 strains. Results of this study suggest that (i) the environmental V. cholerae population in a cholera-endemic area is highly heterogeneous, (ii) selection in the mammalian intestine can cause enrichment of environmental strains with virulence potential, (iii) pathogenicity of V. cholerae involves more virulence genes than currently appreciated, and (iv) most environmental V. cholerae strains are unlikely to attain a pandemic potential by acquisition of TCP and CT genes alone. Because most of the recorded cholera pandemics originated in the Ganges Delta region, this ecological setting presumably favors extensive genetic exchange among V. cholerae strains and thus promotes the rare, multiple-gene transfer events needed to assemble the critical combination of genes required for pandemic spread.
198 citations
TL;DR: Diphtheria-tetanus-pertussis (DTP) and oral polio vaccination were independently associated with decreased risk of death before age 9 months, as were amount of maternal education, maternal age, and birth order of the child.
162 citations
TL;DR: In this article, the authors present the impact of BRAC on selected components of human well-being, such as child survival, nutritional status, expenditure patterns, family planning practices and children's education.
Abstract: Over the decades of the 1980s and 90s many poverty alleviation programmes have been implemented in developing countries. Evaluations of such programmes have traditionally looked at their success in increasing the income levels of participants but less at the wider goals of human well-being. This paper looks at the poverty alleviation programme of BRAC, a large non-governmental organisation in Bangladesh, and, based on carefully designed studies, presents its impact on selected components of ‘human well-being’.
This study found better child survival and nutritional status in households served by the programme. Simular impacts were also found in other areas such as expenditure patterns, family planning practices and children's education. The studies also looked at the impact on the rural power structure and found a substantial change in the networking relationship of health providers. The likely influence of ‘selectivity bias’ on the above results is also discussed. Copyright © 2004 John Wiley & Sons, Ltd.
TL;DR: Different species of Aeromonas and different clones of aeromonas species seem to be associated with hospitalized cases of diarrhoea in Kolkata, India.
Abstract: A comprehensive study was performed to examine incidence, species distribution, drugs sensitivity, virulence genes and molecular fingerprints of Aeromonas species isolated from patients with acute diarrhoea over a period of 2 years in Kolkata, India. Following the Aerokey II scheme, more than 95 % of strains were identified to species level. Seven different species were encountered in this study, with Aeromonas caviae being dominant, followed by Aeromonas hydrophila and Aeromonas veronii biovar sobria. Thirty different serotypes were encountered, with O16, O83 and O85 being dominant, but no serotype was associated specifically with a single species. The majority of Aeromonas strains exhibited multidrug resistance. The alt and act genes, which encode heat-labile cytotonic and cytotoxic enterotoxins, were respectively found in 71.9 and 20.1 % of strains examined. Only 2.4 % of strains carried the heat-stable cytotonic enterotoxin (ast) gene. The hlyA gene was found in 28 % of Aeromonas strains. With few exceptions, genomic diversity of Aeromonas strains belonging to the same serotype was observed by random amplification of polymorphic DNA PCR and ribotyping. Different species of Aeromonas and different clones of Aeromonas species seem to be associated with hospitalized cases of diarrhoea in Kolkata, India.
TL;DR: A simple, novel multiplex PCR assay for rapid detection of Helicobacter pylori infection and for the determination of vacA and cagA genotypes directly from gastric biopsy specimens is developed and evaluated.
Abstract: We developed and evaluated a simple, novel multiplex PCR assay for rapid detection of Helicobacter pylori infection and for the determination of vacA and cagA genotypes directly from gastric biopsy specimens This assay did not require culturing of strains or extraction of DNA from biopsy samples This multiplex PCR assay would be of particularly great value for laboratories in developing countries
TL;DR: The findings of this study add to the evidence that poor nutritional status may increase an individual's susceptibility to chronic arsenic toxicity, or alternatively that arsenicosis may contribute topoor nutritional status.
Abstract: The role of nutritional factors in arsenic metabolism and toxicity is not clear. Provision of certain low protein diets resulted in decreased excretion of DMA and increased tissue retention of arsenic in experimental studies. This paper reports a prevalence comparison study conducted in Bangladesh to assess the nutritional status among the chronic arsenic exposed and unexposed population. 138 exposed individuals diagnosed as arsenicosis patients were selected from three known arsenic endemic villages of Bangladesh and age, sex matched 144 unexposed subjects were randomly selected from three arsenic free villages. The mean arsenic concentration in drinking water for the exposed and unexposed population was 641.15 and 13.5 microg L(-1) respectively. Body Mass Index was found to be lower than 18.5, the cut off point for malnutrition, in 57 (41.31%) out of 138 exposed arsenicosis cases and 31 (21.53%) out of 144 unexposed individuals. The crude prevalence ratio (or risk) was 1.92 (95% CI = 1.33-2.78) for poor nutritional status among the arsenicosis cases compared to the unexposed population. The findings of this study add to the evidence that poor nutritional status may increase an individual's susceptibility to chronic arsenic toxicity, or alternatively that arsenicosis may contribute to poor nutritional status.
TL;DR: Findings suggest that the vibriocidal antibody is an incomplete predictor of protection from V. cholerae infection, and that infection still developed in some contacts with very high titers.
Abstract: The serum vibriocidal antibody is the only recognized predictor of protection from cholera, but no seroepidemiological data have been gathered since the emergence of Vibrio cholerae O139. We assessed the association between the vibriocidal antibody titer and protection from cholera in an endemic setting. Although a higher baseline vibriocidal titer correlated with protection from V. cholerae O1, infection still developed in some contacts with very high titers. No association between baseline vibriocidal titer and protection from V. cholerae O139 infection was found. Our findings suggest that the vibriocidal antibody is an incomplete predictor of protection from V. cholerae infection.
TL;DR: It is shown that innate cells and their mediators are upregulated in acute watery diarrhoea and may need to be simulated in a vaccine to achieve long lasting protection from cholera.
Abstract: Background and aims: The general concept is that as Vibrio cholerae is not invasive, it mediates a non-inflammatory type of infection. This is being re-evaluated based on available data that natural cholera infection or cholera toxin induces a Th2-type of immune profile and stimulates the humoral immune response, innate cells, and mediators in the host. Methods: To perform a comprehensive analyses of the inflammatory components, we studied mucosal biopsies from patients, both adults and children with acute watery diarrhoea caused by V cholerae O1 and O139. Patients with cholera, adults (n = 30) and children (n = 18), as well as healthy controls (n = 24) were studied. Histochemical, immunohistochemical, and ultrastructural studies were carried out to elucidate the contribution of the different factors using paraffin and frozen duodenal and/or rectal sections as appropriate. Samples were collected during the acute stage and during early and/or late convalescence. Results: Following natural cholera infection, patients responded with increases in neutrophil polymorphs during the acute stage (p V cholerae O1 infected patients showed upregulation of myeloperoxidase, lactoferrin, PGHS-1, SCF, tryptase, tumour necrosis factor α, α-defensin, and eotaxin during the acute stage and chymase, interleukin 3 and major basic protein during convalescence. Conclusion: We have shown that innate cells and their mediators are upregulated in acute watery diarrhoea. These cells and factors of the innate arm may be important in the host’s defence against cholera. Such effects may need to be simulated in a vaccine to achieve long lasting protection from cholera.
TL;DR: The efficacy of ferrous fumarate in iron fortification programs to prevent iron deficiency in young children should be evaluated.
TL;DR: Antimicrobial susceptibility of 120 Helicobacter pylori isolates to metronidazole, tetracycline, clarithromycin, and amoxicillin was determined, and 77.5, 15, 10, and 6.6% of the isolates were resistant.
Abstract: Antimicrobial susceptibility of 120 Helicobacter pylori isolates to metronidazole, tetracycline, clarithromycin, and amoxicillin was determined, and 77.5, 15, 10, and 6.6% of the isolates, respectively, were resistant. Only rdxA inactivation and both rdxA and frxA inactivation were responsible for metronidazole resistance in 66% (8 of 12) and 33% (4 of 12) of the isolates, respectively.
TL;DR: In this article, the genetic relatedness of 81 isolates of Vibrio parahaemolyticus O3:K6 was assessed by multilocus sequence typing.
Abstract: The genetic relatedness of 81 isolates of Vibrio parahaemolyticus was assessed by multilocus sequence typing. The strain with serotype O3:K6 emerged as a pandemic pathogen in 1996, with subsequent expansion to include strains having serotypes O1:KUT, O4:K68, and O1:K25. Sequence data from gyrB, recA, dnaE, and gnd revealed that 16 distinct serogroups isolated prior to the pandemic were highly variable and only isolates of serogroup O3:K6 shared two alleles with the pandemic strains. The pandemic strains regardless of serotype were clonal, with 51 of 54 isolates having the identical allelic profile (AP). Serotype alone did not adequately define a pandemic strain: among O1:KUT strains tested, seven strains with the identical pandemic AP carried previously described pandemic markers, while five nonpandemic strains had five distinct APs. Our sequence data provide strong molecular support for the clonal origin of pandemic V. parahaemolyticus O3:K6 and suggest that strains within such a clonal group may acquire previously identified serotypes.
TL;DR: The highest titre of toxin was obtained in vesicle fraction suggesting that the vesicles play an important role in the release of Shiga toxin from periplasmic space by the organism.
Abstract: Effects of various antimicrobials on in vitro Shiga toxin production and release by Shigella dysenteriae serotype 1 was investigated in this study with particular reference to the role of outer membrane vesicles in toxin release by the organism Five antimicrobials, namely nalidixic acid, ciprofloxacin, norfloxacin, fosfomycin and mitomycin C, were chosen for the study and the toxin titre was measured by the reverse passive latex agglutination (RPLA) method using an available kit Only mitomycin C was found to induce production of Shiga toxin in the bacteria and its release by outer membrane vesicles The highest titre of toxin was obtained in vesicle fraction suggesting that the vesicles play an important role in the release of Shiga toxin from periplasmic space by the organism
TL;DR: Evidence of the effectiveness of a non-governmental organization (NGO) primary health care programme in rural Bangladesh is considered based on data from the programme's management information system reported by 27 partner NGOs from 1996-2002, which indicates relatively high coverage has been achieved for reproductive and child health services, as well as lower infant and child mortality.
Abstract: This paper considers evidence of the effectiveness of a non-governmental organization (NGO) primary health care programme in rural Bangladesh. It is based on data from the programme's management information system reported by 27 partner NGOs from 1996-2002. The data indicate relatively high coverage has been achieved for reproductive and child health services, as well as lower infant and child mortality. On the basis of a crude indicator of socio-economic status, the programme is poverty-focused. There is good service coverage among the poorest one-third and others, and the infant and child mortality differential has been eliminated over recent years. A rapid decline in infant mortality among the poorest from 1999-2002 reflects a reduction in neonatal mortality of about 50%. Allowing for some under-reporting and possible misclassification of deaths to the stillbirths category, neonatal mortality is relatively low in the NGO areas. The lower child and maternal mortality for the NGO areas combined, compared with estimates for Bangladesh in recent years, may at least in part be due to high coverage of reproductive and child health services. Other development programmes implemented by many of the NGOs could also have contributed. Despite the limited resources available, and the lower infant and child mortality already achieved, there appears to be scope for further prevention of deaths, particularly those due to birth asphyxia, acute respiratory infection, diarrhoeal disease and accidents. Maternal mortality in the NGO areas was lower in 2000-02 than the most recent estimate for Bangladesh. Further reduction is likely to depend on improved access to qualified community midwives and essential obstetric care at government referral facilities.
TL;DR: The results indicate that MIRU-VNTR typing, along with spoligotyping and deletion analysis, can be used effectively for molecular epidemiological studies to determine ongoing transmission clusters.
Abstract: Genotypic analysis was performed on 48 Mycobacterium tuberculosis complex strains collected from a hospital in Dhaka city. Deletion analysis showed that the isolates were all M. tuberculosis; 13 of them were found to be of the "ancestral" type, while 35 were of the "modern" type, indicating that both endemic (ancestral type) and epidemic (modern type) strains cause tuberculosis in Bangladesh. Genotyping based on the spoligotype and variable-number tandem repeats (VNTR) of mycobacterial interspersed repetitive units (MIRU) was also done. A total of 34 strains (71%) were grouped by spoligotyping into nine different clusters; the largest comprised 15 isolates of the Beijing genotype, whereas the remaining eight clusters consisted of two to five isolates. MIRU-VNTR typing detected 32 different patterns among 44 tested strains, and the 15 Beijing strains were further discriminated by MIRU-VNTR typing (7 distinct patterns for the 15 isolates). These results indicate that MIRU-VNTR typing, along with spoligotyping and deletion analysis, can be used effectively for molecular epidemiological studies to determine ongoing transmission clusters; to our knowledge, this is the first report about the type of strains prevailing in Bangladesh.
TL;DR: Phages with closely related restriction patterns and, in the case of T4-like phages, identical g23 gene sequences were isolated from different patients, suggesting epidemiological links between the patients.
Abstract: A 3-week coliphage survey was conducted in stool samples from 140 Bangladeshi children hospitalized with severe diarrhea. On the Escherichia coli indicator strain K803, all but one phage isolate had 170-kb genomes and the morphology of T4 phage. In spot tests, the individual T4-like phages infected up to 27 out of 40 diarrhea-associated E. coli, representing 22 O serotypes and various virulence factors; only five of them were not infected by any of these new phages. A combination of diagnostic PCR based on g32 (DNA binding) and g23 (major capsid protein) and Southern hybridization revealed that half were T-even phages sensu strictu, while the other half were pseudo-T-even or even more distantly related T4-like phages that failed to cross-hybridize with T4 or between each other. Nineteen percent of the acute stool samples yielded T4-like phages, and the prevalence was lower in convalescent stool samples. T4-like phages were also isolated from environmental and sewage water, but with low frequency and low titers. On the enteropathogenic E. coli strain O127:K63, 14% of the patients yielded phage, all of which were members of the phage family Siphoviridae with 50-kb genomes, showing the morphology of Jersey- and beta-4 like phages and narrow lytic patterns on E. coli O serotypes. Three siphovirus types could be differentiated by lack of cross-hybridization. Only a few stool samples were positive on both indicator strains. Phages with closely related restriction patterns and, in the case of T4-like phages, identical g23 gene sequences were isolated from different patients, suggesting epidemiological links between the patients.
TL;DR: ABSTRACT PCR surveillance of the rstR genes of CTX phages in Vibrio cholerae O1 and O139 showed no relationship between the incidence of disease and changes in the rStR but showed variations in their presence in O1and O139 strains and the occurrence of multiple types in a few strains.
Abstract: PCR surveillance of the rstR genes of CTX phages in Vibrio cholerae O1 and O139 showed no relationship between the incidence of disease and changes in the rstR but showed variations in their presence in O1 and O139 strains and the occurrence of multiple types in a few strains.
TL;DR: In this trial, the availability of zinc supplements, along with ORT and appropriate education programmes, was associated with significantly higher use of OrT and lower use of antibiotics.
Abstract: Excessive use of antibiotics for diarrhoea is a major contributing factor towards increasing rates of antimicrobial resistance in developing countries. Zinc therapy for diarrhoea has been shown to be beneficial in controlled efficacy trials, and it is of interest to determine if availability of zinc syrup for treatment of diarrhoea would satisfy the demand for a 'medicine' for diarrhoea, thus reducing the use of antibiotics, without competing with the use of oral rehydration therapy (ORT). This community-based controlled trial was conducted from November 1998 to October 2000, and all children aged 3-59 months in the study area were included. In this trial, the availability of zinc supplements, along with ORT and appropriate education programmes, was associated with significantly higher use of ORT and lower use of antibiotics.
University of Texas Health Science Center at Houston1, University of Texas at Austin2, University of Texas MD Anderson Cancer Center3, University of Zurich4, Salix Pharmaceuticals5, Medicines for Malaria Venture6, Johns Hopkins University7, International Centre for Diarrhoeal Disease Research, Bangladesh8, Baylor College of Medicine9
TL;DR: Improvement of EAEC-mediated diarrhea with antibiotic treatment supports the pathogenicity of this organism in travelers to developing countries.
TL;DR: The antidiarrheal effects of green banana and pectin are mediated by improvement of small intestinal permeability in addition to their known colonotrophic effects.
Abstract: To evaluate the effects of green banana and pectin (nondigestible, dietary sources of colonic short-chain fatty acids [SCFA]) on intestinal permeability, 57 boys (5–12 months) with persistent diarrhea (≥14 days) were given a week's treatment with a rice-based diet containing either cooked green banana (n=19), pectin (n=17), or rice diet alone (n=21). Intestinal permeability was assessed before and after treatment by giving a lactulose–mannitol (LM) drink and measuring urinary recovery after 5 hr. Treatment with banana significantly (P<0.05) reduced lactulose recovery, increased mannitol recovery, and decreased the LM ratio, indicating improvement of permeability. Pectin produced similar results. Permeability changes were associated with a 50% reduction in stool weights which correlated strongly (green banana, r2 = 0.84, pectin, r2 = 0.86) with the LM ratio. Green banana-derived and SCFA-mediated stimulation of colonic as well as small bowel absorption is responsible for their antidiarrheal effects. The antidiarrheal effects of green banana and pectin are mediated by improvement of small intestinal permeability in addition to their known colonotrophic effects.
TL;DR: Two landmark studies published in 1968 among patients with Vibrio cholera infections demonstrated that although the secretory nature of the diarrhea causes massive stool losses of water and electrolytes sodium-coupled glucose cotransport remains largely intact and continues to stimulate resorption of salt and water, oral rehydation solution works on the elegantly simple physiologic principle of solute cOTransport across the gastrointestinal epithelium.
Abstract: Diarrheal diseases remain important causes of death and morbidity in developing countries with an estimated 1.5 billion episodes and 1.5 million to 2.5 million deaths each year among children younger than 5 years. Although the number of children currently dying from diarrhea continues to be unacceptably high it is substantially lower than the 5 million deaths per year estimated 20 years ago. A critical factor in this reduction in diarrhea deaths has been the widespread adoption of oral rehydration solution (ORS) programs for the treatment and prevention of diarrhea-associated dehydration. Indeed ORS has been hailed as one of the most important medical advances of the past century at least in part because of its simplicity low cost and remarkable ease of use. Oral rehydation solution works on the elegantly simple physiologic principle of solute cotransport across the gastrointestinal epithelium. Briefly landmark studies published in 1968 among patients with Vibrio cholera infections demonstrated that although the secretory nature of the diarrhea causes massive stool losses of water and electrolytes sodium-coupled glucose cotransport remains largely intact and continues to stimulate resorption of salt and water. Clinical trials documenting the efficacy of ORS soon followed in the 1970s and 1980s. (excerpt)
TL;DR: Death rates from violence remained at the same level during the study period while death rates from other causes decreased, and young, not yet married women were a high risk group with respect to death from violence.
TL;DR: Data suggested a high prevalence of STIs, particularly gonorrhea and chlamydia, among HBSWs in Dhaka, Bangladesh.
Abstract: The prevalence of sexually transmitted infections (STIs) and reproductive tract infections (RTIs) among hotel-based sex workers (HBSWs) in Dhaka, Bangladesh, was studied. A total of 400 HBSWs were enrolled in the study during April to July 2002. Endocervical swabs, high vaginal swabs, and blood samples from 400 HBSWs were examined for Neisseria gonorrhoeae (by culture), Chlamydia trachomatis (by PCR), Trichomonas vaginalis (by microscopy), antibody to Treponema pallidum (by both rapid plasma reagin and Treponema pallidum hemagglutination tests), and antibody to herpes simplex virus type 2 (HSV-2) (by enzyme-linked immunosorbent assay). Sociodemographic information as well as gynecological and obstetric information was collected. Among the HBSWs, 228 women (57%) were symptomatic and 172 (43%) were asymptomatic, 35.8% were positive for N. gonorrhoeae, 43.5% were positive for C. trachomatis, and 4.3% were positive for T. vaginalis. A total of 8.5% had syphilis, 34.5% were positive for HSV-2, and 86.8% were positive for at least one RTI or STI. There was no significant difference between the prevalences of STIs among the symptomatic and asymptomatic HBSWs. These data suggested a high prevalence of STIs, particularly gonorrhea and chlamydia, among HBSWs in Dhaka.