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| 3. |
- Abbafati, Cristiana, et al.
(author)
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- 2020
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Journal article (peer-reviewed)
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| 4. |
- Vidal, R. M., et al.
(author)
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Colonization factors among enterotoxigenic Escherichia coli isolates from children with moderate-to-severe diarrhea and from matched controls in the Global Enteric Multicenter Study (GEMS)
- 2019
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In: Plos Neglected Tropical Diseases. - : Public Library of Science (PLoS). - 1935-2735. ; 13:1
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Journal article (peer-reviewed)abstract
- Background Enterotoxigenic Escherichia coli (ETEC) encoding heat-stable enterotoxin (ST) alone or with heat-labile enterotoxin (LT) cause moderate-to-severe diarrhea (MSD) in developing country children. The Global Enteric Multicenter Study (GEMS) identified ETEC encoding ST among the top four enteropathogens. Since the GEMS objective was to provide evidence to guide development and implementation of enteric vaccines and other interventions to diminish diarrheal disease morbidity and mortality, we examined colonization factor (CF) prevalence among ETEC isolates from children age <5 years with MSD and from matched controls in four African and three Asian sites. We also assessed strength of association of specific CFs with MSD. Methodology/Principal findings MSD cases enrolled at healthcare facilities over three years and matched controls were tested in a standardized manner for many enteropathogens. To identify ETEC, three E. coli colonies per child were tested by polymerase chain reaction (PCR) to detect genes encoding LT, ST; confirmed ETEC were examined by PCR for major CFs (Colonization Factor Antigen I [CFA/I] or Coli Surface [CS] antigens CS1-CS6) and minor CFs (CS7, CS12, CS13, CS14, CS17, CS18, CS19, CS20, CS21, CS30). ETEC from 806 cases had a single toxin/CF profile in three tested strains per child. Major CFs, components of multiple ETEC vaccine candidates, were detected in 66.0% of LT/ST and ST-only cases and were associated with MSD versus matched controls by conditional logistic regression (p0.006); major CFs detected in only 25.0% of LT-only cases weren't associated with MSD. ETEC encoding exclusively CS14, identified among 19.9% of 291 ST-only and 1.5% of 259 LT/ST strains, were associated with MSD (p = 0.0011). No other minor CF exhibited prevalence 5% and significant association with MSD. Conclusions/Significance Major CF-based efficacious ETEC vaccines could potentially prevent up to 66% of pediatric MSD cases due to ST-encoding ETEC in developing countries; adding CS14 extends coverage to similar to 77%. Author summary Enterotoxigenic Escherichia coli (ETEC) were found to be one of the four most consistently important agents that cause moderate-to-severe diarrhea among children <5 years of age in a large case-control study, the Global Enteric Multicenter Study, performed in four countries in sub-Saharan Africa and three in South Asia. ETEC attach to the lining of the human small intestine by means of protein colonization factors (CFs), after which bacterial toxins stimulate intestinal secretion resulting in diarrhea. Moderate-to-severe diarrhea in young children in developing countries can lead to malnutrition and death. Vaccines are being developed to prevent ETEC diarrhea and its consequences. Several ETEC vaccines aim to stimulate antibodies (protective proteins) that will bind CFs and prevent the bacteria from attaching to intestinal cells, which should, in turn, prevent ETEC diarrhea. Different types of CFs exist. To guide the development of vaccines intending to provide broad protection against ETEC, one must know the frequency with which the different major CFs are produced by ETEC. This paper reports an extensive systematic survey of ETEC CFs and provides helpful information to guide the development of ETEC vaccines.
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| 8. |
- Hasan, Badrul, et al.
(author)
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High Prevalence of Antibiotic Resistance in Pathogenic Escherichia coli from Large- and Small-Scale Poultry Farms in Bangladesh
- 2011
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In: Avian diseases. - 0005-2086 .- 1938-4351. ; 55:4, s. 689-692
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Journal article (peer-reviewed)abstract
- Antibiotic resistance in avian bacterial pathogens is a common problem in the Bangladesh poultry industry. The aim of the present study was to provide information on the present status of antibiotic resistance patterns in avian pathogenic Escherichia coli in Bangladesh. Of 279 dead or sick poultry of different ages, 101 pathogenic E. coli strains isolated from broilers and layer hens with colibacillosis infections were screened to determine phenotypic expression of antimicrobial resistance against 13 antibiotics used in both veterinary and human medicine in Bangladesh. Of 101 pathogenic E. coli isolates, more than 55% were resistant to at least one or more of the tested compounds, and 36.6% of the isolates showed multiple-drug-resistant phenotypes. The most common resistances observed were against tetracycline (45.5%), trimethoprim-sulphamethoxazole (26.7%), nalidixic acid (25.7%), ampicillin (25.7%), and streptomycin (20.8%). Resistance to ciprofloxacin (12.9%), chlormaphenicol (8.9%), nitrofurantoin (2%), and gentamicin (2%) was also observed, and none of the isolates were resistant to tigecycline as well as extended spectrum beta-lactamase (ESBL) producers. One isolate was resistant to cefuroxime (1%), cefadroxil (1%), and mecillinam (1%) but was not an ESBL producer. Resistance rates, although significant in Bangladeshi isolates, were found to be lower than those reported for avian isolates from the Republic of Korea and clinical, avian, and environmental isolates from Bangladesh. The high level of antibiotic resistance in avian pathogens from Bangladesh is worrisome and indicates that widespread use of antibiotics as feed additives for growth promotion and disease prevention could have negative implications for human and animal health and the environment.
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| 9. |
- Khan, Khalid M., et al.
(author)
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Thyroid hormones and neurobehavioral functions among adolescents chronically exposed to groundwater with geogenic arsenic in Bangladesh
- 2019
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In: Science of the Total Environment. - : Elsevier. - 0048-9697 .- 1879-1026. ; 678, s. 278-287
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Journal article (peer-reviewed)abstract
- Groundwater, the major source of drinking water in Bengal Delta Plain, is contaminated with geogenic arsenic (As) enrichment affecting millions of people. Children exposed to tubewell water containing As may be associated with thyroid dysfunction, which in turn may impact neurodevelopmental outcomes. However, data to support such relationship is sparse. The purpose of this study was to examine if chronic water As (WAs) from Holocene alluvial aquifers in this region was associated with serum thyroid hormone (TH) and if TH biomarkers were related to neurobehavioral (NB) performance in a group of adolescents. A sample of 32 healthy adolescents were randomly drawn from a child cohort in the Health Effects of Arsenic Longitudinal Study (HEALS) in Araihazar, Bangladesh. Half of these participants were consistently exposed to low WAs (<10 μg/L) and the remaining half had high WAs exposure (≥10 μg/L) since birth. Measurements included serum total triiodothyronine (tT3), free thyroxine (fT4), thyrotropin (TSH) and thyroperoxidase antibodies (TPOAb); concurrent WAs and urinary arsenic (UAs); and adolescents' NB performance. WAs and UAs were positively and significantly correlated with TPOAb but were not correlated with TSH, tT3 and fT4. After accounting for covariates, both WAs and UAs demonstrated positive but non-significant relationships with TSH and TPOAb and negative but non-significant relationships with tT3 and fT4. TPOAb was significantly associated with reduced NB performance indicated by positive associations with latencies in simple reaction time (b = 82.58; p < 0.001) and symbol digit (b = 276.85; p = 0.005) tests. TSH was significantly and negatively associated with match-to-sample correct count (b = -0.95; p = 0.05). Overall, we did not observe significant associations between arsenic exposure and TH biomarkers although the relationships were in the expected directions. We observed TH biomarkers to be related to reduced NB performance as hypothesized. Our study indicated a possible mechanism of As-induced neurotoxicity, which requires further investigations for confirmatory findings.
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| 10. |
- Nair, G Balakrish, et al.
(author)
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Cholera due to altered El Tor strains of Vibrio cholerae O1 in Bangladesh.
- 2006
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In: Journal of clinical microbiology. - 0095-1137. ; 44:11, s. 4211-3
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Journal article (peer-reviewed)abstract
- We determined the types of cholera toxin (CT) produced by a collection of 185 Vibrio cholerae O1 strains isolated in Bangladesh over the past 45 years. All of the El Tor strains of V. cholerae O1 isolated since 2001 produced CT of the classical biotype, while those isolated before 2001 produced CT of the El Tor biotype.
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| 11. |
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| 12. |
- Bonnefille, Bénilde, et al.
(author)
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Nontarget Analysis of Polluted Surface Waters in Bangladesh Using Open Science Workflows
- 2023
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In: Environmental Science and Technology. - 0013-936X .- 1520-5851. ; 57:17, s. 6808-6824
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Journal article (peer-reviewed)abstract
- Nontarget mass spectrometry has great potential to reveal patterns of water contamination globally through community science, but few studies are conducted in low-income countries, nor with open-source workflows, and few datasets are FAIR (Findable, Accessible, Interoperable, Reusable). Water was collected from urban and rural rivers around Dhaka, Bangladesh, and analyzed by liquid chromatography high-resolution mass spectrometry in four ionization modes (electrospray ionization +/-, atmospheric pressure chemical ionization +/-) with data -independent MS2 acquisition. The acquisition strategy was complementary: 19,427 and 7365 features were unique to ESI and APCI, respectively. The complexity of water pollution was revealed by >26,000 unique molecular features resolved by MS-DIAL, among which >20,000 correlated with urban sources in Dhaka. A major wastewater treatment plant was not a dominant pollution source, consistent with major contributions from uncontrolled urban drainage, a result that encourages development of further wastewater infrastructures. Matching of deconvoluted MS2 spectra to public libraries resulted in 62 confident annotations (i.e., Level 1-2a) and allowed semiquantification of 42 analytes including pharmaceuticals, pesticides, and personal care products. In silico structure prediction for the top 100 unknown molecular features associated with an urban source allowed 15 additional chemicals of anthropogenic origin to be annotated (i.e., Level 3). The authentic MS2 spectra were uploaded to MassBank Europe, mass spectral data were openly shared on the MassIVE repository, a tool (i.e., MASST) that could be used for community science environmental surveillance was demonstrated, and current limitations were discussed.
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| 13. |
- Chowdhury, Fahima, et al.
(author)
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Concomitant enterotoxigenic Escherichia coli infection induces increased immune responses to Vibrio cholerae O1 antigens in patients with cholera in Bangladesh.
- 2010
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In: Infection and immunity. - 1098-5522. ; 78:5, s. 2117-24
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Journal article (peer-reviewed)abstract
- Vibrio cholerae O1 and enterotoxigenic Escherichia coli (ETEC) are major bacterial pathogens that cause dehydrating disease requiring hospitalization of children and adults. The cholera toxin (CT) produced by V. cholerae O1 and the heat-labile toxin (LT) and/or heat-stable toxin (ST) of ETEC are responsible for secretory diarrhea. We have observed that about 13% of hospitalized diarrheal patients are concomitantly infected with V. cholerae O1 and ETEC. In order to understand the outcome of such dual infections on the clinical and immunological responses in cholera patients, we studied patients infected with V. cholerae O1 (group VC; n = 25), those infected with both V. cholerae O1 and ETEC (group VCET; n = 25), and those infected with ETEC only (group ET; n = 25). The VCET group showed more severe dehydration and had a higher intake of intravenous fluid and more vomiting than the ETEC group (P = 0.01 to 0.003). The VCET patients showed higher vibriocidal responses and increased antibody titers to cholera toxin and lipopolysaccharide (LPS) in plasma than did the V. cholerae O1 patients (P = 0.02 to <0.001). All responses in the V. cholerae O1 and in the VCET groups were more robust than those seen in the group infected with ETEC only (P = 0.01 to <0.001). We thus show that concomitant colonization with ETEC induces immune responses to V. cholerae antigens that are more robust than those seen with V. cholerae O1 infection alone. It is possible that LT or other factors expressed by ETEC may play a role as a mucosal adjuvant in enhancing the immune responses to V. cholerae O1.
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| 14. |
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| 15. |
- Hansson, Henrik, et al.
(author)
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The Teachers’ Portal as a tool for teachers’ professional development in Bangladesh: : Facilitating nationwide networking and digital multimedia content for 40,000 schools
- 2018
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In: ijEDict - International Journal of Education and Development using Information and Communication Technology. - 1814-0556. ; 14:3, s. 113-130
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Journal article (peer-reviewed)abstract
- The Teachers’ Portal (teachers.gov.bd) is an online platform for Bangladeshi teachers designed to store and retrieve digital educational contents of different subjects useful for classroom teaching and students’ learning. The portal also facilitates professional networking among teachers across the country. This study aims to find out the benefits of using this Portal and associated challenges from teachers’ perspective. Following a mixed methods research approach Teachers, head teachers, teacher educators from primary, secondary, madrasa and vocational educational institutions and specialists on teachers’ Portal (N=410) were interviewed and consulted for the study. Telephone interviews, online surveys, Key Informant Interviews (KII), Focused Group Discussions (FGD), Face-to-Face interviews, and large consultative workshops were used to collect data. The results suggest that teachers are motivated to use the Portal as its contents stimulate students’ creativity and encourage students’ active participation in classrooms learning. Besides, it empowers teachers in a number of ways. However, internet connectivity, slow Internet speed, power failure, technical issues, high cost of Internet and unavailability of equipment are found as major challenges. In short, the Teachers’ Portal is a key driver for changing Bangladeshi education and by so doing preparing the young generation with quality education.
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| 16. |
- Harris, Aaron M, et al.
(author)
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Shifting prevalence of major diarrheal pathogens in patients seeking hospital care during floods in 1998, 2004, and 2007 in Dhaka, Bangladesh.
- 2008
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In: The American journal of tropical medicine and hygiene. - 1476-1645. ; 79:5, s. 708-14
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Journal article (peer-reviewed)abstract
- Bangladesh experienced severe flooding and diarrheal epidemics in 2007. We compared flood data from 2007 with 2004 and 1998 for diarrheal patients attending the ICDDR,B hospital in Dhaka. In 2007, Vibrio cholerae O1 (33%), rotavirus (12%), and enterotoxigenic Escherichia coli (ETEC) (12%) were most prevalent. More severe dehydration was seen in 2007 compared with 2004 and 1998 (P < 0.001). In 2007, V. cholerae O1 Inaba (52%) and Ogawa (48%) were seen, whereas in 2004 and 1998 it was primarily Inaba and the Ogawa types, respectively (P < 0.001). In 2007, 51% of ETEC produced the heat labile toxin (LT) (P < 0.001 compared with 2004), 22% expressed the heat stable (ST) (P < 0.001), and 27% were ST/LT positive (P = 0.231). The CS7 colonization factor (CF) was the most prevalent in 2007 (20% compared with 6% in 2004; P = 0.05). Our findings demonstrate alterations in clinical features and phenotypic changes of major bacterial pathogens in the recent Bangladesh flood.
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| 17. |
- Hu, Kelsey, et al.
(author)
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Chronic exposure of arsenic among children in Asia: A current opinion based on epidemiological evidence
- 2024
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In: Current Opinion in Environmental Science and Health. - : Elsevier BV. - 2468-5844. ; 39
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Research review (peer-reviewed)abstract
- The health effects of arsenic (As) exposure are a major global environmental issue affecting millions of people around the globe. Although adult epidemiological studies on As-induced health consequences have been extensively reviewed, but not much comprehensive review has been done targeting children. In this epidemiological review, 64 human subject studies on children were identified after applying exclusion criteria, which addressed an array of health effects of As exposure in early life stages in South and Southeast (S–SE) Asian countries, where a great variability in As exposures has been reported. The present review identified neurocognitive impairment linked to As exposure in early life stages. In utero and childhood As exposures were also associated with genetic and metabolic alteration, elevated pneumonia risk, and skin lesions in several populations in S–SE Asia. Significant associations of As with epigenetic changes, DNA damages, abnormal birth outcomes, and elevated mortality were also reported in epidemiological studies. The findings of this review article may help public health policymakers and clinicians develop early-life intervention strategies to reduce the burden of diseases in As-exposed populations.
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| 18. |
- Khan, Khalid M., et al.
(author)
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Health effects of arsenic exposure in Latin America : An overview of the past eight years of research
- 2020
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In: Science of the Total Environment. - : ELSEVIER. - 0048-9697 .- 1879-1026. ; 710
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Journal article (peer-reviewed)abstract
- Studies conducted over the past eight years in Latin America (IA) have continued to produce new knowledge regarding health impacts of arsenic (As) in drinking water. We conducted a systematic review of 92 peer-reviewed English articles published between 2011 and 2018 to expand our understanding on these health effects. Majority of the LA studies on As have been conducted in Chile and Mexico. Additional data have emerged from As-exposed populations in Argentina, Bolivia, Brazil, Colombia, Ecuador, and Uruguay. The present review has documented recent data on the biomarkers of As exposure, genetic susceptibility and genotoxicity, and risk assessment to further characterize the health effects and exposed populations. Some recent findings on the associations of As with bladder and lung cancers, reproductive outcomes, and declined cognitive performance have been consistent with what we reported in our previous systematic review article. We have found highly convincing evidence of in utero As exposure as a significant risk factor for several health outcomes, particularly for bladder cancer, even at moderate level. New data have emerged regarding the associations of As with breast and laryngeal cancers as well as type 2 diabetes. We observed early life As exposure to be associated with kidney injury, carotid intima-media thickness, and various pulmonary outcomes in children. Other childhood effects such as low birth weight, low gestational age, anemia, increased apoptosis, and decreased cognitive functions were also reported. Studies identified genetic variants of As methyltransferase that could determine susceptibility to As related health outcomes. Arsenic-induced DNA damage and alteration of gene and protein expression have been reported. While the scope of research is still vast, the substantial work done on As exposure and its health effects in LA will help direct further large-scale studies for more comprehensive knowledge and plan appropriate mitigation strategies.
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| 19. |
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| 20. |
- Qadri, F., et al.
(author)
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Enterotoxigenic Escherichia coli and Vibrio cholerae diarrhea, Bangladesh, 2004
- 2005
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In: Emerg Infect Dis. ; 11:7, s. 1104-7
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Journal article (peer-reviewed)abstract
- Flooding in Dhaka in July 2004 caused epidemics of diarrhea. Enterotoxigenic Escherichia coli (ETEC) was almost as prevalent as Vibrio cholerae O1 in diarrheal stools. ETEC that produced heat-stable enterotoxin alone was most prevalent, and 78% of strains had colonization factors. Like V. cholerae O1, ETEC can cause epidemic diarrhea.
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| 21. |
- Qadri, Firdausi, et al.
(author)
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Reduction in capsular content and enhanced bacterial susceptibility to serum killing of Vibrio cholerae O139 associated with the 2002 cholera epidemic in Bangladesh
- 2005
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In: Infect Immun. ; 73:10, s. 6577-6583
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Journal article (peer-reviewed)abstract
- Vibrio cholerae O139 emerged in 1992 as a major cause of epidemic cholera. However, the incidence of disease due to this new serogroup subsequently decreased for almost a decade. In April 2002, there was a dramatic resurgence of V. cholerae O139 in Bangladesh. We compared the phenotypic properties of the bacterial isolates and the immunological responses in patients with disease due to V. cholerae O139 during the 2002 epidemic with those dating to the emergence of this disease in 1993 to 1995. Strains isolated from patients in the two time periods were compared with respect to capsular polysaccharide, their resistance to the bactericidal effect of serum, and their capacity to be used as target strains in complement-mediated vibriocidal assays. Phase-contrast microscopy showed that strains isolated in 2002 had less capsular material than those isolated from 1993 to 1995 (P = <0.001), a finding confirmed by electron microscopic studies. Strains isolated in 2002 were more susceptible to the bactericidal activity of serum compared to strains from 1993 to 1995 (P = 0.013). Compared to results using a standard O139 strain, a modified vibriocidal assay utilizing a 2002 strain, CIRS 134, as the target organism detected higher vibriocidal responses in both O139-infected cholera patients as well as O139 vaccine recipients. The vibriocidal assay utilizing the less encapsulated 2002 strain, CIRS 134, is a more sensitive indicator of adaptive immune responses to recent infection with V. cholerae O139. Consequently, this assay may be useful in studies of both O139-infected patients and recipients of O139 vaccines.
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