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Long-Term Kinetics of Serological Antibodies against Vibrio cholerae Following a Clinical Cholera Case: A Systematic Review and Meta-Analysis. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2022; 19:ijerph19127141. [PMID: 35742404 PMCID: PMC9223532 DOI: 10.3390/ijerph19127141] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/03/2022] [Revised: 06/06/2022] [Accepted: 06/08/2022] [Indexed: 11/16/2022]
Abstract
Background: Approximately 2.9 million people worldwide suffer from cholera each year, many of whom are destitute. However, understanding of immunity against cholera is still limited. Several studies have reported the duration of antibodies following cholera; however, systematic reviews including a quantitative synthesis are lacking. Objective: To meta-analyze cohort studies that have evaluated vibriocidal, cholera toxin B subunit (CTB), and lipopolysaccharide (LPS) antibody levels following a clinical cholera case. Methods: Design: Systematic review and meta-analysis. We searched PubMed and Web of science for studies assessing antibodies against Vibrio cholerae in cohorts of patients with clinical cholera. Two authors independently extracted data and assessed the quality of included studies. Random effects models were used to pool antibody titers in adults and older children (aged ≥ 6 years). In sensitivity analysis, studies reporting data on young children (2–5 years) were included. Results: Nine studies met our inclusion criteria for systematic review and seven for meta-analysis. The pooled mean of vibriocidal antibody titers in adults and older children (aged ≥ 6 years) was 123 on day 2 post-symptom onset, which sharply increased on day 7 (pooled mean = 6956) and gradually waned to 2247 on day 30, 578 on day 90, and 177 on day 360. Anti-CTB IgA antibodies also peaked on day 7 (pooled mean = 49), followed by a rapid decrease on day 30 (pooled mean = 21), and further declined on day 90 (pooled mean = 10), after which it plateaued from day 180 (pooled mean = 8) to 360 (pooled mean = 6). Similarly, anti-CTB IgG antibodies peaked in early convalescence between days 7 (pooled mean = 65) and 30 (pooled mean = 69), then gradually waned on days 90 (pooled mean = 42) and 180 (pooled mean = 30) and returned to baseline on day 360 (pooled mean = 24). Anti-LPS IgA antibodies peaked on day 7 (pooled mean = 124), gradually declined on day 30 (pooled mean = 44), which persisted until day 360 (pooled mean = 10). Anti LPS IgG antibodies peaked on day 7 (pooled mean = 94). Thereafter, they decreased on day 30 (pooled mean = 85), and dropped further on days 90 (pooled mean = 51) and 180 (pooled mean = 47), and returned to baseline on day 360 (pooled mean = 32). Sensitivity analysis including data from young children (aged 2–5 years) showed very similar findings as in the primary analysis. Conclusions: This study confirms that serological antibody (vibriocidal, CTB, and LPS) titers return to baseline levels within 1 year following clinical cholera, i.e., before the protective immunity against subsequent cholera wanes. However, this decay should not be interpreted as waning immunity because immunity conferred by cholera against subsequent disease lasts 3–10 years. Our study provides evidence for surveillance strategies and future research on vaccines and also demonstrates the need for further studies to improve our understanding of immunity against cholera.
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Gut Microbiota and Development of Vibrio cholerae-Specific Long-Term Memory B Cells in Adults after Whole-Cell Killed Oral Cholera Vaccine. Infect Immun 2021; 89:e0021721. [PMID: 34228490 PMCID: PMC8370679 DOI: 10.1128/iai.00217-21] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Cholera is a diarrheal disease caused by Vibrio cholerae that continues to be a major public health concern in populations without access to safe water. IgG- and IgA-secreting memory B cells (MBC) targeting the V. cholerae O-specific polysaccharide (OSP) correlate with protection from infection in persons exposed to V. cholerae and may be a major determinant of long-term protection against cholera. Shanchol, a widely used oral cholera vaccine (OCV), stimulates OSP MBC responses in only some people after vaccination, and the gut microbiota is a possible determinant of variable immune responses observed after OCV. Using 16S rRNA sequencing of feces from the time of vaccination, we compared the gut microbiota among adults with and without MBC responses to OCV. Gut microbial diversity measures were not associated with MBC isotype or OSP-specific responses, but individuals with a higher abundance of Clostridiales and lower abundance of Enterobacterales were more likely to develop an MBC response. We applied protein-normalized fecal supernatants of high and low MBC responders to THP-1-derived human macrophages to investigate the effect of microbial factors at the time of vaccination. Feces from individuals with higher MBC responses induced significantly different IL-1β and IL-6 levels than individuals with lower responses, indicating that the gut microbiota at the time of vaccination may "prime" the mucosal immune response to vaccine antigens. Our results suggest the gut microbiota could impact immune responses to OCVs, and further study of microbial metabolites as potential vaccine adjuvants is warranted.
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Chac D, Dunmire CN, Singh J, Weil AA. Update on Environmental and Host Factors Impacting the Risk of Vibrio cholerae Infection. ACS Infect Dis 2021; 7:1010-1019. [PMID: 33844507 DOI: 10.1021/acsinfecdis.0c00914] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Vibrio cholerae is the causative agent of cholera, a diarrheal disease that kills tens of thousands of people each year. Cholera is transmitted primarily by the ingestion of drinking water contaminated with fecal matter, and a safe water supply remains out of reach in many areas of the world. In this Review, we discuss host and environmental factors that impact the susceptibility to V. cholerae infection and the severity of disease.
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Affiliation(s)
- Denise Chac
- Department of Medicine, Division of Allergy and Infectious Diseases, University of Washington, Seattle, Washington 98109, United States
| | - Chelsea N. Dunmire
- Department of Medicine, Division of Allergy and Infectious Diseases, University of Washington, Seattle, Washington 98109, United States
| | - Jasneet Singh
- Department of Medicine, Division of Allergy and Infectious Diseases, University of Washington, Seattle, Washington 98109, United States
| | - Ana A. Weil
- Department of Medicine, Division of Allergy and Infectious Diseases, University of Washington, Seattle, Washington 98109, United States
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Kaisar MH, Bhuiyan MS, Akter A, Saleem D, Iyer AS, Dash P, Hakim A, Chowdhury F, Khan AI, Calderwood SB, Harris JB, Ryan ET, Qadri F, Charles RC, Bhuiyan TR. Vibrio cholerae Sialidase-Specific Immune Responses Are Associated with Protection against Cholera. mSphere 2021; 6:e01232-20. [PMID: 33910997 PMCID: PMC8092141 DOI: 10.1128/msphere.01232-20] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2020] [Accepted: 04/02/2021] [Indexed: 11/20/2022] Open
Abstract
Cholera remains a major public health problem in resource-limited countries. Vaccination is an important strategy to prevent cholera, but currently available vaccines provide only 3 to 5 years of protection. Understanding immune responses to cholera antigens in naturally infected individuals may elucidate which of these are key to longer-term protection seen following infection. We recently identified Vibrio cholerae O1 sialidase, a neuraminidase that facilitates binding of cholera toxin to intestinal epithelial cells, as immunogenic following infection in two recent high-throughput screens. Here, we present systemic, mucosal, and memory immune responses to sialidase in cholera index cases and evaluated whether systemic responses to sialidase correlated with protection using a cohort of household contacts. Overall, we found age-related differences in antisialidase immune response following cholera. Adults developed significant plasma anti-sialidase IgA, IgG, and IgM responses following infection, whereas older children (≥5 years) developed both IgG and IgM responses, and younger children only developed IgM responses. Neither older children nor younger children had a rise in IgA responses over the convalescent phase of infection (day 7/day 30). On evaluation of mucosal responses and memory B-cell responses to sialidase, we found adults developed IgA antibody-secreting cell (ASC) and memory B-cell responses. Finally, in household contacts, the presence of serum anti-sialidase IgA, IgG, and IgM antibodies at enrollment was associated with a decrease in the risk of subsequent infection. These data show cholera patients develop age-related immune responses against sialidase and suggest that immune responses that target sialidase may contribute to protective immunity against cholera.IMPORTANCE Cholera infection can result in severe dehydration that may lead to death within a short period of time if not treated immediately. Vaccination is an important strategy to prevent the disease. Oral cholera vaccines provide 3 to 5 years of protection, with 60% protective efficacy, while natural infection provides longer-term protection than vaccination. Understanding the immune responses after natural infection is important to better understand immune responses to antigens that mediate longer-term protection. Sialidase is a neuraminidase that facilitates binding of cholera toxin to intestinal epithelial cells. We show here that patients with cholera develop systemic, mucosal, and memory B-cell immune responses to the sialidase antigen of Vibrio cholerae O1 and that plasma responses targeting this antigen correlate with protection.
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Affiliation(s)
- M Hasanul Kaisar
- Infectious Diseases Division, icddr,b (International Centre for Diarrhoeal Disease Research, Bangladesh), Dhaka, Bangladesh
| | - Mohammed Saruar Bhuiyan
- Infectious Diseases Division, icddr,b (International Centre for Diarrhoeal Disease Research, Bangladesh), Dhaka, Bangladesh
| | - Aklima Akter
- Infectious Diseases Division, icddr,b (International Centre for Diarrhoeal Disease Research, Bangladesh), Dhaka, Bangladesh
| | - Danial Saleem
- College of Physicians and Surgeons, Columbia University, New York, New York, USA
| | - Anita S Iyer
- Division of Infectious Diseases, Massachusetts General Hospital, Boston, Massachusetts, USA
- Department of Medicine, Harvard Medical School, Boston, Massachusetts, USA
| | - Pinki Dash
- Infectious Diseases Division, icddr,b (International Centre for Diarrhoeal Disease Research, Bangladesh), Dhaka, Bangladesh
| | - Al Hakim
- Infectious Diseases Division, icddr,b (International Centre for Diarrhoeal Disease Research, Bangladesh), Dhaka, Bangladesh
| | - Fahima Chowdhury
- Infectious Diseases Division, icddr,b (International Centre for Diarrhoeal Disease Research, Bangladesh), Dhaka, Bangladesh
| | - Ashraful Islam Khan
- Infectious Diseases Division, icddr,b (International Centre for Diarrhoeal Disease Research, Bangladesh), Dhaka, Bangladesh
| | - Stephen B Calderwood
- Division of Infectious Diseases, Massachusetts General Hospital, Boston, Massachusetts, USA
- Department of Medicine, Harvard Medical School, Boston, Massachusetts, USA
- Department of Microbiology, Harvard Medical School, Boston, Massachusetts, USA
| | - Jason B Harris
- Division of Infectious Diseases, Massachusetts General Hospital, Boston, Massachusetts, USA
- Division of Global Health, Massachusetts General Hospital for Children, Boston, Massachusetts, USA
- Department of Pediatrics, Harvard Medical School, Boston, Massachusetts, USA
| | - Edward T Ryan
- Division of Infectious Diseases, Massachusetts General Hospital, Boston, Massachusetts, USA
- Department of Medicine, Harvard Medical School, Boston, Massachusetts, USA
- Department of Immunology and Infectious Diseases, Harvard School of Public Health, Boston, Massachusetts, USA
| | - Firdausi Qadri
- Infectious Diseases Division, icddr,b (International Centre for Diarrhoeal Disease Research, Bangladesh), Dhaka, Bangladesh
| | - Richelle C Charles
- Division of Infectious Diseases, Massachusetts General Hospital, Boston, Massachusetts, USA
- Department of Medicine, Harvard Medical School, Boston, Massachusetts, USA
| | - Taufiqur Rahman Bhuiyan
- Infectious Diseases Division, icddr,b (International Centre for Diarrhoeal Disease Research, Bangladesh), Dhaka, Bangladesh
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Azman AS, Lauer SA, Bhuiyan TR, Luquero FJ, Leung DT, Hegde ST, Harris JB, Paul KK, Khaton F, Ferdous J, Lessler J, Salje H, Qadri F, Gurley ES. Vibrio cholerae O1 transmission in Bangladesh: insights from a nationally representative serosurvey. THE LANCET. MICROBE 2020; 1:e336-e343. [PMID: 33345203 PMCID: PMC7738617 DOI: 10.1016/s2666-5247(20)30141-5] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
BACKGROUND Pandemic Vibrio cholerae from cholera-endemic countries around the Bay of Bengal regularly seed epidemics globally. Without reducing cholera in these countries, including Bangladesh, global cholera control might never be achieved. Little is known about the geographical distribution and magnitude of V cholerae O1 transmission nationally. We aimed to describe infection risk across Bangladesh, making use of advances in cholera seroepidemiology, therefore overcoming many of the limitations of current clinic-based surveillance. METHODS We tested serum samples from a nationally representative serosurvey in Bangladesh with eight V cholerae-specific assays. Using these data with a machine-learning model previously validated within a cohort of confirmed cholera cases and their household contacts, we estimated the proportion of the population with evidence of infection by V cholerae O1 in the previous year (annual seroincidence) and used Bayesian geostatistical models to create high-resolution national maps of infection risk. FINDINGS Between Oct 16, 2015, and Jan 24, 2016, we obtained and tested serum samples from 2930 participants (707 households) in 70 communities across Bangladesh. We estimated national annual seroincidence of V cholerae O1 infection of 17·3% (95% CI 10·5-24·1). Our high-resolution maps showed large heterogeneity of infection risk, with community-level annual infection risk within the sampled population ranging from 4·3% to 62·9%. Across Bangladesh, we estimated that 28·1 (95% CI 17·1-39·2) million infections occurred in the year before the survey. Despite having an annual seroincidence of V cholerae O1 infection lower than much of Bangladesh, Dhaka (the capital of Bangladesh and largest city in the country) had 2·0 (95% CI 0·6-3·9) million infections during the same year, primarily because of its large population. INTERPRETATION Serosurveillance provides an avenue for identifying areas with high V cholerae O1 transmission and investigating key risk factors for infection across geographical scales. Serosurveillance could serve as an important method for countries to plan and monitor progress towards 2030 cholera elimination goals. FUNDING The Bill & Melinda Gates Foundation, National Institutes of Health, and US Centers for Disease Control and Prevention.
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Affiliation(s)
- Andrew S Azman
- Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA
| | - Stephen A Lauer
- Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA
| | | | - Francisco J Luquero
- Department of International Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA
- Epicentre, Paris, France
| | - Daniel T Leung
- Division of Infectious Diseases and Division of Microbiology and Immunology, University of Utah School of Medicine, Salt Lake City, UT, USA
| | - Sonia T Hegde
- Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA
| | - Jason B Harris
- Division of Infectious Diseases and Division of Global Health, Massachusetts General Hospital, Boston, MA, USA
- Department of Pediatrics, Harvard School of Medicine, Boston, MA, USA
| | | | | | | | - Justin Lessler
- Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA
| | - Henrik Salje
- Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA
- Mathematical Modelling of Infectious Diseases Unit, Institut Pasteur, Paris, France
| | | | - Emily S Gurley
- Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA
- icddr,b, Dhaka, Bangladesh
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Abstract
PURPOSE OF REVIEW In this review, we will examine updates in cholera epidemiology, advances in our understanding of pathogenesis and protective immunity, and changes to prevention strategies. RECENT FINDINGS New modeling techniques and molecular epidemiology have led to advancements in our understanding of how Vibrio cholerae has persisted and re-emerged in new areas during the seventh pandemic. Use of next-generation sequencing has shed new light on immune responses to disease and vaccination, and the role of the gut microbiome in cholera. Increased efficacy and availability of vaccines have made long-term goals of global control of cholera more achievable. SUMMARY Advancements in our understanding of immunity and susceptibility to V. cholerae, in addition to an increased global commitment to disease prevention, have led to optimism for the future of cholera prevention.
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Anti-O-specific polysaccharide (OSP) immune responses following vaccination with oral cholera vaccine CVD 103-HgR correlate with protection against cholera after infection with wild-type Vibrio cholerae O1 El Tor Inaba in North American volunteers. PLoS Negl Trop Dis 2018; 12:e0006376. [PMID: 29624592 PMCID: PMC5906022 DOI: 10.1371/journal.pntd.0006376] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2018] [Revised: 04/18/2018] [Accepted: 03/08/2018] [Indexed: 01/27/2023] Open
Abstract
Background Cholera is an acute voluminous dehydrating diarrheal disease caused by toxigenic strains of Vibrio cholerae O1 and occasionally O139. A growing body of evidence indicates that immune responses targeting the O-specific polysaccharide (OSP) of V. cholerae are involved in mediating protection against cholera. We therefore assessed whether antibody responses against OSP occur after vaccination with live attenuated oral cholera vaccine CVD 103-HgR, and whether such responses correlate with protection against cholera. Methodology We assessed adult North American volunteers (n = 46) who were vaccinated with 5 × 108 colony-forming units (CFU) of oral cholera vaccine CVD 103-HgR and then orally challenged with approximately 1 × 105 CFU of wild-type V. cholerae O1 El Tor Inaba strain N16961, either 10 or 90 days post-vaccination. Principal findings Vaccination was associated with induction of significant serum IgM and IgA anti-OSP and vibriocidal antibody responses within 10 days of vaccination. There was significant correlation between anti-OSP and vibriocidal antibody responses. IgM and IgA anti-OSP responses on day 10 following vaccination were associated with lower post-challenge stool volume (r = −0.44, P = 0.002; r = −0.36, P = 0.01; respectively), and none of 27 vaccinees who developed a ≥1.5 fold increase in any antibody isotype targeting OSP on day 10 following vaccination compared to baseline developed moderate or severe cholera following experimental challenge, while 5 of 19 who did not develop such anti-OSP responses did (P = 0.01). Conclusion Oral vaccination with live attenuated cholera vaccine CVD 103-HgR induces antibodies that target V. cholerae OSP, and these anti-OSP responses correlate with protection against diarrhea following experimental challenge with V. cholerae O1. Trial registration ClinicalTrials.gov NCT01895855 Cholera is a severe watery diarrheal disease, caused by pathogenic strains of V. cholerae. Protective immunity against cholera is serogroup specific, and serogroup specificity is determined by the O-specific polysaccharide (OSP) of V. cholerae lipopolysaccharide (LPS). Despite this, no previous work has directly assessed correlation of OSP-immune responses and protection against cholera. In this study, we assessed adult North American volunteer’s antibody responses targeting OSP after vaccination with live attenuated oral cholera vaccine CVD 103-HgR, and we assessed correlation of protection against cholera with such antibody responses. Oral vaccination was associated with the induction of significant IgM and IgA responses against OSP, and these responses correlated with vibriocidal responses. There was significant negative correlation of OSP responses and post-challenge stool volume, and none of the volunteers who developed an anti-OSP antibody responses of any isotype of ≥1.5 fold developed moderate or severe cholera following experimental challenge. In summary, vaccination with live attenuated oral cholera vaccine CVD 103-HgR induces antibodies that target V. cholerae OSP, and these responses highly correlate with protection against cholera.
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Allan M, Grandesso F, Pierre R, Magloire R, Coldiron M, Martinez-Pino I, Goffeau T, Gitenet R, François G, Olson D, Porten K, Luquero FJ. High-resolution spatial analysis of cholera patients reported in Artibonite department, Haiti in 2010-2011. Epidemics 2015; 14:1-10. [PMID: 26972509 DOI: 10.1016/j.epidem.2015.08.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2015] [Revised: 08/25/2015] [Accepted: 08/26/2015] [Indexed: 11/24/2022] Open
Abstract
BACKGROUND Cholera is caused by Vibrio cholerae, and is transmitted through fecal-oral contact. Infection occurs after the ingestion of the bacteria and is usually asymptomatic. In a minority of cases, it causes acute diarrhea and vomiting, which can lead to potentially fatal severe dehydration, especially in the absence of appropriate medical care. Immunity occurs after infection and typically lasts 6-36 months. Cholera is responsible for outbreaks in many African and Asian developing countries, and caused localised and episodic epidemics in South America until the early 1990s. Haiti, despite its low socioeconomic status and poor sanitation, had never reported cholera before the recent outbreak that started in October 2010, with over 720,000 cases and over 8700 deaths (Case fatality rate: 1.2%) through 8 december 2014. So far, this outbreak has seen 3 epidemic peaks, and it is expected that cholera will remain in Haiti for some time. METHODOLOGY/FINDINGS To trace the path of the early epidemic and to identify hot spots and potential transmission hubs during peaks, we examined the spatial distribution of cholera patients during the first two peaks in Artibonite, the second-most populous department of Haiti. We extracted the geographic origin of 84,000 patients treated in local health facilities between October 2010 and December 2011 and mapped these addresses to 63 rural communal sections and 9 urban cities. Spatial and cluster analysis showed that during the first peak, cholera spread along the Artibonite River and the main roads, and sub-communal attack rates ranged from 0.1% to 10.7%. During the second peak, remote mountain areas were most affected, although sometimes to very different degrees even in closely neighboring locations. Sub-communal attack rates during the second peak ranged from 0.2% to 13.7%. The relative risks at the sub-communal level during the second phase showed an inverse pattern compared to the first phase. CONCLUSION/SIGNIFICANCE These findings demonstrate the value of high-resolution mapping for pinpointing locations most affected by cholera, and in the future could help prioritize the places in need of interventions such as improvement of sanitation and vaccination. The findings also describe spatio-temporal transmission patterns of the epidemic in a cholera-naïve country such as Haiti. By identifying transmission hubs, it is possible to target prevention strategies that, over time, could reduce transmission of the disease and eventually eliminate cholera in Haiti.
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Affiliation(s)
| | | | - Ronald Pierre
- Artibonite Surveillance Department, MSPP, Gonaïves, Haiti.
| | - Roc Magloire
- Surveillance Department, DELR, Port-au-Prince, Haiti.
| | | | - Isabel Martinez-Pino
- Epicentre, Paris, France; European Programme for Intervention Epidemiology Training (EPIET), European Centre for Disease Prevention and Control (ECDC), Stockholm, Sweden.
| | | | | | | | - David Olson
- Médecins Sans Frontières, New York, NY, USA.
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Falkard B, Uddin T, Arifur Rahman M, Franke MF, Aktar A, Uddin MI, Bhuiyan TR, Leung DT, Charles RC, Larocque RC, Harris JB, Calderwood SB, Qadri F, Ryan ET. Plasma Leptin Levels in Children Hospitalized with Cholera in Bangladesh. Am J Trop Med Hyg 2015; 93:244-249. [PMID: 26055740 PMCID: PMC4530742 DOI: 10.4269/ajtmh.15-0172] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2015] [Accepted: 04/11/2015] [Indexed: 11/07/2022] Open
Abstract
Vibrio cholerae, the cause of cholera, induces both innate and adaptive immune responses in infected humans. Leptin is a hormone that plays a role in both metabolism and mediating immune responses. We characterized leptin levels in 11 children with cholera in Bangladesh, assessing leptin levels on days 2, 7, 30, and 180 following cholera. We found that patients at the acute stage of cholera had significantly lower plasma leptin levels than matched controls, and compared with levels in late convalescence. We then assessed immune responses to V. cholerae antigens in 74 children with cholera, correlating these responses to plasma leptin levels on day 2 of illness. In multivariate analysis, we found an association between day 2 leptin levels and development of later anti-cholera toxin B subunit (CtxB) responses. This finding appeared to be limited to children with better nutritional status. Interestingly, we found no association between leptin levels and antibody responses to V. cholerae lipopolysaccharide, a T cell-independent antigen. Our results suggest that leptin levels may be associated with cholera, including the development of immune responses to T cell-dependent antigens.
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Affiliation(s)
- Brie Falkard
- *Address correspondence to Brie Falkard, Division of Infectious Diseases, Massachusetts General Hospital, Jackson 520, 55 Fruit Street, Boston, MA 02114. E-mail:
| | - Taher Uddin
- †These authors contributed equally to this work
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Abstract
During the current seventh cholera pandemic, Africa bore the major brunt of global disease burden. More than 40 years after its resurgence in Africa in 1970, cholera remains a grave public health problem, characterized by large disease burden, frequent outbreaks, persistent endemicity, and high CFRs, particularly in the region of the central African Great Lakes which might act as reservoirs for cholera. There, cases occur year round with a rise in incidence during the rainy season. Elsewhere in sub-Saharan Africa, cholera occurs mostly in outbreaks of varying size with a constant threat of widespread epidemics. Between 1970 and 2011, African countries reported 3,221,050 suspected cholera cases to the World Health Organization, representing 46 % of all cases reported globally. Excluding the Haitian epidemic, sub-Saharan Africa accounted for 86 % of reported cases and 99 % of deaths worldwide in 2011. The number of cholera cases is possibly much higher than what is reported to the WHO due to the variation in modalities, completeness, and case definition of national cholera data. One source on country specific incidence rates for Africa, adjusting for underreporting, estimates 1,341,080 cases and 160,930 deaths (52.6 % of 2,548,227 estimated cases and 79.6 % of 209,216 estimated deaths worldwide). Another estimates 1,411,453 cases and 53,632 deaths per year, respectively (50 % of 2,836,669 estimated cases and 58.6 % of 91,490 estimated deaths worldwide). Within Africa, half of all cases between 1970 and 2011 were notified from only seven countries: Angola, Democratic Republic of the Congo, Mozambique, Nigeria, Somalia, Tanzania, and South Africa. In contrast to a global trend of decreasing case fatality ratios (CFRs), CFRs have remained stable in Africa at approximately 2 %. Early propagation of cholera outbreaks depends largely on the extent of individual bacterial shedding, host and organism characteristics, the likelihood of people coming into contact with an infectious dose of Vibrio cholerae and on the virulence of the implicated strain. Cholera transmission can then be amplified by several factors including contamination of human water- or food sources; climate and extreme weather events; political and economic crises; high population density combined with poor quality informal housing and poor hygiene practices; spread beyond a local community through human travel and animals, e.g., water birds. At an individual level, cholera risk may increase with decreasing immunity and hypochlorhydria, such as that induced by Helicobacter pylori infection, which is endemic in much of Africa, and may increase individual susceptibility and cholera incidence. Since contaminated water is the main vehicle for the spread of cholera, the obvious long-term solution to eradicate the disease is the provision of safe water to all African populations. This requires considerable human and financial resources and time. In the short and medium term, vaccination may help to prevent and control the spread of cholera outbreaks. Regardless of the intervention, further understanding of cholera biology and epidemiology is essential to identify populations and areas at increased risk and thus ensure the most efficient use of scarce resources for the prevention and control of cholera.
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Affiliation(s)
- Martin A Mengel
- Agence de Médecine Préventive, 164 rue de Vaugirard, 75015, Paris, France,
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