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Falkard B, Charles RC, Matias WR, Mayo-Smith LM, Jerome JG, Offord ES, Xu P, Kováč P, Ryan ET, Qadri F, Franke MF, Ivers LC, Harris JB. Bivalent oral cholera vaccination induces a memory B cell response to the V. cholerae O1-polysaccharide antigen in Haitian adults. PLoS Negl Trop Dis 2019; 13:e0007057. [PMID: 30703094 PMCID: PMC6372202 DOI: 10.1371/journal.pntd.0007057] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2018] [Revised: 02/12/2019] [Accepted: 12/05/2018] [Indexed: 11/19/2022] Open
Abstract
The bivalent killed whole-cell oral cholera vaccine (BivWC) is being increasingly used to prevent cholera. The presence of O-antigen-specific memory B cells (MBC) has been associated with protective immunity against cholera, yet MBC responses have not been evaluated after BivWC vaccination. To address this knowledge gap, we measured V. cholerae O1-antigen MBC responses following BivWC vaccination. Adults in St. Marc, Haiti, received 2 doses of the BivWC vaccine, Shanchol, two weeks apart. Participants were invited to return at days 7, 21, 44, 90, 180 and 360 after the initial vaccination. Serum antibody and MBC responses were assessed at each time-point before and following vaccination. We observed that vaccination with BivWC resulted in significant O-antigen specific MBC responses to both Ogawa and Inaba serotypes that were detected by day 21 and remained significantly elevated over baseline for up to 12 months following vaccination. The BivWC oral cholera vaccine induces durable MBC responses to the V. cholerae O1-antigen. This suggests that long-term protection observed following vaccination with BivWC could be mediated or maintained by MBC responses. Oral cholera vaccines are being increasingly used throughout the world as a key component of cholera prevention programs. While several recent studies suggest oral cholera vaccines may provide durable protection, the potential mechanism that generates this long lasting immune memory and protection are unknown. Unlike antibody and antibody secreting cell responses, memory B cells are thought to be an important part of the immune responses because although these cells do not produce antibody, they are long lived and can be rapidly stimulated to produce antibodies upon re-exposure to infection. Previous studies have shown that memory B cell responses to the Vibrio cholerae O-antigen are associated with protection against cholera infection. In this study, we found that oral cholera vaccine generated long lasting antibody and memory B cell responses to the Vibrio cholerae O-antigen that remained elevated for 6 to 12 months. These findings show that oral cholera vaccination does induce a strong memory B cell response, which could play a role in the generation and maintenance of long-term protection following BivWC vaccination.
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Chen ST, Cahalane AM, Ryan ET, Foreman RK. Case 2-2019: A 36-Year-Old Man with Rash, Abdominal Pain, and Lymphadenopathy. N Engl J Med 2019; 380:275-283. [PMID: 30650323 DOI: 10.1056/nejmcpc1810390] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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Chatham-Stephens K, Medalla F, Hughes M, Appiah GD, Aubert RD, Caidi H, Angelo KM, Walker AT, Hatley N, Masani S, Nash J, Belko J, Ryan ET, Mintz E, Friedman CR. Emergence of Extensively Drug-Resistant Salmonella Typhi Infections Among Travelers to or from Pakistan - United States, 2016-2018. MMWR-MORBIDITY AND MORTALITY WEEKLY REPORT 2019; 68:11-13. [PMID: 30629573 PMCID: PMC6342547 DOI: 10.15585/mmwr.mm6801a3] [Citation(s) in RCA: 73] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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Pfister HB, Kelly M, Qadri F, Ryan ET, Kováč P. Synthesis of glycocluster-containing conjugates for a vaccine against cholera. Org Biomol Chem 2019; 17:4049-4060. [DOI: 10.1039/c9ob00368a] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The glycocluster-containing conjugates for a vaccine against cholera showed immunoreactivity comparable to conventional conjugates.
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Abstract
Respiratory tract infections (RTIs) are a common health problem of international travelers. Travelers may be at increased risk of RTIs due to travel itself (mingling and close quarters in airports, airplanes, cruise ships, and hotels), and due to unique exposure at travel destinations. The clinical spectrum of RTIs in travelers is broad and includes upper RTIs, pharyngitis, otitis, laryngitis, bronchitis, and pneumonia. Most travelers who acquire an RTI only develop mild disease, and only a minority seek medical attention. All travelers should be up to date on any indicated vaccines based on age and medical condition that prevent RTIs, including influenza, measles, pneumococcal diseases, Haemophilus influenzae b, Neisseria meningitidis, diphtheria, and pertussis. Respiratory tract infections (RTIs) are among the most common illnesses reported by travelers. Most RTIs are viral, involve the upper respiratory tract, and do not require specific diagnosis or treatment. Influenza is often considered the most important travel-related infection. Travelers play an integral role in the yearly and global spread of influenza. Lower RTIs, including pneumonia, often require antimicrobial therapy. High-risk groups such as infants, small children, the elderly, and subjects with chronic tracheobronchial or pulmonary disease are at increased risk of developing severe clinical consequences should infection occur. All international travelers should be immunized for seasonal influenza unless otherwise contraindicated, and travelers should be instructed in hand hygiene and sneeze and cough hygiene. All travelers should be up to date on any indicated vaccines that prevent RTIs, including measles, pneumococcal diseases, Haemophilus influenzae b (Hib), meningococcal disease, diphtheria, and pertussis. Travelers may be at increased risk of geographically restricted RTIs, and clinicians should be familiar with the major manifestations of these illnesses.
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Ritter A, Chowdhury F, Becker R, Bhuiyan T, Khan A, Ryan ET, Calderwood SB, LaRocque R, Harris J, Qadri F, Weil A. 1105. Vibriocidal Titer Variation and Likelihood of Protection in Children Compared With Adults in a Cholera Endemic Area. Open Forum Infect Dis 2018. [PMCID: PMC6255347 DOI: 10.1093/ofid/ofy210.939] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Background Vibrio cholerae, the causative agent of cholera, is responsible for significant morbidity and mortality worldwide. Children less than 5 years old have the highest disease burden of cholera in endemic areas. While children develop serum vibriocidal antibody responses to cholera vaccines, they derive less protection from vaccination compared with adults. The aim of our study was to determine whether the vibriocidal immune responses to V. cholerae infection are equally accurate as markers of protection in all age groups. Methods Cholera patients and their household contacts, who are known to be at high risk of V. cholerae infection, were enrolled between 2001 and 2017 in Dhaka, Bangladesh. Baseline vibriocidal titers were measured at the time of enrollment of household contacts, and participants were followed prospectively for development of V. cholerae infection. Results We studied 50 contacts < 5 years old (“young children”), 228 contacts 5–16 years old (“older children”), and 548 contacts > 16 years old (“adults”). The baseline serum vibriocidal titer was higher in contacts who remained uninfected from all age groups than in contacts who developed cholera during the follow-up period (young children: P = 0.0092; older children: P = 0.0003, adults: P = 0.0012). Conclusion We found that higher vibriocidal antibody titers were associated with protection against V. cholerae infection across all three age categories. These findings may help increase our understanding of the protective immune response against V. cholerae infection and have importance for future vaccine development strategies. Acknowledgments: This research was supported by Massachusetts General Hospital training grant T32AI007061. Disclosures All authors: No reported disclosures.
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Sbaih N, Buss B, Goyal D, Rao SR, Benefield R, Walker AT, Esposito DH, Ryan ET, LaRocque RC, Leung DT. Potentially Serious Drug Interactions Resulting From the Pretravel Health Encounter. Open Forum Infect Dis 2018; 5:ofy266. [PMID: 30465013 PMCID: PMC6239081 DOI: 10.1093/ofid/ofy266] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2018] [Accepted: 10/12/2018] [Indexed: 11/14/2022] Open
Abstract
Travelers seen for pretravel health encounters are frequently prescribed new travel-related medications, which may interact with their previously prescribed medications. In a cohort of 76 324 travelers seen at 23 US clinics, we found that 2650 (3.5%) travelers were prescribed travel-related medications with potential for serious drug interactions.
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Andrews JR, Qamar FN, Charles RC, Ryan ET. Extensively Drug-Resistant Typhoid - Are Conjugate Vaccines Arriving Just in Time? N Engl J Med 2018; 379:1493-1495. [PMID: 30332569 DOI: 10.1056/nejmp1803926] [Citation(s) in RCA: 51] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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Khalil IA, Troeger C, Blacker BF, Rao PC, Brown A, Atherly DE, Brewer TG, Engmann CM, Houpt ER, Kang G, Kotloff KL, Levine MM, Luby SP, MacLennan CA, Pan WK, Pavlinac PB, Platts-Mills JA, Qadri F, Riddle MS, Ryan ET, Shoultz DA, Steele AD, Walson JL, Sanders JW, Mokdad AH, Murray CJL, Hay SI, Reiner RC. Morbidity and mortality due to shigella and enterotoxigenic Escherichia coli diarrhoea: the Global Burden of Disease Study 1990-2016. THE LANCET. INFECTIOUS DISEASES 2018; 18:1229-1240. [PMID: 30266330 PMCID: PMC6202441 DOI: 10.1016/s1473-3099(18)30475-4] [Citation(s) in RCA: 331] [Impact Index Per Article: 55.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/17/2018] [Revised: 07/10/2018] [Accepted: 07/16/2018] [Indexed: 01/01/2023]
Abstract
Background Shigella and enterotoxigenic Escherichia coli (ETEC) are bacterial pathogens that are frequently associated with diarrhoeal disease, and are a significant cause of mortality and morbidity worldwide. The Global Burden of Diseases, Injuries, and Risk Factors study 2016 (GBD 2016) is a systematic, scientific effort to quantify the morbidity and mortality due to over 300 causes of death and disability. We aimed to analyse the global burden of shigella and ETEC diarrhoea according to age, sex, geography, and year from 1990 to 2016. Methods We modelled shigella and ETEC-related mortality using a Bayesian hierarchical modelling platform that evaluates a wide range of covariates and model types on the basis of vital registration and verbal autopsy data. We used a compartmental meta-regression tool to model the incidence of shigella and ETEC, which enforces an association between incidence, prevalence, and remission on the basis of scientific literature, population representative surveys, and health-care data. We calculated 95% uncertainty intervals (UIs) for the point estimates. Findings Shigella was the second leading cause of diarrhoeal mortality in 2016 among all ages, accounting for 212 438 deaths (95% UI 136 979–326 913) and about 13·2% (9·2–17·4) of all diarrhoea deaths. Shigella was responsible for 63 713 deaths (41 191–93 611) among children younger than 5 years and was frequently associated with diarrhoea across all adult age groups, increasing in elderly people, with broad geographical distribution. ETEC was the eighth leading cause of diarrhoea mortality in 2016 among all age groups, accounting for 51 186 deaths (26 757–83 064) and about 3·2% (1·8–4·7) of diarrhoea deaths. ETEC was responsible for about 4·2% (2·2–6·8) of diarrhoea deaths in children younger than 5 years. Interpretation The health burden of bacterial diarrhoeal pathogens is difficult to estimate. Despite existing prevention and treatment options, they remain a major cause of morbidity and mortality globally. Additional emphasis by public health officials is needed on a reduction in disease due to shigella and ETEC to reduce disease burden. Funding Bill & Melinda Gates Foundation.
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Andrews JR, Baker S, Marks F, Alsan M, Garrett D, Gellin BG, Saha SK, Qamar FN, Yousafzai MT, Bogoch II, Antillon M, Pitzer VE, Kim JH, John J, Gauld J, Mogasale V, Ryan ET, Luby SP, Lo NC. Typhoid conjugate vaccines: a new tool in the fight against antimicrobial resistance. THE LANCET. INFECTIOUS DISEASES 2018; 19:e26-e30. [PMID: 30170987 DOI: 10.1016/s1473-3099(18)30350-5] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/2017] [Revised: 05/10/2018] [Accepted: 05/17/2018] [Indexed: 10/28/2022]
Abstract
Typhoid fever is an acute systemic infectious disease responsible for an estimated 12-20 million illnesses and over 150 000 deaths annually. In March, 2018, a new recommendation was issued by WHO for the programmatic use of typhoid conjugate vaccines in endemic countries. Health economic analyses of typhoid vaccines have informed funding decisions and national policies regarding vaccine rollout. However, by focusing only on averted typhoid cases and their associated costs, traditional cost-effectiveness analyses might underestimate crucial benefits of typhoid vaccination programmes, because the potential effect of typhoid vaccines on the treatment of patients with non-specific acute febrile illnesses is not considered. For every true case of typhoid fever, three to 25 patients without typhoid disease are treated with antimicrobials unnecessarily, conservatively amounting to more than 50 million prescriptions per year. Antimicrobials for suspected typhoid might therefore be an important selective pressure for the emergence and spread of antimicrobial resistance globally. We propose that large-scale, more aggressive typhoid vaccination programmes-including catch-up campaigns in children up to 15 years of age, and vaccination in lower incidence settings-have the potential to reduce the overuse of antimicrobials and thereby reduce antimicrobial resistance in many bacterial pathogens. Funding bodies and national governments must therefore consider the potential for broad reductions in antimicrobial use and resistance in decisions related to the rollout of typhoid conjugate vaccines.
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Domman D, Chowdhury F, Khan AI, Dorman MJ, Mutreja A, Uddin MI, Paul A, Begum YA, Charles RC, Calderwood SB, Bhuiyan TR, Harris JB, LaRocque RC, Ryan ET, Qadri F, Thomson NR. Defining endemic cholera at three levels of spatiotemporal resolution within Bangladesh. Nat Genet 2018; 50:951-955. [PMID: 29942084 PMCID: PMC6283067 DOI: 10.1038/s41588-018-0150-8] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2017] [Accepted: 05/02/2018] [Indexed: 11/08/2022]
Abstract
Although much focus is placed on cholera epidemics, the greatest burden occurs in settings in which cholera is endemic, including areas of South Asia, Africa and now Haiti1,2. Dhaka, Bangladesh is a megacity that is hyper-endemic for cholera, and experiences two regular seasonal outbreaks of cholera each year3. Despite this, a detailed understanding of the diversity of Vibrio cholerae strains circulating in this setting, and their relationships to annual outbreaks, has not yet been obtained. Here we performed whole-genome sequencing of V. cholerae across several levels of focus and scale, at the maximum possible resolution. We analyzed bacterial isolates to define cholera dynamics at multiple levels, ranging from infection within individuals, to disease dynamics at the household level, to regional and intercontinental cholera transmission. Our analyses provide a genomic framework for understanding cholera diversity and transmission in an endemic setting.
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Sayeed MA, Islam K, Hossain M, Akter NJ, Alam MN, Sultana N, Khanam F, Kelly M, Charles RC, Kováč P, Xu P, Andrews JR, Calderwood SB, Amin J, Ryan ET, Qadri F. Development of a new dipstick (Cholkit) for rapid detection of Vibrio cholerae O1 in acute watery diarrheal stools. PLoS Negl Trop Dis 2018. [PMID: 29538377 PMCID: PMC5862499 DOI: 10.1371/journal.pntd.0006286] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
Recognizing cholera cases early, especially in the initial phase of an outbreak and in areas where cholera has not previously circulated, is a high public health priority. Laboratory capacity in such settings is often limited. To address this, we have developed a rapid diagnostic test (RDT) termed Cholkit that is based on an immunochromatographic lateral flow assay for the diagnosis of cholera cases using stool. Cholkit contains a monoclonal antibody (ICL-33) to the O-specific polysaccharide (OSP) component of V. cholerae O1 lipopolysaccharide, and recognizes both Inaba and Ogawa serotypes. We tested the Cholkit dipstick using fresh stool specimens of 76 adults and children presenting with acute watery diarrhea at the icddr,b hospital in Dhaka, Bangladesh. We compared Cholkit’s performance with those of microbial culture, PCR (targeting the rfb and ctxA genes of V. cholerae) and the commercially available RDT, Crystal VC (Span Diagnostics; Surat, India). We found that all stool specimens with a positive culture for V. cholerae O1 (n = 19) were positive by Cholkit as well as Crystal VC. We then used Bayesian latent class modeling to estimate the sensitivity and specificity of each diagnostic assay. The sensitivity of Cholkit, microbiological culture, PCR and Crystal VC was 98% (95% CI: 88–100), 71% (95% CI: 59–81), 74% (95% CI: 59–86) and 98% (95% CI: 88–100), respectively. The specificity for V. cholerae O1 was 97% (95% CI: 89–100), 100%, 97% (95% CI: 93–99) and 98% (95% CI: 92–100), respectively. Of note, two Crystal VC dipsticks were positive for V. cholerae O139 but negative by culture and PCR in this area without known circulating epidemic V. cholerae O139. In conclusion, the Cholkit dipstick is simple to use, requires no dedicated laboratory capacity, and has a sensitivity and specificity for V. cholerae O1 of 98% and 97%, respectively. Cholkit warrants further evaluation in other settings. Cholera is a severely dehydrating diarrheal disease that can lead to death if remains untreated. The incidence of case fatality is higher at the beginning of the outbreak. Diagnosis of cholera in the early stage of outbreak is a high public health priority. Although countries facing complex emergencies are more vulnerable to cholera outbreak, laboratory capacity in such settings is usually limited. To address this, here we report the development of a rapid diagnostic test (RDT) termed Cholkit for the diagnosis of cholera cases using stool and the assessment of its performance with those of microbial culture, PCR and Crystal VC assay, a commercially available dipstick using a latent class modeling approach.
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North CM, Allen JG, Okello S, Sentongo R, Kakuhikire B, Ryan ET, Tsai AC, Christiani DC, Siedner MJ. HIV Infection, Pulmonary Tuberculosis, and COPD in Rural Uganda: A Cross-Sectional Study. Lung 2018; 196:49-57. [PMID: 29260309 PMCID: PMC6261662 DOI: 10.1007/s00408-017-0080-8] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2017] [Accepted: 12/15/2017] [Indexed: 10/18/2022]
Abstract
PURPOSE HIV is associated with chronic obstructive pulmonary disease (COPD) in high resource settings. Similar relationships are less understood in low resource settings. We aimed to estimate the association between HIV infection, tuberculosis, and COPD in rural Uganda. METHODS The Uganda Non-communicable Diseases and Aging Cohort study observes people 40 years and older living with HIV (PLWH) on antiretroviral therapy, and population-based HIV-uninfected controls in rural Uganda. Participants completed respiratory questionnaires and post-bronchodilator spirometry. RESULTS Among 269 participants with spirometry, median age was 52 (IQR 48-55), 48% (n = 130) were ever-smokers, and few (3%, n = 9) reported a history of COPD or asthma. All participants with prior tuberculosis (7%, n = 18) were PLWH. Among 143 (53%) PLWH, median CD4 count was 477 cells/mm3 and 131 (92%) were virologically suppressed. FEV1 was lower among older individuals (- 0.5%pred/year, 95% CI 0.2-0.8, p < 0.01) and those with a history of tuberculosis (- 14.4%pred, 95% CI - 23.5 to - 5.3, p < 0.01). COPD was diagnosed in 9 (4%) participants, eight of whom (89%) were PLWH, six of whom (67%) had a history of tuberculosis, and all of whom (100%) were men. Among 287 participants with complete symptom questionnaires, respiratory symptoms were more likely among women (AOR 3.9, 95% CI 2.0-7.7, p < 0.001) and those in homes cooking with charcoal (AOR 3.2, 95% CI 1.4-7.4, p = 0.008). CONCLUSION In rural Uganda, COPD may be more prevalent among PLWH, men, and those with prior tuberculosis. Future research is needed to confirm these findings and evaluate their broader impacts on health.
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Iyer AS, Azman AS, Bouhenia M, Deng LO, Anderson CP, Graves M, Kováč P, Xu P, Ryan ET, Harris JB, Sack DA, Luquero FJ, Leung DT. Dried Blood Spots for Measuring Vibrio cholerae-specific Immune Responses. PLoS Negl Trop Dis 2018; 12:e0006196. [PMID: 29377882 PMCID: PMC5805362 DOI: 10.1371/journal.pntd.0006196] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2017] [Revised: 02/08/2018] [Accepted: 12/28/2017] [Indexed: 02/03/2023] Open
Abstract
Background Vibrio cholerae causes over 2 million cases of cholera and 90,000 deaths each year. Serosurveillance can be a useful tool for estimating the intensity of cholera transmission and prioritizing populations for cholera control interventions. Current methods involving venous blood draws and downstream specimen storage and transport methods pose logistical challenges in most settings where cholera strikes. To overcome these challenges, we developed methods for determining cholera-specific immune responses from dried blood spots (DBS). Methodology/principal findings As conventional vibriocidal assay methods were unsuitable for DBS eluates from filter paper, we adopted a drop-plate culture method. We show that DBS collected from volunteers in South Sudan, and stored for prolonged periods in field conditions, retained functional vibriocidal antibodies, the titers of which correlated with paired serum titers determined by conventional spectrophotometric methods (r = 0.94, p = 0.00012). We also showed that eluates from DBS Serum Separator cards could be used with conventional spectrophotometric vibriocidal methods, and that they correlated with paired serum at a wide range of titers (r = 0.96, p<0.0001). Similarly, we used ELISA methods to show that V. cholerae O-specific polysaccharide antibody responses from DBS eluates correlated with results from paired serum for IgG (r = 0.85, p = 0.00006), IgM (r = 0.79, p = 0.00049) and IgA (r = 0.73, p = 0.0019), highlighting its potential for use in determination of isotype-specific responses. Storage of DBS cards at a range of temperatures did not change antibody responses. Conclusion In conclusion, we have developed and demonstrated a proof-of-concept for assays utilizing DBS for assessing cholera-specific immune responses. Cholera remains a major public health issue among underprivileged populations in the developing world. Current methods of disease surveillance are inadequate for identifying key populations at highest risk of cholera. Serosurveillance can provide accurate measurements of an individual or population’s exposure to cholera infection or oral cholera vaccine (OCV) induced immunity, though they require venous blood draw and stringent processing needs. Dried blood spots (DBS) overcome these challenges, acting as a portable surveillance tool suitable for field use. We developed a drop-plate culture method for evaluating vibriocidal and cholera-specific isotype responses using DBS from OCV-immunized volunteers from South Sudan. Blood equivalent to only two drops were spotted on Whatman Protein Saver (WPS) DBS cards. Vibriocidal titers from WPS eluates determined by drop-plate culture methods correlated well with serum based assays. In addition, by using DBS cards capable of automatic separation of serum from blood, we demonstrate that vibriocidal titers and V. cholerae polysaccharide antibody responses could be measured by conventional spectrophotometric methods and that these responses are stable over a range of storage temperatures. In summary, we show that cholera-specific immune responses can be measured using DBS, providing a potential tool for large-scale serosurveillance field studies for cholera.
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Abstract
International travel can result in new illness or exacerbate existing conditions, and primary care clinicians have the opportunity to provide both pre- and posttravel health care. Providers should be familiar with destination-specific disease risks, be knowledgeable about travel and routine vaccines, be prepared to prescribe chemoprophylaxis and self-treatment regimens, and be aware of travel medicine resources.
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Lash RR, Walker AT, Lee CV, LaRocque R, Rao SR, Ryan ET, Brunette G, Holton K, Sotir MJ. Enabling clinicians to easily find location-based travel health recommendations-is innovation needed? J Travel Med 2018; 25:4999198. [PMID: 29788401 PMCID: PMC5991802 DOI: 10.1093/jtm/tay035] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/02/2018] [Accepted: 04/26/2018] [Indexed: 11/14/2022]
Abstract
Background The types of place names and the level of geographic detail that patients report to clinicians regarding their intended travel itineraries vary. The reported place names may not match those in published travel health recommendations, making traveler-specific recommendations potentially difficult and time-consuming to identify. Most published recommendations are at the country level; however, subnational recommendations exist when documented disease risk varies within a country, as for malaria and yellow fever. Knowing the types of place names reported during consultations would be valuable for developing more efficient ways of searching and identifying recommendations, hence we inventoried these descriptors and identified patterns in their usage. Methods The data analyzed were previously collected individual travel itineraries from pretravel consultations performed at Global TravEpiNet (GTEN) travel clinic sites. We selected a clinic-stratified random sample of records from 18 GTEN clinics that contained responses to an open-ended question describing itineraries. We extracted and classified place names into nine types and analyzed patterns relative to common travel-related demographic variables. Results From the 1756 itineraries sampled, 1570 (89%) included one or more place names, totaling 3366 place names. The frequency of different types of place names varied considerably: 2119 (63%) populated place, 336 (10%) tourist destination, 283 (8%) physical geographic area, 206 (6%) vague subnational area, 163 (5%) state, 153 (5%) country, 48 (1%) county, 12 (1%) undefined. Conclusions The types of place names used by travelers to describe travel itineraries during pretravel consultations were often different from the ones referenced in travel health recommendations. This discrepancy means that clinicians must use additional maps, atlases or online search tools to cross-reference the place names given to the available recommendations. Developing new clinical tools that use geographic information systems technology would make it easier and faster for clinicians to find applicable recommendations for travelers.
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Hagmann SHF, Rao SR, LaRocque RC, Erskine S, Jentes ES, Walker AT, Barnett ED, Chen LH, Hamer DH, Ryan ET. Travel Characteristics and Pretravel Health Care Among Pregnant or Breastfeeding U.S. Women Preparing for International Travel. Obstet Gynecol 2017; 130:1357-1365. [PMID: 29112671 PMCID: PMC5909816 DOI: 10.1097/aog.0000000000002360] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
OBJECTIVE To study characteristics and preventive interventions of adult pregnant and breastfeeding travelers seeking pretravel health care in the United States. METHODS This cross-sectional study analyzed data (2009-2014) of pregnant and breastfeeding travelers seen at U.S. travel clinics participating in Global TravEpiNet. Nonpregnant, nonbreastfeeding adult female travelers of childbearing age were used for comparison. We evaluated the prescription of malaria chemoprophylaxis and antibiotics for this population as well as the administration of three travel-related vaccines: hepatitis A, typhoid, and yellow fever. We also evaluated use of tetanus toxoid, reduced diphtheria toxoid, and acellular pertussis and influenza vaccines, because these are widely recommended in pregnancy. RESULTS Of 21,138 female travelers of childbearing age in Global TravEpiNet, 170 (0.8%) were pregnant and 139 (0.7%) were breastfeeding. Many traveled to destinations endemic for mosquito-borne illnesses, including malaria (pregnant: 95%; breastfeeding: 94%), dengue (pregnant: 87%; breastfeeding: 81%), or yellow fever (pregnant: 35%; breastfeeding: 50%). Compared with nonpregnant, nonbreastfeeding adult female travelers, eligible pregnant travelers were less likely to be vaccinated against hepatitis A (28% compared with 51%, P<.001) and typhoid (35% compared with 74%, P<.001). More than 20% of eligible pregnant travelers did not receive influenza vaccination. Yellow fever vaccine was occasionally provided to pregnant and breastfeeding travelers traveling to countries entirely endemic for yellow fever (6 [20%] of 30 pregnant travelers and 18 [46%] of 39 breastfeeding travelers). Half of pregnant travelers and two thirds of breastfeeding travelers preparing to travel to malaria-holoendemic countries received a prescription for malaria prophylaxis. CONCLUSION Most pregnant and breastfeeding travelers seen for pretravel health consultations traveled to destinations with high risk for vector-borne or other travel-related diseases. Destination-specific preventive interventions were frequently underused.
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Park KS, Kim H, Kim S, Lee K, Park S, Song J, Min C, Khanam F, Rashu R, Bhuiyan TR, Ryan ET, Qadri F, Weissleder R, Cheon J, Charles RC, Lee H. Nanomagnetic System for Rapid Diagnosis of Acute Infection. ACS NANO 2017; 11:11425-11432. [PMID: 29121461 PMCID: PMC6296367 DOI: 10.1021/acsnano.7b06074] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Pathogen-activated antibody-secreting cells (ASCs) produce and secrete antigen-specific antibodies. ASCs are detectable in the peripheral blood as early as 3 days after antigen exposure, which makes ASCs a potential biomarker for early disease detection. Here, we present a magnetic capture and detection (MCD) assay for sensitive, on-site detection of ASCs. In this approach, ASCs are enriched through magnetic capture, and secreted antibodies are magnetically detected by a miniaturized nuclear magnetic resonance (μNMR) system. This approach is based entirely on magnetics, which supports high contrast against biological background and simplifies assay procedures. We advanced the MCD system by (i) synthesizing magnetic nanoparticles with high magnetic moments for both cell capture and antibody detection, (ii) developing a miniaturized magnetic device for high-yield cell capture, and (iii) optimizing the μNMR assay for antibody detection. Antibody responses targeting hemolysin E (HlyE) can accurately identify individuals with acute enteric fever. As a proof-of-concept, we applied MCD to detect antibodies produced by HlyE-specific hybridoma cells. The MCD achieved high sensitivity in detecting antibodies secreted from as few as 5 hybridoma cells (50 cells/mL). Importantly, the assay could be performed with whole blood with minimal sample processing.
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Charles RC, Nakajima R, Liang L, Jasinskas A, Berger A, Leung DT, Kelly M, Xu P, Kovác P, Giffen SR, Harbison JD, Chowdhury F, Khan AI, Calderwood SB, Bhuiyan TR, Harris JB, Felgner PL, Qadri F, Ryan ET. Plasma and Mucosal Immunoglobulin M, Immunoglobulin A, and Immunoglobulin G Responses to the Vibrio cholerae O1 Protein Immunome in Adults With Cholera in Bangladesh. J Infect Dis 2017; 216:125-134. [PMID: 28535267 PMCID: PMC5853614 DOI: 10.1093/infdis/jix253] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2017] [Accepted: 05/19/2017] [Indexed: 11/16/2022] Open
Abstract
Background. Cholera is a severe dehydrating illness of humans caused by toxigenic strains of Vibrio cholerae O1 or O139. Identification of immunogenic V. cholerae antigens could lead to a better understanding of protective immunity in human cholera. Methods. We probed microarrays containing 3652 V. cholerae antigens with plasma and antibody-in-lymphocyte supernatant (ALS, a surrogate marker of mucosal immune responses) from patients with severe cholera caused by V. cholerae O1 in Bangladesh and age-, sex-, and ABO-matched Bangladeshi controls. We validated a subset of identified antigens using enzyme-linked immunosorbent assay. Results. Overall, we identified 608 immunoreactive V. cholerae antigens in our screening, 59 of which had higher immunoreactivity in convalescent compared with acute-stage or healthy control samples (34 in plasma, 39 in mucosal ALS; 13 in both sample sets). Identified antigens included cholera toxin B and A subunits, V. cholerae O–specific polysaccharide and lipopolysaccharide, toxin coregulated pilus A, sialidase, hemolysin A, flagellins (FlaB, FlaC, and FlaD), phosphoenolpyruvate-protein phosphotransferase, and diaminobutyrate–2-oxoglutarate aminotransferase. Conclusions. This study is the first antibody profiling of the mucosal and systemic antibody responses to the nearly complete V. cholerae O1 protein immunome; it has identified antigens that may aid in the development of an improved cholera vaccine.
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Angelo KM, Kozarsky PE, Ryan ET, Chen LH, Sotir MJ. What proportion of international travellers acquire a travel-related illness? A review of the literature. J Travel Med 2017; 24:3954792. [PMID: 28931136 PMCID: PMC5825178 DOI: 10.1093/jtm/tax046] [Citation(s) in RCA: 63] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 06/07/2017] [Indexed: 11/12/2022]
Abstract
INTRODUCTION As international travel increases, travellers may be at increased risk of acquiring infectious diseases not endemic in their home countries. Many journal articles and reference books related to travel medicine cite that between 22-64% of international travellers become ill during or after travel; however, this information is minimal, outdated and limited by poor generalizability. We aim to provide a current and more accurate estimate of the proportion of international travellers who acquire a travel-related illness. METHODS We identified studies via PubMed or travel medicine experts, published between January 1, 1976-December 31, 2016 that included the number of international travellers acquiring a travel-related illness. We excluded studies that focused on a single disease or did not determine a rate based on the total number of travellers. We abstracted information on traveller demographics, trip specifics, study enrollment and follow-up and number of ill travellers and their illnesses. RESULTS Of 743 studies, nine met the inclusion criteria. The data sources were from North America (four studies) and Europe (five studies). Most travellers were tourists, the most frequent destination regions were Asia and Africa, and the median trip duration ranged from 8-21 days. Six studies enrolled participants at the travellers' pre-travel consultation. All studies collected data through either extraction from the medical record, weekly diaries, or pre- and post-travel questionnaires. Data collection timeframes varied by study. Between 6-87% of travellers became ill across all studies. Four studies provided the best estimate: between 43-79% of travellers who frequently visited developing nations (e.g. India, Tanzania, and Kenya) became ill; travellers most frequently reported diarrhoea. CONCLUSION This is the most comprehensive assessment available on the proportion of international travellers that develop a travel-related illness. Additional cohort studies would provide needed data to more precisely determine the rates of illness in international travellers. KEYWORDS International travel, travel, illness.
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Hyle EP, Rao SR, Jentes ES, Parker Fiebelkorn A, Hagmann SHF, Taylor Walker A, Walensky RP, Ryan ET, LaRocque RC. Missed Opportunities for Measles, Mumps, Rubella Vaccination Among Departing U.S. Adult Travelers Receiving Pretravel Health Consultations. Ann Intern Med 2017; 167:77-84. [PMID: 28505632 PMCID: PMC5513758 DOI: 10.7326/m16-2249] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Background Measles outbreaks continue to occur in the United States and are mostly due to infections in returning travelers. Objective To describe how providers assessed the measles immunity status of departing U.S. adult travelers seeking pretravel consultation and to assess reasons given for nonvaccination among those considered eligible to receive the measles, mumps, rubella (MMR) vaccine. Design Observational study in U.S. pretravel clinics. Setting 24 sites associated with Global TravEpiNet (GTEN), a Centers for Disease Control and Prevention-funded consortium. Patients Adults (born in or after 1957) attending pretravel consultations at GTEN sites (2009 to 2014). Measurements Structured questionnaire completed by traveler and provider during pretravel consultation. Results 40 810 adult travelers were included; providers considered 6612 (16%) to be eligible for MMR vaccine at the time of pretravel consultation. Of the MMR-eligible, 3477 (53%) were not vaccinated at the visit; of these, 1689 (48%) were not vaccinated because of traveler refusal, 966 (28%) because of provider decision, and 822 (24%) because of health systems barriers. Most MMR-eligible travelers who were not vaccinated were evaluated in the South (2262 travelers [65%]) or at nonacademic centers (1777 travelers [51%]). Nonvaccination due to traveler refusal was most frequent in the South (1432 travelers [63%]) and in nonacademic centers (1178 travelers [66%]). Limitation These estimates could underrepresent the opportunities for MMR vaccination because providers accepted verbal histories of disease and vaccination as evidence of immunity. Conclusion Of U.S. adult travelers who presented for pretravel consultation at GTEN sites, 16% met criteria for MMR vaccination according to the provider's assessment, but fewer than half of these travelers were vaccinated. An increase in MMR vaccination of eligible U.S. adult travelers could reduce the likelihood of importation and transmission of measles virus. Primary Funding Source Centers for Disease Control and Prevention, National Institutes of Health, and the Steve and Deborah Gorlin MGH Research Scholars Award.
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Wong KK, Burdette E, Mahon BE, Mintz ED, Ryan ET, Reingold AL. Recommendations of the Advisory Committee on Immunization Practices for Use of Cholera Vaccine. MMWR-MORBIDITY AND MORTALITY WEEKLY REPORT 2017; 66:482-485. [PMID: 28493859 PMCID: PMC5657988 DOI: 10.15585/mmwr.mm6618a6] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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Xu P, Kelly M, Vann WF, Qadri F, Ryan ET, Kováč P. Conjugate Vaccines from Bacterial Antigens by Squaric Acid Chemistry: A Closer Look. Chembiochem 2017; 18:799-815. [PMID: 28182850 PMCID: PMC5664186 DOI: 10.1002/cbic.201600699] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2016] [Indexed: 11/09/2022]
Abstract
By using O-SP-core (O-SPcNH2 ) polysaccharide, isolated from Vibrio cholera O1 lipopolysaccharide (LPS) and related synthetic substances, a detailed study of factors that affect conjugation of bacterial polysaccharides to protein carriers through squaric acid chemistry to form conjugate vaccines has been carried out. Several previously unrecognized processes that take place during the squarate labeling of the O-SPcNH2 and subsequent conjugation of the formed squarate (O-SPcNH-SqOMe) have been identified. The efficiency of conjugation at pH 8.5, 9.0, and 9.5 to bovine serum albumin (BSA) and to the recombinant tetanus toxin fragment C (rTT-Hc) has been determined. The study led to a protocol for more efficient labeling of O-SPcNH2 antigen with the methyl squarate group, to yield a higher-quality, more potent squarate conjugation reagent. Its use resulted in about twofold increases in conjugation efficiency (from 23-26 % on BSA to 51 % on BSA and 55 % on rTT-Hc). The spent conjugation reagent could be recovered and regenerated by treatment with MeI in the absence of additional base. The immunological properties of the experimental vaccine made from the regenerated conjugation reagent were comparable with those of the immunogen made from the parent O-SPcNH-SqOMe.
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Lammert S, Walker AT, Erskine S, Rao SR, Esposito DH, Ryan ET, Robbins GK, LaRocque RC. Characteristics of US Travelers to Zika Virus-Affected Countries in the Americas, March 2015-October 2016. Emerg Infect Dis 2017; 23:324-327. [PMID: 27926355 PMCID: PMC5324785 DOI: 10.3201/eid2302.161292] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Zika virus has recently been introduced to the Americas and is spreading rapidly. We evaluated the characteristics of US travelers to Zika virus–affected countries who were seen at Global TravEpiNet sites during March 2015–October 2016. Nearly three quarters of travelers were men or women of reproductive age.
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Uddin MI, Islam S, Nishat NS, Hossain M, Rafique TA, Rashu R, Hoq MR, Zhang Y, Saha A, Harris JB, Calderwood SB, Bhuiyan TR, Ryan ET, Leung DT, Qadri F. Biomarkers of Environmental Enteropathy are Positively Associated with Immune Responses to an Oral Cholera Vaccine in Bangladeshi Children. PLoS Negl Trop Dis 2016; 10:e0005039. [PMID: 27824883 PMCID: PMC5100882 DOI: 10.1371/journal.pntd.0005039] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2016] [Accepted: 09/13/2016] [Indexed: 12/14/2022] Open
Abstract
Environmental enteropathy (EE) is a poorly understood condition that refers to chronic alterations in intestinal permeability, absorption, and inflammation, which mainly affects young children in resource-limited settings. Recently, EE has been linked to suboptimal oral vaccine responses in children, although immunological mechanisms are poorly defined. The objective of this study was to determine host factors associated with immune responses to an oral cholera vaccine (OCV). We measured antibody and memory T cell immune responses to cholera antigens, micronutrient markers in blood, and EE markers in blood and stool from 40 Bangladeshi children aged 3-14 years who received two doses of OCV given 14 days apart. EE markers included stool myeloperoxidase (MPO) and alpha anti-trypsin (AAT), and plasma endotoxin core antibody (EndoCab), intestinal fatty acid binding protein (i-FABP), and soluble CD14 (sCD14). We used multiple linear regression analysis with LASSO regularization to identify host factors, including EE markers, micronutrient (nutritional) status, age, and HAZ score, predictive for each response of interest. We found stool MPO to be positively associated with IgG antibody responses to the B subunit of cholera toxin (P = 0.03) and IgA responses to LPS (P = 0.02); plasma sCD14 to be positively associated with LPS IgG responses (P = 0.07); plasma i-FABP to be positively associated with LPS IgG responses (P = 0.01) and with memory T cell responses specific to cholera toxin (P = 0.01); stool AAT to be negatively associated with IL-10 (regulatory) T cell responses specific to cholera toxin (P = 0.02), and plasma EndoCab to be negatively associated with cholera toxin-specific memory T cell responses (P = 0.02). In summary, in a cohort of children 3-14 years old, we demonstrated that the majority of biomarkers of environmental enteropathy were positively associated with immune responses after vaccination with an OCV.
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