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Atekem K, Harding-Esch EM, Martin DL, Downs P, Palmer SL, Kaboré A, Kelly M, Bovary A, Sarr A, Nguessan K, James F, Gwyn S, Wickens K, Bakhtiari A, Boyd S, Aba A, Senyonjo L, Courtright P, Meite A. High prevalence of trachomatous inflammation-follicular with no trachomatous trichiasis: can alternative indicators explain the epidemiology of trachoma in Côte d'Ivoire? Int Health 2023; 15:ii3-ii11. [PMID: 38048384 PMCID: PMC10695457 DOI: 10.1093/inthealth/ihad069] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2023] [Revised: 07/28/2023] [Accepted: 08/01/2023] [Indexed: 12/06/2023] Open
Abstract
Baseline trachoma surveys in Côte d'Ivoire (2019) identified seven evaluation units (EUs) with a trachomatous inflammation-follicular (TF) prevalence ≥10%, but a trachomatous trichiasis (TT) prevalence in individuals ≥15 y of age below the elimination threshold (0.2%). Two of these EUs, Bondoukou 1 and Bangolo 2, were selected for a follow-up survey to understand the epidemiology of trachoma using additional indicators of Chlamydia trachomatis infection (DNA from conjunctival swabs) and exposure (anti-Pgp3 and Ct694 antibodies from dried blood spots [DBSs]). A two-stage cluster sampling methodology was used to select villages and households. All individuals 1-9 y of age from each selected household were recruited, graded for trachoma and had a conjunctival swab and DBS collected. Conjunctival swabs and DBSs were tested using Cepheid GeneXpert and a multiplex bead assay, respectively. The age-adjusted TF and infection prevalence in 1- to 9-year-olds was <1% and <0.3% in both EUs. Age-adjusted seroprevalence was 5.3% (95% confidence interval [CI] 1.5 to 15.6) in Bondoukou 1 and 8.2% (95% CI 4.3 to 13.7) in Bangolo 2. The seroconversion rate for Pgp3 was low, at 1.23 seroconversions/100 children/year (95% CI 0.78 to 1.75) in Bondoukou 1 and 1.91 (95% CI 1.58 to 2.24) in Bangolo 2. Similar results were seen for CT694. These infection, antibody and clinical data provide strong evidence that trachoma is not a public health problem in either EU.
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Affiliation(s)
- Kareen Atekem
- Department of Entomology, Center for Infectious Disease Dynamics, Pennsylvania State University, University Park, PA,USA
- Sightsavers
| | | | - Diana L Martin
- Centers for Disease Control and Prevention, Atlanta, GA,USA
| | | | | | | | | | | | | | | | | | - Sarah Gwyn
- Centers for Disease Control and Prevention, Atlanta, GA,USA
| | - Karana Wickens
- Oak Ridge Institute for Science and Education, Atlanta, GA,USA
| | - Ana Bakhtiari
- International Trachoma Initiative, Task Force for Global Health, Decatur, GA,USA
| | - Sarah Boyd
- International Trachoma Initiative, Task Force for Global Health, Decatur, GA,USA
| | | | | | - Paul Courtright
- Sightsavers
- Kilimanajaro Centre for Community Ophthalmology, Division of Ophthalmology, University of Cape Town, Cape Town, South Africa
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2
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Goodhew EB, Taoaba R, Harding-Esch EM, Gwyn SE, Bakhtiari A, Butcher R, Cama A, Guagliardo SAJ, Jimenez C, Mpyet CD, Tun K, Wickens K, Solomon AW, Martin DL, Tekeraoi R. Changes in trachoma indicators in Kiribati with two rounds of azithromycin mass drug administration, measured in serial population-based surveys. PLoS Negl Trop Dis 2023; 17:e0011441. [PMID: 37418501 PMCID: PMC10355439 DOI: 10.1371/journal.pntd.0011441] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2022] [Revised: 07/19/2023] [Accepted: 06/06/2023] [Indexed: 07/09/2023] Open
Abstract
Baseline mapping in the two major population centers of Kiribati showed that trachoma was a public health problem in need of programmatic interventions. After conducting two annual rounds of antibiotic mass drug administration (MDA), Kiribati undertook trachoma impact surveys in 2019, using standardized two-stage cluster surveys in the evaluation units of Kiritimati Island and Tarawa. In Kiritimati, 516 households were visited and in Tarawa, 772 households were visited. Nearly all households had a drinking water source and access to an improved latrine. The prevalence of trachomatous trichiasis remained above the elimination threshold (0.2% in ≥15-year-olds) and was virtually unchanged from baseline. The prevalence of trachomatous inflammation-follicular (TF) in 1-9-year-olds decreased by approximately 40% from baseline in both evaluation units but remained above the 5% TF prevalence threshold for stopping MDA. TF prevalence at impact survey was 11.5% in Kiritimati and 17.9% in Tarawa. Infection prevalence in 1-9-year-olds by PCR was 0.96% in Kiritimati and 3.3% in Tarawa. Using a multiplex bead assay to measure antibodies to the C. trachomatis antigen Pgp3, seroprevalence in 1-9-year-olds was 30.2% in Kiritimati and 31.4% in Tarawa. The seroconversion rate, in seroconversion events/100 children/year, was 9.0 in Kiritimati and 9.2 in Tarawa. Seroprevalence and seroconversion rates were both assessed by four different assays, with strong agreement between tests. These results show that, despite decreases in indicators associated with infection at impact survey, trachoma remains a public health problem in Kiribati, and provide additional information about changes in serological indicators after MDA.
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Affiliation(s)
| | | | - Emma M. Harding-Esch
- Clinical Research Department, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Sarah E. Gwyn
- Centers for Disease Control and Prevention, Atlanta Georgia
| | - Ana Bakhtiari
- International Trachoma Initiative, Task Force for Global Health, Atlanta, Georgia
| | - Robert Butcher
- Clinical Research Department, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | | | | | | | - Caleb D. Mpyet
- Department of Ophthalmology, College of Health Sciences, University of Jos; Jos, Nigeria, and Sightsavers, Nigeria Country Office, Kaduna, Nigeria
| | - Kab Tun
- Ministry of Health and Medical Services, South Tarawa, Kiribati
| | - Karana Wickens
- Oak Ridge Institute for Science and Education, Oak Ridge, Tennessee
| | - Anthony W. Solomon
- Department of Control of Neglected Tropical Diseases, World Health Organization, Geneva, Switzerland
| | | | - Rabebe Tekeraoi
- Ministry of Health and Medical Services, South Tarawa, Kiribati
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3
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Tedijanto C, Solomon AW, Martin DL, Nash SD, Keenan JD, Lietman TM, Lammie PJ, Aiemjoy K, Amza A, Aragie S, Arzika AM, Callahan EK, Carolan S, Dawed AA, Goodhew EB, Gwyn S, Hammou J, Kadri B, Kalua K, Maliki R, Nassirou B, Seife F, Tadesse Z, West SK, Wittberg DM, Zeru Tadege T, Arnold BF. Monitoring transmission intensity of trachoma with serology. Nat Commun 2023; 14:3269. [PMID: 37277341 PMCID: PMC10241377 DOI: 10.1038/s41467-023-38940-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2023] [Accepted: 05/22/2023] [Indexed: 06/07/2023] Open
Abstract
Trachoma, caused by ocular Chlamydia trachomatis infection, is targeted for global elimination as a public health problem by 2030. To provide evidence for use of antibodies to monitor C. trachomatis transmission, we collated IgG responses to Pgp3 antigen, PCR positivity, and clinical observations from 19,811 children aged 1-9 years in 14 populations. We demonstrate that age-seroprevalence curves consistently shift along a gradient of transmission intensity: rising steeply in populations with high levels of infection and active trachoma and becoming flat in populations near elimination. Seroprevalence (range: 0-54%) and seroconversion rates (range: 0-15 per 100 person-years) correlate with PCR prevalence (r: 0.87, 95% CI: 0.57, 0.97). A seroprevalence threshold of 13.5% (seroconversion rate 2.75 per 100 person-years) identifies clusters with any PCR-identified infection at high sensitivity ( >90%) and moderate specificity (69-75%). Antibody responses in young children provide a robust, generalizable approach to monitor population progress toward and beyond trachoma elimination.
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Affiliation(s)
- Christine Tedijanto
- Francis I. Proctor Foundation, University of California San Francisco, San Francisco, CA, 94158, USA
| | - Anthony W Solomon
- Global Neglected Tropical Diseases Programme, World Health Organization, Geneva, Switzerland
| | - Diana L Martin
- Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, Atlanta, GA, 30329, USA
| | | | - Jeremy D Keenan
- Francis I. Proctor Foundation, University of California San Francisco, San Francisco, CA, 94158, USA
- Department of Ophthalmology, University of California San Francisco, San Francisco, CA, 94158, USA
| | - Thomas M Lietman
- Francis I. Proctor Foundation, University of California San Francisco, San Francisco, CA, 94158, USA
- Department of Ophthalmology, University of California San Francisco, San Francisco, CA, 94158, USA
- Institute for Global Health Sciences, University of California San Francisco, San Francisco, CA, 94143, USA
- Department of Epidemiology and Biostatistics, University of California San Francisco, San Francisco, CA, 94143, USA
| | - Patrick J Lammie
- Neglected Tropical Diseases Support Center, Task Force for Global Health, Atlanta, GA, 30030, USA
| | - Kristen Aiemjoy
- Division of Epidemiology, Department of Public Health Sciences, University of California Davis School of Medicine, Davis, CA, USA
| | - Abdou Amza
- Programme National de Santé Oculaire, Niamey, Niger
- Programme National de Lutte Contre la Cecité, Niamey, Niger
| | - Solomon Aragie
- Francis I. Proctor Foundation, University of California San Francisco, San Francisco, CA, 94158, USA
- The Carter Center Ethiopia, Addis Ababa, Ethiopia
- Infection Biology, Addis Ababa University, Addis Ababa, Ethiopia
| | | | | | - Sydney Carolan
- Francis I. Proctor Foundation, University of California San Francisco, San Francisco, CA, 94158, USA
| | | | - E Brook Goodhew
- Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, Atlanta, GA, 30329, USA
| | - Sarah Gwyn
- Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, Atlanta, GA, 30329, USA
| | - Jaouad Hammou
- Service of Ocular and Otological Diseases, Epidemiology and Disease Control Directorate, Ministry of Health, Rabat, Morocco
| | - Boubacar Kadri
- Programme National de Santé Oculaire, Niamey, Niger
- Programme National de Lutte Contre la Cecité, Niamey, Niger
| | - Khumbo Kalua
- Blantyre Institute for Community Outreach, Blantyre, Malawi
| | | | - Beido Nassirou
- Programme National de Santé Oculaire, Niamey, Niger
- Programme National de Lutte Contre la Cecité, Niamey, Niger
| | - Fikre Seife
- Federal Ministry of Health, Addis Ababa, Ethiopia
| | | | - Sheila K West
- Johns Hopkins School of Medicine, Dana Center for Preventive Ophthalmology, Wilmer Eye Institute, Baltimore, MD, USA
| | - Dionna M Wittberg
- Francis I. Proctor Foundation, University of California San Francisco, San Francisco, CA, 94158, USA
| | | | - Benjamin F Arnold
- Francis I. Proctor Foundation, University of California San Francisco, San Francisco, CA, 94158, USA.
- Department of Ophthalmology, University of California San Francisco, San Francisco, CA, 94158, USA.
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Tedijanto C, Solomon AW, Martin DL, Nash SD, Keenan JD, Lietman TM, Lammie PJ, Aiemjoy K, Amza A, Aragie S, Arzika AM, Callahan EK, Carolan S, Dawed AA, Goodhew EB, Gwyn S, Hammou J, Kadri B, Kalua K, Maliki R, Nassirou B, Seife F, Tadesse Z, West SK, Wittberg DM, Zeru T, Arnold BF. Monitoring transmission intensity of trachoma with serology. MEDRXIV : THE PREPRINT SERVER FOR HEALTH SCIENCES 2023:2023.02.13.23285881. [PMID: 36824972 PMCID: PMC9949201 DOI: 10.1101/2023.02.13.23285881] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/18/2023]
Abstract
Trachoma, caused by ocular Chlamydia trachomatis infection, is targeted for global elimination as a public health problem by 2030. To provide evidence for use of antibodies to monitor C. trachomatis transmission, we collated IgG responses to Pgp3 antigen, PCR positivity, and clinical observations from 19,811 children aged 1- 9 years in 14 populations. We demonstrate that age-seroprevalence curves consistently shift along a gradient of transmission intensity: rising steeply in populations with high levels of infection and active trachoma and becoming flat in populations near elimination. Seroprevalence (range: 0-54%) and seroconversion rates (range: 0-15 per 100 person-years) correlate with PCR prevalence (r: 0.87, 95% CI: 0.57, 0.97). A seroprevalence threshold of 13.5% (seroconversion rate 2.75 per 100 person-years) identifies clusters with any PCR-identified infection at high sensitivity (>90%) and moderate specificity (69-75%). Antibody responses in young children provide a robust, generalizable approach to monitor population progress toward and beyond trachoma elimination.
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Affiliation(s)
- Christine Tedijanto
- Francis I. Proctor Foundation, University of California San Francisco, San Francisco, CA, USA, 94158
| | - Anthony W. Solomon
- Global Neglected Tropical Diseases Programme, World Health Organization, Geneva, Switzerland
| | - Diana L. Martin
- Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, Atlanta, GA, USA 30329
| | | | - Jeremy D. Keenan
- Francis I. Proctor Foundation, University of California San Francisco, San Francisco, CA, USA, 94158
- Department of Ophthalmology, University of California San Francisco, San Francisco, CA, USA, 94158
| | - Thomas M. Lietman
- Francis I. Proctor Foundation, University of California San Francisco, San Francisco, CA, USA, 94158
- Department of Ophthalmology, University of California San Francisco, San Francisco, CA, USA, 94158
- Institute for Global Health Sciences, University of California San Francisco, San Francisco, CA 94143
- Department of Epidemiology and Biostatistics, University of California San Francisco, San Francisco, CA 94143
| | - Patrick J. Lammie
- Neglected Tropical Diseases Support Center, Task Force for Global Health, Atlanta, GA, USA, 30030
| | - Kristen Aiemjoy
- Division of Epidemiology, Department of Public Health Sciences, University of California Davis School of Medicine, Davis, CA, USA
| | - Abdou Amza
- Programme National de Santé Oculaire, Niamey, Niger
- Programme National de Lutte Contre la Cecité, Niamey, Niger
| | - Solomon Aragie
- Francis I. Proctor Foundation, University of California San Francisco, San Francisco, CA, USA, 94158
- The Carter Center Ethiopia, Addis Ababa, Ethiopia
- Infection Biology, Addis Ababa University, Addis Ababa, Ethiopia
| | | | | | - Sydney Carolan
- Francis I. Proctor Foundation, University of California San Francisco, San Francisco, CA, USA, 94158
| | | | - E. Brook Goodhew
- Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, Atlanta, GA, USA 30329
| | - Sarah Gwyn
- Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, Atlanta, GA, USA 30329
| | - Jaouad Hammou
- Service of Ocular and Otological Diseases, Epidemiology and Disease Control Directorate, Ministry of Health, Morocco
| | - Boubacar Kadri
- Programme National de Santé Oculaire, Niamey, Niger
- Programme National de Lutte Contre la Cecité, Niamey, Niger
| | - Khumbo Kalua
- Blantyre Institute for Community Outreach, Malawi
| | | | - Beido Nassirou
- Programme National de Santé Oculaire, Niamey, Niger
- Programme National de Lutte Contre la Cecité, Niamey, Niger
| | - Fikre Seife
- Federal Ministry of Health, Addis Ababa, Ethiopia
| | | | - Sheila K. West
- Johns Hopkins School of Medicine, Dana Center for Preventive Ophthalmology, Wilmer Eye Institute, Baltimore MD USA
| | - Dionna M. Wittberg
- Francis I. Proctor Foundation, University of California San Francisco, San Francisco, CA, USA, 94158
| | - Taye Zeru
- Amhara Public Health Institute, Bahir-Dar, Ethiopia
| | - Benjamin F. Arnold
- Francis I. Proctor Foundation, University of California San Francisco, San Francisco, CA, USA, 94158
- Department of Ophthalmology, University of California San Francisco, San Francisco, CA, USA, 94158
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5
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Goodhew B, Tang X, Goldstein J, Lee J, Martin D, Gwyn S. Validation of immunoassays for the Chlamydia trachomatis antigen Pgp3 using a chimeric monoclonal antibody. Sci Rep 2023; 13:7281. [PMID: 37142607 PMCID: PMC10160048 DOI: 10.1038/s41598-023-33834-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2023] [Accepted: 04/19/2023] [Indexed: 05/06/2023] Open
Abstract
Seroepidemiology, or measuring antibodies to pathogens to estimate population-level exposure, can provide useful public health data. The tests used, however, often lack sufficient validation data due to absence of a gold standard. For many pathogens, serum antibodies can be detected long after resolution of infection, but infection status is often used as a gold standard for antibody positivity. To ensure that recently developed antibody tests for seroepidemiology of Chlamydia trachomatis (Ct), the causative agent of urogenital chlamydia and the blinding eye disease trachoma, have high performance, we generated a chimeric antibody to the immunodominant Ct antigen Pgp3. Two clones were selected to evaluate the test performance of three assays to measure antibodies to Pgp3: multiplex bead assay (MBA), enzyme-linked immunosorbent assay (ELISA), and lateral flow assay (LFA). Overall, each assay demonstrated high accuracy and precision when tested using either clone, and the clones were stable when stored at - 20 °C and 4 °C for almost 2 years. The limit of detection was similar for MBA and LFA, but almost a log-fold higher (i.e. less sensitive) using ELISA. Overall, the chimeric antibodies represent stable control reagents for tests with robust performance and will facilitate deployment of these tests to other laboratories.
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Affiliation(s)
- Brook Goodhew
- Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, Atlanta, Georgia
| | - Xiaoling Tang
- Division of Scientific Resources, Centers for Disease Control and Prevention, Atlanta, Georgia
| | - Jason Goldstein
- Division of Scientific Resources, Centers for Disease Control and Prevention, Atlanta, Georgia
| | - Joo Lee
- Division of Scientific Resources, Centers for Disease Control and Prevention, Atlanta, Georgia
| | - Diana Martin
- Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, Atlanta, Georgia
| | - Sarah Gwyn
- Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, Atlanta, Georgia.
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Saboyá-Díaz MI, Castellanos LG, Morice A, Ade MP, Rey-Benito G, Cooley GM, Scobie HM, Wiegand RE, Coughlin MM, Martin DL. Lessons learned from the implementation of integrated serosurveillance of communicable diseases in the Americas. Rev Panam Salud Publica 2023; 47:e53. [PMID: 36895677 PMCID: PMC9989549 DOI: 10.26633/rpsp.2023.53] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2022] [Accepted: 12/21/2022] [Indexed: 03/09/2023] Open
Abstract
Objective Systematize the experience and identify challenges and lessons learned in the implementation of an initiative for integrated serosurveillance of communicable diseases using a multiplex bead assay in countries of the Americas. Methods Documents produced in the initiative were compiled and reviewed. These included concept notes, internal working papers, regional meetings reports, and survey protocols from the three participating countries (Mexico, Paraguay, and Brazil) and two additional countries (Guyana and Guatemala) where serology for several communicable diseases was included in neglected tropical diseases surveys. Information was extracted and summarized to describe the experience and the most relevant challenges and lessons learned. Results Implementing integrated serosurveys requires interprogrammatic and interdisciplinary work teams for the design of survey protocols to respond to key programmatic questions aligned to the needs of the countries. Valid laboratory results are critical and rely on the standardized installment and roll-out of laboratory techniques. Field teams require adequate training and supervision to properly implement survey procedures. The analysis and interpretation of serosurveys results should be antigen-specific, contextualizing the responses for each disease, and triangulated with programmatic and epidemiological data for making decisions tailored to specific population socioeconomic and ecologic contexts. Conclusions Integrated serosurveillance as a complementary tool for functional epidemiological surveillance systems is feasible to use and key components should be considered: political engagement, technical engagement, and integrated planning. Aspects such as designing the protocol, selecting target populations and diseases, laboratory capacities, anticipating the capacities to analyze and interpret complex data, and how to use it are key.
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Affiliation(s)
- Martha-Idalí Saboyá-Díaz
- Pan American Health Organization Washington, D.C. United States of America Pan American Health Organization, Washington, D.C., United States of America
| | - Luis Gerardo Castellanos
- Pan American Health Organization Washington, D.C. United States of America Pan American Health Organization, Washington, D.C., United States of America
| | - Ana Morice
- Pan American Health Organization Washington, D.C. United States of America Pan American Health Organization, Washington, D.C., United States of America
| | - Maria Paz Ade
- Pan American Health Organization Washington, D.C. United States of America Pan American Health Organization, Washington, D.C., United States of America
| | - Gloria Rey-Benito
- Pan American Health Organization Washington, D.C. United States of America Pan American Health Organization, Washington, D.C., United States of America
| | - Gretchen M Cooley
- Centers for Disease Control and Prevention Atlanta United States of America Centers for Disease Control and Prevention, Atlanta, United States of America
| | - Heather M Scobie
- Centers for Disease Control and Prevention Atlanta United States of America Centers for Disease Control and Prevention, Atlanta, United States of America
| | - Ryan E Wiegand
- Centers for Disease Control and Prevention Atlanta United States of America Centers for Disease Control and Prevention, Atlanta, United States of America
| | - Melissa M Coughlin
- Centers for Disease Control and Prevention Atlanta United States of America Centers for Disease Control and Prevention, Atlanta, United States of America
| | - Diana L Martin
- Centers for Disease Control and Prevention Atlanta United States of America Centers for Disease Control and Prevention, Atlanta, United States of America
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Building an integrated serosurveillance platform to inform public health interventions: Insights from an experts' meeting on serum biomarkers. PLoS Negl Trop Dis 2022; 16:e0010657. [PMID: 36201428 PMCID: PMC9536637 DOI: 10.1371/journal.pntd.0010657] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
The use of biomarkers to measure immune responses in serum is crucial for understanding population-level exposure and susceptibility to human pathogens. Advances in sample collection, multiplex testing, and computational modeling are transforming serosurveillance into a powerful tool for public health program design and response to infectious threats. In July 2018, 70 scientists from 16 countries met to perform a landscape analysis of approaches that support an integrated serosurveillance platform, including the consideration of issues for successful implementation. Here, we summarize the group's insights and proposed roadmap for implementation, including objectives, technical requirements, ethical issues, logistical considerations, and monitoring and evaluation.
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Linear and Machine Learning modelling for spatiotemporal disease predictions: Force-of-Infection of Chagas disease. PLoS Negl Trop Dis 2022; 16:e0010594. [PMID: 35853042 PMCID: PMC9337653 DOI: 10.1371/journal.pntd.0010594] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2022] [Revised: 07/29/2022] [Accepted: 06/18/2022] [Indexed: 12/02/2022] Open
Abstract
Background Chagas disease is a long-lasting disease with a prolonged asymptomatic period. Cumulative indices of infection such as prevalence do not shed light on the current epidemiological situation, as they integrate infection over long periods. Instead, metrics such as the Force-of-Infection (FoI) provide information about the rate at which susceptible people become infected and permit sharper inference about temporal changes in infection rates. FoI is estimated by fitting (catalytic) models to available age-stratified serological (ground-truth) data. Predictive FoI modelling frameworks are then used to understand spatial and temporal trends indicative of heterogeneity in transmission and changes effected by control interventions. Ideally, these frameworks should be able to propagate uncertainty and handle spatiotemporal issues. Methodology/principal findings We compare three methods in their ability to propagate uncertainty and provide reliable estimates of FoI for Chagas disease in Colombia as a case study: two Machine Learning (ML) methods (Boosted Regression Trees (BRT) and Random Forest (RF)), and a Linear Model (LM) framework that we had developed previously. Our analyses show consistent results between the three modelling methods under scrutiny. The predictors (explanatory variables) selected, as well as the location of the most uncertain FoI values, were coherent across frameworks. RF was faster than BRT and LM, and provided estimates with fewer extreme values when extrapolating to areas where no ground-truth data were available. However, BRT and RF were less efficient at propagating uncertainty. Conclusions/significance The choice of FoI predictive models will depend on the objectives of the analysis. ML methods will help characterise the mean behaviour of the estimates, while LM will provide insight into the uncertainty surrounding such estimates. Our approach can be extended to the modelling of FoI patterns in other Chagas disease-endemic countries and to other infectious diseases for which serosurveys are regularly conducted for surveillance. Metrics such as the per susceptible rate of infection acquisition (Force-of-Infection) are crucial to understand the current epidemiological situation and the impact of control interventions for long-lasting diseases in which the infection event might have occurred many years previously, such as Chagas disease. FoI values are estimated from serological age profiles, often obtained in a few locations. However, when using predictive models to estimate the FoI over time and space (including areas where serosurveys had not been conducted), methods able to handle and propagate uncertainty must be implemented; otherwise, overconfident predictions may be obtained. Although Machine Learning (ML) methods are powerful tools, they may not be able to entirely handle this challenge. Therefore, the use of ML must be considered in relation to the aims of the analyses. ML will be more relevant to characterise the central trends of the estimates while Linear Models will help identify areas where further serosurveys should be conducted to improve the reliability of the predictions. Our approaches can be used to generate FoI predictions in other Chagas disease-endemic countries as well as in other diseases for which serological surveillance data are collected.
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Risk of seroconversion and seroreversion of antibodies to Chlamydia trachomatis pgp3 in a longitudinal cohort of children in a low trachoma prevalence district in Tanzania. PLoS Negl Trop Dis 2022; 16:e0010629. [PMID: 35830476 PMCID: PMC9312410 DOI: 10.1371/journal.pntd.0010629] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2022] [Revised: 07/25/2022] [Accepted: 07/01/2022] [Indexed: 11/19/2022] Open
Abstract
Background Serologic testing for chlamydial antibodies is one potential tool for trachoma monitoring. Understanding the dynamics of seroconversion and seroreversion in low endemic districts is critical for determining the value of using serology. Methodology/Principal findings We surveyed a random sample of 2536 children aged 1–9 years in Kongwa, Tanzania, over three years; 1719 (67.8%) participants had all three follow-ups. Surveys assessed trachomatous inflammation—follicular (TF), Chlamydia trachomatis infection, and anti-pgp3 antibodies. Mass drug administration occurred immediately after the first and second follow-up surveys. The cohort was classified into trajectories of change in serostatus, and risk factors were evaluated for seroconversion and seroreversion. We found that 86.2% of seropositives remained seropositive throughout the study, whereas 12.1% seroreverted. Seroreverters were younger (Odds Ratio [OR] = 0.88 for every one-year increase in age, 95% CI = 0.79–0.99). 84.5% of seronegatives remained seronegative, and 13.0% seroconverted. Seroconverters were also younger (OR = 0.92, 95% CI = 0.87–0.98). Seroconversion and seroreversion were not explained by indeterminate values for the intensity of antibody response. Less than 1% of the cohort had unstable changes in serostatus, mostly explained by values in the indeterminate range. TF and infection in the cohort declined over time, while seropositivity increased from 31.5% to 36.4%. Conclusions/Significance Antibody status is relatively stable over time. Both seroconversion and seroreversion occurred over the three years in this low endemic district, especially in younger children. Modeling seroreversion is important for accurate determination of seroconversion. The use of serology as a monitoring tool should target the younger aged children as they will most likely capture recent changes in serostatus. Trachoma, the leading infectious cause of blindness worldwide, is a chronic conjunctivitis caused by repeated infection with Chlamydia trachomatis. As more endemic regions approach the trachoma elimination goal, it becomes critical to identify tools that can be used for monitoring the potential resurgence or re-emergence of trachoma. Serologic testing for chlamydial antibodies is one potential tool. Understanding the risk of seroconversion and seroreversion in children in low endemic districts is critical for determining the value of serology as a monitoring tool. We followed a cohort of children in the formerly trachoma endemic Kongwa district in Tanzania over three years. We demonstrated the relative stability of antibody status with 85–86% of the children retaining their baseline serostatus. We also documented an overall seroconversion rate of 13% and a seroreversion rate of 12%. We found younger ages to be a risk factor for both seroconversion and seroreversion. Our study provides necessary new evidence for the slow rate of overall change in seroprevalence over three years and highlights the potential use of the younger aged children for sero-monitoring of trachoma as they are more likely to reflect the dynamic interplay of true seroconversion and seroreversion. Furthermore, using only cross-sectional serostatus to estimate seroconversion may result in an underestimate if seroreversion rates are not included in the estimation.
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Chan Y, Martin D, Mace KE, Jean SE, Stresman G, Drakeley C, Chang MA, Lemoine JF, Udhayakumar V, Lammie PJ, Priest JW, Rogier EW. Multiplex Serology for Measurement of IgG Antibodies Against Eleven Infectious Diseases in a National Serosurvey: Haiti 2014-2015. Front Public Health 2022; 10:897013. [PMID: 35757611 PMCID: PMC9218545 DOI: 10.3389/fpubh.2022.897013] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2022] [Accepted: 05/18/2022] [Indexed: 11/13/2022] Open
Abstract
Background Integrated surveillance for multiple diseases can be an efficient use of resources and advantageous for national public health programs. Detection of IgG antibodies typically indicates previous exposure to a pathogen but can potentially also serve to assess active infection status. Serological multiplex bead assays have recently been developed to simultaneously evaluate exposure to multiple antigenic targets. Haiti is an island nation in the Caribbean region with multiple endemic infectious diseases, many of which have a paucity of data for population-level prevalence or exposure. Methods A nationwide serosurvey occurred in Haiti from December 2014 to February 2015. Filter paper blood samples (n = 4,438) were collected from participants in 117 locations and assayed for IgG antibodies on a multiplex bead assay containing 15 different antigens from 11 pathogens: Plasmodium falciparum, Toxoplasma gondii, lymphatic filariasis roundworms, Strongyloides stercoralis, chikungunya virus, dengue virus, Chlamydia trachomatis, Treponema pallidum, enterotoxigenic Escherichia coli, Entamoeba histolytica, and Cryptosporidium parvum. Results Different proportions of the Haiti study population were IgG seropositive to the different targets, with antigens from T. gondii, C. parvum, dengue virus, chikungunya virus, and C. trachomatis showing the highest rates of seroprevalence. Antibody responses to T. pallidum and lymphatic filariasis were the lowest, with <5% of all samples IgG seropositive to antigens from these pathogens. Clear trends of increasing seropositivity and IgG levels with age were seen for all antigens except those from chikungunya virus and E. histolytica. Parametric models were able to estimate the rate of seroconversion and IgG acquisition per year for residents of Haiti. Conclusions Multiplex serological assays can provide a wealth of information about population exposure to different infectious diseases. This current Haitian study included IgG targets for arboviral, parasitic, and bacterial infectious diseases representing multiple different modes of host transmission. Some of these infectious diseases had a paucity or complete absence of published serological studies in Haiti. Clear trends of disease burden with respect to age and location in Haiti can be used by national programs and partners for follow-up studies, resource allocation, and intervention planning.
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Affiliation(s)
- YuYen Chan
- The London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Diana Martin
- Division of Parasitic Diseases and Malaria, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, GA, United States
| | - Kimberly E Mace
- Division of Parasitic Diseases and Malaria, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, GA, United States
| | - Samuel E Jean
- Population Services International/Organization Haïtienne de Marketing Social Pour la Santé, Port-au-Prince, Haiti
| | - Gillian Stresman
- The London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Chris Drakeley
- The London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Michelle A Chang
- Division of Parasitic Diseases and Malaria, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, GA, United States
| | - Jean F Lemoine
- Programme National de Contrôle de la Malaria/MSPP, Port-au-Prince, Haiti
| | - Venkatachalam Udhayakumar
- Division of Parasitic Diseases and Malaria, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, GA, United States
| | - Patrick J Lammie
- Division of Parasitic Diseases and Malaria, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, GA, United States
| | - Jeffrey W Priest
- Division of Foodborne, Waterborne, and Environmental Diseases, National Center for Emerging and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention, Atlanta, GA, United States
| | - Eric William Rogier
- Division of Parasitic Diseases and Malaria, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, GA, United States
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11
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Santano R, Rubio R, Grau-Pujol B, Escola V, Muchisse O, Cuamba I, Vidal M, Ruiz-Olalla G, Aguilar R, Gandasegui J, Demontis M, Jamine JC, Cossa A, Sacoor C, Cano J, Izquierdo L, Chitnis CE, Coppel RL, Chauhan V, Cavanagh D, Dutta S, Angov E, van Lieshout L, Zhan B, Muñoz J, Dobaño C, Moncunill G. Evaluation of antibody serology to determine current helminth and Plasmodium falciparum infections in a co-endemic area in Southern Mozambique. PLoS Negl Trop Dis 2022; 16:e0010138. [PMID: 35727821 PMCID: PMC9212154 DOI: 10.1371/journal.pntd.0010138] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2022] [Accepted: 04/22/2022] [Indexed: 11/18/2022] Open
Abstract
Background Soil-transmitted helminths (STH), Schistosoma spp. and Plasmodium falciparum are parasites of major public health importance and co-endemic in many sub-Saharan African countries. Management of these infections requires detection and treatment of infected people and evaluation of large-scale measures implemented. Diagnostic tools are available but their low sensitivity, especially for low intensity helminth infections, leaves room for improvement. Antibody serology could be a useful approach thanks to its potential to detect both current infection and past exposure. Methodology We evaluated total IgE responses and specific-IgG levels to 9 antigens from STH, 2 from Schistosoma spp., and 16 from P. falciparum, as potential markers of current infection in a population of children and adults from Southern Mozambique (N = 715). Antibody responses were measured by quantitative suspension array Luminex technology and their performance was evaluated by ROC curve analysis using microscopic and molecular detection of infections as reference. Principal findings IgG against the combination of EXP1, AMA1 and MSP2 (P. falciparum) in children and NIE (Strongyloides stercoralis) in adults and children had the highest accuracies (AUC = 0.942 and AUC = 0.872, respectively) as markers of current infection. IgG against the combination of MEA and Sm25 (Schistosoma spp.) were also reliable markers of current infection (AUC = 0.779). In addition, IgG seropositivity against 20 out of the 27 antigens in the panel differentiated the seropositive endemic population from the non-endemic population, suggesting a possible role as markers of exposure although sensitivity could not be assessed. Conclusions We provided evidence for the utility of antibody serology to detect current infection with parasites causing tropical diseases in endemic populations. In addition, most of the markers have potential good specificity as markers of exposure. We also showed the feasibility of measuring antibody serology with a platform that allows the integration of control and elimination programs for different pathogens. Parasitic worms and Plasmodium falciparum, the causal agent of malaria, are among the most relevant parasitic diseases of our time and efforts are under way for their control and, ultimately, elimination. An accurate diagnosis is relevant for case management, but also allows calculating the prevalence and evaluating the effectiveness of treatment and control measures. Unfortunately, current diagnostic methods for parasitic worms are not optimal and many infections remain undetected. As for P. falciparum, current diagnostic techniques are satisfactory but do not allow for ascertaining exposure, which is relevant for evaluating control measures. Here we investigated the utility of measuring antibodies to these parasites as a diagnostic method. Our results indicate that it is possible to detect current infection with parasitic worms and P. falciparum using antibody detection with a moderate to high accuracy. We also show that antibodies against the antigens in this study have potential as markers of exposure. Importantly, we used a platform that allows for the simultaneous detection of immunoglobulins to different parasites, which would be extremely useful as a tool to integrate control and elimination programs for several pathogens.
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Affiliation(s)
- Rebeca Santano
- ISGlobal, Hospital Clínic—Universitat de Barcelona, Barcelona, Spain
- * E-mail: (RS); (CD); (GM)
| | - Rocío Rubio
- ISGlobal, Hospital Clínic—Universitat de Barcelona, Barcelona, Spain
| | - Berta Grau-Pujol
- ISGlobal, Hospital Clínic—Universitat de Barcelona, Barcelona, Spain
- Centro de Investigação em Saúde de Manhiça (CISM), Maputo, Mozambique
- Fundación Mundo Sano, Buenos Aires, Argentina
| | - Valdemiro Escola
- Centro de Investigação em Saúde de Manhiça (CISM), Maputo, Mozambique
| | - Osvaldo Muchisse
- Centro de Investigação em Saúde de Manhiça (CISM), Maputo, Mozambique
| | - Inocência Cuamba
- Centro de Investigação em Saúde de Manhiça (CISM), Maputo, Mozambique
| | - Marta Vidal
- ISGlobal, Hospital Clínic—Universitat de Barcelona, Barcelona, Spain
| | - Gemma Ruiz-Olalla
- ISGlobal, Hospital Clínic—Universitat de Barcelona, Barcelona, Spain
| | - Ruth Aguilar
- ISGlobal, Hospital Clínic—Universitat de Barcelona, Barcelona, Spain
| | - Javier Gandasegui
- ISGlobal, Hospital Clínic—Universitat de Barcelona, Barcelona, Spain
| | - Maria Demontis
- Department of Parasitology, Centre of Infectious Diseases, Leiden University Medical Centre (LUMC), Leiden, The Netherlands
| | | | - Anélsio Cossa
- Centro de Investigação em Saúde de Manhiça (CISM), Maputo, Mozambique
| | - Charfudin Sacoor
- Centro de Investigação em Saúde de Manhiça (CISM), Maputo, Mozambique
| | - Jorge Cano
- Communicable and Non-communicable Diseases Cluster (UCN), WHO Regional Office for Africa, Brazzaville, Republic of Congo
| | - Luis Izquierdo
- ISGlobal, Hospital Clínic—Universitat de Barcelona, Barcelona, Spain
- CIBER de Enfermedades Infecciosas (CIBERINFEC), Barcelona, Spain
| | - Chetan E. Chitnis
- Malaria Parasite Biology and Vaccines Unit, Department of Parasites and Insect Vectors, Institut Pasteur, Université de Paris, Paris, France
| | - Ross L. Coppel
- Department of Microbiology, Faculty of Medicine, Nursing and Health Sciences, Monash University, Melbourne, Australia
| | - Virander Chauhan
- Malaria Group, International Centre for Genetic Engineering and Biotechnology (ICGEB), New Delhi, India
| | - David Cavanagh
- Institute of Immunology and Infection Research, University of Edinburgh, Edinburgh, United Kingdom
| | - Sheetij Dutta
- Walter Reed Army Institute of Research (WRAIR), Silver Spring, Maryland, United States of America
| | - Evelina Angov
- Walter Reed Army Institute of Research (WRAIR), Silver Spring, Maryland, United States of America
| | - Lisette van Lieshout
- Department of Parasitology, Centre of Infectious Diseases, Leiden University Medical Centre (LUMC), Leiden, The Netherlands
| | - Bin Zhan
- Baylor College of Medicine (BCM), Houston, Texas, United States of America
| | - José Muñoz
- ISGlobal, Hospital Clínic—Universitat de Barcelona, Barcelona, Spain
- CIBER de Enfermedades Infecciosas (CIBERINFEC), Barcelona, Spain
| | - Carlota Dobaño
- ISGlobal, Hospital Clínic—Universitat de Barcelona, Barcelona, Spain
- CIBER de Enfermedades Infecciosas (CIBERINFEC), Barcelona, Spain
- * E-mail: (RS); (CD); (GM)
| | - Gemma Moncunill
- ISGlobal, Hospital Clínic—Universitat de Barcelona, Barcelona, Spain
- CIBER de Enfermedades Infecciosas (CIBERINFEC), Barcelona, Spain
- * E-mail: (RS); (CD); (GM)
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Abstract
Trachoma is a neglected tropical disease caused by infection with conjunctival strains of Chlamydia trachomatis. It can result in blindness. Pathophysiologically, trachoma is a disease complex composed of two linked chronic processes: a recurrent, generally subclinical infectious-inflammatory disease that mostly affects children, and a non-communicable, cicatricial and, owing to trichiasis, eventually blinding disease that supervenes in some individuals later in life. At least 150 infection episodes over an individual's lifetime are needed to precipitate trichiasis; thus, opportunity exists for a just global health system to intervene to prevent trachomatous blindness. Trachoma is found at highest prevalence in the poorest communities of low-income countries, particularly in sub-Saharan Africa; in June 2021, 1.8 million people worldwide were going blind from the disease. Blindness attributable to trachoma can appear in communities many years after conjunctival C. trachomatis transmission has waned or ceased; therefore, the two linked disease processes require distinct clinical and public health responses. Surgery is offered to individuals with trichiasis and antibiotic mass drug administration and interventions to stimulate facial cleanliness and environmental improvement are designed to reduce infection prevalence and transmission. Together, these interventions comprise the SAFE strategy, which is achieving considerable success. Although much work remains, a continuing public health problem from trachoma in the year 2030 will be difficult for the world to excuse.
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Hammou J, Guagliardo SAJ, Obtel M, Razine R, Haroun AE, Youbi M, Bellefquih AM, White M, Gwyn S, Martin DL. Post-Validation Survey in Two Districts of Morocco after the Elimination of Trachoma as a Public Health Problem. Am J Trop Med Hyg 2022; 106:tpmd211140. [PMID: 35344929 PMCID: PMC9128706 DOI: 10.4269/ajtmh.21-1140] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2021] [Accepted: 01/16/2022] [Indexed: 11/07/2022] Open
Abstract
Trachoma is the leading infectious cause of blindness. In 2016, Morocco was validated by WHO as having eliminated trachoma as a public health problem. We evaluated two previously endemic districts in Morocco for trachomatous inflammation-follicular (TF), trachomatous trichiasis (TT), and antibodies against Chlamydia trachomatis, the causative agent of trachoma. Community-based cross-sectional surveys in the districts of Boumalene Dades and Agdez included 4,445 participants for whom both questionnaire and serology data were available; 58% were aged 1-9 years. Participants had eyes examined for TF and blood collected for analysis of antibodies to the C. trachomatis antigen Pgp3 by both a multiplex bead assay (MBA) and lateral flow assay (LFA). Seroconversion rates (SCR) per 100 people per year were used to estimate changes in the force of infection using Bayesian serocatalytic models. In Agdez, TF prevalence in 1-9-year-olds was 0.3%, seroprevalence ranged from 9.4% to 11.4%, and SCR estimates ranged from 2.4 to 3.0. In Boumalene Dades, TF prevalence in 1-9-year-olds was 0.07%, and modeling data from the different assays indicated a decrease in transmission between 20 and 24 years ago. The TF data support an absence of active trachoma in the two districts examined. However, seroprevalence and SCR in younger people were higher in Agdez than Boumalene Dades, showing that there can be differences in serology metrics in areas with similar TF prevalence. Data will be included in multicountry analyses to better understand potential thresholds for serological surveillance in trachoma.
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Affiliation(s)
- Jaouad Hammou
- Faculty of Medicine and Pharmacy of Rabat, Mohammed V University, Rabat, Morocco
| | - Sarah Anne J. Guagliardo
- Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, Atlanta, Georgia
| | - Majdouline Obtel
- Laboratory of Biostatistics, Clinical Research and Epidemiology, Department of Public Health, Faculty of Medicine and Pharmacy of Rabat, Mohammed V University, Rabat, Morocco
- Laboratory of Community Heath (Public Health, Preventive Medicine and Hygiene), Department of Public Health, Faculty of Medicine and Pharmacy, University Mohammed V, Rabat, Morocco
| | - Rachid Razine
- Laboratory of Biostatistics, Clinical Research and Epidemiology, Department of Public Health, Faculty of Medicine and Pharmacy of Rabat, Mohammed V University, Rabat, Morocco
- Laboratory of Community Heath (Public Health, Preventive Medicine and Hygiene), Department of Public Health, Faculty of Medicine and Pharmacy, University Mohammed V, Rabat, Morocco
| | - Abbas Ermilo Haroun
- Laboratory of Biostatistics, Clinical Research and Epidemiology, Department of Public Health, Faculty of Medicine and Pharmacy of Rabat, Mohammed V University, Rabat, Morocco
- Laboratory of Community Heath (Public Health, Preventive Medicine and Hygiene), Department of Public Health, Faculty of Medicine and Pharmacy, University Mohammed V, Rabat, Morocco
| | - Mohamed Youbi
- Directorate of Epidemiology and Disease Control, Ministry of Health, Rabat, Morocco
| | | | - Michael White
- Infectious Disease Epidemiology and Analytics Unit, Department of Global Health, Institute Pasteur, Paris, France
| | - Sarah Gwyn
- Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, Atlanta, Georgia
| | - Diana L. Martin
- Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, Atlanta, Georgia
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Fornace KM, Senyonjo L, Martin DL, Gwyn S, Schmidt E, Agyemang D, Marfo B, Addy J, Mensah E, Solomon AW, Bailey R, Drakeley CJ, Pullan RL. Characterising spatial patterns of neglected tropical disease transmission using integrated sero-surveillance in Northern Ghana. PLoS Negl Trop Dis 2022; 16:e0010227. [PMID: 35259153 PMCID: PMC8932554 DOI: 10.1371/journal.pntd.0010227] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2021] [Revised: 03/18/2022] [Accepted: 02/03/2022] [Indexed: 11/18/2022] Open
Abstract
Background
As prevalence decreases in pre-elimination settings, identifying the spatial distribution of remaining infections to target control measures becomes increasingly challenging. By measuring multiple antibody responses indicative of past exposure to different pathogens, integrated serological surveys enable simultaneous characterisation of residual transmission of multiple pathogens.
Methodology/Principal findings
Here, we combine integrated serological surveys with geostatistical modelling and remote sensing-derived environmental data to estimate the spatial distribution of exposure to multiple diseases in children in Northern Ghana. The study utilised the trachoma surveillance survey platform (cross-sectional two-stage cluster-sampled surveys) to collect information on additional identified diseases at different stages of elimination with minimal additional cost. Geostatistical modelling of serological data allowed identification of areas with high probabilities of recent exposure to diseases of interest, including areas previously unknown to control programmes. We additionally demonstrate how serological surveys can be used to identify areas with exposure to multiple diseases and to prioritise areas with high uncertainty for future surveys. Modelled estimates of cluster-level prevalence were strongly correlated with more operationally feasible metrics of antibody responses.
Conclusions/Significance
This study demonstrates the potential of integrated serological surveillance to characterise spatial distributions of exposure to multiple pathogens in low transmission and elimination settings when the probability of detecting infections is low.
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Affiliation(s)
- Kimberly M. Fornace
- Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom
- Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Glasgow, United Kingdom
- * E-mail:
| | - Laura Senyonjo
- Research Team, Sightsavers UK, Haywards Heath, United Kingdom
| | - Diana L. Martin
- Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America
| | - Sarah Gwyn
- Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America
| | - Elena Schmidt
- Research Team, Sightsavers UK, Haywards Heath, United Kingdom
| | | | - Benjamin Marfo
- Neglected Tropical Disease Team, Ghana Health Service, Accra, Ghana
| | - James Addy
- Neglected Tropical Disease Team, Ghana Health Service, Accra, Ghana
| | | | - Anthony W. Solomon
- Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom
- Department of Control of Neglected Tropical Diseases, World Health Organization, Geneva, Switzerland
| | - Robin Bailey
- Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Chris J. Drakeley
- Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Rachel L. Pullan
- Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom
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Senyonjo L, Addy J, Martin DL, Agyemang D, Yeboah-Manu D, Gwyn S, Marfo B, Asante-Poku A, Aboe A, Mensah E, Solomon AW, Bailey RL. Surveillance for peri-elimination trachoma recrudescence: Exploratory studies in Ghana. PLoS Negl Trop Dis 2021; 15:e0009744. [PMID: 34543293 PMCID: PMC8519445 DOI: 10.1371/journal.pntd.0009744] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2021] [Revised: 10/15/2021] [Accepted: 08/18/2021] [Indexed: 11/26/2022] Open
Abstract
Introduction To date, eleven countries have been validated as having eliminated trachoma as a public health problem, including Ghana in 2018. Surveillance for recrudescence is needed both pre- and post-validation but evidence-based guidance on appropriate strategies is lacking. We explored two potential surveillance strategies in Ghana. Methodology/principal findings Amongst randomly-selected communities enrolled in pre-validation on-going surveillance between 2011 and 2015, eight were identified as having had trachomatous-inflammation follicular (TF) prevalence ≥5% in children aged 1–9 years between 2012 and 2014. These eight were re-visited in 2015 and 2016 and neighbouring communities were also added (“TF trigger” investigations). Resident children aged 1–9 years were then examined for trachoma and had a conjunctival swab to test for Chlamydia trachomatis (Ct) and a dried blood spot (DBS) taken to test for anti-Pgp3 antibodies. These investigations identified at least one community with evidence of probable recent Ct ocular transmission. However, the approach likely lacks sufficient spatio-temporal power to be reliable. A post-validation surveillance strategy was also evaluated, this reviewed the ocular Ct infection and anti-Pgp3 seroprevalence data from the TF trigger investigations and from the pre-validation surveillance surveys in 2015 and 2016. Three communities identified as having ocular Ct infection >0% and anti-Pgp3 seroprevalence ≥15.0% were identified, and along with three linked communities, were followed-up as part of the surveillance strategy. An additional three communities with a seroprevalence ≥25.0% but no Ct infection were also followed up (“antibody and infection trigger” investigations). DBS were taken from all residents aged ≥1 year and ocular swabs from all children aged 1–9 years. There was evidence of transmission in the group of communities visited in one district (Zabzugu-Tatale). There was no or little evidence of continued transmission in other districts, suggesting previous infection identified was transient or potentially not true ocular Ct infection. Conclusions/significance There is evidence of heterogeneity in Ct transmission dynamics in northern Ghana, even 10 years after wide-scale MDA has stopped. There is added value in monitoring Ct infection and anti-Ct antibodies, using these indicators to interrogate past or present surveillance strategies. This can result in a deeper understanding of transmission dynamics and inform new post-validation surveillance strategies. Opportunities should be explored for integrating PCR and serological-based markers into surveys conducted in trachoma elimination settings. The goal for trachoma programmes is elimination of trachoma as a public health problem. This means that ongoing low-level eye-to-eye transmission of the causative bacterium, Chlamydia trachomatis (Ct), is acceptable. Countries need to implement a suitable surveillance system to identify any return to higher transmission levels. The best methodology for doing this is not known. We first explored the approach used by Ghana in its standard programme, which involved monitoring a limited number of randomly selected communities for evidence of active (inflammatory) trachoma visible in children’s eyes on examination by trained observers. Although this strategy led to identification of at least one community that had probably had recent Ct transmission, the approach is unlikely to consistently identify places where return to higher levels of transmission is a risk. We also explored using information on infection (detected in eye swabs) and antibodies to Ct (detected in the blood) to identify communities at risk. We found evidence of both persistent eye-to-eye Ct transmission and areas where infection was transient and has now gone away. We conclude that the use of infection and antibody data for surveillance of trachoma appears promising.
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Affiliation(s)
- Laura Senyonjo
- Research Team, Sightsavers, Haywards Heath, United Kingdom
- Clinical Research Department, London School of Hygiene & Tropical Medicine, London, United Kingdom
- * E-mail:
| | - James Addy
- Eye Health Department, Ghana Health Service, Accra, Ghana
| | - Diana L. Martin
- Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, Atlanta, United States of America
| | | | - Dorothy Yeboah-Manu
- Bacteriology Department, Noguchi Memorial Institute for Medical Research, Accra, Ghana
| | - Sarah Gwyn
- Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, Atlanta, United States of America
| | - Benjamin Marfo
- Neglected Tropical Diseases Division, Ghana Health Service, Accra, Ghana
| | - Adwoa Asante-Poku
- Bacteriology Department, Noguchi Memorial Institute for Medical Research, Accra, Ghana
| | | | | | - Anthony W. Solomon
- Clinical Research Department, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Robin L. Bailey
- Clinical Research Department, London School of Hygiene & Tropical Medicine, London, United Kingdom
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16
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Oldenburg CE, Aragie S, Amza A, Solomon AW, Brogdon J, Arnold BF, Keenan JD, Lietman TM. Can we eradicate trachoma? A survey of stakeholders. Br J Ophthalmol 2021; 105:1059-1062. [PMID: 32855161 PMCID: PMC8311100 DOI: 10.1136/bjophthalmol-2020-315815] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2020] [Revised: 07/25/2020] [Accepted: 07/27/2020] [Indexed: 12/02/2022]
Abstract
BACKGROUND/AIMS Although tremendous progress towards the 2020 goal of global elimination of trachoma as a public health problem has been made, it will not be achieved. Future targets are now being considered. One option is changing the goal to eradication. We surveyed trachoma experts to assess beliefs related to trachoma eradication and determine perceived obstacles to achieving it. METHODS We conducted a survey at the beginning of a trachoma eradication session at the 2019 Coalition for Operational Research on Neglected Tropical Diseases meeting in National Harbor, Maryland, USA. We asked respondents what the most important goal of azithromycin mass drug administration was for trachoma (control, elimination of infection or eradication) and if and when they believed trachoma eradication would occur. We then asked what the biggest obstacles were to global eradication. RESULTS Fifty-six surveys were returned (95%). Most (91%) participants reported that the most important goal of azithromycin mass drug administration was control or elimination of infection, and 24% of participants reported that global eradication was not possible. Of the 76% who reported a year by which they believed trachoma could be eradicated, most fell between 2040 and 2050. Commonly cited barriers to global eradication included lack of surveillance tools to confirm eradication or monitor for infection recrudescence (32%) and lack of resources (23%). CONCLUSIONS Development of alternative indicators for trachoma surveillance and continued investment in trachoma programmes, particularly focused support in the most heavily affected populations, might increase enthusiasm for the feasibility of eradication.
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Affiliation(s)
- Catherine E Oldenburg
- Department of Ophthalmology, University of California, San Francisco, California, USA
- Department of Epidemiology and Biostatistics, University of California, San Francisco, California, USA
| | | | - Abdou Amza
- Faculté Des Sciences De La Santé, Université Abdou Moumouni De Niamey, Niamey, Niger
- Programme National De Santé Oculaire, Niamey, Niger
| | - Anthony W Solomon
- Department of Control of Neglected Tropical Diseases, World Health Organization, Geneva, Switzerland
| | - Jessica Brogdon
- F.I. Proctor Foundation, University of California, San Francisco, California, USA
| | - Benjamin F Arnold
- Department of Ophthalmology, University of California, San Francisco, California, USA
- F.I. Proctor Foundation, University of California, San Francisco, California, USA
| | - Jeremy D Keenan
- Department of Ophthalmology, University of California, San Francisco, California, USA
- Department of Epidemiology and Biostatistics, University of California, San Francisco, California, USA
- F.I. Proctor Foundation, University of California, San Francisco, California, USA
| | - Thomas M Lietman
- Department of Ophthalmology, University of California, San Francisco, California, USA
- Department of Epidemiology and Biostatistics, University of California, San Francisco, California, USA
- F.I. Proctor Foundation, University of California, San Francisco, California, USA
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17
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Danavall DC, Gwyn S, Anyalechi GE, Bowden KE, Hong J, Kirkcaldy RD, Bernstein KT, Kersh EN, Martin D, Raphael BH. Assessment and utility of 2 Chlamydia trachomatis Pgp3 serological assays for seroprevalence studies among women in the United States. Diagn Microbiol Infect Dis 2021; 101:115480. [PMID: 34325205 DOI: 10.1016/j.diagmicrobio.2021.115480] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2021] [Revised: 06/29/2021] [Accepted: 07/01/2021] [Indexed: 11/27/2022]
Abstract
Two plasmid gene protein (Pgp3)-based serological assays, the Pgp3-ELISA and multiplex bead assay (Pgp3-MBA), were compared and used to estimate seropositivity of Chlamydia trachomatis (CT) among females 14 to 39 years old participating in the National Health and Nutrition Examination Survey between 2013-2016. Of the 2,201 specimens tested, 502 (29.5%, 95% CI 27.6-31.5) were positive using Pgp3-ELISA and 624 (28.4%, 95% CI 26.5-30.3) were positive using Pgp3-MBA. The overall agreement between the assays was 87.7%. Corresponding nucleic acid amplification test (NAAT) results were available for 1,725 specimens (from women 18-39 years old); of these, 42 (2.4%, 95% CI 1.8-3.3) were CT NAAT-positive. Most of the CT NAAT-positive specimens had corresponding positive serological assay results; 33 (78.6%, 95% CI 62.8-89.2) were Pgp3-ELISA-positive and 36 (85.7%, 95% CI 70.8-94.1) were Pgp3-MBA-positive. Although Pgp3-ELISA and Pgp3-MBA demonstrated equivalent performance in this study, an advantage of the Pgp3-MBA over Pgp3-ELISA is that it is well suited for high sample throughput applications.
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Affiliation(s)
- Damien C Danavall
- Division of STD Prevention, Centers for Disease Control and Prevention, Atlanta, GA, USA.
| | - Sarah Gwyn
- Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - Gloria E Anyalechi
- Division of STD Prevention, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - Katherine E Bowden
- Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - Jaeyoung Hong
- Division of STD Prevention, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - Robert D Kirkcaldy
- Division of STD Prevention, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - Kyle T Bernstein
- Division of STD Prevention, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - Ellen N Kersh
- Division of STD Prevention, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - Diana Martin
- Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - Brian H Raphael
- Division of STD Prevention, Centers for Disease Control and Prevention, Atlanta, GA, USA
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18
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Hatherell HA, Simpson H, Baggaley RF, Hollingsworth TD, Pullan RL. Sustainable Surveillance of Neglected Tropical Diseases for the Post-Elimination Era. Clin Infect Dis 2021; 72:S210-S216. [PMID: 33977302 PMCID: PMC8201586 DOI: 10.1093/cid/ciab211] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
The World Health Organization’s (WHO’s) 2030 road map for neglected tropical diseases (NTDs) emphasizes the importance of strengthened, institutionalized “post-elimination” surveillance. The required shift from disease-siloed, campaign-based programming to routine, integrated surveillance and response activities presents epidemiological, logistical, and financial challenges, yet practical guidance on implementation is lacking. Nationally representative survey programs, such as demographic and health surveys (DHS), may offer a platform for the integration of NTD surveillance within national health systems and health information systems. Here, we describe characteristics of DHS and other surveys conducted within the WHO Africa region in terms of frequency, target populations, and sample types and discuss applicability for post-validation and post-elimination surveillance. Maximizing utility depends not only on the availability of improved diagnostics but also on better understanding of the spatial and temporal dynamics of transmission at low prevalence. To this end, we outline priorities for obtaining additional data to better characterize optimal post-elimination surveillance platforms.
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Affiliation(s)
- Hollie-Ann Hatherell
- Department of Disease Control, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Hope Simpson
- Department of Disease Control, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Rebecca F Baggaley
- Department of Respiratory Sciences, University of Leicester, Leicester, United Kingdom
| | | | - Rachel L Pullan
- Department of Disease Control, London School of Hygiene and Tropical Medicine, London, United Kingdom
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19
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Determining seropositivity-A review of approaches to define population seroprevalence when using multiplex bead assays to assess burden of tropical diseases. PLoS Negl Trop Dis 2021; 15:e0009457. [PMID: 34181665 PMCID: PMC8270565 DOI: 10.1371/journal.pntd.0009457] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2020] [Revised: 07/09/2021] [Accepted: 05/10/2021] [Indexed: 11/19/2022] Open
Abstract
Background Serological surveys with multiplex bead assays can be used to assess seroprevalence to multiple pathogens simultaneously. However, multiple methods have been used to generate cut-off values for seropositivity and these may lead to inconsistent interpretation of results. A literature review was conducted to describe the methods used to determine cut-off values for data generated by multiplex bead assays. Methodology/Principal findings A search was conducted in PubMed that included articles published from January 2010 to January 2020, and 308 relevant articles were identified that included the terms “serology”, “cut-offs”, and “multiplex bead assays”. After application of exclusion of articles not relevant to neglected tropical diseases (NTD), vaccine preventable diseases (VPD), or malaria, 55 articles were examined based on their relevance to NTD or VPD. The most frequently applied approaches to determine seropositivity included the use of presumed unexposed populations, mixture models, receiver operating curves (ROC), and international standards. Other methods included the use of quantiles, pre-exposed endemic cohorts, and visual inflection points. Conclusions/Significance For disease control programmes, seropositivity is a practical and easily interpretable health metric but determining appropriate cut-offs for positivity can be challenging. Considerations for optimal cut-off approaches should include factors such as methods recommended by previous research, transmission dynamics, and the immunological backgrounds of the population. In the absence of international standards for estimating seropositivity in a population, the use of consistent methods that align with individual disease epidemiological data will improve comparability between settings and enable the assessment of changes over time. Serological surveys can provide information regarding population-level disease exposure by assessing immune responses created during infection. Multiplex bead assays (MBAs) allow for an integrated serological platform to monitor antibody responses to multiple pathogens concurrently. As programs adopt integrated disease control strategies, MBAs are especially advantageous since many of these diseases may be present in the same population and antibodies against all pathogens of interest can be detected simultaneously from a single blood sample. Interpreting serological data in a programmatic context typically involves classifying individuals as seronegative or seropositive using a ‘cut-off’, whereby anyone with a response above the defined threshold is considered to be seropositive. Although studies increasingly test blood samples with MBAs, published studies have applied different methods of determining seropositivity cut-offs, making results difficult to compare across settings and over time. The lack of harmonized methods for defining seropositivity is due to the absence of international standards, pathogen biology, or assay-specific methods that may impact resulting data. This review highlights the need for a standardized approach for which cut-off methods to use per pathogen when applied to integrated disease surveillance using platforms such as MBAs.
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20
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Cooley GM, Feldstein LR, Bennett SD, Estivariz CF, Weil L, Bohara R, Vandenent M, Mainul Hasan A, Akhtar MS, Uzzaman MS, Billah MM, Conklin L, Ehlman DC, Asiedu K, Solomon AW, Alamgir A, Flora MS, Martin DL. No Serological Evidence of Trachoma or Yaws Among Residents of Registered Camps and Makeshift Settlements in Cox's Bazar, Bangladesh. Am J Trop Med Hyg 2021; 104:2031-2037. [PMID: 33939630 PMCID: PMC8176462 DOI: 10.4269/ajtmh.21-0124] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2021] [Accepted: 03/16/2021] [Indexed: 12/03/2022] Open
Abstract
Successful achievement of global targets for elimination of trachoma as a public health problem and eradication of yaws will require control efforts to reach marginalized populations, including refugees. Testing for serologic evidence of transmission of trachoma and yaws in residents of registered camps and a Makeshift Settlement in Cox’s Bazar District, Bangladesh, was added to a serosurvey for vaccine-preventable diseases (VPDs) conducted April–May 2018. The survey was primarily designed to estimate remaining immunity gaps for VPDs, including diphtheria, measles, rubella, and polio. Blood specimens from 1- to 14-year-olds from selected households were collected and tested for antibody responses against antigens from Treponema pallidum and Chlamydia trachomatis using a multiplex bead assay to evaluate for serologic evidence of the neglected tropical diseases (NTDs) yaws and trachoma, respectively. The prevalence of antibodies against two C. trachomatis antigens in children ranged from 1.4% to 1.5% for Pgp3 and 2.8% to 7.0% for CT694. The prevalence of antibody responses against both of two treponemal antigens (recombinant protein17 and treponemal membrane protein A) tested was 0% to 0.15% in two camps. The data are suggestive of very low or no transmission of trachoma and yaws, currently or previously, in children resident in these communities. This study illustrates how integrated serologic testing can provide needed data to help NTD programs prioritize limited resources.
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Affiliation(s)
- Gretchen M Cooley
- 1Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, Atlanta, Georgia
| | - Leora R Feldstein
- 2Epidemic Intelligence Service, Centers for Disease Control and Prevention, Atlanta, Georgia.,3Global Immunization Division, Centers for Disease Control and Prevention, Atlanta, Georgia
| | - Sarah D Bennett
- 3Global Immunization Division, Centers for Disease Control and Prevention, Atlanta, Georgia
| | - Concepcion F Estivariz
- 3Global Immunization Division, Centers for Disease Control and Prevention, Atlanta, Georgia
| | - Lauren Weil
- 4National Center for Immunization and Respiratory Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia
| | | | | | | | | | - M Salim Uzzaman
- 8Institute of Epidemiology, Disease Control and Research, Dhaka, Bangladesh
| | | | - Laura Conklin
- 3Global Immunization Division, Centers for Disease Control and Prevention, Atlanta, Georgia
| | - Daniel C Ehlman
- 3Global Immunization Division, Centers for Disease Control and Prevention, Atlanta, Georgia
| | | | | | - Asm Alamgir
- 8Institute of Epidemiology, Disease Control and Research, Dhaka, Bangladesh
| | | | - Diana L Martin
- 1Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, Atlanta, Georgia
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21
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Comparison of platforms for testing antibodies to Chlamydia trachomatis antigens in the Democratic Republic of the Congo and Togo. Sci Rep 2021; 11:7225. [PMID: 33790370 PMCID: PMC8012353 DOI: 10.1038/s41598-021-86639-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2020] [Accepted: 03/08/2021] [Indexed: 11/27/2022] Open
Abstract
Trachoma, caused by repeated ocular infection with Chlamydia trachomatis (Ct), is targeted for elimination as a public health problem. Serological testing for antibodies is promising for surveillance; determining useful thresholds will require collection of serological data from settings with different prevalence of the indicator trachomatous inflammation—follicular (TF). Dried blood spots were collected during trachoma mapping in two districts each of Togo and Democratic Republic of the Congo. Anti-Ct antibodies were detected by multiplex bead assay (MBA) and three different lateral flow assays (LFA) and seroprevalence and seroconversion rate (SCR) were determined. By most tests, the district with > 5% TF (the elimination threshold) had five–sixfold higher seroprevalence and tenfold higher SCR than districts with < 5% TF. The agreement between LFA and MBA was improved using a black latex developing reagent. These data show optimization of antibody tests against Ct to better differentiate districts above or below trachoma elimination thresholds.
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22
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Insights from mathematical modelling and quantitative analysis on the proposed 2030 goals for trachoma. Gates Open Res 2021; 3:1721. [PMID: 34027309 PMCID: PMC8111938 DOI: 10.12688/gatesopenres.13086.2] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/04/2021] [Indexed: 01/21/2023] Open
Abstract
Trachoma is a neglected tropical disease and the leading infectious cause of blindness worldwide. The current World Health Organization goal for trachoma is elimination as a public health problem, defined as reaching a prevalence of trachomatous inflammation-follicular below 5% in children (1-9 years) and a prevalence of trachomatous trichiasis in adults below 0.2%. Current targets to achieve elimination were set to 2020 but are being extended to 2030. Mathematical and statistical models suggest that 2030 is a realistic timeline for elimination as a public health problem in most trachoma endemic areas. Although the goal can be achieved, it is important to develop appropriate monitoring tools for surveillance after having achieved the elimination target to check for the possibility of resurgence. For this purpose, a standardized serological approach or the use of multiple diagnostics in complement would likely be required.
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23
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Insights from mathematical modelling and quantitative analysis on the proposed 2030 goals for trachoma. Gates Open Res 2021; 3:1721. [PMID: 34027309 DOI: 10.12688/gatesopenres.13086.1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/12/2019] [Indexed: 11/20/2022] Open
Abstract
Trachoma is a neglected tropical disease and the leading infectious cause of blindness worldwide. The current World Health Organization goal for trachoma is elimination as a public health problem, defined as reaching a prevalence of trachomatous inflammation-follicular below 5% in children (1-9 years) and a prevalence of trachomatous trichiasis in adults below 0.2%. Current targets to achieve elimination were set to 2020 but are being extended to 2030. Mathematical and statistical models suggest that 2030 is a realistic timeline for elimination as a public health problem in most trachoma endemic areas. Although the goal can be achieved, it is important to develop appropriate monitoring tools for surveillance after having achieved the elimination target to check for the possibility of resurgence. For this purpose, a standardized serological approach or the use of multiple diagnostics in complement would likely be required.
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24
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Nash SD, Astale T, Nute AW, Bethea D, Chernet A, Sata E, Zerihun M, Gessese D, Ayenew G, Ayele Z, Melak B, Haile M, Zeru T, Tadesse Z, Arnold BF, Callahan EK, Martin DL. Population-Based Prevalence of Chlamydia trachomatis Infection and Antibodies in Four Districts with Varying Levels of Trachoma Endemicity in Amhara, Ethiopia. Am J Trop Med Hyg 2021; 104:207-215. [PMID: 33200728 PMCID: PMC7790060 DOI: 10.4269/ajtmh.20-0777] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
The Trachoma Control Program in Amhara region, Ethiopia, scaled up the surgery, antibiotics, facial cleanliness, and environmental improvement (SAFE) strategy in all districts starting in 2007. Despite these efforts, many districts still require additional years of SAFE. In 2017, four districts were selected for the assessment of antibody responses against Chlamydia trachomatis antigens and C. trachomatis infection to better understand transmission. Districts with differing endemicity were chosen, whereby one had a previous trachomatous inflammation-follicular (TF) prevalence of ≥ 30% (Andabet), one had a prevalence between 10% and 29.9% (Dera), one had a prevalence between 5% and 10% (Woreta town), and one had a previous TF prevalence of < 5% (Alefa) and had not received antibiotic intervention for 2 years. Survey teams assessed trachoma clinical signs and took conjunctival swabs and dried blood spots (DBS) to measure infection and antibody responses. Trachomatous inflammation-follicular prevalence among children aged 1–9 years was 37.0% (95% CI: 31.1–43.3) for Andabet, 14.7% (95% CI: 10.0–20.5) for Dera, and < 5% for Woreta town and Alefa. Chlamydia trachomatis infection was only detected in Andabet (11.3%). Within these districts, 2,195 children provided DBS. The prevalence of antibody responses to the antigen Pgp3 was 36.9% (95% CI: 29.0–45.6%) for Andabet, 11.3% (95% CI: 5.9–20.6%) for Dera, and < 5% for Woreta town and Alefa. Seroconversion rate for Pgp3 in Andabet was 0.094 (95% CI: 0.069–0.128) events per year. In Andabet district, where SAFE implementation has occurred for 11 years, the antibody data support the finding of persistently high levels of trachoma transmission.
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Affiliation(s)
- Scott D Nash
- 1Trachoma Control Program, The Carter Center, Atlanta, Georgia
| | - Tigist Astale
- 2Trachoma Control Program, The Carter Center, Addis Ababa, Ethiopia
| | - Andrew W Nute
- 1Trachoma Control Program, The Carter Center, Atlanta, Georgia
| | - Danaya Bethea
- 3Centers for Disease Control and Prevention, DPD, Atlanta, Georgia
| | - Ambahun Chernet
- 2Trachoma Control Program, The Carter Center, Addis Ababa, Ethiopia
| | - Eshetu Sata
- 2Trachoma Control Program, The Carter Center, Addis Ababa, Ethiopia
| | - Mulat Zerihun
- 2Trachoma Control Program, The Carter Center, Addis Ababa, Ethiopia
| | - Demelash Gessese
- 2Trachoma Control Program, The Carter Center, Addis Ababa, Ethiopia
| | - Gedefaw Ayenew
- 2Trachoma Control Program, The Carter Center, Addis Ababa, Ethiopia
| | - Zebene Ayele
- 2Trachoma Control Program, The Carter Center, Addis Ababa, Ethiopia
| | - Berhanu Melak
- 2Trachoma Control Program, The Carter Center, Addis Ababa, Ethiopia
| | - Mahteme Haile
- 4Amhara Public Health Institute, Research and Technology Transfer Directorate, Bahir Dar, Ethiopia
| | - Taye Zeru
- 4Amhara Public Health Institute, Research and Technology Transfer Directorate, Bahir Dar, Ethiopia
| | - Zerihun Tadesse
- 2Trachoma Control Program, The Carter Center, Addis Ababa, Ethiopia
| | - Benjamin F Arnold
- 5Francis I. Proctor Foundation, University of California San Francisco, San Francisco, California.,6Department of Ophthalmology, University of California San Francisco, San Francisco, California
| | | | - Diana L Martin
- 3Centers for Disease Control and Prevention, DPD, Atlanta, Georgia
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25
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Macleod CK, Butcher R, Javati S, Gwyn S, Jonduo M, Abdad MY, Roberts CH, Keys D, Koim SP, Ko R, Garap J, Pahau D, Houinei W, Martin DL, Pomat WS, Solomon AW. Trachoma, Anti-Pgp3 Serology, and Ocular Chlamydia trachomatis Infection in Papua New Guinea. Clin Infect Dis 2021; 72:423-430. [PMID: 31965155 PMCID: PMC7850549 DOI: 10.1093/cid/ciaa042] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2019] [Accepted: 01/19/2020] [Indexed: 11/17/2022] Open
Abstract
BACKGROUND In Melanesia, the prevalence of trachomatous inflammation-follicular (TF) suggests that public health-level interventions against active trachoma are needed. However, the prevalence of trachomatous trichiasis is below the threshold for elimination as a public health problem and evidence of conjunctival infection with trachoma's causative organism (Chlamydia trachomatis [CT]) is rare. Here, we examine the prevalence of ocular infection with CT and previous exposure to CT in three evaluation units (EUs) of Papua New Guinea. METHODS All individuals aged 1-9 years who were examined for clinical signs of trachoma in 3 Global Trachoma Mapping Project EUs were eligible to take part in this study (N = 3181). Conjunctival swabs were collected from 349 children with TF and tested by polymerase chain reaction to assess for ocular CT infection. Dried blood spots were collected from 2572 children and tested for anti-Pgp3 antibodies using a multiplex assay. RESULTS The proportion of children with TF who had CT infection was low across all 3 EUs (overall 2%). Anti-Pgp3 seroprevalence was 5.2% overall and there was no association between anti-Pgp3 antibody level and presence of TF. In 2 EUs, age-specific seroprevalence did not increase significantly with increasing age in the 1- to 9-year-old population. In the third EU, there was a statistically significant change with age but the overall seroprevalence and peak age-specific seroprevalence was very low. CONCLUSIONS Based on these results, together with similar findings from the Solomon Islands and Vanuatu, the use of TF to guide antibiotic mass drug administration decisions in Melanesia should be reviewed.
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Affiliation(s)
- Colin K Macleod
- London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Robert Butcher
- London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Sarah Javati
- Papua New Guinea Institute of Medical Research, Goroka, Papua New Guinea
| | - Sarah Gwyn
- Centers for Disease Control and Prevention, Atlanta, Georgia, USA
| | - Marinjho Jonduo
- Papua New Guinea Institute of Medical Research, Goroka, Papua New Guinea
| | - Mohammad Yazid Abdad
- Papua New Guinea Institute of Medical Research, Goroka, Papua New Guinea
- National Centre for Infectious Diseases, Singapore
| | - Chrissy H Roberts
- London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Drew Keys
- Brien Holden Vision Institute Foundation, Sydney, Australia
| | | | - Robert Ko
- Department of Ophthalmology, Port Moresby General Hospital, Port Moresby, Papua New Guinea
| | - Jambi Garap
- Department of Ophthalmology, Port Moresby General Hospital, Port Moresby, Papua New Guinea
| | - David Pahau
- Department of Ophthalmology, Boram General Hospital, Wewak, Papua New Guinea
| | - Wendy Houinei
- Neglected Tropical Diseases, National Department of Health, Port Moresby, Papua New Guinea
| | - Diana L Martin
- Centers for Disease Control and Prevention, Atlanta, Georgia, USA
| | - William S Pomat
- Papua New Guinea Institute of Medical Research, Goroka, Papua New Guinea
| | - Anthony W Solomon
- London School of Hygiene and Tropical Medicine, London, United Kingdom
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26
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Lessons learned for surveillance strategies for trachoma elimination as a public health problem, from the evaluation of approaches utilised by Guinea worm and onchocerciasis programmes: A literature review. PLoS Negl Trop Dis 2021; 15:e0009082. [PMID: 33507903 PMCID: PMC7872237 DOI: 10.1371/journal.pntd.0009082] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2019] [Revised: 02/09/2021] [Accepted: 12/17/2020] [Indexed: 11/18/2022] Open
Abstract
Introduction A number of neglected tropical diseases are targeted for elimination or eradication. An effective surveillance system is critical to determine if these goals have been achieved and maintained. Trachoma has two related but morphologically different presentations that are monitored for elimination, the active infectious form of trachoma and trachomatous trichiasis (TT), the progression of the disease. There are a number of lessons learnt from the Guinea worm surveillance system that are particularly compatible for TT surveillance and the onchocerciasis surveillance system which can provide insights for surveillance of the infectious form of trachoma. Methods/Principal findings A literature search of peer-reviewed published papers and grey literature was conducted using PUBMED and Google Scholar for articles relating to dracunculiasis or Guinea worm, onchocerciasis and trachoma, along with surveillance or elimination or eradication. The abstracts of relevant papers were read and inclusion was determined based on specified inclusion and exclusion criteria. The credibility and bias of relevant papers were also critically assessed using published criteria. A total of 41 papers were identified that were eligible for inclusion into the review. The Guinea worm programme is designed around a surveillance-containment strategy and combines both active and passive surveillance approaches, with a focus on village-based surveillance and reporting. Although rumour reporting and a monetary incentive for the identification of confirmed Guinea worm cases have been reported as successful for identifying previously unknown transmission there is little unbiased evidence to support this conclusion. More rigorous evidence through a randomised controlled trial, influenced by motivational factors identified through formative research, would be necessary in order to consider applicability for TT case finding in an elimination setting. The onchocerciasis surveillance strategy focuses on active surveillance through sentinel surveillance of villages and breeding sites. It relies on an entomological component, monitoring infectivity rates of black flies and an epidemiological component, tracking exposure to infection in humans. Challenges have included the introduction of relatively complex diagnostics that are not readily available in onchocerciasis endemic countries and target thresholds, which are practically unattainable with current diagnostic tests. Although there is utility in monitoring for infection and serological markers in trachoma surveillance, it is important that adequate considerations are made to ensure evidence-based and achievable guidelines for their utility are put in place. Conclusions/Significance The experiences of both the Guinea worm and onchocerciasis surveillance strategies have very useful lessons for trachoma surveillance, pre- and post-validation. The use of a monetary reward for identification of TT cases and further exploration into the use of infection and serological indicators particularly in a post-validation setting to assist in identifying recrudescence would be of particular relevance. The next step would be a real-world evaluation of their relative applicability for trachoma surveillance. The design of a surveillance system needs to be carefully thought out to ensure it provides sufficient evidence to determine if a disease or infection is eliminated or eradicated. If inappropriate it can lead to on-going transmission and resurgence of infection or disease or the unnecessary continuation of interventions, wasting valuable resources. Guinea worm is a disease that is painful and debilitating, for which there is no drug or vaccine. The aim is to eradicate the disease and as such the Guinea worm programme is designed around a strategy of identification of cases and their containment to prevent onward transmission. Onchocerciasis if left untreated can lead to blindness. The aim is to eliminate the disease through the interruption of transmission. A literature review was conducted to determine available evidence and identify lessons that can be learnt from the surveillance of both diseases for the design of trachoma surveillance strategies in the endgame. The potential utility of rumour reporting and a monetary incentive for the identification of a confirmed case of Guinea worm could be explored for trichiasis case finding. Trichiasis is the progression of trachoma and leads to significant ocular morbidity. The introduction of tests for infection and antibodies and the utility of sentinel surveillance as utilised for onchocerciasis are interesting considerations for active trachoma surveillance post-validation and has potential to identify recrudescence cost-effectively. The experiences of both the Guinea worm and onchocerciasis surveillance strategies have very useful lessons that can be trialled for trachoma surveillance. However, their real-world applicability and implications for trachoma need to be evaluated before any changes in guidelines are proposed.
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Amza A, Kadri B, Nassirou B, Arzika AM, Austin A, Nyatigo F, Lebas E, Arnold BF, Lietman TM, Oldenburg CE. Azithromycin Reduction to Reach Elimination of Trachoma (ARRET): study protocol for a cluster randomized trial of stopping mass azithromycin distribution for trachoma. BMC Ophthalmol 2021; 21:15. [PMID: 33407263 PMCID: PMC7789605 DOI: 10.1186/s12886-020-01776-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2020] [Accepted: 12/17/2020] [Indexed: 12/23/2022] Open
Abstract
Background The World Health Organization (WHO) recommends annual mass azithromycin distribution until districts drop below 5% prevalence of trachomatous inflammation—follicular (TF). Districts with very low TF prevalence may have little or no transmission of the ocular strains of Chlamydia trachomatis that cause trachoma, and additional rounds of mass azithromycin distribution may not be useful. Here, we describe the protocol for a randomized controlled trial designed to evaluate whether mass azithromycin distribution can be stopped prior to the current WHO guidelines. Methods The Azithromycin Reduction to Reach Elimination of Trachoma (ARRET) study is a 1:1 community randomized non-inferiority trial designed to evaluate whether mass azithromycin distribution can be stopped in districts with baseline prevalence of TF under 20%. Communities in Maradi, Niger are randomized after baseline assessment either to continued annual mass azithromycin distribution or stopping annual azithromycin distribution over a 3-year period. We will compare the prevalence of ocular C. trachomatis (primary outcome), TF and other clinical signs of trachoma, and serologic markers of trachoma after 3 years. We hypothesize that stopping annual azithromycin distribution will be non-inferior to continued annual azithromycin distributions for all markers of trachoma prevalence and transmission. Discussion The results of this trial are anticipated to provide potentially guideline-changing evidence for when mass azithromycin distributions can be stopped in low TF prevalence areas. Trial registration number This study is registered at clinicaltrials.gov (NCT04185402). Registered December 4, 2019; prospectively registered pre-results.
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Affiliation(s)
- Abdou Amza
- Programme National de Santé Oculaire, Ministere de la Santé Publique, Niamey, Niger
| | - Boubacar Kadri
- Programme National de Santé Oculaire, Ministere de la Santé Publique, Niamey, Niger
| | - Beido Nassirou
- Programme National de Santé Oculaire, Ministere de la Santé Publique, Niamey, Niger
| | - Ahmed M Arzika
- Centre de Recherche et d'Intervention en Santé Publique, Niamey, Niger
| | - Ariana Austin
- Francis I Proctor Foundation, University of California, San Francisco, USA
| | - Fanice Nyatigo
- Francis I Proctor Foundation, University of California, San Francisco, USA
| | - Elodie Lebas
- Francis I Proctor Foundation, University of California, San Francisco, USA
| | - Benjamin F Arnold
- Francis I Proctor Foundation, University of California, San Francisco, USA.,Department of Ophthalmology, University of California, 490 Illinois St, Floor 2, San Francisco, CA, 94158, USA
| | - Thomas M Lietman
- Francis I Proctor Foundation, University of California, San Francisco, USA.,Department of Ophthalmology, University of California, 490 Illinois St, Floor 2, San Francisco, CA, 94158, USA.,Department of Epidemiology & Biostatistics, University of California, San Francisco, USA
| | - Catherine E Oldenburg
- Francis I Proctor Foundation, University of California, San Francisco, USA. .,Department of Ophthalmology, University of California, 490 Illinois St, Floor 2, San Francisco, CA, 94158, USA. .,Department of Epidemiology & Biostatistics, University of California, San Francisco, USA.
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Ondigo BN, Hamre KES, Frosch AEP, Ayodo G, White MT, John CC. Antibody Profiles to P. falciparum Antigens Over Time Characterize Acute and Long-Term Malaria Exposure in an Area of Low and Unstable Transmission. Am J Trop Med Hyg 2020; 103:2189-2197. [PMID: 33124539 DOI: 10.4269/ajtmh.19-0480] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Prevalence and levels of antibodies to multiple Plasmodium falciparum antigens show promise as tools for estimating malaria exposure. In a highland area of Kenya with unstable transmission, we assessed the presence and levels of antibodies to 12 pre-erythrocytic and blood-stage P. falciparum antigens by multiplex cytometric bead assay or ELISA in 604 individuals in August 2007, with follow-up testing in this cohort in April 2008, April 2009, and May 2010. Four hundred individuals were tested at all four time points. During this period, the only substantial malaria incidence occurred from April to August 2009. Antibody prevalence in adults was high at all time points (> 70%) for apical membrane antigen 1, erythrocyte-binding antigen 175, erythrocyte-binding protein-2, glutamate rich protein (GLURP)-R2, merozoite surface protein (MSP) 1 (19), MSP-1 (42), and liver-stage antigen-1; moderate (30-70%) for GLURP-R0, MSP-3, and thrombospondin-related adhesive protein; and low (< 30%) for SE and circumsporozoite protein (CSP). Changes in community-wide malaria exposure were best reflected in decreasing antibody levels overtime for highly immunogenic antigens, and in antibody seroprevalence overtime for the less-immunogenic antigens. Over the 3 years, antibody levels to all antigens except CSP and schizont extract (SE) decreased in an age-dependent manner. Prevalence and levels of antibodies to all antigens except CSP and SE increased with age. Increases in antibody prevalence and levels to CSP and SE coincided with increases in community-wide malaria incidence. Antibody levels to multiple P. falciparum antigens decrease in the absence of consistent transmission. Multiplex assays that assess both the presence and level of antibodies to multiple pre-erythrocytic and blood-stage P. falciparum antigens may provide the most useful estimates of past and recent malaria transmission in areas of unstable transmission and could be useful tools in malaria control and elimination campaigns.
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Affiliation(s)
- Bartholomew N Ondigo
- Laboratory of Malaria Immunology and Vaccinology, National Institute of Allergy and Infectious Diseases, National Institutes of Health (NIH), Bethesda, Maryland.,Centre for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya.,Department of Biochemistry and Molecular Biology, Egerton University, Nakuru, Kenya
| | - Karen E S Hamre
- CDC Foundation, Atlanta, Georgia.,Division of Epidemiology and Community Health, University of Minnesota, Minneapolis, Minnesota.,Division of Global Pediatrics, University of Minnesota, Minneapolis, Minnesota
| | - Anne E P Frosch
- Hennepin Healthcare Research Institute, Minneapolis, Minnesota.,Department of Medicine, University of Minnesota, Minneapolis, Minnesota
| | - George Ayodo
- School of Health Sciences, Jaramogi Oginga Odinga University of Science and Technology, Siaya, Kenya.,Centre for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya
| | - Michael T White
- Department of Parasites and Insect Vectors, Institut Pasteur, Paris, France
| | - Chandy C John
- Division of Global Pediatrics, University of Minnesota, Minneapolis, Minnesota.,Centre for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya.,Ryan White Center for Pediatric Infectious Diseases and Global Health, Indiana University School of Medicine, Indianapolis, Indiana
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Dixon MA, Winskill P, Harrison WE, Whittaker C, Schmidt V, Sarti E, Bawm S, Dione MM, Thomas LF, Walker M, Basáñez MG. Force-of-infection of Taenia solium porcine cysticercosis: a modelling analysis to assess global incidence and prevalence trends. Sci Rep 2020; 10:17637. [PMID: 33077748 PMCID: PMC7572398 DOI: 10.1038/s41598-020-74007-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2019] [Accepted: 09/14/2020] [Indexed: 11/26/2022] Open
Abstract
The World Health Organization (WHO) called, in 2012, for a validated strategy towards Taenia solium taeniasis/cysticercosis control and elimination. Estimating pig force-of-infection (FoI, the average rate at which susceptible pigs become infected) across geographical settings will help understand local epidemiology and inform effective intervention design. Porcine cysticercosis (PCC) age-prevalence data (from 15 studies in Latin America, Africa and Asia) were identified through systematic review. Catalytic models were fitted to the data using Bayesian methods, incorporating uncertainty in diagnostic performance, to estimate rates of antibody seroconversion, viable metacestode acquisition, and seroreversion/infection loss. There was evidence of antibody seroreversion across 5 studies, and of infection loss in 6 studies measured by antigen or necropsy, indicating transient serological responses and natural resolution of infection. Concerted efforts should be made to collect robust data using improved diagnostics to better understand geographical heterogeneities in T. solium transmission to support post-2020 WHO targets.
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Affiliation(s)
- Matthew A Dixon
- Department of Infectious Disease Epidemiology and London Centre for Neglected Tropical Disease Research (LCNTDR), Faculty of Medicine, School of Public Health, Imperial College London, London, W2 1PG, UK.
- MRC Centre for Global Infectious Disease Analysis, Department of Infectious Disease Epidemiology, Faculty of Medicine, School of Public Health, Imperial College London, London, W2 1PG, UK.
| | - Peter Winskill
- MRC Centre for Global Infectious Disease Analysis, Department of Infectious Disease Epidemiology, Faculty of Medicine, School of Public Health, Imperial College London, London, W2 1PG, UK
| | - Wendy E Harrison
- SCI Foundation, Edinburgh House, 170 Kennington Lane, London, SE11 5DP, UK
| | - Charles Whittaker
- MRC Centre for Global Infectious Disease Analysis, Department of Infectious Disease Epidemiology, Faculty of Medicine, School of Public Health, Imperial College London, London, W2 1PG, UK
| | - Veronika Schmidt
- Department of Neurology, Center for Global Health, Technical University Munich (TUM), Munich, Germany
- Centre for Global Health, Institute of Health and Society, University of Oslo, Oslo, Norway
| | - Elsa Sarti
- Sanofi Pasteur Latin America, Av. Universidad N° 1738, Colonia Coyoacán, 04000, Mexico, D.F., Mexico
| | - Saw Bawm
- University of Veterinary Science, Yezin, Nay Pyi Taw, 15013, Myanmar
| | - Michel M Dione
- International Livestock Research Institute, 01 BP 1496, Ouagadougou, Burkina Faso
| | - Lian F Thomas
- International Livestock Research Institute (ILRI), Old Naivasha Road, PO Box 30709-00100, Nairobi, Kenya
- Institute for Infection and Global Health, University of Liverpool, 8 West Derby Street, Liverpool, L69 7BE, UK
| | - Martin Walker
- Department of Pathobiology and Population Sciences and London Centre for Neglected Tropical Disease Research (LCNTDR), Royal Veterinary College, Hatfield, AL9 7TA, UK
| | - Maria-Gloria Basáñez
- Department of Infectious Disease Epidemiology and London Centre for Neglected Tropical Disease Research (LCNTDR), Faculty of Medicine, School of Public Health, Imperial College London, London, W2 1PG, UK
- MRC Centre for Global Infectious Disease Analysis, Department of Infectious Disease Epidemiology, Faculty of Medicine, School of Public Health, Imperial College London, London, W2 1PG, UK
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Martin DL, Saboyà-Díaz MI, Abashawl A, Alemayeh W, Gwyn S, Hooper PJ, Keenan J, Kalua K, Szwarcwald CL, Nash S, Oldenburg C, West SK, White M, Solomon AW. The use of serology for trachoma surveillance: Current status and priorities for future investigation. PLoS Negl Trop Dis 2020; 14:e0008316. [PMID: 32970672 PMCID: PMC7514076 DOI: 10.1371/journal.pntd.0008316] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Affiliation(s)
- Diana L Martin
- Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America
| | - Martha Idalí Saboyà-Díaz
- Communicable Diseases and Environmental Determinants of Health Department, Pan-American Health Organization, Washington, DC, United States of America
| | - Aida Abashawl
- Berhan Public Health and Eye Care Consultancy, Addis Ababa, Ethiopia
| | - Wondu Alemayeh
- Berhan Public Health and Eye Care Consultancy, Addis Ababa, Ethiopia.,The Fred Hollows Foundation, Addis Ababa, Ethiopia
| | - Sarah Gwyn
- Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America
| | - Pamela J Hooper
- International Trachoma Initiative, Task Force for Global Health, Decatur, Georgia, United States of America
| | - Jeremy Keenan
- Francis I. Proctor Foundation, University of California at San Francisco, San Francisco, California, United States of America.,Department of Ophthalmology, University of California at San Francisco, San Francisco, California, United States of America
| | - Khumbo Kalua
- Department of Ophthalmology, University of Malawi, College of Medicine Blantyre, Malawi
| | - Celia Landmann Szwarcwald
- Institute of Scientific and Technological Communication and information in Health, Oswaldo Cruz Foundation, Rio de Janeiro, Brazil
| | - Scott Nash
- Trachoma Control Program, The Carter Center, Atlanta, Georgia, United States of America
| | - Catherine Oldenburg
- Francis I. Proctor Foundation, University of California at San Francisco, San Francisco, California, United States of America.,Department of Ophthalmology, University of California at San Francisco, San Francisco, California, United States of America.,Department of Epidemiology and Biostatistics, University of California at San Francisco, San Francisco, California, United States of America
| | - Sheila K West
- Wilmer Eye Institute, Johns Hopkins School of Medicine, Baltimore, Maryland, United States of America
| | - Michael White
- Malaria: Parasites & Hosts, Department of Parasites and Insect Vectors, Institut Pasteur, Paris, France
| | - Anthony W Solomon
- Department of Control of Neglected Tropical Diseases, World Health Organization, Geneva, Switzerland
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Aiemjoy K, Aragie S, Wittberg DM, Tadesse Z, Callahan EK, Gwyn S, Martin D, Keenan JD, Arnold BF. Seroprevalence of antibodies against Chlamydia trachomatis and enteropathogens and distance to the nearest water source among young children in the Amhara Region of Ethiopia. PLoS Negl Trop Dis 2020; 14:e0008647. [PMID: 32877398 PMCID: PMC7491729 DOI: 10.1371/journal.pntd.0008647] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2020] [Revised: 09/15/2020] [Accepted: 07/27/2020] [Indexed: 11/19/2022] Open
Abstract
The transmission of trachoma, caused by repeat infections with Chlamydia trachomatis, and many enteropathogens are linked to water quantity. We hypothesized that children living further from a water source would have higher exposure to C. trachomatis and enteric pathogens as determined by antibody responses. We used a multiplex bead assay to measure IgG antibody responses to C. trachomatis, Giardia intestinalis, Cryptosporidium parvum, Entamoeba histolytica, Salmonella enterica, Campylobacter jejuni, enterotoxigenic Escherichia coli (ETEC) and Vibrio cholerae in eluted dried blood spots collected from 2267 children ages 0-9 years in 40 communities in rural Ethiopia in 2016. Linear distance from the child's house to the nearest water source was calculated. We derived seroprevalence cutoffs using external negative control populations, if available, or by fitting finite mixture models. We used targeted maximum likelihood estimation to estimate differences in seroprevalence according to distance to the nearest water source. Seroprevalence among 1-9-year-olds was 43% for C. trachomatis, 28% for S. enterica, 70% for E. histolytica, 54% for G. intestinalis, 96% for C. jejuni, 76% for ETEC and 94% for C. parvum. Seroprevalence increased with age for all pathogens. Median distance to the nearest water source was 473 meters (IQR 268, 719). Children living furthest from a water source had a 12% (95% CI: 2.6, 21.6) higher seroprevalence of S. enterica and a 12.7% (95% CI: 2.9, 22.6) higher seroprevalence of G. intestinalis compared to children living nearest. Seroprevalence for C. trachomatis and enteropathogens was high, with marked increases for most enteropathogens in the first two years of life. Children living further from a water source had higher seroprevalence of S. enterica and G. intestinalis indicating that improving access to water in the Ethiopia's Amhara region may reduce exposure to these enteropathogens in young children.
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Affiliation(s)
- Kristen Aiemjoy
- Division of Infectious Diseases and Geographic Medicine, Stanford University School of Medicine, Stanford, California, United States of America
| | | | - Dionna M. Wittberg
- Francis I. Proctor Foundation, University of California San Francisco, San Francisco, California, United States of America
| | | | | | - Sarah Gwyn
- U.S. Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America
| | - Diana Martin
- U.S. Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America
| | - Jeremy D. Keenan
- Francis I. Proctor Foundation, University of California San Francisco, San Francisco, California, United States of America
| | - Benjamin F. Arnold
- Francis I. Proctor Foundation, University of California San Francisco, San Francisco, California, United States of America
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Fine-scale heterogeneity in Schistosoma mansoni force of infection measured through antibody response. Proc Natl Acad Sci U S A 2020; 117:23174-23181. [PMID: 32868437 PMCID: PMC7502727 DOI: 10.1073/pnas.2008951117] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Schistosomiasis is one of the most common parasitic diseases in the world, and most infected people (90%) live in Africa. Global control efforts use measures of population-level transmission to target programs and assess progress toward elimination. Monitoring Schistosoma mansoni transmission has traditionally relied on examining stool with microscopy, which is difficult to scale in large programs and has low sensitivity as infection burdens decline. Our results show that antibody-based measures of transmission align well with stool-based measures, provide higher sensitivity at lower levels of transmission, and enable fine-scale estimates of force of infection by geography and age. The findings represent a major step toward use of serosurveillance to guide schistosomiasis control efforts in Africa. Schistosomiasis is among the most common parasitic diseases in the world, with over 142 million people infected in low- and middle-income countries. Measuring population-level transmission is centrally important in guiding schistosomiasis control programs. Traditionally, human Schistosoma mansoni infections have been detected using stool microscopy, which is logistically difficult at program scale and has low sensitivity when people have low infection burdens. We compared serological measures of transmission based on antibody response to S. mansoni soluble egg antigen (SEA) with stool-based measures of infection among 3,663 preschool-age children in an area endemic for S. mansoni in western Kenya. We estimated force of infection among children using the seroconversion rate and examined how it varied geographically and by age. At the community level, serological measures of transmission aligned with stool-based measures of infection (ρ = 0.94), and serological measures provided more resolution for between-community differences at lower levels of infection. Force of infection showed a clear gradient of transmission with distance from Lake Victoria, with 94% of infections and 93% of seropositive children in communities <1.5 km from the lake. Force of infection increased through age 3 y, by which time 65% (95% CI: 53%, 75%) of children were SEA positive in high-transmission communities—2 y before they would be reached by school-based deworming programs. Our results show that serologic surveillance platforms represent an important opportunity to guide and monitor schistosomiasis control programs, and that in high-transmission settings preschool-age children represent a key population missed by school-based deworming programs.
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Ocular Chlamydia trachomatis infection, anti-Pgp3 antibodies and conjunctival scarring in Vanuatu and Tarawa, Kiribati before antibiotic treatment for trachoma. J Infect 2020; 80:454-461. [PMID: 32017971 PMCID: PMC7113835 DOI: 10.1016/j.jinf.2020.01.015] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2019] [Revised: 01/20/2020] [Accepted: 01/21/2020] [Indexed: 11/21/2022]
Abstract
In Vanuatu, ocular Chlamydia infection prevalence is low; in Kiribati it is high. In Vanuatu, Pgp3 seroprevalence does not increase in childhood; in Kiribati it does. Conjunctival scarring is more common in adults in Kiribati than in Vanuatu. Trachomatous inflammation—follicular lacks specificity for ocular Chlamydia infection. Non-TF markers may help to determine need for interventions against active trachoma.
Introduction In the peri-elimination setting, the positive predictive value of trachomatous inflammation–follicular (TF), the primary marker used to determine need for antibiotics for trachoma, is suboptimal. Here, three non-TF measures are used to compare two regions where TF prevalence exceeds the threshold for intervention, but where the Chlamydia trachomatis (Ct) prevalence is different. Methods Population prevalence of trachoma was measured in Vanuatu (n = 3470) and Kiribati (n = 2922). Dried blood spots (DBS) and conjunctival photographs were collected from every survey participant, and conjunctival swabs were collected from those aged 1–9 years. Individuals were tested for blood anti-Pgp3 antibodies, Ct DNA at the conjunctiva and severity of conjunctival scarring. Results The prevalence of TF in 1–9-year-olds was 16.5% in Vanuatu and 38.2% in Tarawa. 7% of people aged ≥1 year in Vanuatu had conjunctival scarring compared to 27% in Tarawa. The prevalence of ocular Ct infection in 1–9-year-olds was 1.5% in Vanuatu and 27.4% in Tarawa. The seroconversion rate amongst 1–9-year-old children in Vanuatu and Tarawa was 0.018 and 0.197 events per child per year, respectively. Conclusions Comparing Vanuatu to Tarawa demonstrates several markers that could be used to differentiate the trachoma status of populations in these (and other) locations.
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Saboyá-Díaz MI, Betanzos-Reyes AF, West SK, Muñoz B, Castellanos LG, Espinal M. Trachoma elimination in Latin America: prioritization of municipalities for surveillance activities. Rev Panam Salud Publica 2019; 43:e93. [PMID: 33659029 PMCID: PMC7919757 DOI: 10.26633/rpsp.2019.93] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2019] [Accepted: 09/23/2019] [Indexed: 12/25/2022] Open
Abstract
Objective To identify and prioritize municipalities in 22 countries of Latin America for trachoma surveillance activities, to measure the absence or prevalence of trachoma, and to support validation and trachoma elimination efforts in the Region of the Americas. Methods A prioritization scale was developed in 2017 to rank each municipality by considering a combination of three characteristics: (a) its trachoma vulnerability index, derived from three socioeconomic factors known to be risks for trachoma-lack of access to improved sanitation, to clean drinking water, and to adequate education, according to housing census data from early 2017; (b) its history of trachoma in countries where the disease was not a known public health problem in 2016; and (c) whether or not it shares a border with a municipality where trachoma was a known public health problem in 2016. Municipalities in 22 countries were classified as either very high, high, medium, or low priority for trachoma surveillance. From the Caribbean, only Trinidad and Tobago met inclusion criteria. Results The prioritization scale identified 1 053 municipalities in Brazil, Colombia, and Guatemala as very high priority for trachoma surveillance. In Ecuador, El Salvador, Guyana, Paraguay, Peru, Suriname, and Venezuela, 183 municipalities were ranked as high priority, and in Argentina, Belize, Bolivia, Chile, Dominican Republic, Honduras, Nicaragua, Panama, and Uruguay, 677 municipalities were designated a medium priority for trachoma surveillance. Conclusions This prioritization scale will be useful to countries in Latin America that still need to ascertain their current trachoma situation. The absence or prevalence of trachoma in countries designated as very high and high priority for trachoma surveillance activities must be studied to determine the extent of the disease in Latin America.
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Affiliation(s)
- Martha Idalí Saboyá-Díaz
- Communicable Diseases and Environmental Determinants of Health Department Pan American Health Organization/World Health Organization Washington, DC United States of the America Communicable Diseases and Environmental Determinants of Health Department, Pan American Health Organization/World Health Organization, Washington, DC, United States of the America
| | - Angel F Betanzos-Reyes
- Centro de Investigación sobre Enfermedades Infecciosas Instituto Nacional de Salud Pública de México CuernavacaMorelos Mexico Centro de Investigación sobre Enfermedades Infecciosas, Instituto Nacional de Salud Pública de México, Cuernavaca, Morelos, Mexico
| | - Sheila K West
- Dana Center for Preventive Ophthalmology Wilmer Eye Institute, Johns Hopkins Hospital BaltimoreMaryland United States of America Dana Center for Preventive Ophthalmology, Wilmer Eye Institute, Johns Hopkins Hospital, Baltimore, Maryland, United States of America
| | - Beatriz Muñoz
- Dana Center for Preventive Ophthalmology Wilmer Eye Institute, Johns Hopkins Hospital BaltimoreMaryland United States of America Dana Center for Preventive Ophthalmology, Wilmer Eye Institute, Johns Hopkins Hospital, Baltimore, Maryland, United States of America
| | - Luis Gerardo Castellanos
- Communicable Diseases and Environmental Determinants of Health Department Pan American Health Organization/World Health Organization Washington, DC United States of the America Communicable Diseases and Environmental Determinants of Health Department, Pan American Health Organization/World Health Organization, Washington, DC, United States of the America
| | - Marcos Espinal
- Communicable Diseases and Environmental Determinants of Health Department Pan American Health Organization/World Health Organization Washington, DC United States of the America Communicable Diseases and Environmental Determinants of Health Department, Pan American Health Organization/World Health Organization, Washington, DC, United States of the America
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Burr SE, Hart J, Samikwa L, Chaima D, Cooley G, Martin D, Masika M, Solomon AW, Bailey RL, Kalua K. Pgp3 seroprevalence and associations with active trachoma and ocular Chlamydia trachomatis infection in Malawi: cross-sectional surveys in six evaluation units. PLoS Negl Trop Dis 2019; 13:e0007749. [PMID: 31658258 PMCID: PMC6816554 DOI: 10.1371/journal.pntd.0007749] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2019] [Accepted: 09/04/2019] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Following one to five years of antibiotic mass drug administration (MDA) for the elimination of trachoma as a public health problem, programmes must conduct impact surveys to inform decisions on whether MDA is still needed. These decisions are currently based on the prevalence of trachomatous inflammation-follicular (TF), which, after MDA, correlates poorly with prevalence of ocular Chlamydia trachomatis infection. METHODOLOGY/PRINCIPAL FINDINGS Impact surveys in six evaluation units (EUs) of Malawi were used as a platform to explore associations between the prevalence of TF, ocular C. trachomatis infection and anti-Pgp3 antibodies one year after the third annual round of MDA. Participants were examined for trachoma using the World Health Organization simplified grading system. Ocular swabs and dried blood spots (DBS) were collected from children aged 1-9 years. Swabs were tested for C. trachomatis DNA using GeneXpert. DBS were assayed for anti-Pgp3 antibodies using ELISA. EU-level prevalence of TF in children aged 1-9 years ranged from 4.7% (95% CI 3.4-6.3) to 7.2% (95% CI 5.8-8.9). Prevalence of C. trachomatis infection in children ranged from 0.1% (95% CI 0.0-0.6) to 0.7% (95% CI 0.3-1.3) while Pgp3 seroprevalence ranged from 6.9% (95% CI 5.4-8.6) to 12.0% (95% CI 10.1-14.0) and increased with age. CONCLUSIONS/SIGNIFICANCE Based on current global policy, the prevalence of TF indicates that a further year of antibiotic MDA is warranted in four of six EUs yet the very low levels of infection cast doubt on the universal applicability of TF-based cut-offs for antibiotic MDA. Pgp3 seroprevalence was similar to that reported following MDA in other settings that have reached the elimination target however the predictive value of any particular level of seropositivity with respect to risk of subsequent infection recrudescence is, as yet, unknown.
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Affiliation(s)
- Sarah E. Burr
- Department of Clinical Research, London School of Hygiene & Tropical Medicine, London, United Kingdom
- College of Medicine, University of Malawi, Blantyre, Malawi
| | - John Hart
- Department of Clinical Research, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Lyson Samikwa
- College of Medicine, University of Malawi, Blantyre, Malawi
| | - David Chaima
- College of Medicine, University of Malawi, Blantyre, Malawi
| | - Gretchen Cooley
- Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America
| | - Diana Martin
- Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America
| | | | - Anthony W. Solomon
- Department of Clinical Research, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Robin L. Bailey
- Department of Clinical Research, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Khumbo Kalua
- College of Medicine, University of Malawi, Blantyre, Malawi
- Blantyre Institute for Community Outreach, Blantyre, Malawi
- * E-mail:
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36
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Arnold BF, Martin DL, Juma J, Mkocha H, Ochieng JB, Cooley GM, Omore R, Goodhew EB, Morris JF, Costantini V, Vinjé J, Lammie PJ, Priest JW. Enteropathogen antibody dynamics and force of infection among children in low-resource settings. eLife 2019; 8:45594. [PMID: 31424386 PMCID: PMC6746552 DOI: 10.7554/elife.45594] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2019] [Accepted: 08/15/2019] [Indexed: 01/22/2023] Open
Abstract
Little is known about enteropathogen seroepidemiology among children in low-resource settings. We measured serological IgG responses to eight enteropathogens (Giardia intestinalis, Cryptosporidium parvum, Entamoeba histolytica, Salmonella enterica, enterotoxigenic Escherichia coli, Vibrio cholerae, Campylobacter jejuni, norovirus) in cohorts from Haiti, Kenya, and Tanzania. We studied antibody dynamics and force of infection across pathogens and cohorts. Enteropathogens shared common seroepidemiologic features that enabled between-pathogen comparisons of transmission. Overall, exposure was intense: for most pathogens the window of primary infection was <3 years old; for highest transmission pathogens primary infection occurred within the first year. Longitudinal profiles demonstrated significant IgG boosting and waning above seropositivity cutoffs, underscoring the value of longitudinal designs to estimate force of infection. Seroprevalence and force of infection were rank-preserving across pathogens, illustrating the measures provide similar information about transmission heterogeneity. Our findings suggest antibody response can be used to measure population-level transmission of diverse enteropathogens in serologic surveillance. Diarrhea, which is caused by bacteria such as Salmonella or by viruses like norovirus, is the fourth leading cause of death among children worldwide, with children in low-resource settings being at highest risk. The pathogens that cause diarrhea spread when stool from infected people comes into contact with new hosts, for example, through inadequate sanitation or by drinking contaminated water. Currently, the best way to track these infections is to collect stool samples from people and test them for the presence of the pathogens. Unfortunately, this is costly and difficult to do on a large scale outside of clinical settings, making it hard to track the spread of diarrhea-causing pathogens. The body produces antibodies – small proteins that can detect specific pathogens – in response to an infection. These antibodies help ward off future infections by the same pathogen, so if they are present in the blood, this indicates a current or previous infection. Scientists already collect blood samples to track malaria, HIV and vaccine-preventable diseases in low-resource settings. These samples could be tested more broadly to measure the levels of antibodies against diarrhea-causing pathogens. Now, Arnold et al. have used blood samples collected from children in Haiti, Kenya, and Tanzania to measure antibody responses to 8 diarrhea-causing pathogens. The results showed that many children in these settings had been infected with all 8 pathogens before age three, and that all of the pathogens shared similar age-dependent patterns of antibody response. This finding enabled Arnold et al. to combine antibody measurements with statistical models to estimate each pathogen’s force of infection, that is, the rate at which susceptible individuals in the population become infected. This is a key step for epidemiologists to understand which pathogens cause the most infections in a population. The experiments show that testing blood samples for antibodies could provide scientists with a new tool to track the transmission of diarrhea-causing pathogens in low-resource settings. This information could help public health officials design and test efforts to prevent diarrhea, for example, by improving water treatment or developing vaccines.
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Affiliation(s)
- Benjamin F Arnold
- Division of Epidemiology and Biostatistics, University of California, Berkeley, Berkeley, United States.,Francis I. Proctor Foundation, University of California, San Francisco, San Francisco, United States.,Department of Ophthalmology, University of California, San Francisco, San Francisco, United States
| | - Diana L Martin
- Division of Parasitic Diseases and Malaria, United States Centers for Disease Control and Prevention, Atlanta, United States
| | - Jane Juma
- Kenya Medical Research Institute, Centre for Global Health Research, Kisumu, Kenya
| | - Harran Mkocha
- Kongwa Trachoma Project, Kongwa, United Republic of Tanzania
| | - John B Ochieng
- Kenya Medical Research Institute, Centre for Global Health Research, Kisumu, Kenya
| | - Gretchen M Cooley
- Division of Parasitic Diseases and Malaria, United States Centers for Disease Control and Prevention, Atlanta, United States
| | - Richard Omore
- Kenya Medical Research Institute, Centre for Global Health Research, Kisumu, Kenya
| | - E Brook Goodhew
- Division of Parasitic Diseases and Malaria, United States Centers for Disease Control and Prevention, Atlanta, United States
| | - Jamae F Morris
- Department of African-American Studies, Georgia State University, Atlanta, United States
| | - Veronica Costantini
- Division of Viral Diseases, United States Centers for Disease Control and Prevention, Atlanta, United States
| | - Jan Vinjé
- Division of Viral Diseases, United States Centers for Disease Control and Prevention, Atlanta, United States
| | - Patrick J Lammie
- Division of Parasitic Diseases and Malaria, United States Centers for Disease Control and Prevention, Atlanta, United States.,Neglected Tropical Diseases Support Center, Task Force for Global Health, Decatur, United States
| | - Jeffrey W Priest
- Division of Foodborne, Waterborne, and Environmental Diseases, United States Centers for Disease Control and Prevention, Atlanta, United States
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