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Nash SD, Chernet A, Moncada J, Stewart AEP, Astale T, Sata E, Zerihun M, Gessese D, Melak B, Ayenew G, Ayele Z, Chanyalew M, Lietman TM, Callahan EK, Schachter J, Tadesse Z. Ocular Chlamydia trachomatis infection and infectious load among pre-school aged children within trachoma hyperendemic districts receiving the SAFE strategy, Amhara region, Ethiopia. PLoS Negl Trop Dis 2020; 14:e0008226. [PMID: 32421719 PMCID: PMC7259799 DOI: 10.1371/journal.pntd.0008226] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2019] [Revised: 05/29/2020] [Accepted: 03/17/2020] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND After approximately 5 years of SAFE (surgery, antibiotics, facial cleanliness, environmental improvement) interventions for trachoma, hyperendemic (trachomatous inflammation-follicular (TF) ≥30%) districts remained in Amhara, Ethiopia. This study's aim was to characterize the epidemiology of Chlamydia trachomatis (Ct) infection and load among pre-school aged children living under the SAFE strategy. METHODS Conjunctival swabs from a population-based sample of children aged 1-5 years collected between 2011 and 2015 were assayed to provide Ct infection data from 4 endemic zones (comprised of 58 districts). Ct load was determined using a calibration curve. Children were graded for TF and trachomatous inflammation-intense (TI). RESULTS 7,441 children were swabbed in 4 zones. TF and TI prevalence were 39.9% (95% confidence Interval [CI]: 37.5%, 42.4%), and 9.2% (95% CI: 8.1%, 10.3%) respectively. Ct infection prevalence was 6.0% (95% CI: 5.0%, 7.2%). Infection was highest among children aged 2 to 4 years (6.6%-7.0%). Approximately 10% of infection occurred among children aged 1 year. Ct load decreased with age (P = 0.002), with the highest loads observed in children aged 1 year (P = 0.01) vs. aged 5 years. Participants with TF (P = 0.20) and TI (P<0.01) had loads greater than individuals without active trachoma. CONCLUSIONS In this hyperendemic setting, it appears that the youngest children may contribute in meaningful ways towards persistent active trachoma.
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Affiliation(s)
- Scott D. Nash
- Trachoma Control Program, The Carter Center, Atlanta, United States of America
| | - Ambahun Chernet
- Trachoma Control Program, The Carter Center, Addis Ababa, Ethiopia
| | - Jeanne Moncada
- Department of Laboratory Medicine, University of California, San Francisco, United States of America
| | - Aisha E. P. Stewart
- Trachoma Control Program, The Carter Center, Atlanta, United States of America
| | - Tigist Astale
- Trachoma Control Program, The Carter Center, Addis Ababa, Ethiopia
| | - Eshetu Sata
- Trachoma Control Program, The Carter Center, Addis Ababa, Ethiopia
| | - Mulat Zerihun
- Trachoma Control Program, The Carter Center, Addis Ababa, Ethiopia
| | - Demelash Gessese
- Trachoma Control Program, The Carter Center, Addis Ababa, Ethiopia
| | - Berhanu Melak
- Trachoma Control Program, The Carter Center, Addis Ababa, Ethiopia
| | - Gedefaw Ayenew
- Trachoma Control Program, The Carter Center, Addis Ababa, Ethiopia
| | - Zebene Ayele
- Trachoma Control Program, The Carter Center, Addis Ababa, Ethiopia
| | - Melsew Chanyalew
- Health Promotion and Disease Prevention Core Process, Amhara Regional Health Bureau, Bahir Dar, Ethiopia
| | - Thomas M. Lietman
- Francis I. Proctor Foundation, University of California, San Francisco, United States of America
| | - E. Kelly Callahan
- Trachoma Control Program, The Carter Center, Atlanta, United States of America
| | - Julius Schachter
- Department of Laboratory Medicine, University of California, San Francisco, United States of America
| | - Zerihun Tadesse
- Trachoma Control Program, The Carter Center, Addis Ababa, Ethiopia
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Trachoma: Time to Talk Eradication. Ophthalmology 2019; 127:11-13. [PMID: 31864470 DOI: 10.1016/j.ophtha.2019.11.001] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2019] [Revised: 11/03/2019] [Accepted: 11/06/2019] [Indexed: 11/23/2022] Open
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Evans JR, Solomon AW, Kumar R, Perez Á, Singh BP, Srivastava RM, Harding‐Esch E. Antibiotics for trachoma. Cochrane Database Syst Rev 2019; 9:CD001860. [PMID: 31554017 PMCID: PMC6760986 DOI: 10.1002/14651858.cd001860.pub4] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
BACKGROUND Trachoma is the world's leading infectious cause of blindness. In 1996, WHO launched the Alliance for the Global Elimination of Trachoma by the year 2020, based on the 'SAFE' strategy (surgery, antibiotics, facial cleanliness, and environmental improvement). OBJECTIVES To assess the evidence supporting the antibiotic arm of the SAFE strategy by assessing the effects of antibiotics on both active trachoma (primary objective), Chlamydia trachomatis infection of the conjunctiva, antibiotic resistance, and adverse effects (secondary objectives). SEARCH METHODS We searched relevant electronic databases and trials registers. The date of the last search was 4 January 2019. SELECTION CRITERIA We included randomised controlled trials (RCTs) that satisfied either of two criteria: (a) trials in which topical or oral administration of an antibiotic was compared to placebo or no treatment in people or communities with trachoma, (b) trials in which a topical antibiotic was compared with an oral antibiotic in people or communities with trachoma. We also included studies addressing different dosing strategies in the population. DATA COLLECTION AND ANALYSIS: We used standard methods expected by Cochrane. We assessed the certainty of the evidence using the GRADE approach. MAIN RESULTS We identified 14 studies where individuals with trachoma were randomised and 12 cluster-randomised studies. Any antibiotic versus control (individuals)Nine studies (1961 participants) randomised individuals with trachoma to antibiotic or control (no treatment or placebo). All of these studies enrolled children and young people with active trachoma. The antibiotics used in these studies included topical (oxy)tetracycline (5 studies), doxycycline (2 studies), and sulfonamides (4 studies). Four studies had more than two study arms. In general these studies were poorly reported, and it was difficult to judge risk of bias.These studies provided low-certainty evidence that people with active trachoma treated with antibiotics experienced a reduction in active trachoma at three months (risk ratio (RR) 0.78, 95% confidence interval (CI) 0.69 to 0.89; 1961 people; 9 RCTs; I2 = 73%) and 12 months (RR 0.74, 95% CI 0.55 to 1.00; 1035 people; 4 RCTs; I2 = 90%). Low-certainty evidence was available for ocular infection at three months (RR 0.81, 95% CI 0.63 to 1.04; 297 people; 4 RCTs; I2 = 0%) and 12 months (RR 0.25, 95% CI 0.08 to 0.78; 129 people; 1 RCT). None of these studies assessed antimicrobial resistance. In those studies that reported harms, no serious adverse effects were reported (low-certainty evidence).Oral versus topical antibiotics (individuals)Eight studies (1583 participants) compared oral and topical antibiotics. Only one study included people older than 21 years of age. Oral antibiotics included azithromycin (5 studies), sulfonamides (2 studies), and doxycycline (1 study). Topical antibiotics included (oxy)tetracycline (6 studies), azithromycin (1 study), and sulfonamide (1 study). These studies were poorly reported, and it was difficult to judge risk of bias.There was low-certainty evidence of little or no difference in effect between oral and topical antibiotics on active trachoma at three months (RR 0.97, 95% CI 0.81 to 1.16; 953 people; 6 RCTs; I2 = 63%) and 12 months (RR 0.93, 95% CI 0.75 to 1.15; 886 people; 5 RCTs; I2 = 56%). There was very low-certainty evidence for ocular infection at three or 12 months. Antimicrobial resistance was not assessed. In those studies that reported adverse effects, no serious adverse effects were reported; one study reported abdominal pain with azithromycin; one study reported a couple of cases of nausea with azithromycin; and one study reported three cases of reaction to sulfonamides (low-certainty evidence).Oral azithromycin versus control (communities)Four cluster-randomised studies compared antibiotic with no or delayed treatment. Data were available on active trachoma at 12 months from two studies but could not be pooled because of reporting differences. One study at low risk of bias found a reduced prevalence of active trachoma 12 months after a single dose of azithromycin in communities with a high prevalence of infection (RR 0.58, 95% CI 0.52 to 0.65; 1247 people). The other, lower quality, study in low-prevalence communities reported similar median prevalences of infection at 12 months: 9.3% in communities treated with azithromycin and 8.2% in untreated communities. We judged this moderate-certainty evidence for a reduction in active trachoma with treatment, downgrading one level for inconsistency between the two studies. Two studies reported ocular infection at 12 months and data could be pooled. There was a reduction in ocular infection (RR 0.36, 0.31 to 0.43; 2139 people) 12 months after mass treatment with a single dose compared with no treatment (moderate-certainty evidence). There was high-certainty evidence of an increased risk of resistance of Streptococcus pneumoniae, Staphylococcus aureus, and Escherichia coli to azithromycin, tetracycline, and clindamycin in communities treated with azithromycin, with approximately 5-fold risk ratios at 12 months. The evidence did not support increased resistance to penicillin or trimethoprim-sulfamethoxazole. None of the studies measured resistance to C trachomatis. No serious adverse events were reported. The main adverse effect noted for azithromycin (˜10%) was abdominal pain, vomiting, and nausea.Oral azithromycin versus topical tetracycline (communities)Three cluster-randomised studies compared oral azithromycin with topical tetracycline. The evidence was inconsistent for active trachoma and ocular infection at three and 12 months (low-certainty evidence) and was not pooled due to considerable heterogeneity. Antimicrobial resistance and adverse effects were not reported.Different dosing strategiesSix studies compared different strategies for dosing. There were: mass treatment at different dosing intervals; applying cessation or stopping rules to mass treatment; strategies to increase mass treatment coverage. There was no strong evidence to support any variation in the recommended annual mass treatment. AUTHORS' CONCLUSIONS Antibiotic treatment may reduce the risk of active trachoma and ocular infection in people infected with C trachomatis, compared to no treatment/placebo, but the size of the treatment effect in individuals is uncertain. Mass antibiotic treatment with single dose oral azithromycin reduces the prevalence of active trachoma and ocular infection in communities. There is no strong evidence to support any variation in the recommended periodicity of annual mass treatment. There is evidence of an increased risk of antibiotic resistance at 12 months in communities treated with antibiotics.
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Affiliation(s)
- Jennifer R Evans
- London School of Hygiene & Tropical MedicineCochrane Eyes and Vision, ICEHKeppel StreetLondonUKWC1E 7HT
| | - Anthony W Solomon
- World Health OrganizationDepartment of Control of Neglected Tropical DiseasesGenevaSwitzerland
| | - Rahul Kumar
- King George's Medical UniversityDepartment of PharmacologyLucknowUPIndia226003
| | - Ángela Perez
- Health Technology Assessment InstituteDeveloping Clinical Practice GuidelinesAutopista Norte # 118‐30 Off 201BogotáColombia110111
| | - Balendra P Singh
- King George's Medical UniversityDepartment of Prosthodontics, Crowns and BridgesShahmina RoadFaculty of Dental SciencesLucknowUttar PradeshIndia226003
| | | | - Emma Harding‐Esch
- London School of Hygiene & Tropical MedicineClinical Research Department, Facullty of Infectious and Tropical DiseasesLondonUK
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Amza A, Kadri B, Nassirou B, Cotter SY, Stoller NE, West SK, Bailey RL, Porco TC, Keenan JD, Lietman TM, Oldenburg CE. Community-level Association between Clinical Trachoma and Ocular Chlamydia Infection after MASS Azithromycin Distribution in a Mesoendemic Region of Niger. Ophthalmic Epidemiol 2019; 26:231-237. [PMID: 30957594 PMCID: PMC9982651 DOI: 10.1080/09286586.2019.1597129] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Purpose: The clinical sign trachomatous inflammation - follicular (TF) is used to monitor indication for and response to mass azithromycin distribution in trachoma-endemic communities. Here, we assess the relationship between TF, trachomatous inflammation - intense (TI), and infection with ocular Chlamydia trachomatis over time during annual mass azithromycin distribution. Methods: We used data from a cluster-randomized trial of mass azithromycin distribution for trachoma control in a mesoendemic region of Niger. This study includes 24 communities that received 3 years of annual mass azithromycin distribution. TF, TI, and ocular chlamydia infection were monitored among children aged 0-5 years. We assessed the correlation between the prevalence of ocular chlamydia infection and 1) TF and 2) TI prevalence over time. Results: At baseline, ocular chlamydia prevalence was 21.2% (95% CI 14.3-28.1%), TF prevalence was 27.7% (95% CI 21.2-34.2%), and TI prevalence was 8.3% (95% CI 5.2-11.5%). The prevalence of all three measures decreased significantly over time (P < 0.001). At baseline, ocular chlamydia infection prevalence was strongly correlated with both TF (rho = 0.78, P < 0.0001) and TI (rho = 0.76, P < 0.0001). The correlation between ocular chlamydia infection and both TF and TI was weak at months 12 and 24. At 36 months, when TF prevalence had dropped below 10%, ocular chlamydia infection and TF were moderately correlated (rho = 0.70, P= 0.0002). Conclusions: Both TF and TI are good indicators of infection prevalence prior to mass azithromycin distribution. However, this relationship may be affected by repeated rounds of mass azithromycin distribution.
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Affiliation(s)
- Abdou Amza
- Programme FSS/Université Abdou Moumouni de Niamey, Programme Nationale des Soins Oculaire, Niamey, Niger
| | - Boubacar Kadri
- Programme FSS/Université Abdou Moumouni de Niamey, Programme Nationale des Soins Oculaire, Niamey, Niger
| | - Beido Nassirou
- Programme FSS/Université Abdou Moumouni de Niamey, Programme Nationale des Soins Oculaire, Niamey, Niger
| | - Sun Y Cotter
- Francis I. Proctor Foundation, University of California, San Francisco, USA
| | - Nicole E. Stoller
- Francis I. Proctor Foundation, University of California, San Francisco, USA
| | - Sheila K West
- Dana Center for Preventive Ophthalmology, Wilmer Eye Institute, Johns Hopkins University, Baltimore, Maryland, USA
| | - Robin L. Bailey
- Clinical Research Unit, Department of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Travis C. Porco
- Francis I. Proctor Foundation, University of California, San Francisco, USA,Department of Ophthalmology, University of California, San Francisco, USA,Department of Epidemiology & Biostatistics, University of California, San Francisco, USA
| | - Jeremy D. Keenan
- Francis I. Proctor Foundation, University of California, San Francisco, USA,Department of Ophthalmology, University of California, San Francisco, USA,Department of Epidemiology & Biostatistics, University of California, San Francisco, USA
| | - Thomas M. Lietman
- Francis I. Proctor Foundation, University of California, San Francisco, USA,Department of Ophthalmology, University of California, San Francisco, 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, San Francisco, USA
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Ramadhani AM, Derrick T, Macleod D, Holland MJ, Burton MJ. The Relationship between Active Trachoma and Ocular Chlamydia trachomatis Infection before and after Mass Antibiotic Treatment. PLoS Negl Trop Dis 2016; 10:e0005080. [PMID: 27783678 PMCID: PMC5082620 DOI: 10.1371/journal.pntd.0005080] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2016] [Accepted: 09/28/2016] [Indexed: 12/02/2022] Open
Abstract
Background Trachoma is a blinding disease, initiated in early childhood by repeated conjunctival infection with the obligate intracellular bacterium Chlamydia trachomatis. The population prevalence of the clinical signs of active trachoma; ‘‘follicular conjunctivitis” (TF) and/or ‘‘intense papillary inflammation” (TI), guide programmatic decisions regarding the initiation and cessation of mass drug administration (MDA). However, the persistence of TF following resolution of infection at both the individual and population level raises concerns over the suitability of this clinical sign as a marker for C. trachomatis infection. Methodology/Principle Findings We systematically reviewed the literature for population-based studies and those including randomly selected individuals, which reported the prevalence of the clinical signs of active trachoma and ocular C. trachomatis infection by nucleic acid amplification test. We performed a meta-analysis to assess the relationship between active trachoma and C. trachomatis infection before and after MDA. TF and C. trachomatis infection were strongly correlated prior to MDA (r = 0.92, 95%CI 0.83 to 0.96, p<0.0001); the relationship was similar when the analysis was limited to children. A moderate correlation was found between TI and prevalence of infection. Following MDA, the relationship between TF and infection prevalence was weaker (r = 0.60, 95%CI 0.25 to 0.81, p = 0.003) and there was no correlation between TI and C. trachomatis infection. Conclusions/Significance Prior to MDA, TF is a good indicator of the community prevalence of C. trachomatis infection. Following MDA, the prevalence of TF tends to overestimate the underlying infection prevalence. In order to prevent unnecessary additional rounds of MDA and to accurately ascertain when elimination goals have been reached, a cost-effective test for C. trachomatis that can be administered in low-resource settings remains desirable. Trachoma is the leading infectious cause of blindness worldwide, caused by the bacterium Chlamydia trachomatis. Repeated infection of the conjunctiva during childhood can initiate chronic conjunctival inflammation. This can lead to conjunctival scarring, in turning of the eyelashes, abrasion of the eyelashes on the cornea and eventually blindness later in adulthood. The World Health Organization recommends mass drug administration (MDA) for infection control when the prevalence of the clinical sign of Active Trachoma (TF) is ≥10% in 1–9 year olds. This systematic review of the literature examined the relationship between TF and C. trachomatis infection before and after MDA in order to evaluate the usefulness of TF for guiding trachoma control programmes. The population prevalence of TF and C. trachomatis infection were strongly correlated prior to MDA, however the relationship was weaker after MDA with a greater tendency for TF to overestimate the underlying infection prevalence. A cost effective test for C. trachomatis suitable for use in low resource settings could prevent unnecessary additional rounds of MDA in the population and could identify when trachoma elimination goals have been reached at an earlier time point.
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Affiliation(s)
- Athumani M. Ramadhani
- Clinical Research Department, Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, United Kingdom
- Kilimanjaro Christian Medical Centre, Moshi, Tanzania
- * E-mail:
| | - Tamsyn Derrick
- Clinical Research Department, Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, United Kingdom
- Kilimanjaro Christian Medical Centre, Moshi, Tanzania
| | - David Macleod
- Tropical Epidemiology Group. London School of Hygiene & Tropical Medicine, United Kingdom
| | - Martin J. Holland
- Clinical Research Department, Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, United Kingdom
| | - Matthew J. Burton
- Clinical Research Department, Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, United Kingdom
- Moorfields Eye Hospital, London, United Kingdom
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Liu F, Porco TC, Amza A, Kadri B, Nassirou B, West SK, Bailey RL, Keenan JD, Lietman TM. Short-term forecasting of the prevalence of clinical trachoma: utility of including delayed recovery and tests for infection. Parasit Vectors 2015; 8:535. [PMID: 26489933 PMCID: PMC4618840 DOI: 10.1186/s13071-015-1115-8] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2015] [Accepted: 09/28/2015] [Indexed: 12/03/2022] Open
Abstract
Background The World Health Organization aims to control blinding trachoma by 2020. Decisions on whether to start and stop mass treatments and when to declare that control has been achieved are currently based on clinical examination data generated in population-based surveys. Thresholds are based on the district-level prevalence of trachomatous inflammation–follicular (TF) in children aged 1–9 years. Forecasts of which districts may and may not meet TF control goals by the 2020 target date could affect resource allocation in the next few years. Methods We constructed a hidden Markov model fit to the prevalence of two clinical signs of trachoma and PCR data in 24 communities from the recent PRET-Niger trial. The prevalence of TF in children in each community at 36 months was forecast given data from earlier time points. Forecasts were scored by the likelihood of the observed results. We assessed whether use of TF with additional TI and PCR data rather than just the use of TF alone improves forecasts, and separately whether incorporating a delay in TF recovery is beneficial. Results Including TI and PCR data did not significantly improve forecasts of TF. Forecasts of TF prevalence at 36 months by the model with the delay in TF recovery were significantly better than forecasts by the model without the delay in TF recovery (p = 0.003). A zero-inflated truncated normal observation model was better than a truncated normal observation model, and better than a sensitivity-specificity observation model. Conclusion The results in this study suggest that future studies could consider using just TF data for forecasting, and should include a delay in TF recovery. Trial registration Clinicaltrials.gov NCT00792922 Electronic supplementary material The online version of this article (doi:10.1186/s13071-015-1115-8) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Fengchen Liu
- F.I. Proctor Foundation, University of California San Francisco, 513 Parnassus, Medical Sciences 309A, San Francisco, CA, 94143-0944, USA.
| | - Travis C Porco
- F.I. Proctor Foundation, University of California San Francisco, 513 Parnassus, Medical Sciences 309A, San Francisco, CA, 94143-0944, USA. .,Department of Ophthalmology, University of California San Francisco, San Francisco, CA, USA. .,Department of Epidemiology and Biostatistics, University of California San Francisco, San Francisco, CA, USA.
| | - Abdou Amza
- Programme FSS/Université Abdou Moumouni de Niamey, Programme National de Santé Oculaire, Niamey, Niger.
| | - Boubacar Kadri
- Programme FSS/Université Abdou Moumouni de Niamey, Programme National de Santé Oculaire, Niamey, Niger.
| | - Baido Nassirou
- Programme FSS/Université Abdou Moumouni de Niamey, Programme National de Santé Oculaire, Niamey, Niger.
| | - Sheila K West
- Dana Center for Preventive Ophthalmology, Wilmer Eye Institute, Johns Hopkins University, Baltimore, MD, USA.
| | - Robin L Bailey
- Clinical Research Unit, Department of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, UK.
| | - Jeremy D Keenan
- F.I. Proctor Foundation, University of California San Francisco, 513 Parnassus, Medical Sciences 309A, San Francisco, CA, 94143-0944, USA. .,Department of Ophthalmology, University of California San Francisco, San Francisco, CA, USA.
| | - Thomas M Lietman
- F.I. Proctor Foundation, University of California San Francisco, 513 Parnassus, Medical Sciences 309A, San Francisco, CA, 94143-0944, USA. .,Department of Ophthalmology, University of California San Francisco, San Francisco, CA, USA. .,Department of Epidemiology and Biostatistics, University of California San Francisco, San Francisco, CA, USA.
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Abstract
Trachoma is the most common infectious cause of blindness. Repeated episodes of infection with Chlamydia trachomatis in childhood lead to severe conjunctival inflammation, scarring, and potentially blinding inturned eyelashes (trichiasis or entropion) in later life. Trachoma occurs in resource-poor areas with inadequate hygiene, where children with unclean faces share infected ocular secretions. Much has been learnt about the epidemiology and pathophysiology of trachoma. Integrated control programmes are implementing the SAFE Strategy: surgery for trichiasis, mass distribution of antibiotics, promotion of facial cleanliness, and environmental improvement. This strategy has successfully eliminated trachoma in several countries and global efforts are underway to eliminate blinding trachoma worldwide by 2020.
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Affiliation(s)
- Hugh R Taylor
- Melbourne School of Population and Global Health, University of Melbourne, Carlton, VIC, Australia.
| | - Matthew J Burton
- International Centre for Eye Health, Department of Clinical Research, London School of Hygiene & Tropical Medicine, London, UK
| | - Danny Haddad
- Global Vision Initiative, Emory Eye Center, Emory University School of Medicine, Atlanta, GA, USA
| | - Sheila West
- Wilmer Eye Institute, Johns Hopkins Hospital, Baltimore, MD, USA
| | - Heathcote Wright
- Centre for Eye Research Australia, University of Melbourne, East Melbourne, VIC, Australia
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Haile M, Tadesse Z, Gebreselassie S, Ayele B, Gebre T, Yu SN, Stoller NE, Gaynor BD, Porco TC, Emerson PM, Lietman TM, Keenan JD. The association between latrine use and trachoma: a secondary cohort analysis from a randomized clinical trial. Am J Trop Med Hyg 2013; 89:717-20. [PMID: 24002488 DOI: 10.4269/ajtmh.13-0299] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
Latrine use has been promoted as a component of an integrated strategy for trachoma control. As part of a randomized trial in Ethiopia, 12 communities received a mass azithromycin distribution followed by a latrine promotion intervention. A random sample of children ages 0-9 years in each community was monitored longitudinally for ocular chlamydia. After latrine construction ended, those communities with a higher proportion of households using latrines were more likely to experience a reduction in the prevalence of ocular chlamydia. Specifically, for each 10% increase in latrine use, there was a 2.0% decrease (95% confidence interval = 0.2-3.9% decrease) in the community prevalence of ocular chlamydia over the subsequent year (P = 0.04).
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Affiliation(s)
- Meron Haile
- Francis I. Proctor Foundation, University of California, San Francisco, California; The Carter Center, Addis Ababa, Ethiopia; Departments of Ophthalmology and Epidemiology and Biostatistics, University of California, San Francisco, California; The Carter Center, Atlanta, Georgia; Institute for Global Health, University of California, San Francisco, California
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Lavett DK, Lansingh VC, Carter MJ, Eckert KA, Silva JC. Will the SAFE strategy be sufficient to eliminate trachoma by 2020? Puzzlements and possible solutions. ScientificWorldJournal 2013; 2013:648106. [PMID: 23766701 PMCID: PMC3671555 DOI: 10.1155/2013/648106] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2013] [Accepted: 03/13/2013] [Indexed: 11/18/2022] Open
Abstract
Since the inception of (the Global Elimination of Blinding Trachoma) GET 2020 in 1997 and the implementation of the SAFE strategy a year later, much progress has been made toward lowering the prevalence of trachoma worldwide with elimination of the disease in some countries. However, high recurrence of trichiasis after surgery, difficulty in controlling the reemergence of infection after mass distribution of azithromycin in some communities, the incomplete understanding of environment in relation to the disease, and the difficulty in establishing the prevalence of the disease in low endemic areas are some of the issues still facing completion of the GET 2020 goals. In this narrative review, literature was searched from 1998 to January 2013 in PubMed for original studies and reviews. Reasons for these ongoing problems are discussed, and several suggestions are made as avenues for exploration in relation to improving the SAFE strategy with emphasis on improving surgical quality and management of the mass treatment with antibiotics. In addition, more research needs to be done to better understand the approach to improve sanitation, hygiene, and environment. The main conclusion of this review is that scale-up is needed for all SAFE components, and more research should be generated from communities outside of Africa and Asia.
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Affiliation(s)
- Diane K. Lavett
- Strategic Solutions, Inc., 1143 Salsbury Avenue, Cody, WY 82414, USA
| | - Van C. Lansingh
- International Agency for the Prevention of Blindness/VISION 2020 Latin America, 3720 San Simeon Circle, Weston, FL 33331, USA
- Hamilton Eye Institute, University of Memphis, Memphis, TN 38152, USA
| | - Marissa J. Carter
- Strategic Solutions, Inc., 1143 Salsbury Avenue, Cody, WY 82414, USA
| | - Kristen A. Eckert
- Strategic Solutions, Inc., 1143 Salsbury Avenue, Cody, WY 82414, USA
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Koukounari A, Moustaki I, Grassly NC, Blake IM, Basáñez MG, Gambhir M, Mabey DCW, Bailey RL, Burton MJ, Solomon AW, Donnelly CA. Using a nonparametric multilevel latent Markov model to evaluate diagnostics for trachoma. Am J Epidemiol 2013; 177:913-22. [PMID: 23548755 PMCID: PMC3639724 DOI: 10.1093/aje/kws345] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
In disease control or elimination programs, diagnostics are essential for assessing the impact of interventions, refining treatment strategies, and minimizing the waste of scarce resources. Although high-performance tests are desirable, increased accuracy is frequently accompanied by a requirement for more elaborate infrastructure, which is often not feasible in the developing world. These challenges are pertinent to mapping, impact monitoring, and surveillance in trachoma elimination programs. To help inform rational design of diagnostics for trachoma elimination, we outline a nonparametric multilevel latent Markov modeling approach and apply it to 2 longitudinal cohort studies of trachoma-endemic communities in Tanzania (2000–2002) and The Gambia (2001–2002) to provide simultaneous inferences about the true population prevalence of Chlamydia trachomatis infection and disease and the sensitivity, specificity, and predictive values of 3 diagnostic tests for C. trachomatis infection. Estimates were obtained by using data collected before and after mass azithromycin administration. Such estimates are particularly important for trachoma because of the absence of a true “gold standard” diagnostic test for C. trachomatis. Estimated transition probabilities provide useful insights into key epidemiologic questions about the persistence of disease and the clearance of infection as well as the required frequency of surveillance in the postelimination setting.
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Affiliation(s)
- Artemis Koukounari
- Correspondence to Dr. Artemis Koukounari, Medical Research Council Centre for Outbreak Analysis and Modelling, Department of Infectious Disease Epidemiology, Imperial College London, London, W2 1PG, United Kingdom (e-mail: )
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Development and evaluation of a next-generation digital PCR diagnostic assay for ocular Chlamydia trachomatis infections. J Clin Microbiol 2013; 51:2195-203. [PMID: 23637300 PMCID: PMC3697714 DOI: 10.1128/jcm.00622-13] [Citation(s) in RCA: 86] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Droplet digital PCR (ddPCR) is an emulsion PCR process that performs absolute quantitation of nucleic acids. We developed a ddPCR assay for Chlamydia trachomatis infections and found it to be accurate and precise. Using PCR mixtures containing plasmids engineered to include the PCR target sequences, we were able to quantify with a dynamic range between 0.07 and 3,160 targets/μl (r2 = 0.9927) with >95% confidence. Using 1,509 clinical conjunctival swab samples from a population in which trachoma is endemic in Guinea Bissau, we evaluated the specificity and sensitivity of the quantitative ddPCR assay in diagnosing ocular C. trachomatis infections by comparing the performances of ddPCR and the Roche Amplicor CT/NG test. We defined ddPCR tests as positive when we had ≥95% confidence in a nonzero estimate of target load. The sensitivity of ddPCR against Amplicor was 73.3% (95% confidence interval [CI], 67.9 to 78.7%), and specificity was 99.1% (95% CI, 98.6 to 99.6%). Negative and positive predictive values were 94.6% (95% CI, 93.4 to 95.8%) and 94.5% (95% CI, 91.3 to 97.7%), respectively. Based on Amplicor CT/NG testing, the estimated population prevalence of C. trachomatis ocular infection was ∼17.5%. Receiver-operator curve analysis was used to select critical cutoff values for use in clinical settings in which a balance between higher sensitivity and specificity is required. We concluded that ddPCR is an effective diagnostic technology suitable for both research and clinical use in diagnosing ocular C. trachomatis infections.
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