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Harte AJ, Ghasemian E, Pickering H, Houghton J, Chernet A, Sata E, Yismaw G, Zeru T, Tadesse Z, Callahan EK, Nash SD, Holland MJ. Unravelling Chlamydia trachomatis diversity in Amhara, Ethiopia: MLVA-ompA sequencing as a molecular typing tool for trachoma. PLoS Negl Trop Dis 2024; 18:e0012143. [PMID: 38662795 PMCID: PMC11075894 DOI: 10.1371/journal.pntd.0012143] [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: 01/31/2024] [Revised: 05/07/2024] [Accepted: 04/08/2024] [Indexed: 05/08/2024] Open
Abstract
Trachoma is the leading infectious cause of blindness worldwide and is now largely confined to around 40 low- and middle-income countries. It is caused by Chlamydia trachomatis (Ct), a contagious intracellular bacterium. The World Health Organization recommends mass drug administration (MDA) with azithromycin for treatment and control of ocular Ct infections, alongside improving facial cleanliness and environmental conditions to reduce transmission. To understand the molecular epidemiology of trachoma, especially in the context of MDA and transmission dynamics, the identification of Ct genotypes could be useful. While many studies have used the Ct major outer membrane protein gene (ompA) for genotyping, it has limitations. Our study applies a typing system novel to trachoma, Multiple Loci Variable Number Tandem Repeat Analysis combined with ompA (MLVA-ompA). Ocular swabs were collected post-MDA from four trachoma-endemic zones in Ethiopia between 2011-2017. DNA from 300 children with high Ct polymerase chain reaction (PCR) loads was typed using MLVA-ompA, utilizing 3 variable number tandem repeat (VNTR) loci within the Ct genome. Results show that MLVA-ompA exhibited high discriminatory power (0.981) surpassing the recommended threshold for epidemiological studies. We identified 87 MLVA-ompA variants across 26 districts. No significant associations were found between variants and clinical signs or chlamydial load. Notably, overall Ct diversity significantly decreased after additional MDA rounds, with a higher proportion of serovar A post-MDA. Despite challenges in sequencing one VNTR locus (CT1299), MLVA-ompA demonstrated cost-effectiveness and efficiency relative to whole genome sequencing, providing valuable information for trachoma control programs on local epidemiology. The findings suggest the potential of MLVA-ompA as a reliable tool for typing ocular Ct and understanding transmission dynamics, aiding in the development of targeted interventions for trachoma control.
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Affiliation(s)
- Anna J. Harte
- The London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Ehsan Ghasemian
- The London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Harry Pickering
- The London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Joanna Houghton
- The London School of Hygiene and Tropical Medicine, London, United Kingdom
| | | | | | | | - Taye Zeru
- The Amhara Regional Health Bureau, Bahir Dar, Ethiopia
| | | | | | - Scott D. Nash
- The Carter Center, Atlanta, Georgia, United States of America
| | - Martin J. Holland
- The London School of Hygiene and Tropical Medicine, London, United Kingdom
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Sié A, Ouattara M, Bountogo M, Boudo V, Ouedraogo T, Compaoré G, Dah C, Bagagnan C, Lebas E, Hu H, Rice J, Porco TC, Arnold BF, Lietman TM, Oldenburg CE. Azithromycin during Routine Well-Infant Visits to Prevent Death. N Engl J Med 2024; 390:221-229. [PMID: 38231623 DOI: 10.1056/nejmoa2309495] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/19/2024]
Abstract
BACKGROUND Mass distribution of azithromycin to children 1 to 59 months of age has been shown to reduce childhood all-cause mortality in some sub-Saharan African regions, with the largest reduction seen among infants younger than 12 months of age. Whether the administration of azithromycin at routine health care visits for infants would be effective in preventing death is unclear. METHODS We conducted a randomized, placebo-controlled trial of a single dose of azithromycin (20 mg per kilogram of body weight) as compared with placebo, administered during infancy (5 to 12 weeks of age). The primary end point was death before 6 months of age. Infants were recruited at routine vaccination or other well-child visits in clinics and through community outreach in three regions of Burkina Faso. Vital status was assessed at 6 months of age. RESULTS Of the 32,877 infants enrolled from September 2019 through October 2022, a total of 16,416 infants were randomly assigned to azithromycin and 16,461 to placebo. Eighty-two infants in the azithromycin group and 75 infants in the placebo group died before 6 months of age (hazard ratio, 1.09; 95% confidence interval [CI], 0.80 to 1.49; P = 0.58); the absolute difference in mortality was 0.04 percentage points (95% CI, -0.10 to 0.21). There was no evidence of an effect of azithromycin on mortality in any of the prespecified subgroups, including subgroups defined according to age, sex, and baseline weight, and no evidence of a difference between the two trial groups in the incidence of adverse events. CONCLUSIONS In this trial conducted in Burkina Faso, we found that administration of azithromycin to infants through the existing health care system did not prevent death. (Funded by the Bill and Melinda Gates Foundation; CHAT ClinicalTrials.gov number, NCT03676764.).
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Affiliation(s)
- Ali Sié
- From Centre de Recherche en Santé de Nouna, Nouna, Burkina Faso (A.S., M.O., M.B., V.B., T.O., G.C., C.D., C.B.); and the Francis I. Proctor Foundation (E.L., H.H., T.C.P., B.F.A., T.M.L., C.E.O., J.R.), the Department of Epidemiology and Biostatistics (T.C.P., T.M.L., C.E.O.), the Department of Ophthalmology (T.C.P., B.F.A., T.M.L., C.E.O.), and the Institute for Global Health Sciences (T.M.L., C.E.O.), University of California, San Francisco, San Francisco
| | - Mamadou Ouattara
- From Centre de Recherche en Santé de Nouna, Nouna, Burkina Faso (A.S., M.O., M.B., V.B., T.O., G.C., C.D., C.B.); and the Francis I. Proctor Foundation (E.L., H.H., T.C.P., B.F.A., T.M.L., C.E.O., J.R.), the Department of Epidemiology and Biostatistics (T.C.P., T.M.L., C.E.O.), the Department of Ophthalmology (T.C.P., B.F.A., T.M.L., C.E.O.), and the Institute for Global Health Sciences (T.M.L., C.E.O.), University of California, San Francisco, San Francisco
| | - Mamadou Bountogo
- From Centre de Recherche en Santé de Nouna, Nouna, Burkina Faso (A.S., M.O., M.B., V.B., T.O., G.C., C.D., C.B.); and the Francis I. Proctor Foundation (E.L., H.H., T.C.P., B.F.A., T.M.L., C.E.O., J.R.), the Department of Epidemiology and Biostatistics (T.C.P., T.M.L., C.E.O.), the Department of Ophthalmology (T.C.P., B.F.A., T.M.L., C.E.O.), and the Institute for Global Health Sciences (T.M.L., C.E.O.), University of California, San Francisco, San Francisco
| | - Valentin Boudo
- From Centre de Recherche en Santé de Nouna, Nouna, Burkina Faso (A.S., M.O., M.B., V.B., T.O., G.C., C.D., C.B.); and the Francis I. Proctor Foundation (E.L., H.H., T.C.P., B.F.A., T.M.L., C.E.O., J.R.), the Department of Epidemiology and Biostatistics (T.C.P., T.M.L., C.E.O.), the Department of Ophthalmology (T.C.P., B.F.A., T.M.L., C.E.O.), and the Institute for Global Health Sciences (T.M.L., C.E.O.), University of California, San Francisco, San Francisco
| | - Thierry Ouedraogo
- From Centre de Recherche en Santé de Nouna, Nouna, Burkina Faso (A.S., M.O., M.B., V.B., T.O., G.C., C.D., C.B.); and the Francis I. Proctor Foundation (E.L., H.H., T.C.P., B.F.A., T.M.L., C.E.O., J.R.), the Department of Epidemiology and Biostatistics (T.C.P., T.M.L., C.E.O.), the Department of Ophthalmology (T.C.P., B.F.A., T.M.L., C.E.O.), and the Institute for Global Health Sciences (T.M.L., C.E.O.), University of California, San Francisco, San Francisco
| | - Guillaume Compaoré
- From Centre de Recherche en Santé de Nouna, Nouna, Burkina Faso (A.S., M.O., M.B., V.B., T.O., G.C., C.D., C.B.); and the Francis I. Proctor Foundation (E.L., H.H., T.C.P., B.F.A., T.M.L., C.E.O., J.R.), the Department of Epidemiology and Biostatistics (T.C.P., T.M.L., C.E.O.), the Department of Ophthalmology (T.C.P., B.F.A., T.M.L., C.E.O.), and the Institute for Global Health Sciences (T.M.L., C.E.O.), University of California, San Francisco, San Francisco
| | - Clarisse Dah
- From Centre de Recherche en Santé de Nouna, Nouna, Burkina Faso (A.S., M.O., M.B., V.B., T.O., G.C., C.D., C.B.); and the Francis I. Proctor Foundation (E.L., H.H., T.C.P., B.F.A., T.M.L., C.E.O., J.R.), the Department of Epidemiology and Biostatistics (T.C.P., T.M.L., C.E.O.), the Department of Ophthalmology (T.C.P., B.F.A., T.M.L., C.E.O.), and the Institute for Global Health Sciences (T.M.L., C.E.O.), University of California, San Francisco, San Francisco
| | - Cheik Bagagnan
- From Centre de Recherche en Santé de Nouna, Nouna, Burkina Faso (A.S., M.O., M.B., V.B., T.O., G.C., C.D., C.B.); and the Francis I. Proctor Foundation (E.L., H.H., T.C.P., B.F.A., T.M.L., C.E.O., J.R.), the Department of Epidemiology and Biostatistics (T.C.P., T.M.L., C.E.O.), the Department of Ophthalmology (T.C.P., B.F.A., T.M.L., C.E.O.), and the Institute for Global Health Sciences (T.M.L., C.E.O.), University of California, San Francisco, San Francisco
| | - Elodie Lebas
- From Centre de Recherche en Santé de Nouna, Nouna, Burkina Faso (A.S., M.O., M.B., V.B., T.O., G.C., C.D., C.B.); and the Francis I. Proctor Foundation (E.L., H.H., T.C.P., B.F.A., T.M.L., C.E.O., J.R.), the Department of Epidemiology and Biostatistics (T.C.P., T.M.L., C.E.O.), the Department of Ophthalmology (T.C.P., B.F.A., T.M.L., C.E.O.), and the Institute for Global Health Sciences (T.M.L., C.E.O.), University of California, San Francisco, San Francisco
| | - Huiyu Hu
- From Centre de Recherche en Santé de Nouna, Nouna, Burkina Faso (A.S., M.O., M.B., V.B., T.O., G.C., C.D., C.B.); and the Francis I. Proctor Foundation (E.L., H.H., T.C.P., B.F.A., T.M.L., C.E.O., J.R.), the Department of Epidemiology and Biostatistics (T.C.P., T.M.L., C.E.O.), the Department of Ophthalmology (T.C.P., B.F.A., T.M.L., C.E.O.), and the Institute for Global Health Sciences (T.M.L., C.E.O.), University of California, San Francisco, San Francisco
| | - Jessica Rice
- From Centre de Recherche en Santé de Nouna, Nouna, Burkina Faso (A.S., M.O., M.B., V.B., T.O., G.C., C.D., C.B.); and the Francis I. Proctor Foundation (E.L., H.H., T.C.P., B.F.A., T.M.L., C.E.O., J.R.), the Department of Epidemiology and Biostatistics (T.C.P., T.M.L., C.E.O.), the Department of Ophthalmology (T.C.P., B.F.A., T.M.L., C.E.O.), and the Institute for Global Health Sciences (T.M.L., C.E.O.), University of California, San Francisco, San Francisco
| | - Travis C Porco
- From Centre de Recherche en Santé de Nouna, Nouna, Burkina Faso (A.S., M.O., M.B., V.B., T.O., G.C., C.D., C.B.); and the Francis I. Proctor Foundation (E.L., H.H., T.C.P., B.F.A., T.M.L., C.E.O., J.R.), the Department of Epidemiology and Biostatistics (T.C.P., T.M.L., C.E.O.), the Department of Ophthalmology (T.C.P., B.F.A., T.M.L., C.E.O.), and the Institute for Global Health Sciences (T.M.L., C.E.O.), University of California, San Francisco, San Francisco
| | - Benjamin F Arnold
- From Centre de Recherche en Santé de Nouna, Nouna, Burkina Faso (A.S., M.O., M.B., V.B., T.O., G.C., C.D., C.B.); and the Francis I. Proctor Foundation (E.L., H.H., T.C.P., B.F.A., T.M.L., C.E.O., J.R.), the Department of Epidemiology and Biostatistics (T.C.P., T.M.L., C.E.O.), the Department of Ophthalmology (T.C.P., B.F.A., T.M.L., C.E.O.), and the Institute for Global Health Sciences (T.M.L., C.E.O.), University of California, San Francisco, San Francisco
| | - Thomas M Lietman
- From Centre de Recherche en Santé de Nouna, Nouna, Burkina Faso (A.S., M.O., M.B., V.B., T.O., G.C., C.D., C.B.); and the Francis I. Proctor Foundation (E.L., H.H., T.C.P., B.F.A., T.M.L., C.E.O., J.R.), the Department of Epidemiology and Biostatistics (T.C.P., T.M.L., C.E.O.), the Department of Ophthalmology (T.C.P., B.F.A., T.M.L., C.E.O.), and the Institute for Global Health Sciences (T.M.L., C.E.O.), University of California, San Francisco, San Francisco
| | - Catherine E Oldenburg
- From Centre de Recherche en Santé de Nouna, Nouna, Burkina Faso (A.S., M.O., M.B., V.B., T.O., G.C., C.D., C.B.); and the Francis I. Proctor Foundation (E.L., H.H., T.C.P., B.F.A., T.M.L., C.E.O., J.R.), the Department of Epidemiology and Biostatistics (T.C.P., T.M.L., C.E.O.), the Department of Ophthalmology (T.C.P., B.F.A., T.M.L., C.E.O.), and the Institute for Global Health Sciences (T.M.L., C.E.O.), University of California, San Francisco, San Francisco
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Shafi Abdurahman O, Last A, Macleod D, Habtamu E, Versteeg B, Dumessa G, Guye M, Nure R, Adugna D, Miecha H, Greenland K, Burton MJ. Trachoma risk factors in Oromia Region, Ethiopia. PLoS Negl Trop Dis 2023; 17:e0011679. [PMID: 37934731 PMCID: PMC10629622 DOI: 10.1371/journal.pntd.0011679] [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: 06/28/2023] [Accepted: 09/21/2023] [Indexed: 11/09/2023] Open
Abstract
BACKGROUND Trachoma, the leading infectious cause of blindness, is caused by the bacterium Chlamydia trachomatis (Ct). Despite enormous disease control efforts and encouraging progress, trachoma remains a significant public health problem in 44 countries. Ethiopia has the greatest burden of trachoma worldwide, however, robust data exploring transmission risk factors and the association between socio-economic status is lacking from some regions. This is the first study to investigate these factors in this South-Eastern region of Oromia, Ethiopia. METHODOLOGY/PRINCIPAL FINDINGS A total of 1211 individuals were enrolled from 247 households in Shashemene Rural district in Oromia Region between 11th April and 25th June 2018, of whom 628 (51.9%) were female and 526 (43.4%) were children aged 1-9 years. Three standardised ophthalmic nurses examined each participant for the presence of active trachoma using the WHO simplified trachoma grading system. Conjunctival swab samples were collected from the upper tarsal conjunctiva of the left eye of each participant. Ct was detected using quantitative PCR. Risk factor data were collected through structured interviews and direct observations. Clinical signs of trachomatous inflammation-follicular among children aged 1-9 (TF1-9) were observed in at least one eye of 106/526 (20.2%) and trachomatous inflammation-intense among children aged 1-9 (TI1-9) were observed in at least one eye of 10/526 (1.9%). We detected Ct by PCR in 23 individuals, of whom 18 (78.3%) were in children aged 1-9 years. Among the 106 children aged 1-9 years with TF, 12 (11.3%) were Ct PCR positive and among 20 children aged 1-9 years with TI, 4 (20.0%) were Ct PCR positive. In a multivariable model, adjusting for household clustering, active trachoma was associated with younger age, the poorest households (aOR = 2.56, 95% CI 1.21-5.51), presence of flies on the face (aOR = 2.87, 95% CI 1.69-6.46), and ocular discharge (aOR = 1.89, 95% CI 1.03-3.24). Pre-school children face washing more than once a day had lower odds of having active trachoma (aOR = 0.59, 95% CI 0.19-0.84). The same was true for washing children's clothing at least once per week (aOR = 0.27, 95% CI 0.33-1.02). CONCLUSION/SIGNIFICANCE Younger age, personal hygiene in this age group (presence of ocular and nasal discharges, infrequent washing of faces and clothing) and fly-eye contacts are potential risk factors for trachoma in this setting, suggesting that hygiene interventions and environmental improvements are required to suppress transmission to ensure sustained reduction in disease burden Further studies are needed to evaluate these interventions for trachoma control and elimination. Trachoma remains a disease associated with lower socio-economic status, emphasising the need for continued implementation of control measures in addition to poverty reduction interventions in this region.
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Affiliation(s)
- Oumer Shafi Abdurahman
- International Centre for Eye Health, Clinical Research Department, Faculty of Infectious and Tropical diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom
- The Fred Hollows Foundation, Addis Ababa, Ethiopia
| | - Anna Last
- International Centre for Eye Health, Clinical Research Department, Faculty of Infectious and Tropical diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - David Macleod
- International Centre for Eye Health, Clinical Research Department, Faculty of Infectious and Tropical diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Esmael Habtamu
- International Centre for Eye Health, Clinical Research Department, Faculty of Infectious and Tropical diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Bart Versteeg
- International Centre for Eye Health, Clinical Research Department, Faculty of Infectious and Tropical diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | | | - Meseret Guye
- The Fred Hollows Foundation, Addis Ababa, Ethiopia
| | - Rufia Nure
- The Fred Hollows Foundation, Addis Ababa, Ethiopia
| | - Dereje Adugna
- Oromia Regional Health Bureau, Addis Ababa, Ethiopia
| | - Hirpha Miecha
- Oromia Regional Health Bureau, Addis Ababa, Ethiopia
| | - Katie Greenland
- Environmental Health Group, Department for Disease Control, Faculty of Infectious and Tropical. Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Matthew J. Burton
- International Centre for Eye Health, Clinical Research Department, Faculty of Infectious and Tropical diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom
- National Institute for Health Research Biomedical Research Centre for Ophthalmology at Moorfields Eye Hospital NHS Foundation Trust and UCL Institute of Ophthalmology, London, United Kingdom
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Barazanji M, Ngo JD, Powe JA, Schneider KP, Rychtář J, Taylor D. Modeling the "F" in "SAFE": The dynamic game of facial cleanliness in trachoma prevention. PLoS One 2023; 18:e0287464. [PMID: 37352249 PMCID: PMC10289400 DOI: 10.1371/journal.pone.0287464] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2023] [Accepted: 06/06/2023] [Indexed: 06/25/2023] Open
Abstract
Trachoma, a neglected tropical disease (NTDs) caused by bacterium Chlamydia trachomatis, is a leading cause of infectious blindness. Efforts are underway to eliminate trachoma as a public health problem by using the "SAFE" strategy. While mathematical models are now standard tools used to support elimination efforts and there are a variety of models studying different aspects of trachoma transmission dynamics, the "F" component of the strategy corresponding to facial cleanliness has received very little attention so far. In this paper, we incorporate human behavior into a standard epidemiological model and develop a dynamical game during which individuals practice facial cleanliness based on their epidemiological status and perceived benefits and costs. We found that the number of infectious individuals generally increases with the difficulty to access a water source. However, this increase happens only during three transition periods and the prevalence stays constant otherwise. Consequently, improving access to water can help eliminate trachoma, but the improvement needs to be significant enough to cross at least one of the three transition thresholds; otherwise the improved access will have no noticeable effect.
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Affiliation(s)
- Mary Barazanji
- Department of Kinesiology and Health Sciences, Virginia Commonwealth University, Richmond, VA, United States of America
| | - Janesah D. Ngo
- Department of Biology, Virginia Commonwealth University, Richmond, VA, United States of America
| | - Jule A. Powe
- Department of Mathematics and Applied Mathematics, Virginia Commonwealth University, Richmond, VA, United States of America
| | - Kimberley P. Schneider
- Department of Chemistry, Virginia Commonwealth University, Richmond, VA, United States of America
| | - Jan Rychtář
- Department of Mathematics and Applied Mathematics, Virginia Commonwealth University, Richmond, VA, United States of America
| | - Dewey Taylor
- Department of Mathematics and Applied Mathematics, Virginia Commonwealth University, Richmond, VA, United States of America
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Bilchut AH, Burroughs HR, Oldenburg CE, Lietman TM. Trachoma Control: A Glass Half Full? Am J Trop Med Hyg 2023; 108:237-238. [PMID: 36623481 PMCID: PMC9896326 DOI: 10.4269/ajtmh.22-0760] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2022] [Accepted: 12/08/2022] [Indexed: 01/11/2023] Open
Affiliation(s)
- Awraris H. Bilchut
- School of Public Health, Asrat Woldeyes Health Science Campus, Debre Berhan University, Debre Berhan, Ethiopia
| | - Hadley R. Burroughs
- Francis I Proctor Foundation, University of California, San Francisco, San Francisco, California
| | - Catherine E. Oldenburg
- Francis I Proctor Foundation, University of California, San Francisco, San Francisco, California;,Department of Ophthalmology, University of California, San Francisco, San Francisco, California;,Department of Epidemiology and Biostatistics, University of California, San Francisco, San Francisco, California;,Institute for Global Health Sciences, University of California, San Francisco, San Francisco, California
| | - Thomas M. Lietman
- Francis I Proctor Foundation, University of California, San Francisco, San Francisco, California;,Department of Ophthalmology, University of California, San Francisco, San Francisco, California;,Department of Epidemiology and Biostatistics, University of California, San Francisco, San Francisco, California;,Institute for Global Health Sciences, University of California, San Francisco, San Francisco, California,Address correspondence to Thomas M. Lietman, Francis I Proctor Foundation, University of California, San Francisco, 490 Illinois St., 2nd Floor, San Francisco, CA 94143-0944. E-mail:
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Olesen SW. Uses of mathematical modeling to estimate the impact of mass drug administration of antibiotics on antimicrobial resistance within and between communities. Infect Dis Poverty 2022; 11:75. [PMID: 35773748 PMCID: PMC9245243 DOI: 10.1186/s40249-022-00997-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2021] [Accepted: 06/09/2022] [Indexed: 12/02/2022] Open
Abstract
Background Antibiotics are a key part of modern healthcare, but their use has downsides, including selecting for antibiotic resistance, both in the individuals treated with antibiotics and in the community at large. When evaluating the benefits and costs of mass administration of azithromycin to reduce childhood mortality, effects of antibiotic use on antibiotic resistance are important but difficult to measure, especially when evaluating resistance that “spills over” from antibiotic-treated individuals to other members of their community. The aim of this scoping review was to identify how the existing literature on antibiotic resistance modeling could be better leveraged to understand the effect of mass drug administration (MDA) on antibiotic resistance. Main text Mathematical models of antibiotic use and resistance may be useful for estimating the expected effects of different MDA implementations on different populations, as well as aiding interpretation of existing data and guiding future experimental design. Here, strengths and limitations of models of antibiotic resistance are reviewed, and possible applications of those models in the context of mass drug administration with azithromycin are discussed. Conclusions Statistical models of antibiotic use and resistance may provide robust and relevant estimates of the possible effects of MDA on resistance. Mechanistic models of resistance, while able to more precisely estimate the effects of different implementations of MDA on resistance, may require more data from MDA trials to be accurately parameterized. Graphical Abstract ![]()
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Affiliation(s)
- Scott W Olesen
- Department of Immunology and Infectious Diseases, Harvard Chan School, Boston, MA, USA.
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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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Dynamics of Trachoma Epidemic in Human Contact Network with Seasonally Varying Infectious Medium. PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES INDIA SECTION A-PHYSICAL SCIENCES 2021. [DOI: 10.1007/s40010-021-00754-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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Melo JS, Aragie S, Chernet A, Tadesse Z, Dagnew A, Hailu D, Haile M, Zeru T, Wittberg DM, Nash SD, Callahan EK, Arnold BF, Porco TC, Lietman TM, Keenan JD. Targeted Antibiotics for Trachoma: A Cluster-Randomized Trial. Clin Infect Dis 2021; 73:979-986. [PMID: 33674869 DOI: 10.1093/cid/ciab193] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2020] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND Current guidelines recommend community-wide mass azithromycin for trachoma, but a targeted treatment strategy could reduce the volume of antibiotics required. METHODS In total, 48 Ethiopian communities were randomized to mass, targeted, or delayed azithromycin distributions. In the targeted arm, only children aged 6 months to 5 years with evidence of ocular chlamydia received azithromycin, distributed thrice over the following year. The primary outcome was ocular chlamydia at months 12 and 24, comparing the targeted and delayed arms (0-5 year-olds, superiority analysis) and the targeted and mass azithromycin arms (8-12 year-olds, noninferiority analysis, 10% noninferiority margin). RESULTS At baseline, the mean prevalence of ocular chlamydia in the 3 arms ranged from 7% to 9% among 0-5 year-olds and from 3% to 9% among 8-12 year-olds. Averaged across months 12-24, the mean prevalence of ocular chlamydia among 0-5 year-olds was 16.7% (95% confidence interval [CI]: 9.0%-24.4%) in the targeted arm and 22.3% (95% CI: 11.1%-33.6%) in the delayed arm (P = .61). The final mean prevalence of ocular chlamydia among 8-12 year-olds was 13.5% (95% CI: 7.9%-19.1%) in the targeted arm and 5.5% (95% CI: 0.3%-10.7%) in the mass treatment arm (adjusted risk difference 8.5 percentage points [pp] higher in the targeted arm, 95% CI: 0.9 pp-16.1 pp higher). CONCLUSIONS Antibiotic treatments targeted to infected preschool children did not result in significantly less ocular chlamydia infections compared with untreated communities and did not meet noninferiority criteria relative to mass azithromycin distributions. Targeted approaches may require treatment of a broader segment of the population in areas with hyperendemic trachoma.
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Affiliation(s)
- Jason S Melo
- Francis I. Proctor Foundation, University of California San Francisco, San Francisco, California, USA
| | | | | | | | - Adane Dagnew
- The Carter Center Ethiopia, Addis Ababa, Ethiopia
| | | | | | - Tàye Zeru
- Amhara Public Health Institute, Bahir Dar, Ethiopia
| | - Dionna M Wittberg
- Francis I. Proctor Foundation, University of California San Francisco, San Francisco, California, USA
| | | | | | - Benjamin F Arnold
- Francis I. Proctor Foundation, University of California San Francisco, San Francisco, California, USA.,Department of Ophthalmology, University of California San Francisco, San Francisco, California, USA
| | - Travis C Porco
- Francis I. Proctor Foundation, University of California San Francisco, San Francisco, California, USA.,Department of Epidemiology and Biostatistics, University of California San Francisco, San Francisco, California, USA.,Department of Ophthalmology, University of California San Francisco, San Francisco, California, USA
| | - Thomas M Lietman
- Francis I. Proctor Foundation, University of California San Francisco, San Francisco, California, USA.,Department of Epidemiology and Biostatistics, University of California San Francisco, San Francisco, California, USA.,Department of Ophthalmology, University of California San Francisco, San Francisco, California, USA.,Institute for Global Health, University of California San Francisco, San Francisco, California, USA
| | - Jeremy D Keenan
- Francis I. Proctor Foundation, University of California San Francisco, San Francisco, California, USA.,Department of Ophthalmology, University of California San Francisco, San Francisco, California, USA
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10
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Mahmud H, Landskroner E, Amza A, Aragie S, Godwin WW, de Hostos Barth A, O’Brien KS, Lietman TM, Oldenburg CE. Stopping azithromycin mass drug administration for trachoma: A systematic review. PLoS Negl Trop Dis 2021; 15:e0009491. [PMID: 34237074 PMCID: PMC8266061 DOI: 10.1371/journal.pntd.0009491] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022] Open
Abstract
The World Health Organization (WHO) recommends continuing azithromycin mass drug administration (MDA) for trachoma until endemic regions drop below 5% prevalence of active trachoma in children aged 1–9 years. Azithromycin targets the ocular strains of Chlamydia trachomatis that cause trachoma. Regions with low prevalence of active trachoma may have little if any ocular chlamydia, and, thus, may not benefit from azithromycin treatment. Understanding what happens to active trachoma and ocular chlamydia prevalence after stopping azithromycin MDA may improve future treatment decisions. We systematically reviewed published evidence for community prevalence of both active trachoma and ocular chlamydia after cessation of azithromycin distribution. We searched electronic databases for all peer-reviewed studies published before May 2020 that included at least 2 post-MDA surveillance surveys of ocular chlamydia and/or the active trachoma marker, trachomatous inflammation–follicular (TF) prevalence. We assessed trends in the prevalence of both indicators over time after stopping azithromycin MDA. Of 140 identified studies, 21 met inclusion criteria and were used for qualitative synthesis. Post-MDA, we found a gradual increase in ocular chlamydia infection prevalence over time, while TF prevalence generally gradually declined. Ocular chlamydia infection may be a better measurement tool compared to TF for detecting trachoma recrudescence in communities after stopping azithromycin MDA. These findings may guide future trachoma treatment and surveillance efforts. Trachoma, caused by repeated infections with ocular Chlamydia trachomatis, substantially contributes to the global burden of blindness. Community-wide distribution of the oral antibiotic azithromycin in trachoma endemic regions has contributed to significant decline in the prevalence of both ocular chlamydia infection and clinical findings of active trachoma. After azithromycin mass drug administration (MDA) stops, both ocular chlamydia and active trachoma can return. Our systematic review finds that ocular chlamydia infection may return to communities faster than signs of active trachoma, which may help better understand the utility of different trachoma indicators for post-MDA surveillance.
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Affiliation(s)
- Hamidah Mahmud
- University of California, San Francisco School of Medicine, San Francisco, California, United States of America
- Francis I. Proctor Foundation, University of California, San Francisco, California, United States of America
| | - Emma Landskroner
- Francis I. Proctor Foundation, University of California, San Francisco, California, United States of America
| | - Abdou Amza
- Programme National de Santé Oculaire, Niamey, Niger
| | | | - William W. Godwin
- Francis I. Proctor Foundation, University of California, San Francisco, California, United States of America
| | - Anna de Hostos Barth
- Francis I. Proctor Foundation, University of California, San Francisco, California, United States of America
| | - Kieran S. O’Brien
- Francis I. Proctor Foundation, University of California, San Francisco, California, United States of America
| | - Thomas M. Lietman
- Francis I. Proctor Foundation, University of California, San Francisco, California, United States of America
- Department of Ophthalmology, University of California, San Francisco, California, United States of America
- Department of Epidemiology & Biostatistics, University of California, San Francisco, California, United States of America
| | - Catherine E. Oldenburg
- Francis I. Proctor Foundation, University of California, San Francisco, California, United States of America
- Department of Ophthalmology, University of California, San Francisco, California, United States of America
- Department of Epidemiology & Biostatistics, University of California, San Francisco, California, United States of America
- * E-mail:
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11
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Wright HR, Turner A, Taylor HR. Trachoma and poverty: unnecessary blindness further disadvantages the poorest people in the poorest countries. Clin Exp Optom 2021; 90:422-8. [DOI: 10.1111/j.1444-0938.2007.00218.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Affiliation(s)
- Heathcote R Wright
- Centre for Eye Research Australia, The University of Melbourne, WHO Collaborating Centre for the Prevention of Blindness, East Melbourne VIC, Australia
- Vision CRC, University of New South Wales, Sydney NSW, Australia
E‐mail:
| | - Angus Turner
- Centre for Eye Research Australia, The University of Melbourne, WHO Collaborating Centre for the Prevention of Blindness, East Melbourne VIC, Australia
| | - Hugh R Taylor
- Centre for Eye Research Australia, The University of Melbourne, WHO Collaborating Centre for the Prevention of Blindness, East Melbourne VIC, Australia
- Vision CRC, University of New South Wales, Sydney NSW, Australia
E‐mail:
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12
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Blumberg S, Borlase A, Prada JM, Solomon AW, Emerson P, Hooper PJ, Deiner MS, Amoah B, Hollingsworth TD, Porco TC, Lietman TM. Implications of the COVID-19 pandemic in eliminating trachoma as a public health problem. Trans R Soc Trop Med Hyg 2021; 115:222-228. [PMID: 33449114 PMCID: PMC7928550 DOI: 10.1093/trstmh/traa170] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2020] [Revised: 11/07/2020] [Accepted: 01/09/2021] [Indexed: 11/13/2022] Open
Abstract
Background Progress towards elimination of trachoma as a public health problem has been substantial, but the coronavirus disease 2019 (COVID-19) pandemic has disrupted community-based control efforts. Methods We use a susceptible-infected model to estimate the impact of delayed distribution of azithromycin treatment on the prevalence of active trachoma. Results We identify three distinct scenarios for geographic districts depending on whether the basic reproduction number and the treatment-associated reproduction number are above or below a value of 1. We find that when the basic reproduction number is <1, no significant delays in disease control will be caused. However, when the basic reproduction number is >1, significant delays can occur. In most districts, 1 y of COVID-related delay can be mitigated by a single extra round of mass drug administration. However, supercritical districts require a new paradigm of infection control because the current strategies will not eliminate disease. Conclusions If the pandemic can motivate judicious, community-specific implementation of control strategies, global elimination of trachoma as a public health problem could be accelerated.
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Affiliation(s)
- Seth Blumberg
- Francis I Proctor Foundation, University of California, San Francisco, San Francisco, CA, USA
| | | | - Joaquin M Prada
- Faculty of Health and Medical Sciences, University of Surrey, Guildford, UK
| | - Anthony W Solomon
- Department of Control of Neglected Tropical Diseases, World Health Organization, Geneva, Switzerland
| | - Paul Emerson
- International Trachoma Initiative, Task Force for Global Health, Decatur, GA, USA
| | - Pamela J Hooper
- International Trachoma Initiative, Task Force for Global Health, Decatur, GA, USA
| | - Michael S Deiner
- Francis I Proctor Foundation, University of California, San Francisco, San Francisco, CA, USA
| | - Benjamin Amoah
- Lancaster Medical School, Lancaster University, Bailrigg, Lancaster, UK
| | | | - Travis C Porco
- Francis I Proctor Foundation, University of California, San Francisco, San Francisco, CA, USA.,Department of Epidemiology and Biostatistics, University of California, San Francisco, San Francisco, CA, USA
| | - Thomas M Lietman
- Francis I Proctor Foundation, University of California, San Francisco, San Francisco, CA, USA.,Department of Epidemiology and Biostatistics, University of California, San Francisco, San Francisco, CA, USA.,Institute for Global Health Sciences, University of California, San Francisco, San Francisco, CA, USA.,Department of Ophthalmology, University of California, San Francisco, San Francisco, CA, USA
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13
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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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14
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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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15
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Blumberg S, Borlase A, Prada JM, Solomon AW, Emerson P, Hooper PJ, Deiner MS, Amoah B, Hollingsworth D, Porco TC, Lietman TM. Implications of the COVID-19 pandemic on eliminating trachoma as a public health problem. MEDRXIV : THE PREPRINT SERVER FOR HEALTH SCIENCES 2020. [PMID: 33140063 PMCID: PMC7605574 DOI: 10.1101/2020.10.26.20219691] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Background: Progress towards elimination of trachoma as a public health problem has been substantial, but the COVID-19 pandemic has disrupted community-based control efforts. Methods: We use a susceptible-infected model to estimate the impact of delayed distribution of azithromycin treatment on the prevalence of active trachoma. Results: We identify three distinct scenarios for geographic districts depending on whether the basic reproduction number and the treatment-associated reproduction number are above or below a value of one. We find that when the basic reproduction number is below one, no significant delays in disease control will be caused. However, when the basic reproduction number is above one, significant delays can occur. In most districts a year of COVID-related delay can be mitigated by a single extra round of mass drug administration. However, supercritical districts require a new paradigm of infection control because the current strategies will not eliminate disease. Conclusion: If the pandemic can motivate judicious, community-specific implementation of control strategies, global elimination of trachoma as a public health problem could be accelerated.
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Affiliation(s)
| | | | - Joaquin M Prada
- Faculty of Health and Medical Sciences, University of Surrey, UK
| | - Anthony W Solomon
- Department of Control of Neglected Tropical Diseases, World Health Organization, Geneva, Switzerland
| | - Paul Emerson
- International Trachoma Initiative, The Task Force for Global Health, USA
| | - Pamela J Hooper
- International Trachoma Initiative, The Task Force for Global Health, USA
| | | | - Benjamin Amoah
- Lancaster Medical School, Lancaster University, Bailrigg, Lancaster, UK
| | | | - Travis C Porco
- Francis I Proctor Foundation, UCSF, USA.,Department of Epidemiology and Biostatistics, UCSF, USA
| | - Thomas M Lietman
- Francis I Proctor Foundation, UCSF, USA.,Department of Epidemiology and Biostatistics, UCSF, USA.,Institute for Global Health Sciences, UCSF, USA.,Department of Ophthalmology, UCSF, USA
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16
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Toor J, Adams ER, Aliee M, Amoah B, Anderson RM, Ayabina D, Bailey R, Basáñez MG, Blok DJ, Blumberg S, Borlase A, Rivera RC, Castaño MS, Chitnis N, Coffeng LE, Crump RE, Das A, Davis CN, Davis EL, Deiner MS, Diggle PJ, Fronterre C, Giardina F, Giorgi E, Graham M, Hamley JID, Huang CI, Kura K, Lietman TM, Lucas TCD, Malizia V, Medley GF, Meeyai A, Michael E, Porco TC, Prada JM, Rock KS, Le Rutte EA, Smith ME, Spencer SEF, Stolk WA, Touloupou P, Vasconcelos A, Vegvari C, de Vlas SJ, Walker M, Hollingsworth TD. Predicted Impact of COVID-19 on Neglected Tropical Disease Programs and the Opportunity for Innovation. Clin Infect Dis 2020; 72:1463-1466. [PMID: 32984870 PMCID: PMC7543306 DOI: 10.1093/cid/ciaa933] [Citation(s) in RCA: 49] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2020] [Accepted: 07/10/2020] [Indexed: 11/12/2022] Open
Abstract
Due to the COVID-19 pandemic, many key neglected tropical disease (NTD) activities have been postponed. This hindrance comes at a time when the NTDs are progressing towards their ambitious goals for 2030. Mathematical modelling on several NTDs, namely gambiense sleeping sickness, lymphatic filariasis, onchocerciasis, schistosomiasis, soil-transmitted helminthiases (STH), trachoma, and visceral leishmaniasis, shows that the impact of this disruption will vary across the diseases. Programs face a risk of resurgence, which will be fastest in high-transmission areas. Furthermore, of the mass drug administration diseases, schistosomiasis, STH, and trachoma are likely to encounter faster resurgence. The case-finding diseases (gambiense sleeping sickness and visceral leishmaniasis) are likely to have fewer cases being detected but may face an increasing underlying rate of new infections. However, once programs are able to resume, there are ways to mitigate the impact and accelerate progress towards the 2030 goals.
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Affiliation(s)
- Jaspreet Toor
- Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, Oxford, United Kingdom
| | - Emily R Adams
- Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Maryam Aliee
- Mathematics Institute, University of Warwick, Coventry, United Kingdom,Zeeman Institute for Systems Biology and Infectious Disease Epidemiology Research, University of Warwick, Coventry, United Kingdom
| | - Benjamin Amoah
- Centre for Health Informatics, Computing and Statistics, Lancaster University, Lancaster, United Kingdom
| | - Roy M Anderson
- London Centre for Neglected Tropical Disease Research, Department of Infectious Disease Epidemiology, Imperial College London, London, United Kingdom,Medical Research Council Centre for Global Infectious Disease Analysis, Department of Infectious Disease Epidemiology, School of Public Health, Imperial College London, London, United Kingdom,The DeWorm3 Project, Natural History Museum, London, United Kingdom
| | - Diepreye Ayabina
- Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, Oxford, United Kingdom
| | - Robin Bailey
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Maria-Gloria Basáñez
- London Centre for Neglected Tropical Disease Research, Department of Infectious Disease Epidemiology, Imperial College London, London, United Kingdom,Medical Research Council Centre for Global Infectious Disease Analysis, Department of Infectious Disease Epidemiology, School of Public Health, Imperial College London, London, United Kingdom
| | - David J Blok
- Department of Public Health, Erasmus University Medical Center Rotterdam, Rotterdam, The Netherlands
| | - Seth Blumberg
- Francis I Proctor Foundation, University of California, San Francisco, California, United States of America
| | - Anna Borlase
- Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, Oxford, United Kingdom
| | - Rocio Caja Rivera
- Department of Biological Sciences, University of Notre Dame, Notre Dame, Indiana, United States of America
| | - María Soledad Castaño
- Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, Basel, Switzerland,University of Basel, Basel, Switzerland
| | - Nakul Chitnis
- Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, Basel, Switzerland,University of Basel, Basel, Switzerland
| | - Luc E Coffeng
- Department of Public Health, Erasmus University Medical Center Rotterdam, Rotterdam, The Netherlands
| | - Ronald E Crump
- Mathematics Institute, University of Warwick, Coventry, United Kingdom,Zeeman Institute for Systems Biology and Infectious Disease Epidemiology Research, University of Warwick, Coventry, United Kingdom,The School of Life Sciences, University of Warwick, Coventry, United Kingdom
| | - Aatreyee Das
- Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, Basel, Switzerland,University of Basel, Basel, Switzerland
| | - Christopher N Davis
- Mathematics Institute, University of Warwick, Coventry, United Kingdom,Zeeman Institute for Systems Biology and Infectious Disease Epidemiology Research, University of Warwick, Coventry, United Kingdom
| | - Emma L Davis
- Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, Oxford, United Kingdom
| | - Michael S Deiner
- Francis I Proctor Foundation, University of California, San Francisco, California, United States of America,Department of Ophthalmology, University of California, San Francisco, California, United States of America
| | - Peter J Diggle
- Centre for Health Informatics, Computing and Statistics, Lancaster University, Lancaster, United Kingdom
| | - Claudio Fronterre
- Centre for Health Informatics, Computing and Statistics, Lancaster University, Lancaster, United Kingdom
| | - Federica Giardina
- Department of Public Health, Erasmus University Medical Center Rotterdam, Rotterdam, The Netherlands
| | - Emanuele Giorgi
- Centre for Health Informatics, Computing and Statistics, Lancaster University, Lancaster, United Kingdom
| | - Matthew Graham
- Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, Oxford, United Kingdom,Centre for Mathematical Modelling of Infectious Disease, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Jonathan I D Hamley
- London Centre for Neglected Tropical Disease Research, Department of Infectious Disease Epidemiology, Imperial College London, London, United Kingdom,Medical Research Council Centre for Global Infectious Disease Analysis, Department of Infectious Disease Epidemiology, School of Public Health, Imperial College London, London, United Kingdom
| | - Ching-I Huang
- Mathematics Institute, University of Warwick, Coventry, United Kingdom,Zeeman Institute for Systems Biology and Infectious Disease Epidemiology Research, University of Warwick, Coventry, United Kingdom
| | - Klodeta Kura
- London Centre for Neglected Tropical Disease Research, Department of Infectious Disease Epidemiology, Imperial College London, London, United Kingdom,Medical Research Council Centre for Global Infectious Disease Analysis, Department of Infectious Disease Epidemiology, School of Public Health, Imperial College London, London, United Kingdom
| | - Thomas M Lietman
- Francis I Proctor Foundation, University of California, San Francisco, California, United States of America,Department of Ophthalmology, University of California, San Francisco, California, United States of America,Department of Epidemiology & Biostatistics, University of California, San Francisco, California, United States of America
| | - Tim C D Lucas
- Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, Oxford, United Kingdom
| | - Veronica Malizia
- Department of Public Health, Erasmus University Medical Center Rotterdam, Rotterdam, The Netherlands
| | - Graham F Medley
- Centre for Mathematical Modelling of Infectious Disease, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Aronrag Meeyai
- Centre for Mathematical Modelling of Infectious Disease, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Edwin Michael
- Department of Biological Sciences, University of Notre Dame, Notre Dame, Indiana, United States of America
| | - Travis C Porco
- Francis I Proctor Foundation, University of California, San Francisco, California, United States of America,Department of Ophthalmology, University of California, San Francisco, California, United States of America,Department of Epidemiology & Biostatistics, University of California, San Francisco, California, United States of America
| | - Joaquin M Prada
- School of Veterinary Medicine, Faculty of Health and Medical Sciences, University of Surrey, Guildford, United Kingdom
| | - Kat S Rock
- Mathematics Institute, University of Warwick, Coventry, United Kingdom,Zeeman Institute for Systems Biology and Infectious Disease Epidemiology Research, University of Warwick, Coventry, United Kingdom
| | - Epke A Le Rutte
- Department of Public Health, Erasmus University Medical Center Rotterdam, Rotterdam, The Netherlands,Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, Basel, Switzerland,University of Basel, Basel, Switzerland
| | - Morgan E Smith
- Department of Biological Sciences, University of Notre Dame, Notre Dame, Indiana, United States of America
| | - Simon E F Spencer
- Zeeman Institute for Systems Biology and Infectious Disease Epidemiology Research, University of Warwick, Coventry, United Kingdom,Department of Statistics, University of Warwick, Coventry, United Kingdom
| | - Wilma A Stolk
- Department of Public Health, Erasmus University Medical Center Rotterdam, Rotterdam, The Netherlands
| | | | - Andreia Vasconcelos
- Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, Oxford, United Kingdom
| | - Carolin Vegvari
- London Centre for Neglected Tropical Disease Research, Department of Infectious Disease Epidemiology, Imperial College London, London, United Kingdom,Medical Research Council Centre for Global Infectious Disease Analysis, Department of Infectious Disease Epidemiology, School of Public Health, Imperial College London, London, United Kingdom
| | - Sake J de Vlas
- Department of Public Health, Erasmus University Medical Center Rotterdam, Rotterdam, The Netherlands
| | - Martin Walker
- London Centre for Neglected Tropical Disease Research, Department of Infectious Disease Epidemiology, Imperial College London, London, United Kingdom,London Centre for Neglected Tropical Disease Research, Department of Pathobiology and Population Sciences, Royal Veterinary College, University of London, Hatfield, Hertfordshire, United Kingdom
| | - T Déirdre Hollingsworth
- Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, Oxford, United Kingdom,Correspondence: T. D. Hollingsworth, Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, Old Road Campus, Oxford OX3 7LF, UK ()
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17
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Lietman TM, Ayele B, Gebre T, Zerihun M, Tadesse Z, Emerson PM, Nash SD, Porco TC, Keenan JD, Oldenburg CE. Frequency of Mass Azithromycin Distribution for Ocular Chlamydia in a Trachoma Endemic Region of Ethiopia: A Cluster Randomized Trial. Am J Ophthalmol 2020; 214:143-150. [PMID: 32171768 PMCID: PMC9982657 DOI: 10.1016/j.ajo.2020.02.019] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2019] [Revised: 02/24/2020] [Accepted: 02/25/2020] [Indexed: 10/24/2022]
Abstract
PURPOSE Annual mass azithromycin distribution significantly reduces the prevalence of ocular Chlamydia trachomatis, the causative organism of trachoma. However, in some areas a decade or more of treatment has not controlled infection. Here, we compared multiple treatment arms from a community-randomized trial to evaluate whether increasing frequency of azithromycin distribution decreases prevalence in the short term. METHODS Seventy-two communities in Goncha Siso Enesie woreda in the Amhara region of Northern Ethiopia were randomized to 1 of 6 azithromycin distribution strategies: (1) delayed, (2) annual, (3) biannual, (4) quarterly to children only, (5) biennial, or (6) biennial plus latrine promotion. We analyzed data from the 60 communities in the delayed, annual, biannual, quarterly, and biennial distribution arms at the 12-month study visit. Communities in the annual and biennial distribution arm were combined, as they each had a single distribution before any 12-month retreatment. We assessed the effect of increased frequency of azithromycin distribution on ocular chlamydia prevalence. RESULTS Ocular chlamydia prevalence was significantly different across azithromycin distribution frequency in children (P < .0001) and adults (P < .0001), with lower prevalence associated with higher frequency. Among children, quarterly azithromycin distribution led to a significantly greater reduction in ocular chlamydia prevalence than the World Health Organization-recommended annual treatment prevalence (mean difference -11.4%, 95% confidence interval -19.5 to -3.3%, P = .007). CONCLUSIONS Increased frequency of azithromycin distribution leads to decreased ocular chlamydia prevalence over a short-term period. In some regions with high levels of ocular chlamydia prevalence, additional azithromycin distributions may help achieve local elimination of infection.
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Affiliation(s)
- Thomas M. Lietman
- Francis I Proctor Foundation, University of California, San Francisco,Department of Ophthalmology, University of California, San Francisco,Department of Epidemiology and Biostatistics, University of California, San Francisco
| | - Berhan Ayele
- The Carter Center Ethiopia, Addis Ababa, Ethiopia
| | - Teshome Gebre
- International Trachoma Initiative, Addis Ababa, Ethiopia
| | | | | | | | | | - Travis C. Porco
- Francis I Proctor Foundation, University of California, San Francisco,Department of Ophthalmology, University of California, San Francisco,Department of Epidemiology and Biostatistics, University of California, San Francisco
| | - Jeremy D. Keenan
- Francis I Proctor Foundation, University of California, San Francisco,Department of Ophthalmology, University of California, San Francisco,Department of Epidemiology and Biostatistics, University of California, San Francisco
| | - Catherine E. Oldenburg
- Francis I Proctor Foundation, University of California, San Francisco,Department of Ophthalmology, University of California, San Francisco,Department of Epidemiology and Biostatistics, University of California, San Francisco
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18
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Stewart AEP, Zerihun M, Gessese D, Melak B, Sata E, Nute AW, Astale T, Endeshaw T, Teferi T, Tadesse Z, Callahan EK, Chanyalew M, Gaudie B, Emerson PM, King JD, Nash SD. Progress to Eliminate Trachoma as a Public Health Problem in Amhara National Regional State, Ethiopia: Results of 152 Population-Based Surveys. Am J Trop Med Hyg 2020; 101:1286-1295. [PMID: 31549612 PMCID: PMC6896880 DOI: 10.4269/ajtmh.19-0450] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
At baseline in 2006, Amhara National Regional State, Ethiopia, was the most trachoma-endemic region in the country. Trachoma impact surveys (TIS) were conducted in all districts between 2010 and 2015, following 3–5 years of intervention with the WHO-recommended SAFE (surgery, antibiotics, facial cleanliness, and environmental improvement) strategy. A multistage cluster random sampling design was used to estimate the district-level prevalence of trachoma. In total, 1,887 clusters in 152 districts were surveyed, from which 208,265 individuals from 66,089 households were examined for clinical signs of trachoma. The regional prevalence of trachomatous inflammation-follicular (TF) and trachomatous inflammation-intense among children aged 1–9 years was 25.9% (95% CI: 24.9–26.9) and 5.5% (95% CI: 5.2–6.0), respectively. The prevalence of trachomatous scarring and trachomatous trichiasis among adults aged ≥ 15 years was 12.9% (95% CI: 12.2–13.6) and 3.9% (95% CI: 3.7–4.1), respectively. Among children aged 1–9 years, 76.5% (95% CI: 75.3–77.7) presented with a clean face; 66.2% (95% CI: 64.1–68.2) of households had access to water within 30 minutes round-trip, 48.1% (95% CI: 45.5–50.6) used an improved water source, and 46.2% (95% CI: 44.8–47.5) had evidence of a used latrine. Nine districts had a prevalence of TF below the elimination threshold of 5%. In hyperendemic areas, 3–5 years of implementation of SAFE is insufficient to achieve trachoma elimination as a public health problem; additional years of SAFE and several rounds of TIS will be required before trachoma is eliminated.
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Affiliation(s)
| | | | | | | | | | | | | | | | - Tesfaye Teferi
- International Trachoma Initiative, Addis Ababa, Ethiopia
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19
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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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Lietman TM, Pinsent A, Liu F, Deiner M, Hollingsworth TD, Porco TC. Models of Trachoma Transmission and Their Policy Implications: From Control to Elimination. Clin Infect Dis 2019; 66:S275-S280. [PMID: 29860288 PMCID: PMC5982784 DOI: 10.1093/cid/ciy004] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Despite great progress in eliminating trachoma from the majority of worldwide districts, trachoma control seems to have stalled in some endemic districts. Can mathematical models help suggest the way forward? We review specific achievements of models in trachoma control in the past. Models showed that, even with incomplete coverage, mass drug administration could eliminate disease through a spillover effect, somewhat analogous to how incomplete vaccine campaigns can eliminate disease through herd protection. Models also suggest that elimination can always be achieved if enough people are treated often enough with an effective enough drug. Other models supported the idea that targeting ages at highest risk or continued improvements in hygiene and sanitation can contribute meaningfully to trachoma control. Models of intensive targeting of a core group may point the way to final eradication even in areas with substantial transmission and within-community heterogeneity.
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Affiliation(s)
- Thomas M Lietman
- Francis I. Proctor Foundation, San Francisco.,Department of Ophthalmology, San Francisco.,Department of Epidemiology and Biostatistics, San Francisco.,Global Health Sciences, University of California, San Francisco
| | - Amy Pinsent
- School of Public Health and Preventative Medicine, Monash University, Melbourne, Australia
| | | | - Michael Deiner
- Francis I. Proctor Foundation, San Francisco.,Department of Ophthalmology, San Francisco
| | - T Deirdre Hollingsworth
- Big Data Institute, Li Ka Shing Centre for Health Information and Discovery, University of Oxford, United Kingdom
| | - Travis C Porco
- Francis I. Proctor Foundation, San Francisco.,Department of Ophthalmology, San Francisco.,Department of Epidemiology and Biostatistics, San Francisco
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21
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Stromal Fibroblasts Drive Host Inflammatory Responses That Are Dependent on Chlamydia trachomatis Strain Type and Likely Influence Disease Outcomes. mBio 2019; 10:mBio.00225-19. [PMID: 30890604 PMCID: PMC6426598 DOI: 10.1128/mbio.00225-19] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Chlamydia trachomatis is a human pathogen and the leading cause of preventable blindness and sexually transmitted diseases in the world. Certain C. trachomatis strains cause ocular disease, while others cause upper genital tract pathology. However, little is known about the cellular or immunologic basis for these differences. Here, we compared the abilities of the strain types to infect, replicate, and initiate an immune response in primary human ocular and urogenital epithelial cells, as well as in fibroblasts from the underlying stroma. While there were no significant differences in infection rates or intracellular growth for any strain in any cell type, proinflammatory responses were driven not by the epithelial cells but by fibroblasts and were distinct between ocular and urogenital strains. Our findings suggest that primary fibroblasts are a novel and more appropriate model for studies of immune responses that will expand our understanding of the differential pathological disease outcomes caused by various C. trachomatis strain types. Chlamydia trachomatis ocular strains cause a blinding disease known as trachoma. These strains rarely cause urogenital infections and are not found in the upper genital tract or rectum. Urogenital strains are responsible for a self-limited conjunctivitis and the sequelae of infertility, ectopic pregnancy, and hemorrhagic proctitis. However, the differential cellular responses that drive these clinically observed disease outcomes are not completely understood. Primary conjunctival, endocervical, and endometrial epithelial and stromal fibroblast cells, HeLa229 cells, and immortalized conjunctival epithelial (HCjE) cells were infected with the ocular A/Har-13 (A) and Ba/Apache-2 (Ba) strains and urogenital D/UW-3 (D) and E/Bour (E) strains. Infection rates, progeny production, and cytokine/chemokine secretion levels were evaluated in comparison with those in uninfected cells. All strain types infected all cell types with similar levels of efficacy and development. However, progeny production levels differed among primary cells: Ba produced significantly more progeny than E in endocervical and endometrial fibroblasts, while A progeny were less abundant than E progeny. C.trachomatis infection of primary epithelial cells elicited an increase in pro- and anti-inflammatory mediators compared to levels in uninfected cells, but there were no significant differences by strain type. In contrast, for primary fibroblasts, ocular strains elicited significant increases in the pro- and anti-inflammatory mediators macrophage inflammatory protein (MIP)-1β, thymus- and activation-regulated chemokine (TARC), interleukin (IL)-2, IL-12p70, and interferon gamma-induced protein 10 (IP-10) compared to levels in urogenital strains, while urogenital strains elicited a distinct and significant increase in the proinflammatory mediators IL-1α, IL-1β, IL-8, gamma interferon (IFN-γ), and granulocyte-macrophage colony-stimulating factor (GM-CSF). Our data indicate that primary fibroblasts, not epithelial cells, drive host inflammatory responses that are dependent on strain type and likely influence disease outcomes, establishing their importance as a novel model for studies of C. trachomatis disease pathogenesis.
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O'Brien KS, Emerson P, Hooper PJ, Reingold AL, Dennis EG, Keenan JD, Lietman TM, Oldenburg CE. Antimicrobial resistance following mass azithromycin distribution for trachoma: a systematic review. THE LANCET. INFECTIOUS DISEASES 2019; 19:e14-e25. [PMID: 30292480 DOI: 10.1016/s1473-3099(18)30444-4] [Citation(s) in RCA: 82] [Impact Index Per Article: 16.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/07/2018] [Revised: 06/21/2018] [Accepted: 07/10/2018] [Indexed: 01/12/2023]
Abstract
Mass azithromycin distribution is a core component of trachoma control programmes and could reduce mortality in children younger than 5 years in some settings. In this systematic review we synthesise evidence on the emergence of antimicrobial resistance after mass azithromycin distribution. We searched electronic databases for publications up to June 14, 2018. We included studies of any type (excluding modelling studies, surveillance reports, and review articles) on community-wide distribution of oral azithromycin for the prevention and treatment of trachoma that assessed macrolide resistance, without restrictions to the type of organism. We extracted prevalence of resistance from published reports and requested unpublished data from authors of included studies. Of 213 identified studies, 19 met inclusion criteria (12 assessed Streptococcus pneumoniae) and were used for qualitative synthesis. Macrolide resistance after azithromycin distribution was reported in three of the five organisms studied. The lack of resistance in Chlamydia trachomatis suggests that azithromycin might remain effective for trachoma programmes, but evidence is scarce. As mass azithromycin distribution for trachoma continues and is considered for other indications, ongoing monitoring of antimicrobial resistance will be required.
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Affiliation(s)
- Kieran S O'Brien
- Francis I Proctor Foundation, University of California, San Francisco, CA, USA; Division of Epidemiology, University of California, Berkeley, CA, USA
| | - Paul Emerson
- International Trachoma Initiative, Decatur, GA, USA
| | - P J Hooper
- International Trachoma Initiative, Decatur, GA, USA
| | - Arthur L Reingold
- Division of Epidemiology, University of California, Berkeley, CA, USA
| | - Elena G Dennis
- Francis I Proctor Foundation, University of California, San Francisco, CA, USA
| | - Jeremy D Keenan
- Francis I Proctor Foundation, University of California, San Francisco, CA, USA; Department of Ophthalmology, University of California, San Francisco, CA, USA
| | - Thomas M Lietman
- Francis I Proctor Foundation, University of California, San Francisco, CA, USA; Department of Ophthalmology, University of California, San Francisco, CA, USA; Department of Epidemiology & Biostatistics, University of California, San Francisco, CA, USA
| | - Catherine E Oldenburg
- Francis I Proctor Foundation, University of California, San Francisco, CA, USA; Department of Epidemiology & Biostatistics, University of California, San Francisco, CA, USA.
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23
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Pinsent A, Solomon AW, Bailey RL, Bid R, Cama A, Dean D, Goodhew B, Gwyn SE, Jack KR, Kandel RP, Kama M, Massae P, Macleod C, Mabey DCW, Migchelsen S, Müller A, Sandi F, Sokana O, Taoaba R, Tekeraoi R, Martin DL, White MT. The utility of serology for elimination surveillance of trachoma. Nat Commun 2018; 9:5444. [PMID: 30575720 PMCID: PMC6303365 DOI: 10.1038/s41467-018-07852-0] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2018] [Accepted: 11/27/2018] [Indexed: 11/24/2022] Open
Abstract
Robust surveillance methods are needed for trachoma control and recrudescence monitoring, but existing methods have limitations. Here, we analyse data from nine trachoma-endemic populations and provide operational thresholds for interpretation of serological data in low-transmission and post-elimination settings. Analyses with sero-catalytic and antibody acquisition models provide insights into transmission history within each population. To accurately estimate sero-conversion rates (SCR) for trachoma in populations with high-seroprevalence in adults, the model accounts for secondary exposure to Chlamydia trachomatis due to urogenital infection. We estimate the population half-life of sero-reversion for anti-Pgp3 antibodies to be 26 (95% credible interval (CrI): 21–34) years. We show SCRs below 0.015 (95% confidence interval (CI): 0.0–0.049) per year correspond to a prevalence of trachomatous inflammation—follicular below 5%, the current threshold for elimination of active trachoma as a public health problem. As global trachoma prevalence declines, we may need cross-sectional serological survey data to inform programmatic decisions. Robust surveillance methods are needed for trachoma control and recrudescence monitoring, but existing methods have limitations. Here, Pinsent et al. analyse data from nine trachoma-endemic populations and provide operational thresholds for interpretation of serological data in low transmission and post-elimination settings.
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Affiliation(s)
- Amy Pinsent
- Department of Public Health and Preventative Medicine, Monash University, Melbourne, VIC, 3004, Australia. .,Department of Infectious Disease Epidemiology, London School of Hygiene & Tropical Medicine, London, WC1E 7HT, UK.
| | - Anthony W Solomon
- Department of Control of Neglected Tropical Diseases, World Health Organization, 1211, Geneva 27, Switzerland.,Clinical Research Department, London School of Hygiene & Tropical Medicine, London, WC1E 7HT, UK
| | - Robin L Bailey
- Clinical Research Department, London School of Hygiene & Tropical Medicine, London, WC1E 7HT, UK
| | - Rhiannon Bid
- Clinical Research Department, London School of Hygiene & Tropical Medicine, London, WC1E 7HT, UK
| | - Anaseini Cama
- International Agency for the Prevention of Blindness, Western Pacific Region, Suva, Fiji.,The Fred Hollows Foundation, Level 2, 61 Dunning Ave, Rosebury, NSW, 2018, Australia
| | - Deborah Dean
- UCSF Benioff Children's Hospital Oakland Research Institute, 5700 Martin Luther King Jr Way, Oakland, CA, 94609, USA
| | - Brook Goodhew
- Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, 1600 Clifton Road, Atlanta, GA, 30333, USA
| | - Sarah E Gwyn
- Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, 1600 Clifton Road, Atlanta, GA, 30333, USA
| | - Kelvin R Jack
- Eyecare Department, Ministry of Health, Honiara, Solomon Islands
| | | | - Mike Kama
- Department of Communicable Diseases, Ministry of Health, Suva, Fiji
| | - Patrick Massae
- Department of Ophthalmology, Kilimanjaro Christian Medical Centre, Moshi, Tanzania
| | - Colin Macleod
- Clinical Research Department, London School of Hygiene & Tropical Medicine, London, WC1E 7HT, UK.,Sightsavers, 35 Perrymount Road, Haywards Heath, RH16 6NG, UK
| | - David C W Mabey
- Clinical Research Department, London School of Hygiene & Tropical Medicine, London, WC1E 7HT, UK
| | - Stephanie Migchelsen
- Clinical Research Department, London School of Hygiene & Tropical Medicine, London, WC1E 7HT, UK
| | - Andreas Müller
- Centre for Eye Research Australia, Level 7/32 Gisborne St, East Melbourne, VIC, 3002, Australia
| | - Frank Sandi
- Department of Ophthalmology, Kilimanjaro Christian Medical Centre, Moshi, Tanzania.,The University of Dodoma, Dodoma, Tanzania
| | - Oliver Sokana
- Eyecare Department, Ministry of Health, Honiara, Solomon Islands
| | - Raebwebwe Taoaba
- Eye Department, Ministry of Health and Medical Services, South Tarawa, Kiribati
| | - Rabebe Tekeraoi
- Eye Department, Ministry of Health and Medical Services, South Tarawa, Kiribati
| | - Diana L Martin
- Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, 1600 Clifton Road, Atlanta, GA, 30333, USA
| | - Michael T White
- Malaria: Parasites & Hosts, Department of Parasites and Insect Vectors, Institut Pasteur, 25-28 Rue du Dr Roux, 75015, Paris, France
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24
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Childhood Mortality After Mass Distribution of Azithromycin: A Secondary Analysis of the PRET Cluster-randomized Trial in Niger. Pediatr Infect Dis J 2018; 37:1082-1086. [PMID: 29561511 PMCID: PMC6138579 DOI: 10.1097/inf.0000000000001992] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
BACKGROUND Mass distributions of azithromycin for trachoma have been associated with secondary benefits, including reductions in child mortality. METHODS In the Partnership for the Rapid Elimination of Trachoma cluster-randomized trial in Niger, 24 communities were randomized to annual treatment of everyone and 24 communities were randomized to biannual treatment of children under 12 for 3 years (clinicaltrials.gov, NCT00792922). Treatment was a single dose of directly observed oral azithromycin (20 mg/kg up to 1 g in adults). Vital status was assessed during annual census and monitoring visits. In this prespecified secondary analysis, we compared the mortality rate among children 6 months to less than 5 years of age by treatment arm using negative binomial regression. RESULTS Among children 6 months to less than 5 years of age, 404 deaths occurred during the study period. The mortality rate was 35.6 deaths per 1000 person-years (231 deaths, 95% CI: 30.9-40.9) in the annual arm and 29.0 deaths per 1000 person-years (173 deaths, 95% CI: 24.8-33.8) in the biannual arm. The mortality rate ratio comparing children in the biannual arm to the annual arm was 0.81 (95% CI: 0.66-1.00, P = 0.07; primary outcome). The mortality rate ratio comparing children who died from infectious causes in the biannual arm to the annual arm was 0.73 (95% CI: 0.57-0.94; P = 0.02). No adverse events were reported. CONCLUSIONS This secondary analysis of a cluster-randomized trial found a nonsignificant 19% decrease in mortality among children 6 months to less than 5 years of age who received biannual azithromycin compared with children who received annual azithromycin. This study was conducted in a high mortality, trachoma-endemic area; thus, results may be specific to this environment only. In addition, the trial was neither designed nor powered to detect a mortality effect, and we cannot rule out the possibility that mortality differences resulted from bias.
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Identifying a sufficient core group for trachoma transmission. PLoS Negl Trop Dis 2018; 12:e0006478. [PMID: 30296259 PMCID: PMC6175502 DOI: 10.1371/journal.pntd.0006478] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2018] [Accepted: 04/25/2018] [Indexed: 11/19/2022] Open
Abstract
Background In many infectious diseases, a core group of individuals plays a disproportionate role in transmission. If these individuals were effectively prevented from transmitting infection, for example with a perfect vaccine, then the disease would disappear in the remainder of the community. No vaccine has yet proven effective against the ocular strains of chlamydia that cause trachoma. However, repeated treatment with oral azithromycin may be able to prevent individuals from effectively transmitting trachoma. Methodology/Principal findings Here we assess several methods for identifying a core group for trachoma, assuming varying degrees of knowledge about the transmission process. We determine the minimal core group from a completely specified model, fitted to results from a large Ethiopian trial. We compare this benchmark to a core group that could actually be identified from information available to trachoma programs. For example, determined from the rate of return of infection in a community after mass treatments, or from the equilibrium prevalence of infection. Conclusions/Significance Sufficient groups are relatively easy for programs to identify, but will likely be larger than the theoretical minimum. Public health programs can in theory target treatment to a core group of individuals responsible for a disproportionate amount of transmission. The smallest group of individuals who need to be vaccinated to eventually eliminate an infectious disease is easy to find in theory, but not in practice. While no vaccine has proven effective for trachoma, intensive periodic treatment may be able to effectively prevent individuals from transmitting infection. Here we use a variety of methods to find a core group for trachoma transmission, including methods that use information available to trachoma programs. We show that the rate that infection returns into a community after mass treatment, or the pre-treatment prevalence of an infectious disease should work, but will include more individuals than the theoretical minimum core group.
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26
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Keenan JD, Tadesse Z, Gebresillasie S, Shiferaw A, Zerihun M, Emerson PM, Callahan K, Cotter SY, Stoller NE, Porco TC, Oldenburg CE, Lietman TM. Mass azithromycin distribution for hyperendemic trachoma following a cluster-randomized trial: A continuation study of randomly reassigned subclusters (TANA II). PLoS Med 2018; 15:e1002633. [PMID: 30106956 PMCID: PMC6091918 DOI: 10.1371/journal.pmed.1002633] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/20/2018] [Accepted: 07/05/2018] [Indexed: 12/04/2022] Open
Abstract
BACKGROUND The World Health Organization recommends annual mass azithromycin administration in communities with at least 10% prevalence of trachomatous inflammation-follicular (TF) in children, with further treatment depending on reassessment after 3-5 years. However, the effect of stopping mass azithromycin distribution after multiple rounds of treatment is not well understood. Here, we report the results of a cluster-randomized trial where communities that had received 4 years of treatments were then randomized to continuation or discontinuation of treatment. METHODS AND FINDINGS In all, 48 communities with 3,938 children aged 0-9 years at baseline in northern Ethiopia had received 4 years of annual or twice yearly mass azithromycin distribution as part of the TANA I trial. We randomized these communities to either continuation or discontinuation of treatment. Individuals in the communities in the continuation arm were offered either annual or twice yearly distribution of a single directly observed dose of oral azithromycin. The primary outcome was community prevalence of ocular chlamydial infection in a random sample of children aged 0-9 years, 36 months after baseline. We also assessed the change from baseline to 36 months in ocular chlamydia prevalence within each arm. We compared 36-month ocular chlamydia prevalence in communities randomized to continuation versus discontinuation in a model adjusting for baseline ocular chlamydia prevalence. A secondary prespecified analysis assessed the rate of change over time in ocular chlamydia prevalence between arms. In the continuation arm, mean antibiotic coverage was greater than 90% at all time points. In the discontinuation arm, the mean prevalence of infection in children aged 0-9 years increased from 8.3% (95% CI 4.2% to 12.4%) at 0 months to 14.7% (95% CI 8.7% to 20.8%, P = 0.04) at 36 months. Ocular chlamydia prevalence in communities where mass azithromycin distribution was continued was 7.2% (95% CI 3.3% to 11.0%) at baseline and 6.6% (95% CI 1.1% to 12.0%, P = 0.64) at 36 months. The 36-month prevalence of ocular chlamydia was significantly lower in communities continuing treatment compared with those discontinuing treatment (P = 0.03). Limitations of the study include uncertain generalizability outside of trachoma hyperendemic regions. CONCLUSIONS In this study, ocular chlamydia infection rebounded after 4 years of periodic mass azithromycin distribution. Continued distributions did not completely eliminate infection in all communities or meet WHO control goals, although they did prevent resurgence. TRIAL REGISTRATION This study was prospectively registered at clinicaltrials.gov (clinicaltrials.gov NCT01202331).
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Affiliation(s)
- Jeremy D. Keenan
- Francis I. Proctor Foundation, University of California, San Francisco, San Francisco, California, United States of America
- Department of Ophthalmology, University of California, San Francisco, San Francisco, California, United States of America
- * E-mail:
| | | | | | | | | | - Paul M. Emerson
- The Carter Center, Atlanta, Georgia, United States of America
| | - Kelly Callahan
- The Carter Center, Atlanta, Georgia, United States of America
| | - Sun Y. Cotter
- Francis I. Proctor Foundation, University of California, San Francisco, San Francisco, California, United States of America
| | - Nicole E. Stoller
- Francis I. Proctor Foundation, University of California, San Francisco, San Francisco, California, United States of America
| | - Travis C. Porco
- Francis I. Proctor Foundation, University of California, San Francisco, San Francisco, California, United States of America
- Department of Ophthalmology, University of California, San Francisco, San Francisco, California, United States of America
- Department of Epidemiology and Biostatistics, University of California, San Francisco, San Francisco, California, United States of America
| | - Catherine E. Oldenburg
- Francis I. Proctor Foundation, University of California, San Francisco, San Francisco, California, United States of America
- Department of Ophthalmology, University of California, San Francisco, San Francisco, California, United States of America
- Department of Epidemiology and Biostatistics, University of California, San Francisco, San Francisco, California, United States of America
| | - Thomas M. Lietman
- Francis I. Proctor Foundation, University of California, San Francisco, San Francisco, California, United States of America
- Department of Ophthalmology, University of California, San Francisco, San Francisco, California, United States of America
- Department of Epidemiology and Biostatistics, University of California, San Francisco, San Francisco, California, United States of America
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27
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Astale T, Sata E, Zerihun M, Nute AW, Stewart AEP, Gessese D, Ayenew G, Melak B, Chanyalew M, Tadesse Z, Callahan EK, Nash SD. Population-based coverage survey results following the mass drug administration of azithromycin for the treatment of trachoma in Amhara, Ethiopia. PLoS Negl Trop Dis 2018; 12:e0006270. [PMID: 29451881 PMCID: PMC5833287 DOI: 10.1371/journal.pntd.0006270] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2017] [Revised: 03/01/2018] [Accepted: 01/25/2018] [Indexed: 11/18/2022] Open
Abstract
Background Trachoma is the leading infectious cause of blindness worldwide. In communities where the district level prevalence of trachomatous inflammation-follicular among children ages 1–9 years is ≥5%, WHO recommends annual mass drug administration (MDA) of antibiotics with the aim of at least 80% coverage. Population-based post-MDA coverage surveys are essential to understand the effectiveness of MDA programs, yet published reports from trachoma programs are rare. Methods In the Amhara region of Ethiopia, a population-based MDA coverage survey was conducted 3 weeks following the 2016 MDA to estimate the zonal prevalence of self-reported drug coverage in all 10 administrative zones. Survey households were selected using a multi-stage cluster random sampling design and all individuals in selected households were presented with a drug sample and asked about taking the drug during the campaign. Zonal estimates were weighted and confidence intervals were calculated using survey procedures. Self-reported drug coverage was then compared with regional reported administrative coverage. Results Region-wide, 24,248 individuals were enumerated, of which, 20,942 (86.4%) individuals were present. The regional self-reported antibiotic coverage was 76.8% (95%Confidence Interval (CI):69.3–82.9%) in the population overall and 77.4% (95%CI = 65.7–85.9%) among children ages 1–9 years old. Zonal coverage ranged from 67.8% to 90.2%. Five out of 10 zones achieved a coverage >80%. In all zones, the reported administrative coverage was greater than 90% and was considerably higher than self-reported MDA coverage. Main reasons reported for MDA campaign non-attendance included being physically unable to get to MDA site (22.5%), traveling (20.6%), and not knowing about the campaign (21.0%). MDA refusal was low (2.8%) in this population. Conclusions Although self-reported MDA coverage in Amhara was greater than 80% in some zones, programmatic improvements are warranted throughout Amhara to achieve higher coverage. These results will be used to enhance community mobilization and improve training for MDA distributors and supervisors to improve coverage in future MDAs. Mass drug administration (MDA) with antibiotics is a key component of the trachoma control strategy. The World Health Organization (WHO) recommends that at least 80% of the target population should be reached with MDA. Drug coverage estimates from population-based surveys may increase our understanding of factors affecting the effectiveness of MDA. We conducted a region-wide population-based survey to estimate the prevalence of self-reported drug coverage in all ten administrative zones of Amhara region, an area with a population of approximately 21 million people. The self-reported drug coverage was greater than 80% in five of the ten zones and was 76.8% region-wide. Zonal administrative coverage reports were greater than 90% and were considerably higher than self-reported coverage in all zones. The discrepancy between administrative and self-report coverages also suggest that efforts should be made to better understand the reasons for the disparity in the two measures. The main reasons reported for not attending the MDA included being physically unable to get to the distribution site, traveling during the campaign, and lack of knowledge about the campaign. These findings suggest that making the distribution site accessible to all individuals, informing constituents about timing of the campaign to allow for travel, and providing adequate information about the campaign would improve MDA participation.
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Affiliation(s)
- Tigist Astale
- Trachoma Control Program, The Carter Center, Addis Ababa, Ethiopia
- * E-mail:
| | - Eshetu Sata
- Trachoma Control Program, The Carter Center, Addis Ababa, Ethiopia
| | - Mulat Zerihun
- Trachoma Control Program, The Carter Center, Addis Ababa, Ethiopia
| | - Andrew W. Nute
- Trachoma Control Program, The Carter Center, Atlanta, Georgia, United States of America
| | - Aisha E. P. Stewart
- Trachoma Control Program, The Carter Center, Atlanta, Georgia, United States of America
| | - Demelash Gessese
- Trachoma Control Program, The Carter Center, Addis Ababa, Ethiopia
| | - Gedefaw Ayenew
- Trachoma Control Program, The Carter Center, Addis Ababa, Ethiopia
| | - Berhanu Melak
- Trachoma Control Program, The Carter Center, Addis Ababa, Ethiopia
| | - Melsew Chanyalew
- Health Promotion and Disease Prevention Core Process, The Amhara Regional Health Bureau, Bahir Dar, Ethiopia
| | - Zerihun Tadesse
- Trachoma Control Program, The Carter Center, Addis Ababa, Ethiopia
| | - E. Kelly Callahan
- Trachoma Control Program, The Carter Center, Atlanta, Georgia, United States of America
| | - Scott D. Nash
- Trachoma Control Program, The Carter Center, Atlanta, Georgia, United States of America
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Last AR, Burr SE, Harding-Esch E, Cassama E, Nabicassa M, Roberts CH, Mabey DCW, Holland MJ, Bailey RL. The impact of a single round of community mass treatment with azithromycin on disease severity and ocular Chlamydia trachomatis load in treatment-naïve trachoma-endemic island communities in West Africa. Parasit Vectors 2017; 10:624. [PMID: 29282126 PMCID: PMC5745817 DOI: 10.1186/s13071-017-2566-x] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2016] [Accepted: 12/03/2017] [Indexed: 10/29/2022] Open
Abstract
BACKGROUND Trachoma, a neglected tropical disease, is caused by ocular infection with Chlamydia trachomatis (Ct). The World Health Organization (WHO) recommends three annual rounds of community mass drug treatment with azithromycin (MDA) if the prevalence of follicular trachoma in 1-9 year olds (TF1-9) exceeds 10% at district level to achieve an elimination target of district-level TF1-9 below 5% after. To evaluate this strategy in treatment-naïve trachoma-endemic island communities in Guinea Bissau, we conducted a cross-sectional population-based trachoma survey on four islands. The upper tarsal conjunctivae of each participant were clinically assessed for trachoma and conjunctival swabs were obtained (n = 1507). We used a droplet digital PCR assay to detect Ct infection and estimate bacterial load. We visited the same households during a second cross-sectional survey and repeated the ocular examination and obtained conjunctival swabs from these households one year after MDA (n = 1029). RESULTS Pre-MDA TF1-9 was 22.0% (136/618). Overall Ct infection prevalence (CtI) was 18.6% (25.4% in 1-9 year olds). Post-MDA (estimated coverage 70%), TF1-9 and CtI were significantly reduced (7.4% (29/394, P < 0.001) and 3.3% (34/1029, P < 0.001) (6.6% in 1-9 year olds, P < 0.001), respectively. Median ocular Ct load was reduced from 2038 to 384 copies/swab (P < 0.001). Following MDA cases of Ct infection were highly clustered (Moran's I 0.27, P < 0.001), with fewer clusters of Ct infection overall, fewer clusters of cases with high load infections and less severe disease. CONCLUSIONS Despite a significant reduction in the number of clusters of Ct infection, mean Ct load, disease severity and presence of clusters of cases of high load Ct infection suggesting the beginning of trachoma control in isolated island communities, following a single round of MDA we demonstrate that transmission is still ongoing. These detailed data are useful in understanding the epidemiology of ocular Ct infection in the context of MDA and the tools employed may have utility in determining trachoma elimination and surveillance activities in similar settings.
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Affiliation(s)
- Anna R Last
- Clinical Research Department, London School of Hygiene and Tropical Medicine, Keppel Street, London, WC1E 7HT, UK.
| | - Sarah E Burr
- Clinical Research Department, London School of Hygiene and Tropical Medicine, Keppel Street, London, WC1E 7HT, UK.,Disease Control and Elimination Theme, Medical Research Council Unit The Gambia, P.OBox 273, Banjul, Atlantic Boulevard, Fajara, The, Gambia
| | - Emma Harding-Esch
- Clinical Research Department, London School of Hygiene and Tropical Medicine, Keppel Street, London, WC1E 7HT, UK
| | - Eunice Cassama
- Programa Nacional de Saúde de Visão, Ministério de Saúde Publica, P.O. Box 50, Avenida de Unidade Africana, Bisssau, Guinea-Bissau
| | - Meno Nabicassa
- Programa Nacional de Saúde de Visão, Ministério de Saúde Publica, P.O. Box 50, Avenida de Unidade Africana, Bisssau, Guinea-Bissau
| | - Chrissy H Roberts
- Clinical Research Department, London School of Hygiene and Tropical Medicine, Keppel Street, London, WC1E 7HT, UK
| | - David C W Mabey
- Clinical Research Department, London School of Hygiene and Tropical Medicine, Keppel Street, London, WC1E 7HT, UK
| | - Martin J Holland
- Clinical Research Department, London School of Hygiene and Tropical Medicine, Keppel Street, London, WC1E 7HT, UK
| | - Robin L Bailey
- Clinical Research Department, London School of Hygiene and Tropical Medicine, Keppel Street, London, WC1E 7HT, UK
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29
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Oldenburg CE, Amza A, Kadri B, Nassirou B, Cotter SY, Stoller NE, West SK, Bailey RL, Porco TC, Gaynor BD, Keenan JD, Lietman TM. Comparison of Mass Azithromycin Coverage Targets of Children in Niger: A Cluster-Randomized Trachoma Trial. Am J Trop Med Hyg 2017; 98:389-395. [PMID: 29260659 DOI: 10.4269/ajtmh.17-0501] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
Repeated oral azithromycin distribution targeted only to children has proven effective in reducing the ocular Chlamydia that causes trachoma. Here, we assess whether an enhanced coverage target of at least 90% of children is superior to the World Health Organization recommendation of at least 80%. Twenty-four trachoma-endemic communities in Matamèye, Niger, were randomized to a single day of azithromycin distribution aiming for at least 80% coverage or up to 4 days of treatment and > 90% coverage of children under age 12. All distributions were biannual. Children < 5 years of age and adults > 15 years were monitored for ocular Chlamydia infection by polymerase chain reaction every 6 months for 36 months in children and at baseline and 36 months in adults. Ocular Chlamydia prevalence in children decreased from 24.9% (95% confidence interval [CI] 15.9-33.8%) to 4.4% (95% CI 0.6-8.2%, P < 0.001) at 36 months in the standard coverage arm and from 15.6% (95% CI 10.0-21.2%) to 3.3% (95% CI 1.0-5.5%; P < 0.001) in the enhanced coverage arm. Enhanced coverage reduced ocular Chlamydia prevalence in children more quickly over time compared with standard (P = 0.04). There was no difference between arms at 36 months in children (2.4% lower with enhanced coverage, 95% CI 7.7-12.5%; P = 0.60). No infection was detected in adults at 36 months. Increasing antibiotic coverage among children from 80% to 90% may yield only short term improvements for trachoma control programs. Targeting treatment to children alone may be sufficient for trachoma control in this setting.
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Affiliation(s)
- Catherine E Oldenburg
- Department of Ophthalmology, University of California San Francisco, San Francisco, California.,F.I. Proctor Foundation, University of California San Francisco, San Francisco, California
| | - 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
| | - Beido Nassirou
- Programme FSS/Université Abdou Moumouni de Niamey, Programme National de Santé Oculaire, Niamey, Niger
| | - Sun Y Cotter
- F.I. Proctor Foundation, University of California San Francisco, San Francisco, California
| | - Nicole E Stoller
- F.I. Proctor Foundation, University of California San Francisco, San Francisco, California
| | - Sheila K West
- Dana Center for Preventive Ophthalmology, Wilmer Eye Institute, Johns Hopkins University, Baltimore, Maryland
| | - Robin L Bailey
- Clinical Research Unit, Department of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Travis C Porco
- Department of Epidemiology & Biostatistics, University of California San Francisco, San Francisco, California.,Department of Ophthalmology, University of California San Francisco, San Francisco, California.,F.I. Proctor Foundation, University of California San Francisco, San Francisco, California
| | - Bruce D Gaynor
- Department of Ophthalmology, University of California San Francisco, San Francisco, California.,F.I. Proctor Foundation, University of California San Francisco, San Francisco, California
| | - Jeremy D Keenan
- Department of Epidemiology & Biostatistics, University of California San Francisco, San Francisco, California.,Department of Ophthalmology, University of California San Francisco, San Francisco, California.,F.I. Proctor Foundation, University of California San Francisco, San Francisco, California
| | - Thomas M Lietman
- Department of Ophthalmology, University of California San Francisco, San Francisco, California.,F.I. Proctor Foundation, University of California San Francisco, San Francisco, California.,Department of Epidemiology & Biostatistics, University of California San Francisco, San Francisco, California
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30
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Hamiltonian Analysis of Subcritical Stochastic Epidemic Dynamics. COMPUTATIONAL AND MATHEMATICAL METHODS IN MEDICINE 2017; 2017:4253167. [PMID: 28932256 PMCID: PMC5592420 DOI: 10.1155/2017/4253167] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/31/2017] [Revised: 06/07/2017] [Accepted: 06/12/2017] [Indexed: 11/23/2022]
Abstract
We extend a technique of approximation of the long-term behavior of a supercritical stochastic epidemic model, using the WKB approximation and a Hamiltonian phase space, to the subcritical case. The limiting behavior of the model and approximation are qualitatively different in the subcritical case, requiring a novel analysis of the limiting behavior of the Hamiltonian system away from its deterministic subsystem. This yields a novel, general technique of approximation of the quasistationary distribution of stochastic epidemic and birth-death models and may lead to techniques for analysis of these models beyond the quasistationary distribution. For a classic SIS model, the approximation found for the quasistationary distribution is very similar to published approximations but not identical. For a birth-death process without depletion of susceptibles, the approximation is exact. Dynamics on the phase plane similar to those predicted by the Hamiltonian analysis are demonstrated in cross-sectional data from trachoma treatment trials in Ethiopia, in which declining prevalences are consistent with subcritical epidemic dynamics.
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31
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Worden L, Porco TC. Products of Compartmental Models in Epidemiology. COMPUTATIONAL AND MATHEMATICAL METHODS IN MEDICINE 2017; 2017:8613878. [PMID: 28900467 PMCID: PMC5576399 DOI: 10.1155/2017/8613878] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/28/2017] [Accepted: 06/28/2017] [Indexed: 11/18/2022]
Abstract
We show that many structured epidemic models may be described using a straightforward product structure in this paper. Such products, derived from products of directed graphs, may represent useful refinements including geographic and demographic structure, age structure, gender, risk groups, or immunity status. Extension to multistrain dynamics, that is, pathogen heterogeneity, is also shown to be feasible in this framework. Systematic use of such products may aid in model development and exploration, can yield insight, and could form the basis of a systematic approach to numerical structural sensitivity analysis.
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Affiliation(s)
- Lee Worden
- Francis I. Proctor Foundation, University of California San Francisco, San Francisco, CA, USA
| | - Travis C. Porco
- Francis I. Proctor Foundation, University of California San Francisco, San Francisco, CA, USA
- Department of Ophthalmology, University of California, San Francisco, CA, USA
- Department of Epidemiology and Biostatistics, University of California San Francisco, San Francisco, CA, USA
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32
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Gao D, Lietman TM, Dong CP, Porco TC. Mass drug administration: the importance of synchrony. MATHEMATICAL MEDICINE AND BIOLOGY : A JOURNAL OF THE IMA 2017; 34:241-260. [PMID: 27118395 PMCID: PMC6201266 DOI: 10.1093/imammb/dqw005] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/30/2015] [Accepted: 02/16/2016] [Indexed: 11/13/2022]
Abstract
Mass drug administration, a strategy in which all individuals in a population are subject to treatment without individual diagnosis, has been recommended by the World Health Organization for controlling and eliminating several neglected tropical diseases, including trachoma and soil-transmitted helminths. In this article, we derive effective reproduction numbers and average post-treatment disease prevalences of a simple susceptible-infectious-susceptible epidemic model with constant, impulsive synchronized and non-synchronized drug administration strategies. In the non-synchronized model, the individuals in the population are treated at most once per period and their treatment times are uniformly distributed. Mathematically, the set of pulses for the non-synchronized model has the cardinality of the continuum. We show that synchronized and constant strategies are, respectively, the most and least effective treatments in disease control. Elimination through synchronized treatment is always possible when adequate drug efficacy and coverage are fulfilled and sustained. For a strategy with multiple rounds of synchronized treatment per period, the average post-treatment prevalence is irrelevant what the time differences between treatments are, as long as there are the same number of treatments per period.
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Affiliation(s)
- Daozhou Gao
- Mathematics and Science College, Shanghai Normal University, Shanghai 200234, China and Francis I. Proctor Foundation, University of California, San Francisco, CA 94143-0412, USA
| | - Thomas M. Lietman
- Francis I. Proctor Foundation, University of California, San Francisco, CA 94143-0412, USA, Department of Ophthalmology, University of California, San Francisco, CA 94143-0412, USA and Department of Epidemiology & Biostatistics, University of California, San Francisco, CA 94143-0412, USA
| | - Chao-Ping Dong
- Institute of Mathematics, Hunan University, Changsha, Hunan 410082, China
| | - Travis C. Porco
- Francis I. Proctor Foundation, University of California, San Francisco, CA 94143-0412, USA, Department of Ophthalmology, University of California, San Francisco, CA 94143-0412, USA and Department of Epidemiology & Biostatistics, University of California, San Francisco, CA 94143-0412, USA
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33
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Pinsent A, Liu F, Deiner M, Emerson P, Bhaktiari A, Porco TC, Lietman T, Gambhir M. Probabilistic forecasts of trachoma transmission at the district level: A statistical model comparison. Epidemics 2017; 18:48-55. [PMID: 28279456 PMCID: PMC5340843 DOI: 10.1016/j.epidem.2017.01.007] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2016] [Revised: 01/20/2017] [Accepted: 01/31/2017] [Indexed: 11/09/2022] Open
Abstract
The World Health Organization and its partners are aiming to eliminate trachoma as a public health problem by 2020. In this study, we compare forecasts of TF prevalence in 2011 for 7 different statistical and mechanistic models across 9 de-identified trachoma endemic districts, representing 4 unique trachoma endemic countries. We forecast TF prevalence between 1-6 years ahead in time and compare the 7 different models to the observed 2011 data using a log-likelihood score. An SIS model, including a district-specific random effect for the district-specific transmission coefficient, had the highest log-likelihood score across all 9 districts and was therefore the best performing model. While overall the deterministic transmission model was the least well performing model, although it did comparably well to the other models for 8 of 9 districts. We perform a statistically rigorous comparison of the forecasting ability of a range of mathematical and statistical models across multiple endemic districts between 1 and 6 years ahead of the last collected TF prevalence data point in 2011, assessing results against surveillance data. This study is a step towards making statements about likelihood and time to elimination with regard to the WHO GET2020 goals.
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Affiliation(s)
- Amy Pinsent
- Department of Public Health and Preventative Medicine, Monash University, Melbourne, Australia.
| | - Fengchen Liu
- F.I. Proctor Foundation, University of California San Francisco, San Francisco, CA, USA
| | - Michael Deiner
- F.I. Proctor Foundation, University of California San Francisco, San Francisco, CA, USA; Department of Ophthalmology, University of California San Francisco, San Francisco, CA, USA
| | - Paul Emerson
- International Trachoma Initiative, Atlanta, GA, USA; School of Public Health, Emory University, Atlanta, GA, USA
| | | | - Travis C Porco
- F.I. Proctor Foundation, University of California San Francisco, San Francisco, CA, 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
| | - Thomas Lietman
- F.I. Proctor Foundation, University of California San Francisco, San Francisco, CA, 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; Global Health Sciences, University of California San Francisco, San Francisco, CA, USA
| | - Manoj Gambhir
- Department of Public Health and Preventative Medicine, Monash University, Melbourne, Australia
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34
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Pinsent A, Gambhir M. Improving our forecasts for trachoma elimination: What else do we need to know? PLoS Negl Trop Dis 2017; 11:e0005378. [PMID: 28182664 PMCID: PMC5321453 DOI: 10.1371/journal.pntd.0005378] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2016] [Revised: 02/22/2017] [Accepted: 02/01/2017] [Indexed: 11/20/2022] Open
Abstract
The World Health Organization (WHO) has targeted trachoma for elimination as a public health concern by 2020. Mathematical modelling is used for a range of infectious diseases to assess the impact of different intervention strategies on the prevalence of infection or disease. Here we evaluate the performance of four different mechanistic mathematical models that could all realistically represent trachoma transmission. We fit the four different mechanistic models of trachoma transmission to cross-sectional age-specific Polymerase Chain Reaction (PCR) and Trachomatous inflammation, follicular (TF) prevalence data. We estimate 4 or 3 parameters within each model, including the duration of an individual's infection and disease episode using Markov Chain Monte Carlo. We assess the performance of each models fit to the data by calculating the deviance information criterion. We then model the implementation of different interventions for each model structure to assess the feasibility of elimination of trachoma with different model structures. A model structure which allowed some re-infection in the disease state (Model 2) was statistically the most well performing model. All models struggled to fit to the very high prevalence of active disease in the youngest age group. Our simulations suggested that for Model 3, with annual antibiotic treatment and transmission reduction, the chance of reducing active disease prevalence to < 5% within 5 years was very low, while Model 2 and 4 could ensure that active disease prevalence was reduced within 5 years. Model 2 here fitted to the data best of the models evaluated. The appropriate level of susceptibility to re-infection was, however, challenging to identify given the amount and kind of data available. We demonstrate that the model structure assumed can lead to different end points following the implementation of the same interventions. Our findings are likely to extend beyond trachoma and should be considered when modelling other neglected tropical diseases.
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Affiliation(s)
- Amy Pinsent
- Department of Epidemiology and Preventive Medicine, Faculty of Medicine, Nursing and Health Sciences, Monash University, Melbourne, Victoria, Australia
| | - Manoj Gambhir
- Department of Epidemiology and Preventive Medicine, Faculty of Medicine, Nursing and Health Sciences, Monash University, Melbourne, Victoria, Australia
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35
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Gao D, Porco TC, Ruan S. Coinfection Dynamics of Two Diseases in a Single Host Population. JOURNAL OF MATHEMATICAL ANALYSIS AND APPLICATIONS 2016; 442:171-188. [PMID: 27667856 PMCID: PMC5032845 DOI: 10.1016/j.jmaa.2016.04.039] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
A susceptible-infectious-susceptible (SIS) epidemic model that describes the coinfection and cotransmission of two infectious diseases spreading through a single population is studied. The host population consists of two subclasses: susceptible and infectious, and the infectious individuals are further divided into three subgroups: those infected by the first agent/pathogen, the second agent/pathogen, and both. The basic reproduction numbers for all cases are derived which completely determine the global stability of the system if the presence of one agent/pathogen does not affect the transmission of the other. When the constraint on the transmissibility of the dually infected hosts is removed, we introduce the invasion reproduction number, compare it with two other types of reproduction number and show the uniform persistence of both diseases under certain conditions. Numerical simulations suggest that the system can display much richer dynamics such as backward bifurcation, bistability and Hopf bifurcation.
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Affiliation(s)
- Daozhou Gao
- Mathematics and Science College, Shanghai Normal University, Shanghai, China
- Francis I. Proctor Foundation, University of California, San Francisco, CA, USA
| | - Travis C. Porco
- Francis I. Proctor Foundation, University of California, San Francisco, CA, USA
- Department of Ophthalmology, University of California, San Francisco, CA, USA
- Department of Epidemiology & Biostatistics, University of California, San Francisco, CA, USA
| | - Shigui Ruan
- Department of Mathematics, University of Miami, Coral Gables, FL, USA
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36
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Pinsent A, Blake IM, Basáñez MG, Gambhir M. Mathematical Modelling of Trachoma Transmission, Control and Elimination. ADVANCES IN PARASITOLOGY 2016; 94:1-48. [PMID: 27756453 DOI: 10.1016/bs.apar.2016.06.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
The World Health Organization has targeted the elimination of blinding trachoma by the year 2020. To this end, the Global Elimination of Blinding Trachoma (GET, 2020) alliance relies on a four-pronged approach, known as the SAFE strategy (S for trichiasis surgery; A for antibiotic treatment; F for facial cleanliness and E for environmental improvement). Well-constructed and parameterized mathematical models provide useful tools that can be used in policy making and forecasting in order to help to control trachoma and understand the feasibility of this large-scale elimination effort. As we approach this goal, the need to understand the transmission dynamics of infection within areas of different endemicities, to optimize available resources and to identify which strategies are the most cost-effective becomes more pressing. In this study, we conducted a review of the modelling literature for trachoma and identified 23 articles that included a mechanistic or statistical model of the transmission, dynamics and/or control of (ocular) Chlamydia trachomatis. Insights into the dynamics of trachoma transmission have been generated through both deterministic and stochastic models. A large body of the modelling work conducted to date has shown that, to varying degrees of effectiveness, antibiotic administration can reduce or interrupt trachoma transmission. However, very little analysis has been conducted to consider the effect of nonpharmaceutical interventions (and particularly the F and E components of the SAFE strategy) in helping to reduce transmission. Furthermore, very few of the models identified in the literature review included a structure that permitted tracking of the prevalence of active disease (in the absence of active infection) and the subsequent progression to disease sequelae (the morbidity associated with trachoma and ultimately the target of GET 2020 goals). This represents a critical gap in the current trachoma modelling literature, which makes it difficult to reliably link infection and disease. In addition, it hinders the application of modelling to assist the public health community in understanding whether trachoma programmes are on track to reach the GET goals by 2020. Another gap identified in this review was that of the 23 articles examined, only one considered the cost-effectiveness of the interventions implemented. We conclude that although good progress has been made towards the development of modelling frameworks for trachoma transmission, key components of disease sequelae representation and economic evaluation of interventions are currently missing from the available literature. We recommend that rapid advances in these areas should be urgently made to ensure that mathematical models for trachoma transmission can robustly guide elimination efforts and quantify progress towards GET 2020.
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Affiliation(s)
- A Pinsent
- Monash University, Melbourne, VIC, Australia
| | - I M Blake
- Imperial College London, London, United Kingdom
| | - M G Basáñez
- Imperial College London, London, United Kingdom
| | - M Gambhir
- Monash University, Melbourne, VIC, Australia
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37
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Gambhir M, Grassly NC, Burton MJ, Solomon AW, Taylor HR, Mabey DC, Blake IM, Basáñez MG. Estimating the Future Impact of a Multi-Pronged Intervention Strategy on Ocular Disease Sequelae Caused by Trachoma: A Modeling Study. Ophthalmic Epidemiol 2016; 22:394-402. [PMID: 26653262 PMCID: PMC4841017 DOI: 10.3109/09286586.2015.1081249] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Purpose: Trachoma control programs are underway in endemic regions worldwide. They are based on the SAFE strategy (Surgery for trichiasis, Antibiotic distribution, Facial cleanliness, and Environmental improvement). Although much is known about the effect of community-wide treatment with antibiotics on the prevalence of Chlamydia trachomatis, the impact of the SAFE strategy on severe ocular disease sequelae (the main focus of the Global Elimination of blinding Trachoma by 2020 program) remains largely unknown. Methods: We use a mathematical model to explore the impact of each of the components of the SAFE strategy, individually and together, on disease sequelae, arising from repeat infection and subsequent conjunctival scarring. We ask whether two elimination goals, to reduce the prevalence of trachomatous trichiasis to 1 per 1000 persons, and the incidence of corneal opacity to 1 per 10,000 persons per annum, are achievable, and which combinations of interventions have the greatest impact on these indicators. Results: In high prevalence communities (here, >20% infection of children aged 1–9 years), a combination of efforts is needed to bring down sustainably the prevalence and incidence of ocular disease sequelae. Conclusion: The mass delivery of antibiotics is highly beneficial for the clearance of infection, inflammation and prevention of subsequent scarring, but needs to be supplemented with sustained reductions in transmission and surgery to consider realistically the elimination of blindness by the year 2020.
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Affiliation(s)
- Manoj Gambhir
- a Department of Epidemiology and Preventive Medicine , Monash University , Melbourne , Victoria , Australia
| | - Nicholas C Grassly
- b Department of Infectious Disease Epidemiology , Imperial College London , London, UK .,c MRC Centre for Outbreak Analysis and Modelling , Department of Infectious Disease Epidemiology, Imperial College London , London, UK
| | - Matthew J Burton
- d Clinical Research Department , Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine , London , UK , and
| | - Anthony W Solomon
- d Clinical Research Department , Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine , London , UK , and
| | - Hugh R Taylor
- e Indigenous Eye Health Unit, Melbourne School of Population Health, The University of Melbourne , East Melbourne, Victoria, Australia
| | - David C Mabey
- d Clinical Research Department , Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine , London , UK , and
| | - Isobel M Blake
- b Department of Infectious Disease Epidemiology , Imperial College London , London, UK .,c MRC Centre for Outbreak Analysis and Modelling , Department of Infectious Disease Epidemiology, Imperial College London , London, UK
| | - María-Gloria Basáñez
- b Department of Infectious Disease Epidemiology , Imperial College London , London, UK
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Pinsent A, Burton MJ, Gambhir M. Enhanced antibiotic distribution strategies and the potential impact of facial cleanliness and environmental improvements for the sustained control of trachoma: a modelling study. BMC Med 2016; 14:71. [PMID: 27194136 PMCID: PMC4872360 DOI: 10.1186/s12916-016-0614-6] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/08/2016] [Accepted: 04/05/2016] [Indexed: 11/25/2022] Open
Abstract
BACKGROUND Despite some success in controlling trachoma with repeated mass drug administration (MDA), some hyperendemic regions are not responding as fast as anticipated. Available data suggests that individuals with higher bacterial infection loads are less likely to resolve infection following a single dose of treatment, and thus remain a source of re-emergent infection following treatment. We assessed the potential impact of a new double-dose antibiotic distribution strategy in addition to enhanced facial cleanliness (F) and environmental improvements (E). METHODS Using a within-community mathematical model of trachoma transmission we assessed the impact of a new double-dose antibiotic distribution strategy given 2 weeks apart, with and without enhanced F&E. We compared the annual double-dose strategy to single-dose annual MDA treatment in hyper-, meso- and hypoendemic settings, and to biannual MDA at 6-monthly intervals in hyperendemic communities. RESULTS The findings from our mathematical model suggest that implementing the new double-dose strategy for 5 years or less was predicted to control infection more successfully than annual or 6-monthly treatment. Infection was controlled more readily if treatment was combined with enhanced F&E. The results appeared robust to variation in a number of key epidemiological parameters. To have long-term impact on transmission, enhanced F&E is essential for high transmission settings. CONCLUSION Our current findings are based on simualtion modelling only, due to lack of epidemilogical data, however they do suggest that the annual double-dose treatment strategy is encouraging for trachoma control. In high transmission settings, both MDA and enhanced F&E are needed for sustained control.
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Affiliation(s)
- Amy Pinsent
- Department of Epidemiology and Preventive Medicine, Monash University, Melbourne, Australia.
| | - Matthew J Burton
- International Centre for Eye Health, Department of Clinical Research, London School of Hygiene & Tropical Medicine, London, UK
| | - Manoj Gambhir
- Department of Epidemiology and Preventive Medicine, Monash University, Melbourne, Australia
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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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Gambhir M, Pinsent A. Possible changes in the transmissibility of trachoma following MDA and transmission reduction: implications for the GET2020 goals. Parasit Vectors 2015; 8:530. [PMID: 26490436 PMCID: PMC4618927 DOI: 10.1186/s13071-015-1133-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2015] [Accepted: 10/02/2015] [Indexed: 11/26/2022] Open
Abstract
BACKGROUND The role of mass drug administration (MDA) and the implementation of transmission reduction measures are essential to successfully control and eliminate a wide range of NTDs, including the ocular disease trachoma. Immunity to trachoma infection acts by reducing the duration of an individual's infectious period and by reducing their infectivity with each successive infection. METHODS In this study, we use a model of trachoma infection, which includes population immunity, to explore the impact of treatment and transmission reduction measures on trachoma prevalence. Specifically, we investigate the possibility of increasing transmissibility of trachoma arising as MDA and transmission reduction measures are scaled up in endemic settings. RESULTS We demonstrate this increase in transmissibility by calculating the effective reproduction number during several simulated control programmes and show that it is related to a decrease in the level of immunity in the population. CONCLUSIONS This effect should be studied in the field by measuring the rate of return of infection and disease in at least two separate age groups. If the decline of population immunity is operating, it should be accounted for when planning for the GET2020 goal of eliminating blinding trachoma by 2020.
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Affiliation(s)
- Manoj Gambhir
- Department of Epidemiology and Preventive Medicine, Monash University, Melbourne, Australia.
| | - Amy Pinsent
- Department of Epidemiology and Preventive Medicine, Monash University, Melbourne, Australia
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Liu F, Porco TC, Amza A, Kadri B, Nassirou B, West SK, Bailey RL, Keenan JD, Solomon AW, Emerson PM, Gambhir M, Lietman TM. Short-term Forecasting of the Prevalence of Trachoma: Expert Opinion, Statistical Regression, versus Transmission Models. PLoS Negl Trop Dis 2015; 9:e0004000. [PMID: 26302380 PMCID: PMC4547743 DOI: 10.1371/journal.pntd.0004000] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2015] [Accepted: 07/21/2015] [Indexed: 11/17/2022] Open
Abstract
Background Trachoma programs rely on guidelines made in large part using expert opinion of what will happen with and without intervention. Large community-randomized trials offer an opportunity to actually compare forecasting methods in a masked fashion. Methods The Program for the Rapid Elimination of Trachoma trials estimated longitudinal prevalence of ocular chlamydial infection from 24 communities treated annually with mass azithromycin. Given antibiotic coverage and biannual assessments from baseline through 30 months, forecasts of the prevalence of infection in each of the 24 communities at 36 months were made by three methods: the sum of 15 experts’ opinion, statistical regression of the square-root-transformed prevalence, and a stochastic hidden Markov model of infection transmission (Susceptible-Infectious-Susceptible, or SIS model). All forecasters were masked to the 36-month results and to the other forecasts. Forecasts of the 24 communities were scored by the likelihood of the observed results and compared using Wilcoxon’s signed-rank statistic. Findings Regression and SIS hidden Markov models had significantly better likelihood than community expert opinion (p = 0.004 and p = 0.01, respectively). All forecasts scored better when perturbed to decrease Fisher’s information. Each individual expert’s forecast was poorer than the sum of experts. Interpretation Regression and SIS models performed significantly better than expert opinion, although all forecasts were overly confident. Further model refinements may score better, although would need to be tested and compared in new masked studies. Construction of guidelines that rely on forecasting future prevalence could consider use of mathematical and statistical models. Forecasts of infectious diseases are rarely made in a falsifiable manner. Trachoma trials offer an opportunity to actually compare forecasting methods in a masked fashion. The World Health Organization recommends at least three annual antibiotic mass drug administrations where the prevalence of trachoma is greater than 10% in children aged 1–9 years, with coverage at least at 80%. The Program for the Rapid Elimination of Trachoma trials estimated longitudinal prevalence of ocular chlamydial infection from 24 communities treated annually with mass azithromycin. Here, we compared forecasts of the prevalence of infection in each of the 24 communities at 36 months (given antibiotic coverage and biannual assessments from baseline through 30 months, and masked to the 36-month assessments) made by experts, statistical regression, and a transmission model. The transmission model was better than regression, with both far better than experts’ opinion. Construction of guidelines that rely on forecasting future prevalence could consider use of mathematical and statistical models.
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Affiliation(s)
- Fengchen Liu
- Francis I. Proctor Foundation, University of California San Francisco, San Francisco, California, United States of America
| | - Travis C Porco
- Francis I. Proctor Foundation, University of California San Francisco, San Francisco, California, United States of America; Department of Ophthalmology, University of California San Francisco, San Francisco, California, United States of America; Department of Epidemiology & Biostatistics, University of California San Francisco, San Francisco, California, United States of America
| | - 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, Maryland, United States of America
| | - Robin L Bailey
- Clinical Research Unit, Department of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Jeremy D Keenan
- Francis I. Proctor Foundation, University of California San Francisco, San Francisco, California, United States of America; Department of Ophthalmology, University of California San Francisco, San Francisco, California, United States of America
| | - Anthony W Solomon
- Department of Control of Neglected Tropical Diseases, World Health Organization, Geneva, Switzerland
| | - Paul M Emerson
- International Trachoma Initiative, Atlanta, Georgia, United States of America
| | - Manoj Gambhir
- Department of Epidemiology and Preventive Medicine, Monash University, Melbourne, Australia
| | - Thomas M Lietman
- Francis I. Proctor Foundation, University of California San Francisco, San Francisco, California, United States of America; Department of Ophthalmology, University of California San Francisco, San Francisco, California, United States of America; Department of Epidemiology & Biostatistics, University of California San Francisco, San Francisco, California, United States of America
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Jimenez V, Gelderblom HC, Mann Flueckiger R, Emerson PM, Haddad D. Mass drug administration for trachoma: how long is not long enough? PLoS Negl Trop Dis 2015; 9:e0003610. [PMID: 25799168 PMCID: PMC4370651 DOI: 10.1371/journal.pntd.0003610] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2014] [Accepted: 02/09/2015] [Indexed: 11/20/2022] Open
Abstract
Background Blinding trachoma is targeted for elimination by 2020 using the SAFE strategy (Surgery, Antibiotics, Facial cleanliness, and Environmental improvements). Annual mass drug administration (MDA) with azithromycin is a cornerstone of this strategy. If baseline prevalence of clinical signs of trachomatous inflammation – follicular among 1-9 year-olds (TF1-9) is ≥10% but <30%, the World Health Organization guidelines are for at least 3 annual MDAs; if ≥30%, 5. We assessed the likelihood of achieving the global elimination target of TF1-9 <5% at 3 and 5 year evaluations using program reports. Methodology/Principal Findings We used the International Trachoma Initiative’s prevalence and treatment database. Of 283 cross-sectional survey pairs with baseline and follow-up data, MDA was conducted in 170 districts. Linear and logistic regression modeling was applied to these to investigate the effect of MDA on baseline prevalence. Reduction to <5% was less likely, though not impossible, at higher baseline TF1-9 prevalences. Increased number of annual MDAs, as well as no skipped MDAs, were significant predictors of reduced TF1-9 at follow-up. The probability of achieving the <5% target was <50% for areas with ≥30% TF1-9 prevalence at baseline, even with 7 or more continuous annual MDAs. Conclusions Number of annual MDAs alone appears insufficient to predict program progress; more information on the effects of baseline prevalence, coverage, and underlying environmental and hygienic conditions is needed. Programs should not skip MDAs, and at prevalences >30%, 7 or more annual MDAs may be required to achieve the target. There are five years left before the 2020 deadline to eliminate blinding trachoma. Low endemic settings are poised to succeed in their elimination goals. However, newly-identified high prevalence districts warrant immediate inclusion in the global program. Intensified application of the SAFE strategy is needed in order to guarantee blinding trachoma elimination by 2020. Trachoma, the world’s leading infectious cause of blindness, is scheduled for elimination by 2020. Reaching this elimination target depends on successful implementation of the SAFE strategy (Surgery, Antibiotics, Facial cleanliness, and Environmental improvements). Annual mass antibiotic distributions are key to breaking the cycle of transmission in a community. However, it is not clear how many annual mass treatments need to be carried out in order to achieve elimination. Our study analyzes the effect of mass antibiotic distribution on different baseline prevalence levels of trachoma, in order to assess factors that affect the success of reaching elimination goals. We find that the prevailing belief, which suggests that 3 annual mass treatments can achieve local elimination of trachoma at prevalences between 10–30%, and 5 annual mass treatments for districts above this benchmark, is probably incorrect. In fact, much longer intervals may be required with “business as usual” programmatic strategies, which often include skipped years of treatment. Districts with high prevalence levels may require more intense treatment strategies to eliminate trachoma. Intensified recommendations must be implemented without delay in order to reach the 2020 elimination deadline.
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Affiliation(s)
- Violeta Jimenez
- Hubert Department of Global Health, Rollins School of Public Health, Emory University, Atlanta, Georgia, United States of America
- International Trachoma Initiative, Task Force for Global Health, Emory University, Atlanta, Georgia, United States of America
- Global Ophthalmology Emory, Emory Eye Center, Emory University School of Medicine, Atlanta, Georgia, United States of America
| | - Huub C. Gelderblom
- International Trachoma Initiative, Task Force for Global Health, Emory University, Atlanta, Georgia, United States of America
| | - Rebecca Mann Flueckiger
- International Trachoma Initiative, Task Force for Global Health, Emory University, Atlanta, Georgia, United States of America
| | - Paul M. Emerson
- International Trachoma Initiative, Task Force for Global Health, Emory University, Atlanta, Georgia, United States of America
| | - Danny Haddad
- Hubert Department of Global Health, Rollins School of Public Health, Emory University, Atlanta, Georgia, United States of America
- Global Ophthalmology Emory, Emory Eye Center, Emory University School of Medicine, Atlanta, Georgia, United States of America
- * E-mail:
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Lietman TM, Gebre T, Abdou A, Alemayehu W, Emerson P, Blumberg S, Keenan JD, Porco TC. The distribution of the prevalence of ocular chlamydial infection in communities where trachoma is disappearing. Epidemics 2015; 11:85-91. [PMID: 25979286 PMCID: PMC4986606 DOI: 10.1016/j.epidem.2015.03.003] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2013] [Revised: 03/10/2015] [Accepted: 03/13/2015] [Indexed: 11/16/2022] Open
Abstract
Mathematical models predict that the prevalence of infection in different
communities where an infectious disease is disappearing should approach a
geometric distribution. Trachoma programs offer an opportunity to test this
hypothesis, as the World Health Organization (WHO) has targeted trachoma to be
eliminated as a public health concern by the year 2020. We assess the
distribution of the community prevalence of childhood ocular chlamydia infection
from periodic, cross-sectional surveys in two areas of Ethiopia. These surveys
were taken in a controlled setting, where infection was documented to be
disappearing over time. For both sets of surveys, the geometric distribution had
the most parsimonious fit of the distributions tested, and goodness-of-fit
testing was consistent with the prevalence of each community being drawn from a
geometric distribution. When infection is disappearing, the single sufficient
parameter describing a geometric distribution captures much of the
distributional information found from examining every community. The relatively
heavy tail of the geometric suggests that the presence of an occasional
high-prevalence community is to be expected, and does not necessarily reflect a
transmission hot spot or program failure. A single cross-sectional survey can
reveal which direction a program is heading. A geometric distribution of the
prevalence of infection across communities may be an encouraging sign,
consistent with a disease on its way to eradication.
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Affiliation(s)
- Thomas M Lietman
- F.I Proctor Foundation, San Francisco, CA, USA; Department of Ophthalmology, San Francisco, CA, USA; Department of Epidemiology & Biostatistics, University of California, San Francisco, CA, USA.
| | | | - Amza Abdou
- Programme National de Lutte Contre la Cecité, Niamey, Niger
| | - Wondu Alemayehu
- F.I Proctor Foundation, San Francisco, CA, USA; Department of Ophthalmology, San Francisco, CA, USA; Department of Epidemiology & Biostatistics, University of California, San Francisco, CA, USA; The Carter Center, Atlanta, GA, USA; Programme National de Lutte Contre la Cecité, Niamey, Niger; NIH Fogarty International Center, Bethesda, MD, USA; Berhan Health, Addis Ababa, Ethiopia
| | | | - Seth Blumberg
- F.I Proctor Foundation, San Francisco, CA, USA; NIH Fogarty International Center, Bethesda, MD, USA
| | - Jeremy D Keenan
- F.I Proctor Foundation, San Francisco, CA, USA; Department of Ophthalmology, San Francisco, CA, USA
| | - Travis C Porco
- F.I Proctor Foundation, San Francisco, CA, USA; Department of Ophthalmology, San Francisco, CA, USA; Department of Epidemiology & Biostatistics, University of California, 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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Liu F, Porco TC, Mkocha HA, Muñoz B, Ray KJ, Bailey RL, Lietman TM, West SK. The efficacy of oral azithromycin in clearing ocular chlamydia: mathematical modeling from a community-randomized trachoma trial. Epidemics 2014; 6:10-7. [PMID: 24593917 PMCID: PMC4420489 DOI: 10.1016/j.epidem.2013.12.001] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2013] [Revised: 12/05/2013] [Accepted: 12/11/2013] [Indexed: 11/29/2022] Open
Abstract
Mass oral azithromycin distributions have dramatically reduced the prevalence of the ocular strains of chlamydia that cause trachoma. Assessing efficacy of the antibiotic in an individual is important in planning trachoma elimination. However, the efficacy is difficult to estimate, because post-treatment laboratory testing may be complicated by nonviable organisms or reinfection. Here, we monitored ocular chlamydial infection twice a year in pre-school children in 32 communities as part of a cluster-randomized clinical trial in Tanzania (prevalence in children was lowered from 22.0% to 4.7% after 3-year of annual treatment). We used a mathematical transmission model to estimate the prevalence of infection immediately after treatment, and found the effective field efficacy of antibiotic in an individual to be 67.6% (95% CI: 56.5–75.1%) in this setting. Sensitivity analyses suggested that these results were not dependent on specific assumptions about the duration of infection. We found no evidence of decreased efficacy during the course of the trial. We estimated an 89% chance of elimination after 10 years of annual treatment with 95% coverage.
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Affiliation(s)
- Fengchen Liu
- F.I. Proctor Foundation, University of California, San Francisco, CA, USA
| | - Travis C Porco
- F.I. Proctor Foundation, University of California, San Francisco, CA, USA; Department of Ophthalmology, University of California, San Francisco, CA, USA; Department of Epidemiology & Biostatistics, University of California, San Francisco, CA, USA.
| | | | - Beatriz Muñoz
- Wilmer Eye Institute, Johns Hopkins Hospital, Baltimore, MD, USA
| | - Kathryn J Ray
- F.I. Proctor Foundation, University of California, San Francisco, CA, USA
| | - Robin L Bailey
- Faculty of Infectious and Tropical Diseases, Clinical Research Department, London School of Hygiene & Tropical and Medicine, London, UK
| | - Thomas M Lietman
- F.I. Proctor Foundation, University of California, San Francisco, CA, USA; Department of Ophthalmology, University of California, San Francisco, CA, USA; Department of Epidemiology & Biostatistics, University of California, San Francisco, CA, USA; Institute for Global Health, University of California, San Francisco, CA, USA
| | - Sheila K West
- Wilmer Eye Institute, Johns Hopkins Hospital, Baltimore, MD, USA
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Admassu F, Bayu S, Bejiga A, Amare B. Active trachoma two years after three rounds of azithromycin mass treatment in Cheha District Gurage Zone, Southern Ethiopia. BMC Pediatr 2013; 13:199. [PMID: 24289535 PMCID: PMC4219499 DOI: 10.1186/1471-2431-13-199] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/30/2013] [Accepted: 11/27/2013] [Indexed: 11/19/2022] Open
Abstract
Background Azithromycin mass distribution was given to residents of Gurage zone Cheha district in 2004, 2005 and 2006 for three consecutive years with more than 90% coverage. The effect of treatment in the study community was not yet determined. The present study was therefore designed to assess the effect of azithromycin on the prevalence of active trachoma two years after three rounds of mass treatment of the community at Cheha district, Gurage zone. Methods A multistage stratified cluster random survey was employed to determine the prevalence of active trachoma among children aged 1 to 9. Selected children were examined for trachoma using the simplified WHO grading system and their households were assessed for trachoma risk factors. Results This survey demonstrated that the prevalence of active trachoma in the study community was 22.8% (95% CI 18.24% - 27.36%) that was lower than that of Southern Nations, Nationalities, and People's Regional prevalence (33.2%) in 2006. Only 27.6% (95% CI 25.7% - 30.1%) of the study population had a safe and clean water supply, whereas 42.7% (95% CI 39.8% - 46.2%) of the visited households had simple pit latrines. Conclusion This survey demonstrated that despite repeated mass oral azithromycin distributions, the prevalence of active trachoma was still high. Therefore, the other components of the SAFE strategy such as fly control program, improving the water sources, measures to improve face washing and construction of utilizable latrines that are being implemented through the health extension package have to be integrated with mass azithromycin treatment to eliminate active trachoma in the district.
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Affiliation(s)
- Fisseha Admassu
- Department of Medical Biochemistry, University of Gondar, College of Medicine and Health Sciences, Gondar, Ethiopia.
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Liu F, Porco TC, Ray KJ, Bailey RL, Mkocha H, Muñoz B, Quinn TC, Lietman TM, West SK. Assessment of transmission in trachoma programs over time suggests no short-term loss of immunity. PLoS Negl Trop Dis 2013; 7:e2303. [PMID: 23875038 PMCID: PMC3708821 DOI: 10.1371/journal.pntd.0002303] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2012] [Accepted: 05/18/2013] [Indexed: 11/18/2022] Open
Abstract
Trachoma programs have dramatically reduced the prevalence of the ocular chlamydia that cause the disease. Some have hypothesized that immunity to the infection may be reduced because of program success in reducing the incidence of infection, and transmission may then increase. Longitudinal studies of multiple communities would be necessary to test this hypothesis. Here, we quantify transmission using an estimated basic reproduction number based on 32 communities during the first, second, and third years of an antibiotic treatment program. We found that there is little to no increase in the basic reproduction number over time. The estimated linear trend in the basic reproduction number, , was found to be −0.025 per year, 95% CI −0.167 to 0.117 per year. We are unable to find evidence supporting any loss of immunity over the course of a 3-year program. This is encouraging, as it allows the possibility that repeated mass antibiotic distributions may eliminate infection from even the most severely affected areas. Trachoma, caused by repeated infections by the ocular strains of Chlamydia trachomatis, is the most common infectious cause of blindness in the world. Treatment for trachoma includes mass azithromycin treatments to the entire community. To reduce the prevalence of infection, the World Health Organization (WHO) advocates at least three annual community-wide distributions of oral antibiotics in affected areas, with further mass treatments based on the prevalence of trachoma. Trachoma programs have dramatically reduced the community prevalence of infection, and some have argued that lowered prevalence of infection may lead to reductions in immunity, and that less immunity may in turn lead to increased transmission from what infection remains. Here, we used a stochastic transmission model to analyze data collected from a 3-year antibiotic treatment program (a 32-community, cluster-randomized clinical trial in Tanzania) to assess whether or not transmission actually increases during elimination campaigns. We found no evidence supporting any increase in transmission over the course of the program. The absence of a short term increase in transmission as the prevalence decreases is good news for trachoma programs.
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Affiliation(s)
- Fengchen Liu
- F.I. Proctor Foundation, University of California, San Francisco, California, United States of America
| | - Travis C. Porco
- F.I. Proctor Foundation, University of California, San Francisco, California, United States of America
- Department of Ophthalmology, University of California, San Francisco, California, United States of America
- Department of Epidemiology and Biostatistics, University of California, San Francisco, California, United States of America
- * E-mail:
| | - Kathryn J. Ray
- F.I. Proctor Foundation, University of California, San Francisco, California, United States of America
| | - Robin L. Bailey
- Faculty of Infectious and Tropical Diseases, Clinical Research Department, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | | | - Beatriz Muñoz
- Wilmer Eye Institute, Johns Hopkins Hospital, Baltimore, Maryland, United States of America
| | - Thomas C. Quinn
- Johns Hopkins Center for Global Health, Johns Hopkins University, Baltimore, Maryland, United States of America
| | - Thomas M. Lietman
- F.I. Proctor Foundation, University of California, San Francisco, California, United States of America
- Department of Ophthalmology, University of California, San Francisco, California, United States of America
- Department of Epidemiology and Biostatistics, University of California, San Francisco, California, United States of America
| | - Sheila K. West
- Wilmer Eye Institute, Johns Hopkins Hospital, Baltimore, Maryland, United States of America
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Amza A, Kadri B, Nassirou B, Yu SN, Stoller NE, Bhosai SJ, Zhou Z, McCulloch CE, West SK, Bailey RL, Keenan JD, Lietman TM, Gaynor BD. The easiest children to reach are most likely to be infected with ocular Chlamydia trachomatis in trachoma endemic areas of Niger. PLoS Negl Trop Dis 2013; 7:e1983. [PMID: 23326612 PMCID: PMC3542188 DOI: 10.1371/journal.pntd.0001983] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2012] [Accepted: 11/07/2012] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Control programs for trachoma use mass antibiotic distributions to treat ocular Chlamydia trachomatis in an effort to eliminate this disease worldwide. To determine whether children infected with ocular Chlamydia are more likely to present later for examination than those who are uninfected, we compare the order of presentation for examination of children 0-5 years, and the presence of ocular Chlamydia by PCR in 4 villages in Niger where trachoma is endemic. METHODS We conducted a cluster-randomized, controlled trial where 48 randomly selected villages in Niger are divided into 4 study arms of different mass treatment strategies. In a substudy of the main trial, we randomly selected 1 village from each of the 4 study arms (4 total villages) and we evaluated the odds of ocular Chlamydia versus the rank order of presentation for examination and laboratory assessment before treatment was offered. FINDINGS We found the odds of harboring ocular Chlamydia dropped by more than 70% from the first child examined to the last child examined (OR 0.27, 95% CI 0.13-0.59, P = 0.001) in the 4 randomly selected villages. We found the odds of active trachoma dropped by 80% from the first child examined to the last child examined (OR 0.20, 95% CI 0.10-0.4, P<0.0001) in the 48 villages in the main trial. INTERPRETATION This study demonstrates that even if the WHO recommended 80% treatment coverage is not reached in certain settings, children 0-5 years with the greatest probability of ocular Chlamydia have higher odds of receiving attention because they are the first to present. These results suggest there may be diminishing returns when using scarce resources to track down the last few children in a mass treatment program. TRIAL REGISTRATION ClinicalTrials.gov NCT00792922.
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Affiliation(s)
- Abdou Amza
- Programme National de Lutte Contre la Cecité, Niamey, Niger
| | - Boubacar Kadri
- Programme National de Lutte Contre la Cecité, Niamey, Niger
| | - Baido Nassirou
- Programme National de Lutte Contre la Cecité, Niamey, Niger
| | - Sun N. Yu
- F.I. Proctor Foundation, University of California San Francisco, San Francisco, California, United States of America
| | - Nicole E. Stoller
- F.I. Proctor Foundation, University of California San Francisco, San Francisco, California, United States of America
| | - Satasuk J. Bhosai
- F.I. Proctor Foundation, University of California San Francisco, San Francisco, California, United States of America
| | - Zhaoxia Zhou
- F.I. Proctor Foundation, University of California San Francisco, San Francisco, California, United States of America
| | - Charles E. McCulloch
- Department of Epidemiology & Biostatistics, University of California San Francisco, San Francisco, California, United States of America
| | - Sheila K. West
- Dana Center for Preventive Ophthalmology, Wilmer Eye Institute, Johns Hopkins University, Baltimore, Maryland, United States of America
| | - Robin L. Bailey
- Clinical Research Unit, Department of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Jeremy D. Keenan
- F.I. Proctor Foundation, University of California San Francisco, San Francisco, California, United States of America
- Department of Ophthalmology, University of California San Francisco, San Francisco, California, United States of America
| | - Thomas M. Lietman
- F.I. Proctor Foundation, University of California San Francisco, San Francisco, California, United States of America
- Department of Epidemiology & Biostatistics, University of California San Francisco, San Francisco, California, United States of America
- Department of Ophthalmology, University of California San Francisco, San Francisco, California, United States of America
- Institute for Global Health, University of California San Francisco, San Francisco, California, United States of America
| | - Bruce D. Gaynor
- F.I. Proctor Foundation, University of California San Francisco, San Francisco, California, United States of America
- Department of Ophthalmology, University of California San Francisco, San Francisco, California, United States of America
- * E-mail:
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49
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Abstract
Trachoma, a chronic conjunctivitis caused by Chlamydia trachomatis, is the leading infectious cause of blindness worldwide. In recognition of this public health problem, the World Health Assembly has targeted the year 2020 to eliminate blinding trachoma, and a multifaceted strategy (SAFE) is recommended, including antibiotics for treatment of infection. Trachoma is a disease of entire communities, and the pool of infection resides largely in preschool age children. Thus, for endemic communities, mass treatment with antibiotics annually for at least 3-5 years is carried out. The antibiotics used, the effectiveness of this approach, and the challenges of antibiotic treatment of communities are discussed, concluding with a view towards the elimination of trachoma in the future.
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Affiliation(s)
- Sheila West
- Wilmer RM 129, Johns Hopkins University, 600 N Wolfe Street, Baltimore, MD 21205, USA.
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50
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Abstract
In this fun, interactive exercise, students simulate an infectious disease outbreak among themselves that conceptually integrates two historically distinct fields in epidemiology.
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