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Atekem K, Harding-Esch EM, Martin DL, Downs P, Palmer SL, Kaboré A, Kelly M, Bovary A, Sarr A, Nguessan K, James F, Gwyn S, Wickens K, Bakhtiari A, Boyd S, Aba A, Senyonjo L, Courtright P, Meite A. High prevalence of trachomatous inflammation-follicular with no trachomatous trichiasis: can alternative indicators explain the epidemiology of trachoma in Côte d'Ivoire? Int Health 2023; 15:ii3-ii11. [PMID: 38048384 PMCID: PMC10695457 DOI: 10.1093/inthealth/ihad069] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2023] [Revised: 07/28/2023] [Accepted: 08/01/2023] [Indexed: 12/06/2023] Open
Abstract
Baseline trachoma surveys in Côte d'Ivoire (2019) identified seven evaluation units (EUs) with a trachomatous inflammation-follicular (TF) prevalence ≥10%, but a trachomatous trichiasis (TT) prevalence in individuals ≥15 y of age below the elimination threshold (0.2%). Two of these EUs, Bondoukou 1 and Bangolo 2, were selected for a follow-up survey to understand the epidemiology of trachoma using additional indicators of Chlamydia trachomatis infection (DNA from conjunctival swabs) and exposure (anti-Pgp3 and Ct694 antibodies from dried blood spots [DBSs]). A two-stage cluster sampling methodology was used to select villages and households. All individuals 1-9 y of age from each selected household were recruited, graded for trachoma and had a conjunctival swab and DBS collected. Conjunctival swabs and DBSs were tested using Cepheid GeneXpert and a multiplex bead assay, respectively. The age-adjusted TF and infection prevalence in 1- to 9-year-olds was <1% and <0.3% in both EUs. Age-adjusted seroprevalence was 5.3% (95% confidence interval [CI] 1.5 to 15.6) in Bondoukou 1 and 8.2% (95% CI 4.3 to 13.7) in Bangolo 2. The seroconversion rate for Pgp3 was low, at 1.23 seroconversions/100 children/year (95% CI 0.78 to 1.75) in Bondoukou 1 and 1.91 (95% CI 1.58 to 2.24) in Bangolo 2. Similar results were seen for CT694. These infection, antibody and clinical data provide strong evidence that trachoma is not a public health problem in either EU.
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Affiliation(s)
- Kareen Atekem
- Department of Entomology, Center for Infectious Disease Dynamics, Pennsylvania State University, University Park, PA,USA
- Sightsavers
| | | | - Diana L Martin
- Centers for Disease Control and Prevention, Atlanta, GA,USA
| | | | | | | | | | | | | | | | | | - Sarah Gwyn
- Centers for Disease Control and Prevention, Atlanta, GA,USA
| | - Karana Wickens
- Oak Ridge Institute for Science and Education, Atlanta, GA,USA
| | - Ana Bakhtiari
- International Trachoma Initiative, Task Force for Global Health, Decatur, GA,USA
| | - Sarah Boyd
- International Trachoma Initiative, Task Force for Global Health, Decatur, GA,USA
| | | | | | - Paul Courtright
- Sightsavers
- Kilimanajaro Centre for Community Ophthalmology, Division of Ophthalmology, University of Cape Town, Cape Town, South Africa
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2
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Lynch KD, Brian G, Ahwang T, Morotti W, Wharton G, Newie T, Newie V, Perrett C, Ware W, Mosby L, Walters S, Brown A, Whop LJ, Lambert SB. Assessing the Prevalence of Trachoma: Lessons from Community Screening with Laboratory Testing in Australia's Torres Strait Islands. Ophthalmic Epidemiol 2023; 30:663-670. [PMID: 36281525 DOI: 10.1080/09286586.2022.2136389] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Accepted: 10/08/2022] [Indexed: 10/31/2022]
Abstract
PURPOSE We undertook a screening program between 2016 and 2019 to determine if trachoma was endemic in the Torres Strait Islands of Queensland, Australia. METHODS Eleven screening surveys assessing trachoma prevalence were undertaken in seven communities using the World Health Organization (WHO) simplified grading tool. Additionally, an ophthalmologist performed a detailed clinical assessment including examination for Herbert's pits and corneal pannus and, where clinically indicated, collection of conjunctival specimens to investigate the presence of Chlamydia trachomatis nucleic acid. RESULTS Prevalence of trachomatous inflammation-follicular (TF) in children aged 5-9 years for the aggregated first survey across all communities was 6% (17/284). No child had trachomatous inflammation-intense, trachomatous scarring, corneal pannus, or Herbert's pits. Of the 66 times any child was tested for C. trachomatis by polymerase chain reaction (PCR), the result was negative. No cicatricial trachoma was identified amongst the adults (n = 186) who were opportunistically offered examination. CONCLUSION Whilst TF was present, the lack of intense inflammatory thickening in any child examined, the lack of end-stage trachomatous disease, and the lack of ocular C. trachomatis detection by PCR indicate trachoma is not endemic in the Torres Strait Islands, and no ongoing public health intervention is required. These findings add to a growing body of evidence suggesting that use of the WHO simplified grading tool alone in the peri-elimination setting may overestimate the community burden of trachoma.
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Affiliation(s)
- Kathleen D Lynch
- Communicable Diseases Branch, Prevention Division, Queensland Health, Brisbane, Australia
- UQ Centre for Clinical Research, the University of Queensland, Brisbane, Australia
| | - Garry Brian
- Communicable Diseases Branch, Prevention Division, Queensland Health, Brisbane, Australia
| | - Tomisina Ahwang
- Primary Health Care Services, Northern Sector, Torres and Cape Hospital and Health Service, Thursday Island, Australia
| | - Wendy Morotti
- Communicable Diseases Branch, Prevention Division, Queensland Health, Brisbane, Australia
| | - Ghislaine Wharton
- Primary Health Care Services, Northern Sector, Torres and Cape Hospital and Health Service, Thursday Island, Australia
- Best Practice Eyecare, Golden Beach, Australia
| | - Tomi Newie
- Primary Health Care Services, Northern Sector, Torres and Cape Hospital and Health Service, Thursday Island, Australia
| | - Victoria Newie
- Primary Health Care Services, Northern Sector, Torres and Cape Hospital and Health Service, Thursday Island, Australia
| | - Christine Perrett
- Primary Health Care Services, Northern Sector, Torres and Cape Hospital and Health Service, Thursday Island, Australia
| | - Wagie Ware
- Primary Health Care Services, Northern Sector, Torres and Cape Hospital and Health Service, Thursday Island, Australia
| | - Lucy Mosby
- Primary Health Care Services, Northern Sector, Torres and Cape Hospital and Health Service, Thursday Island, Australia
| | - Shelley Walters
- Primary Health Care Services, Northern Sector, Torres and Cape Hospital and Health Service, Thursday Island, Australia
| | - Anthony Brown
- Primary Health Care Services, Northern Sector, Torres and Cape Hospital and Health Service, Thursday Island, Australia
- Chief Executive, South West Hospital and Health Service, Roma, Australia
| | - Lisa J Whop
- National Centre for Epidemiology & Population Health, Australian National University, Canberra, Australia
| | - Stephen B Lambert
- Communicable Diseases Branch, Prevention Division, Queensland Health, Brisbane, Australia
- UQ Centre for Clinical Research, the University of Queensland, Brisbane, Australia
- Surveillance, Coverage, Evaluation and Social Science, National Centre for Immunisation Research and Surveillance, Westmead, Australia
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3
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Lynch KD, Morotti W, Brian G, Ketchup L, Kingston K, Starr M, Ware RS, Everill B, Asgar N, O'Keefe A, Whop LJ, Kaldor JM, Lambert SB. Clinical signs of trachoma and laboratory evidence of ocular Chlamydia trachomatis infection in a remote Queensland community: a serial cross-sectional study. Med J Aust 2022; 217:538-543. [PMID: 36180097 PMCID: PMC9827872 DOI: 10.5694/mja2.51735] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2022] [Revised: 08/03/2022] [Accepted: 08/15/2022] [Indexed: 01/12/2023]
Abstract
OBJECTIVES To compare the findings of standard clinical assessments and of complementary clinical and laboratory methods for determining whether community-wide treatment for trachoma is warranted in a remote Queensland community. DESIGN Three cross-sectional screening surveys, 2019-2021, complemented by laboratory pathology testing. SETTING Small community in northwest Queensland with geographic and cultural ties to Northern Territory communities where trachoma persists. PARTICIPANTS Children aged 1-14 years; opportunistic screening of people aged 15 years or more. MAIN OUTCOME MEASURES Prevalence of clinical signs of trachoma, Chlamydia trachomatis infection, ocular non-chlamydial infections, and seropositivity for antibodies to the C. trachomatis Pgp3 protein. RESULTS During the three surveys, 73 examinations of 58 children aged 1-4 years, 309 of 171 aged 5-9 years, and 142 of 105 aged 10-14 years for trachoma were undertaken, as were 171 examinations of 164 people aged 15 years or more; 691 of 695 examinations were of Aboriginal or Torres Strait Islander people (99%), 337 were of girls or young women (48%). Clinical signs consistent with trachomatous inflammation-follicular were identified in 5-9-year-old children 23 times (7%), including in eleven with non-chlamydial infections and one with a C. trachomatis infection. One child (10-14 years) met the criteria for trachomatous scarring. Two of 272 conjunctival swab samples (all ages) were polymerase chain reaction-positive for C. trachomatis (0.7%). Two of 147 people aged 15 years or more examined in 2019 had trichiasis, both aged 40 years or more. Seven of 53 children aged 1-9 years in 2019 and seven of 103 in 2021 were seropositive for anti-Pgp3 antibodies. CONCLUSIONS Despite the prevalence of clinical signs consistent with trachomatous inflammation-follicular among 5-9-year-old children exceeding the 5% threshold for community-wide treatment, laboratory testing indicated that childhood exposure to ocular C. trachomatis is rare in this community. Laboratory testing should be integrated into Australian trachoma guidelines.
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Affiliation(s)
- Kathleen D Lynch
- UQ Centre for Clinical ResearchUniversity of QueenslandBrisbaneQLD,Communicable Diseases Branch, Queensland HealthBrisbaneQLD
| | - Wendy Morotti
- Communicable Diseases Branch, Queensland HealthBrisbaneQLD
| | - Garry Brian
- Communicable Diseases Branch, Queensland HealthBrisbaneQLD
| | | | | | - Mitchell Starr
- St Vincent’s Centre for Applied Medical Research, St Vincent's HospitalSydneyNSW
| | - Robert S Ware
- Menzies Health Institute QueenslandGriffith UniversityBrisbaneQLD
| | - Beth Everill
- Queensland Department of Education and TrainingBrisbaneQLD
| | | | - Anne O'Keefe
- North West Hospital and Health ServiceMount IsaQLD
| | - Lisa J Whop
- National Centre for Epidemiology and Population HealthAustralian National UniversityCanberraACT
| | - John M Kaldor
- Kirby InstituteUniversity of New South WalesSydneyNSW
| | - Stephen B Lambert
- UQ Centre for Clinical ResearchUniversity of QueenslandBrisbaneQLD,Communicable Diseases Branch, Queensland HealthBrisbaneQLD,National Centre for Immunisation Research and Surveillance, Sydney Children's Hospitals NetworkSydneyNSW
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Saboyá-Díaz MI, Carey Angeles CA, Avellaneda Yajahuanca RDS, Meléndez Ruíz SK, Cabrera R, Honorio Morales HA, Pachas PE, Guardo M, Renneker KK, Muñoz BE, West SK. Associated factors of the co-occurrence of trachoma and soil-transmitted helminthiases in children 1 to 9 years old in rural communities of the Amazon basin in Loreto Department, Peru: Results from a population-based survey. PLoS Negl Trop Dis 2022; 16:e0010532. [PMID: 35877683 PMCID: PMC9312473 DOI: 10.1371/journal.pntd.0010532] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2021] [Accepted: 05/24/2022] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND There is evidence of the occurrence of trachoma in Peru, and studies have shown that soil-transmitted helminthiases (STH) are affecting rural communities in the Amazon basin in Loreto Department. This study was done to estimate trachoma prevalence, STH prevalence, and the associated factors for both diseases in children aged 1-9 years in rural communities of Peru. METHODOLOGY A population-based cross-sectional survey was carried out in rural communities of Loreto. A standardized survey questionnaire with individual and household risk factors related to both diseases was used. Ocular examination was done for all participants aged one year and above, and eye swab samples were collected from children with follicular trachoma (TF). Anthropometric measurements, stool samples for STH, and blood samples for hemoglobin measurement were taken from children. PRINCIPAL FINDINGS TF prevalence was 7.74% (95% CI 5.08-11.63%), STH prevalence was 49.49% (95% CI 25.00-52.43%), and prevalence of co-occurrence of both diseases was 5.06% (95% CI 2.80-8.98%) in children aged 1-9 years. Being at age 3-8 years old (AOR = 6.76; 95% CI 1.346-33.947), have an unclean face (AOR = 24.64; 95% CI 6.787-89.444), and having been dewormed in the last six months (AOR = 2.47; 95% CI 1.106-5.514), were risk factors of TF. Being a female (AOR = 0.22; 95% CI 0.103-0.457) was associated with decreased odds of TF. Having been dewormed in the last six months (AOR = 0.30; 95% CI 0.139-0.628) was a preventative factor for STH. Risk factors for children with both diseases mirrored the findings for risk factors for individual diseases. CONCLUSIONS Neglected tropical diseases and associated risk factors overlap in communities living in vulnerable conditions in the Amazon basin of Peru. These findings support the need to implement integrated interventions, including mass drug administration, water, sanitation, and hygiene for both diseases in the study area.
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Affiliation(s)
- Martha Idalí Saboyá-Díaz
- Communicable Diseases and Environmental Determinants of Health Department, Pan American Health Organization, Washington, District of Columbia, United States of America
| | | | | | | | | | | | - Paul E. Pachas
- National Center of Public Health, National Institute of Health of Peru, Lima, Peru
| | - Monica Guardo
- Health Surveillance, Disease Prevention, and Control, Pan American Health Organization, Guatemala City, Guatemala
| | - Kristen K. Renneker
- International Trachoma Initiative, The Task Force for Global Health, Decatur, Georgia, United States of America
| | - Beatriz E. Muñoz
- Dana Center for Preventive Ophthalmology, Wilmer Eye Institute, Johns Hopkins University, Baltimore, Maryland, United States of America
| | - Sheila K. West
- Dana Center for Preventive Ophthalmology, Wilmer Eye Institute, Johns Hopkins University, Baltimore, Maryland, United States of America
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5
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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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Lynch KD, Apadinuwe SC, Lambert SB, Hillgrove T, Starr M, Catlett B, Ware RS, Cama A, Webster S, Harding-Esch EM, Bakhtiari A, Butcher R, Cunningham P, Martin D, Gwyn S, Solomon AW, Garabwan C, Kaldor JM, Vaz Nery S. A national survey integrating clinical, laboratory, and WASH data to determine the typology of trachoma in Nauru. PLoS Negl Trop Dis 2022; 16:e0010275. [PMID: 35439248 PMCID: PMC9017947 DOI: 10.1371/journal.pntd.0010275] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2021] [Accepted: 02/24/2022] [Indexed: 11/23/2022] Open
Abstract
Background The epidemiology of trachoma in several Pacific Islands differs from other endemic settings, in that there is a high prevalence of clinical signs of trachoma, particularly trachomatous inflammation—follicular (TF), but few cases of trichiasis and limited evidence of ocular chlamydial infection. This so-called “Pacific enigma” has led to uncertainty regarding the appropriate public health response. In 2019 alongside Nauru’s national trachoma population survey, we performed bacteriological and serological assessments of children to better understand the typology of trachoma and to determine whether there is a need for trachoma interventions. Methods We used two-stage cluster sampling, examining residents aged ≥1 year and collecting household-level water, sanitation, and hygiene (WASH) variables. Children aged 1–9 years provided conjunctival swabs and finger-prick dried blood spots to investigate the presence of Chlamydia trachomatis nucleic acid and anti-Pgp3 antibodies, respectively. Principal Findings In 818 participants aged 1–9 years, the age-adjusted TF prevalence was 21.8% (95% CI 15.2–26.2%); ocular C. trachomatis prevalence was 34.5% (95% CI 30.6–38.9), and anti-Pgp3 antibody prevalence was 32.1% (95% CI 28.4%–36.3%). The age- and gender-adjusted prevalence of trichiasis in ≥15-year-olds was 0.3% (95% CI 0.00–0.85), but no individual with trichiasis had trachomatous scarring (TS). Multivariable analysis showed an association between age and both TF (OR per year of age 1.3 [95% CI 1.2–1.4]) and anti-Pgp3 positivity (OR 1.2 [95% CI 1.2–1.3]). There were high rates of access to water and sanitation and no WASH variable was associated with the presence of TF. Conclusions TF, nucleic acid, and age-specific antibody prevalence collectively indicate that high levels of C. trachomatis transmission among children present a high risk of ocular damage due to trachoma. The absence of trichiasis with trachomatous scarring suggest a relatively recent increase in transmission intensity. In contrast to several neighbouring Pacific Island nations, Nauruan children are heavily affected by active trachoma and the cause is ocular infection with C. trachomatis. Comprehensive public health intervention to control trachoma in Nauru is required. The use of laboratory markers for current and previous C. trachomatis infection should be considered in baseline trachoma prevalence surveys as we approach global elimination of trachoma, and in settings with inconsistent findings during previous screening exercises.
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Affiliation(s)
- Kathleen D. Lynch
- UQ Centre for Clinical Research, University of Queensland, Brisbane, Australia
- * E-mail:
| | | | - Stephen B. Lambert
- UQ Centre for Clinical Research, University of Queensland, Brisbane, Australia
- National Centre for Immunisation Research and Surveillance, Westmead, New South Wales, Australia
| | | | - Mitchell Starr
- NSW State Reference Laboratory for HIV, St Vincent’s Centre for Applied Medical Research, St Vincent’s Hospital, Sydney, Australia
| | - Beth Catlett
- NSW State Reference Laboratory for HIV, St Vincent’s Centre for Applied Medical Research, St Vincent’s Hospital, Sydney, Australia
| | - Robert S. Ware
- Menzies Health Institute Queensland and School of Medicine, Griffith University, Brisbane, Australia
| | | | - Sara Webster
- The Fred Hollows Foundation, Melbourne, Australia
| | - Emma M. Harding-Esch
- Clinical Research Department, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Ana Bakhtiari
- International Trachoma Initiative, Task Force for Global Health, Decatur, Georgia, United States of America
| | - Robert Butcher
- Clinical Research Department, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Philip Cunningham
- NSW State Reference Laboratory for HIV, St Vincent’s Centre for Applied Medical Research, St Vincent’s Hospital, Sydney, Australia
| | - Diana Martin
- Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America
| | - Sarah Gwyn
- Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America
| | - Anthony W. Solomon
- Department of Control of Neglected Tropical Diseases, World Health Organization, Geneva, Switzerland
| | | | - John M. Kaldor
- The Kirby Institute, University of New South Wales, Sydney, Australia
| | - Susana Vaz Nery
- The Kirby Institute, University of New South Wales, Sydney, Australia
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7
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Odonkor M, Naufal F, Mkocha H, Funga N, Muñoz B, West SK. The Impact of Image Quality and Trachomatous Inflammation on Using Photography for Trachoma Prevalence Surveys. Transl Vis Sci Technol 2022; 11:11. [PMID: 35266968 PMCID: PMC8934551 DOI: 10.1167/tvst.11.3.11] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Purpose Graded images can be used for trachoma prevalence surveys, but there is concern for mismatch between image and field grades of the upper tarsal conjunctiva. We aimed to determine if poor photograph quality and/or inflammation may contribute to differential grading of trachomatous inflammation—follicular (TF) between field and photograph graders. Methods We developed a simplified and expanded image quality grading tool. Agreement was assessed using kappa statistic. We included 5417 eyes with both field and image grades for TF. Eyes where the field and adjudicated photograph TF grades did not match were identified (mismatched) and assigned an image quality (IQ) score and a potential mismatch reason. We also assigned IQ scores to a stratified random sample of 60 eyes with matching field and photograph TF grades (matched). Results There were 5240 eyes that had matching grades, whereas 177 eyes (3.3%) were mismatched. Overall quality was high, even in mismatched eyes. There was no difference in overall or specific IQ metrics between eyes with matching grades and eyes with mismatched grades (P = 0.59). Mismatched eyes had worse inflammation compared to matched eyes (P = 0.048). The primary reason for calling TF in the field but not in the photographs appeared to be the number of follicles observed. Conclusions Image quality did not explain mismatch between field grades and image grades from this prevalence survey. Inflammation made mismatch more likely. Translational Relevance Our quality grading scheme rapidly identifies image quality issues for training. Standardizing TF grading in the presence of inflammation will improve field and photograph grading.
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Affiliation(s)
- Michelle Odonkor
- Dana Center for Preventive Ophthalmology, Wilmer Eye Institute, Johns Hopkins University, Baltimore, MD, USA
| | - Fahd Naufal
- Dana Center for Preventive Ophthalmology, Wilmer Eye Institute, Johns Hopkins University, Baltimore, MD, USA
| | | | | | - Beatriz Muñoz
- Dana Center for Preventive Ophthalmology, Wilmer Eye Institute, Johns Hopkins University, Baltimore, MD, USA
| | - Sheila K West
- Dana Center for Preventive Ophthalmology, Wilmer Eye Institute, Johns Hopkins University, Baltimore, MD, USA
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8
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Lynch KD, Brian G, Ahwang T, Newie T, Newie V, Perrett C, Wharton G, Brown A, Tozer S, Kaldor JM, Whop LJ, Andrews RM, Lambert SB. Discord between presence of follicular conjunctivitis and Chlamydia trachomatis infection in a single Torres Strait Island community: a cross-sectional survey. Aust N Z J Public Health 2022; 46:155-160. [PMID: 34978363 DOI: 10.1111/1753-6405.13179] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2021] [Revised: 08/01/2021] [Accepted: 09/01/2021] [Indexed: 11/28/2022] Open
Abstract
OBJECTIVE Recent surveys identified trachomatous inflammation - follicular (TF) at endemic levels in the Torres Strait Islands; however, local health staff do not report trachomatous trichiasis (TT) in adults. We undertook a cross-sectional survey involving eye examination and microbiological testing to better understand this disconnect. METHODS We examined 169 of 207 (82%) residents and collected ocular swabs for polymerase chain reaction (PCR) testing for Chlamydia trachomatis. Other viral PCR tests and bacterial culture were also performed. RESULTS TF prevalence in children aged 5-9 years was 23% (7/30). No ocular C. trachomatis was identified by PCR. For the 72 participants (43%) with follicles, bacterial culture was positive for 11 (15%) individuals. No individual had trachomatous trichiasis. CONCLUSIONS Follicular conjunctivitis consistent with TF was prevalent but ocular C. trachomatis and cicatricial trachoma were absent. Non-chlamydial infections or environmental causes of follicular conjunctivitis may be causing TF in this community. Implications for public health: In similar settings, reliance on simplified clinical assessment alone may lead to an overestimation of the public health problem posed by trachoma. Consideration should be given to incorporating C. trachomatis PCR, and in certain settings, a detailed clinical exam could be performed by an experienced ophthalmologist during prevalence surveys.
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Affiliation(s)
- Kathleen D Lynch
- Communicable Diseases Branch, Prevention Division, Queensland Health.,UQ Centre for Clinical Research, The University of Queensland
| | - Garry Brian
- Communicable Diseases Branch, Prevention Division, Queensland Health.,Torres and Cape Hospital and Health Service, Queensland
| | | | - Tomi Newie
- Torres and Cape Hospital and Health Service, Queensland
| | | | | | - Ghislaine Wharton
- Torres and Cape Hospital and Health Service, Queensland.,Cairns Eye & Laser Centre, Cairns, Queensland
| | - Anthony Brown
- Torres and Cape Hospital and Health Service, Queensland
| | - Sarah Tozer
- UQ Centre for Clinical Research, The University of Queensland
| | | | - Lisa J Whop
- Menzies School of Health Research, Charles Darwin University, Northern Territory.,National Centre for Epidemiology and Population Health, The Australian National University, Australian Capital Territory
| | - Ross M Andrews
- Menzies School of Health Research, Charles Darwin University, Northern Territory.,National Centre for Epidemiology and Population Health, The Australian National University, Australian Capital Territory
| | - Stephen B Lambert
- Communicable Diseases Branch, Prevention Division, Queensland Health.,UQ Centre for Clinical Research, The University of Queensland.,National Centre for Epidemiology and Population Health, The Australian National University, Australian Capital Territory
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9
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Senyonjo L, Addy J, Martin DL, Agyemang D, Yeboah-Manu D, Gwyn S, Marfo B, Asante-Poku A, Aboe A, Mensah E, Solomon AW, Bailey RL. Surveillance for peri-elimination trachoma recrudescence: Exploratory studies in Ghana. PLoS Negl Trop Dis 2021; 15:e0009744. [PMID: 34543293 PMCID: PMC8519445 DOI: 10.1371/journal.pntd.0009744] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2021] [Revised: 10/15/2021] [Accepted: 08/18/2021] [Indexed: 11/26/2022] Open
Abstract
Introduction To date, eleven countries have been validated as having eliminated trachoma as a public health problem, including Ghana in 2018. Surveillance for recrudescence is needed both pre- and post-validation but evidence-based guidance on appropriate strategies is lacking. We explored two potential surveillance strategies in Ghana. Methodology/principal findings Amongst randomly-selected communities enrolled in pre-validation on-going surveillance between 2011 and 2015, eight were identified as having had trachomatous-inflammation follicular (TF) prevalence ≥5% in children aged 1–9 years between 2012 and 2014. These eight were re-visited in 2015 and 2016 and neighbouring communities were also added (“TF trigger” investigations). Resident children aged 1–9 years were then examined for trachoma and had a conjunctival swab to test for Chlamydia trachomatis (Ct) and a dried blood spot (DBS) taken to test for anti-Pgp3 antibodies. These investigations identified at least one community with evidence of probable recent Ct ocular transmission. However, the approach likely lacks sufficient spatio-temporal power to be reliable. A post-validation surveillance strategy was also evaluated, this reviewed the ocular Ct infection and anti-Pgp3 seroprevalence data from the TF trigger investigations and from the pre-validation surveillance surveys in 2015 and 2016. Three communities identified as having ocular Ct infection >0% and anti-Pgp3 seroprevalence ≥15.0% were identified, and along with three linked communities, were followed-up as part of the surveillance strategy. An additional three communities with a seroprevalence ≥25.0% but no Ct infection were also followed up (“antibody and infection trigger” investigations). DBS were taken from all residents aged ≥1 year and ocular swabs from all children aged 1–9 years. There was evidence of transmission in the group of communities visited in one district (Zabzugu-Tatale). There was no or little evidence of continued transmission in other districts, suggesting previous infection identified was transient or potentially not true ocular Ct infection. Conclusions/significance There is evidence of heterogeneity in Ct transmission dynamics in northern Ghana, even 10 years after wide-scale MDA has stopped. There is added value in monitoring Ct infection and anti-Ct antibodies, using these indicators to interrogate past or present surveillance strategies. This can result in a deeper understanding of transmission dynamics and inform new post-validation surveillance strategies. Opportunities should be explored for integrating PCR and serological-based markers into surveys conducted in trachoma elimination settings. The goal for trachoma programmes is elimination of trachoma as a public health problem. This means that ongoing low-level eye-to-eye transmission of the causative bacterium, Chlamydia trachomatis (Ct), is acceptable. Countries need to implement a suitable surveillance system to identify any return to higher transmission levels. The best methodology for doing this is not known. We first explored the approach used by Ghana in its standard programme, which involved monitoring a limited number of randomly selected communities for evidence of active (inflammatory) trachoma visible in children’s eyes on examination by trained observers. Although this strategy led to identification of at least one community that had probably had recent Ct transmission, the approach is unlikely to consistently identify places where return to higher levels of transmission is a risk. We also explored using information on infection (detected in eye swabs) and antibodies to Ct (detected in the blood) to identify communities at risk. We found evidence of both persistent eye-to-eye Ct transmission and areas where infection was transient and has now gone away. We conclude that the use of infection and antibody data for surveillance of trachoma appears promising.
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Affiliation(s)
- Laura Senyonjo
- Research Team, Sightsavers, Haywards Heath, United Kingdom
- Clinical Research Department, London School of Hygiene & Tropical Medicine, London, United Kingdom
- * E-mail:
| | - James Addy
- Eye Health Department, Ghana Health Service, Accra, Ghana
| | - Diana L. Martin
- Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, Atlanta, United States of America
| | | | - Dorothy Yeboah-Manu
- Bacteriology Department, Noguchi Memorial Institute for Medical Research, Accra, Ghana
| | - Sarah Gwyn
- Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, Atlanta, United States of America
| | - Benjamin Marfo
- Neglected Tropical Diseases Division, Ghana Health Service, Accra, Ghana
| | - Adwoa Asante-Poku
- Bacteriology Department, Noguchi Memorial Institute for Medical Research, Accra, Ghana
| | | | | | - Anthony W. Solomon
- Clinical Research Department, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Robin L. Bailey
- Clinical Research Department, London School of Hygiene & Tropical Medicine, London, United Kingdom
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10
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Macleod CK, Butcher R, Javati S, Gwyn S, Jonduo M, Abdad MY, Roberts CH, Keys D, Koim SP, Ko R, Garap J, Pahau D, Houinei W, Martin DL, Pomat WS, Solomon AW. Trachoma, Anti-Pgp3 Serology, and Ocular Chlamydia trachomatis Infection in Papua New Guinea. Clin Infect Dis 2021; 72:423-430. [PMID: 31965155 PMCID: PMC7850549 DOI: 10.1093/cid/ciaa042] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2019] [Accepted: 01/19/2020] [Indexed: 11/17/2022] Open
Abstract
BACKGROUND In Melanesia, the prevalence of trachomatous inflammation-follicular (TF) suggests that public health-level interventions against active trachoma are needed. However, the prevalence of trachomatous trichiasis is below the threshold for elimination as a public health problem and evidence of conjunctival infection with trachoma's causative organism (Chlamydia trachomatis [CT]) is rare. Here, we examine the prevalence of ocular infection with CT and previous exposure to CT in three evaluation units (EUs) of Papua New Guinea. METHODS All individuals aged 1-9 years who were examined for clinical signs of trachoma in 3 Global Trachoma Mapping Project EUs were eligible to take part in this study (N = 3181). Conjunctival swabs were collected from 349 children with TF and tested by polymerase chain reaction to assess for ocular CT infection. Dried blood spots were collected from 2572 children and tested for anti-Pgp3 antibodies using a multiplex assay. RESULTS The proportion of children with TF who had CT infection was low across all 3 EUs (overall 2%). Anti-Pgp3 seroprevalence was 5.2% overall and there was no association between anti-Pgp3 antibody level and presence of TF. In 2 EUs, age-specific seroprevalence did not increase significantly with increasing age in the 1- to 9-year-old population. In the third EU, there was a statistically significant change with age but the overall seroprevalence and peak age-specific seroprevalence was very low. CONCLUSIONS Based on these results, together with similar findings from the Solomon Islands and Vanuatu, the use of TF to guide antibiotic mass drug administration decisions in Melanesia should be reviewed.
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Affiliation(s)
- Colin K Macleod
- London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Robert Butcher
- London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Sarah Javati
- Papua New Guinea Institute of Medical Research, Goroka, Papua New Guinea
| | - Sarah Gwyn
- Centers for Disease Control and Prevention, Atlanta, Georgia, USA
| | - Marinjho Jonduo
- Papua New Guinea Institute of Medical Research, Goroka, Papua New Guinea
| | - Mohammad Yazid Abdad
- Papua New Guinea Institute of Medical Research, Goroka, Papua New Guinea
- National Centre for Infectious Diseases, Singapore
| | - Chrissy H Roberts
- London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Drew Keys
- Brien Holden Vision Institute Foundation, Sydney, Australia
| | | | - Robert Ko
- Department of Ophthalmology, Port Moresby General Hospital, Port Moresby, Papua New Guinea
| | - Jambi Garap
- Department of Ophthalmology, Port Moresby General Hospital, Port Moresby, Papua New Guinea
| | - David Pahau
- Department of Ophthalmology, Boram General Hospital, Wewak, Papua New Guinea
| | - Wendy Houinei
- Neglected Tropical Diseases, National Department of Health, Port Moresby, Papua New Guinea
| | - Diana L Martin
- Centers for Disease Control and Prevention, Atlanta, Georgia, USA
| | - William S Pomat
- Papua New Guinea Institute of Medical Research, Goroka, Papua New Guinea
| | - Anthony W Solomon
- London School of Hygiene and Tropical Medicine, London, United Kingdom
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11
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Solomon AW, Kello AB, Bangert M, West SK, Taylor HR, Tekeraoi R, Foster A. The simplified trachoma grading system, amended. Bull World Health Organ 2020; 98:698-705. [PMID: 33177759 PMCID: PMC7652564 DOI: 10.2471/blt.19.248708] [Citation(s) in RCA: 41] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2019] [Revised: 07/06/2020] [Accepted: 07/07/2020] [Indexed: 11/27/2022] Open
Abstract
A simplified grading system for trachoma was published by the World Health Organization (WHO) in 1987. Intended for use by non-specialist personnel working at community level, the system includes five signs, each of which can be present or absent in any eye: (i) trachomatous trichiasis; (ii) corneal opacity; (iii) trachomatous inflammation—follicular; (iv) trachomatous inflammation—intense; and (v) trachomatous scarring. Though neither perfectly sensitive nor perfectly specific for trachoma, these signs have been essential tools for identifying populations that need interventions to eliminate trachoma as a public health problem. In 2018, at WHO’s 4th global scientific meeting on trachoma, the definition of one of the signs, trachomatous trichiasis, was amended to exclude trichiasis that affects only the lower eyelid. This paper presents the amended system, updates its presentation, offers notes on its use and identifies areas of ongoing debate.
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Affiliation(s)
- Anthony W Solomon
- Department of Control of Neglected Tropical Diseases, World Health Organization, Avenue Appia 20, 1211 Geneva 27, Switzerland
| | - Amir B Kello
- World Health Organization Regional Office for Africa, Brazzaville, Congo
| | - Mathieu Bangert
- Department of Control of Neglected Tropical Diseases, World Health Organization, Avenue Appia 20, 1211 Geneva 27, Switzerland
| | - Sheila K West
- Wilmer Eye Institute, Johns Hopkins University, Baltimore, United States of America
| | - Hugh R Taylor
- Melbourne School of Population and Global Health, University of Melbourne, Melbourne, Australia
| | - Rabebe Tekeraoi
- Eye Department, Ministry of Health and Medical Services, South Tarawa, Kiribati
| | - Allen Foster
- International Centre for Eye Health, London School of Hygiene & Tropical Medicine, London, England
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12
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Butcher R, Tagabasoe J, Manemaka J, Bong A, Garae M, Daniel L, Roberts C, Handley BL, Hu VH, Harding-Esch EM, Bakhtiari A, Willis R, Müller A, Kaldor J, Le Mesurier R, Mabey D, Cama A, Sokana O, Taleo F, Taylor HR, Solomon AW. Conjunctival scarring, corneal pannus and Herbert's pits in adolescent children in trachoma-endemic populations of the Solomon Islands and Vanuatu. Clin Infect Dis 2020; 73:e2773-e2780. [PMID: 32776137 PMCID: PMC8563182 DOI: 10.1093/cid/ciaa1151] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2020] [Indexed: 11/21/2022] Open
Abstract
Background In the Solomon Islands and Vanuatu, the sign trachomatous inflammation—follicular (TF) is common, but ocular infection with Chlamydia trachomatis is not. It is therefore debatable whether azithromycin mass drug administration (MDA), the recommended antibiotic treatment strategy for trachoma’s elimination as a public health problem, is necessary in this setting. We set out to estimate what proportion of adolescents were at risk of progression of trachomatous scarring. Methods A cross-sectional survey was undertaken of all children aged 10–14 years resident in communities identified as high-TF clusters during previous population-based mapping. Graders examined children for clinical evidence of trachomatous scarring, pannus, and Herbert’s pits (HPs) or limbal follicles in both eyes. A dried blood spot was collected from each child and tested for antibodies to C. trachomatis. Results A total of 492 children in 24 villages of the Solomon Islands and Vanuatu were examined. In total, 35/492 (7%) of children had limbal signs (pannus and/or HPs) plus any conjunctival scarring. And 9/492 (2%) had limbal signs and moderate or severe conjunctival scarring; 22% of children were anti-Pgp3 seropositive. Conclusions Few adolescents here are at risk of future complications from trachoma, supporting the conclusion that further antibiotic MDA is not currently required for trachoma elimination purposes in these settings.
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Affiliation(s)
- Robert Butcher
- Clinical Research Department, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Junely Tagabasoe
- Eye Department, Solomon Islands Ministry of Health and Medical Services, Honiara, Solomon Islands
| | - Joseph Manemaka
- Health Promotion Department, Solomon Islands Ministry of Health and Medical Services, Honiara, Solomon Islands
| | - Annie Bong
- Eye Department, Vanuatu Ministry of Health, Port Vila, Vanuatu
| | - Mackline Garae
- Department of Neglected Tropical Diseases, Vanuatu Ministry of Health, Port Vila, Vanuatu
| | - Lui Daniel
- Eye Department, Vanuatu Ministry of Health, Port Vila, Vanuatu
| | - Chrissy Roberts
- Clinical Research Department, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Becca L Handley
- Clinical Research Department, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Victor H Hu
- Clinical Research Department, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Emma M Harding-Esch
- Clinical Research Department, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | | | | | - Andreas Müller
- Centre for Eye Research Australia, University of Melbourne, Melbourne, Australia.,Programme for Blindness and Visual Impairment, World Health Organization, Geneva, Switzerland
| | - John Kaldor
- Kirby Institute, University of New South Wales, Sydney, Australia
| | | | - David Mabey
- Clinical Research Department, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Anasaini Cama
- The Fred Hollows Foundation, Carlton, Victoria, Australia
| | - Oliver Sokana
- Eye Department, Solomon Islands Ministry of Health and Medical Services, Honiara, Solomon Islands
| | - Fasihah Taleo
- Department of Neglected Tropical Diseases, Vanuatu Ministry of Health, Port Vila, Vanuatu.,Country Office, World Health Organization, Port Vila, Vanuatu
| | - Hugh R Taylor
- Indigenous Eye Health, Melbourne School of Population and Global Health, University of Melbourne, Melbourne, Australia
| | - Anthony W Solomon
- Clinical Research Department, London School of Hygiene & Tropical Medicine, London, United Kingdom.,Department of Control of Neglected Tropical Diseases, World Health Organization, Geneva, Switzerland
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13
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Ocular Chlamydia trachomatis infection, anti-Pgp3 antibodies and conjunctival scarring in Vanuatu and Tarawa, Kiribati before antibiotic treatment for trachoma. J Infect 2020; 80:454-461. [PMID: 32017971 PMCID: PMC7113835 DOI: 10.1016/j.jinf.2020.01.015] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2019] [Revised: 01/20/2020] [Accepted: 01/21/2020] [Indexed: 11/21/2022]
Abstract
In Vanuatu, ocular Chlamydia infection prevalence is low; in Kiribati it is high. In Vanuatu, Pgp3 seroprevalence does not increase in childhood; in Kiribati it does. Conjunctival scarring is more common in adults in Kiribati than in Vanuatu. Trachomatous inflammation—follicular lacks specificity for ocular Chlamydia infection. Non-TF markers may help to determine need for interventions against active trachoma.
Introduction In the peri-elimination setting, the positive predictive value of trachomatous inflammation–follicular (TF), the primary marker used to determine need for antibiotics for trachoma, is suboptimal. Here, three non-TF measures are used to compare two regions where TF prevalence exceeds the threshold for intervention, but where the Chlamydia trachomatis (Ct) prevalence is different. Methods Population prevalence of trachoma was measured in Vanuatu (n = 3470) and Kiribati (n = 2922). Dried blood spots (DBS) and conjunctival photographs were collected from every survey participant, and conjunctival swabs were collected from those aged 1–9 years. Individuals were tested for blood anti-Pgp3 antibodies, Ct DNA at the conjunctiva and severity of conjunctival scarring. Results The prevalence of TF in 1–9-year-olds was 16.5% in Vanuatu and 38.2% in Tarawa. 7% of people aged ≥1 year in Vanuatu had conjunctival scarring compared to 27% in Tarawa. The prevalence of ocular Ct infection in 1–9-year-olds was 1.5% in Vanuatu and 27.4% in Tarawa. The seroconversion rate amongst 1–9-year-old children in Vanuatu and Tarawa was 0.018 and 0.197 events per child per year, respectively. Conclusions Comparing Vanuatu to Tarawa demonstrates several markers that could be used to differentiate the trachoma status of populations in these (and other) locations.
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14
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Alkhidir AAI, Holland MJ, Elhag WI, Williams CA, Breuer J, Elemam AE, El Hussain KMK, Ournasseir MEH, Pickering H. Whole-genome sequencing of ocular Chlamydia trachomatis isolates from Gadarif State, Sudan. Parasit Vectors 2019; 12:518. [PMID: 31685017 PMCID: PMC6829945 DOI: 10.1186/s13071-019-3770-7] [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] [Received: 04/23/2019] [Accepted: 10/25/2019] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Trachoma, caused by ocular Chlamydia trachomatis, is the leading infectious cause of blindness worldwide. Sudan first reported trachoma in the 1930s and has since been consistently endemic. Ocular C. trachomatis previously isolated from trachoma patients in Sudan in 1963 was antigenically identical to an isolate from Saudi Arabia (A/SA1). No contemporary ocular C. trachomatis whole genome sequences have been reported from Sudan. METHODS This study sequenced twenty ocular C. trachomatis isolates to improve understanding of pathogen diversity in North-East Africa and examine for genomic variation specific to Sudan, possibly related to the persistence of trachoma in surveyed communities. High quality, whole genome sequences were obtained from 12/20 isolates. RESULTS All isolates were serovar A and had tarP and trpA sequences typical of classical, ocular C. trachomatis isolates. The Sudanese isolates formed a closely related subclade within the T2-trachoma clade of C. trachomatis phylogeny distinct from geographically disparate ocular isolates, with little intra-population diversity. We found 333 SNPs that were conserved in Sudanese ocular isolates but rare compared to other ocular C. trachomatis populations, which were focused in two genomic loci (CTA0172-CTA0173 and CTA0482). CONCLUSIONS Limited intra-population diversity and geographical clustering of ocular C. trachomatis suggests minimal transmission between and slow diversification within trachoma-endemic communities. However, diversity may have been higher pre-treatment in these communities. Over-representation of Sudan-specific SNPs in three genes suggests they may have an impact on C. trachomatis growth and transmission in this population.
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Affiliation(s)
| | - Martin J Holland
- Clinical Research Department, London School of Hygiene & Tropical Medicine, London, UK
| | - Wafa Ibrahim Elhag
- Faculty of Medical Laboratory Sciences, Al-Neelain University, Khartoum, Sudan
| | | | - Judith Breuer
- Division of Infection and Immunity, University College London, London, UK.,Microbiology, Virology, and Infection Control, Great Ormond Street Hospital for Children, NHS Foundation Trust, London, UK
| | | | | | | | - Harry Pickering
- Clinical Research Department, London School of Hygiene & Tropical Medicine, London, UK
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15
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Harding-Esch EM, Holland MJ, Schémann JF, Sillah A, Sarr B, Christerson L, Pickering H, Molina-Gonzalez S, Sarr I, Andreasen AA, Jeffries D, Grundy C, Mabey DCW, Herrmann B, Bailey RL. Impact of a single round of mass drug administration with azithromycin on active trachoma and ocular Chlamydia trachomatis prevalence and circulating strains in The Gambia and Senegal. Parasit Vectors 2019; 12:497. [PMID: 31640755 PMCID: PMC6805539 DOI: 10.1186/s13071-019-3743-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2019] [Accepted: 10/09/2019] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Mass drug administration (MDA) with azithromycin is a cornerstone of the trachoma elimination strategy. Although the global prevalence of active trachoma has declined considerably, prevalence persists or even increases in some communities and districts. To increase understanding of MDA impact, we investigated the prevalence of active trachoma and ocular C. trachomatis prevalence, organism load, and circulating strains at baseline and one-year post-MDA in The Gambia and Senegal. METHODS Pre- and one-year post-MDA, children aged 0-9 years were examined for clinical signs of trachoma in six Gambian and 12 Senegalese villages. Ocular swabs from each child's right conjunctiva were tested for evidence of ocular C. trachomatis infection and organism load (ompA copy number), and ompA and multi-locus sequence typing (MLST) was performed. RESULTS A total of 1171 children were examined at baseline and follow-up in The Gambia. Active trachoma prevalence decreased from 23.9% to 17.7%, whereas ocular C. trachomatis prevalence increased from 3.0% to 3.8%. In Senegal, 1613 and 1771 children were examined at baseline and follow-up, respectively. Active trachoma prevalence decreased from 14.9% to 8.0%, whereas ocular C. trachomatis prevalence increased from 1.8% to 3.6%. Higher organism load was associated with having active trachoma and severe inflammation. Sequence typing demonstrated that all Senegalese samples were genovar A, whereas Gambian samples were a mix of genovars A and B. MLST provided evidence of clustering at village and household levels and demonstrated differences of strain variant frequencies in Senegal, indicative of an "outbreak". MLST, including partial ompA typing, provided greater discriminatory power than complete ompA typing. CONCLUSIONS We found that one round of MDA led to an overall decline in active trachoma prevalence but no impact on ocular C. trachomatis infection, with heterogeneity observed between villages studied. This could not be explained by MDA coverage or number of different circulating strains pre- and post-MDA. The poor correlation between active trachoma and infection prevalence supports the need for further work on alternative indicators to clinical signs for diagnosing ocular C. trachomatis infection. MLST typing has potential molecular epidemiology utility, including better understanding of transmission dynamics, although relationship to whole-genome sequence variability requires further exploration.
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Affiliation(s)
- Emma M. Harding-Esch
- London School of Hygiene & Tropical Medicine, Keppel Street, London, WC1E 7HT UK
| | - Martin J. Holland
- London School of Hygiene & Tropical Medicine, Keppel Street, London, WC1E 7HT UK
- Medical Research Council Laboratories, PO Box 273, Fajara, Banjul, The Gambia
| | | | - Ansumana Sillah
- National Eye Health Programme, Ministry of Health and Social Welfare, Kanifing, The Gambia
| | - Boubacar Sarr
- Programme National de Lutte Contre la Cécité, Ministère de la Santé, BP 3817, Dakar, Sénégal
| | - Linus Christerson
- Department of Clinical Microbiology, Uppsala University, Uppsala, Sweden
| | - Harry Pickering
- London School of Hygiene & Tropical Medicine, Keppel Street, London, WC1E 7HT UK
| | | | - Isatou Sarr
- Medical Research Council Laboratories, PO Box 273, Fajara, Banjul, The Gambia
| | - Aura A. Andreasen
- London School of Hygiene & Tropical Medicine, Keppel Street, London, WC1E 7HT UK
| | - David Jeffries
- Medical Research Council Laboratories, PO Box 273, Fajara, Banjul, The Gambia
| | - Chris Grundy
- London School of Hygiene & Tropical Medicine, Keppel Street, London, WC1E 7HT UK
| | - David C. W. Mabey
- London School of Hygiene & Tropical Medicine, Keppel Street, London, WC1E 7HT UK
| | - Bjorn Herrmann
- Department of Clinical Microbiology, Uppsala University, Uppsala, Sweden
| | - Robin L. Bailey
- London School of Hygiene & Tropical Medicine, Keppel Street, London, WC1E 7HT UK
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16
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Correia M, Brunner D, Sharma M, Andrade V, Magno J, Müller A, Pereira BM, Thumann G, Verma N, Bangert M, Kreis AJ, Solomon AW. A search for trachoma in Timor-Leste: no evidence to justify undertaking population-based prevalence surveys. Ophthalmic Epidemiol 2019; 25:131-137. [PMID: 30806540 PMCID: PMC6858277 DOI: 10.1080/09286586.2018.1545037] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Purpose We sought evidence to justify undertaking population-based trachoma surveys in Timor-Leste, believing that in the absence of such evidence, the country could be categorized as not needing interventions to eliminate trachoma. Methods We undertook a systematic review of published literature on trachoma in Timor-Leste, with results updated to 28 April 2018. We also undertook a series of clinic- and field-based screening exercises, consisting of: (1) in October 2015, conjunctival examination of all children attending a school in Vila, Atauro Island; (2) from 1 November 2016 to 30 April 2017, examination for trichiasis, by specifically-trained frontline eye workers, of all individuals presenting to the ophthalmic clinics of six referral hospitals and five district eye clinics; and (3) house-to-house case searches in a total of 110 households, drawn from three communities that were reported by investigators from the 2016 Rapid Assessment of Avoidable Blindness (RAAB) to include residents with trachoma. Results Three RAABs (2005, 2009–2010, 2016) and two relevant published papers were identified. The 2016 RAAB reported one female subject to have been diagnosed with trachomatous corneal opacity. Re-examination of that individual revealed that she had ankyloblepharon, without evidence of trichiasis or entropion. No children on Atauro Island, no clinic attendees, and no individuals examined in the targeted house-to-house searches had any sign of trachoma. Conclusion Trachoma is very unlikely to be a public health problem in Timor-Leste. It would not be appropriate to incur the costs of conducting formal population-based trachoma prevalence surveys here.
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Affiliation(s)
- Marcelino Correia
- a National Eye Center , Guido Valadares National Hospital , Dili , Timor-Leste
| | - David Brunner
- b Oxford Eye Hospital , Oxford University Hospitals , Oxford , UK
| | - Manoj Sharma
- a National Eye Center , Guido Valadares National Hospital , Dili , Timor-Leste.,c East Timor Eye Program , Royal Australasian College of Surgeons , Dili , Timor-Leste.,d Faculty of Medicine , National University of East Timor , Dili , Timor-Leste
| | - Valerio Andrade
- a National Eye Center , Guido Valadares National Hospital , Dili , Timor-Leste
| | - Julia Magno
- e Lumbini Eye Institute , Siddharthanagar , Nepal
| | - Andreas Müller
- f Centre for Eye Research Australia , University of Melbourne , Melbourne , Australia
| | | | - Gabriele Thumann
- g Ophthalmology Department , Hôpital Universitaire de Genève , Geneva , Switzerland
| | - Nitin Verma
- b Oxford Eye Hospital , Oxford University Hospitals , Oxford , UK.,h Faculty of Medicine , University of Tasmania , Hobart , Australia.,i Department of Ophthalmology , Royal Hobart Hospital , Hobart , Australia
| | - Mathieu Bangert
- j Department of Control of Neglected Tropical Diseases , World Health Organization , Geneva , Switzerland
| | - Andréas J Kreis
- b Oxford Eye Hospital , Oxford University Hospitals , Oxford , UK.,g Ophthalmology Department , Hôpital Universitaire de Genève , Geneva , Switzerland
| | - Anthony W Solomon
- j Department of Control of Neglected Tropical Diseases , World Health Organization , Geneva , Switzerland
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17
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O'Neill CE, Skilton RJ, Pearson SA, Filardo S, Andersson P, Clarke IN. Genetic Transformation of a C. trachomatis Ocular Isolate With the Functional Tryptophan Synthase Operon Confers an Indole-Rescuable Phenotype. Front Cell Infect Microbiol 2018; 8:434. [PMID: 30619780 PMCID: PMC6302012 DOI: 10.3389/fcimb.2018.00434] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2018] [Accepted: 11/30/2018] [Indexed: 11/13/2022] Open
Abstract
Chlamydia trachomatis is the leading cause of preventable blindness and the most common bacterial sexually transmitted infection. Different strains are associated with ocular or urogenital infections, and a proposed mechanism that may explain this tissue tropism is the active tryptophan biosynthesis pathway encoded by the genomic trpRBA operon in urogenital strains. Here we describe genetic complementation studies that are essential to confirm the role of tryptophan synthase in the context of an ocular C. trachomatis genomic background. Ocular strain A2497 was transformed with the (urogenital) pSW2::GFP shuttle vector showing that there is no strain tropism barrier to this plasmid vector; moreover, transformation had no detrimental effect on the growth kinetics of A2497, which is important given the low transformation efficiency of C. trachomatis. A derivative of the pSW2::GFP vector was used to deliver the active tryptophan biosynthesis genes from a urogenital strain of C. trachomatis (Soton D1) to A2497 with the aim of complementing the truncated trpA gene common to most ocular strains. After confirmation of intact TrpA protein expression in the transformed A2497, the resulting transformants were cultivated in tryptophan-depleted medium with and without indole or tryptophan, showing that complementation of the truncated trpA gene by the intact and functional urogenital trpRBA operon was sufficient to bestow an indole rescuable phenotype upon A2497. This study proves that pSW2::GFP derived vectors do not conform to the cross-strain transformation barrier reported for other chlamydia shuttle vectors, suggesting these as a universal vector for transformation of all C. trachomatis strains. This vector promiscuity enabled us to test the indole rescue hypothesis by transforming ocular strain A2497 with the functional urogenital trpRBA operon, which complemented the non-functional tryptophan synthase. These data confirm that the trpRBA operon is necessary and sufficient for chlamydia to survive in tryptophan-limited environments such as the female urogenital tract.
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Affiliation(s)
- Colette Elizabeth O'Neill
- Molecular Microbiology Group, Department of Clinical and Experimental Science, Southampton General Hospital, University Medical School, Southampton, United Kingdom
| | - Rachel Jane Skilton
- Molecular Microbiology Group, Department of Clinical and Experimental Science, Southampton General Hospital, University Medical School, Southampton, United Kingdom
| | - Sarah Ann Pearson
- Molecular Microbiology Group, Department of Clinical and Experimental Science, Southampton General Hospital, University Medical School, Southampton, United Kingdom
| | - Simone Filardo
- Section of Microbiology, Department of Public Health and Infectious Diseases, Sapienza University, Rome, Italy
| | - Patiyan Andersson
- Global and Tropical Health Division, Menzies School of Health Research, Charles Darwin University, Darwin, NT, Australia
| | - Ian Nicholas Clarke
- Molecular Microbiology Group, Department of Clinical and Experimental Science, Southampton General Hospital, University Medical School, Southampton, United Kingdom
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Loveridge-Easther C, Murray N, Gale J. Management of trachoma in the Pacific: have we got it wrong? Clin Exp Ophthalmol 2018; 47:149-150. [PMID: 30066471 DOI: 10.1111/ceo.13366] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2018] [Accepted: 07/20/2018] [Indexed: 11/25/2022]
Affiliation(s)
| | - Neil Murray
- Lakes District Health Board, Rotorua, New Zealand
| | - Jesse Gale
- Capital and Coast District Health Board, Wellington, New Zealand.,Department of Surgery and Anaesthesia, University of Otago Wellington, Wellington, New Zealand
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Butcher R, Sokana O, Jack K, Sui L, Russell C, Last A, Martin DL, Burton MJ, Solomon AW, Mabey DCW, Roberts CH. Clinical signs of trachoma are prevalent among Solomon Islanders who have no persistent markers of prior infection with Chlamydia trachomatis. Wellcome Open Res 2018; 3:14. [PMID: 29588922 PMCID: PMC5854984 DOI: 10.12688/wellcomeopenres.13423.2] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/09/2018] [Indexed: 01/15/2023] Open
Abstract
Background: The low population prevalence of trachomatous trichiasis and high prevalence of trachomatous inflammation–follicular (TF) provide contradictory estimates of the magnitude of the public health threat from trachoma in the Solomon Islands. Improved characterisation of the biology of trachoma in the region may support policy makers as they decide what interventions are required. Here, age-specific profiles of anti-Pgp3 antibodies and conjunctival scarring were examined to determine whether there is evidence of ongoing transmission and pathology from ocular
Chlamydia trachomatis (
Ct)
infection. Methods: A total of 1511 individuals aged ≥1 year were enrolled from randomly selected households in 13 villages in which >10% of children aged 1–9 years had TF prior to a single round of azithromycin mass drug administration undertaken six months previously. Blood was collected to be screened for antibodies to the
Ct antigen Pgp3. Tarsal conjunctival photographs were collected for analysis of scarring severity. Results: Anti-Pgp3 seropositivity was 18% in 1–9 year olds, sharply increasing around the age of sexual debut to reach 69% in those over 25 years. Anti-Pgp3 seropositivity did not increase significantly between the ages of 1–9 years and was not associated with TF (p=0.581) or scarring in children (p=0.472). Conjunctival scars were visible in 13.1% of photographs. Mild (p<0.0001) but not severe (p=0.149) scars increased in prevalence with age. Conclusions: Neither conjunctival scars nor lymphoid follicles were associated with antibodies to
Ct, suggesting that they are unlikely to be a direct result of ocular
Ct infection
. Clinical signs of trachoma were prevalent in this population but were not indicative of the underlying rates of
Ct infection. The current World Health Organization guidelines for trachoma elimination indicated that this population should receive intervention with mass distribution of antibiotics, but the data presented here suggest that this may not have been appropriate.
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Affiliation(s)
- Robert Butcher
- Clinical Research Department, London School of Hygiene & Tropical Medicine, London, UK
| | - Oliver Sokana
- Eye Department, Solomon Islands Ministry of Health and Medical Services, Honiara, Solomon Islands
| | - Kelvin Jack
- Eye Department, Solomon Islands Ministry of Health and Medical Services, Honiara, Solomon Islands
| | - Leslie Sui
- Primary Care Department, Lata Hospital, Lata, Solomon Islands
| | | | - Anna Last
- Clinical Research Department, London School of Hygiene & Tropical Medicine, London, UK
| | - Diana L Martin
- Division of Parasitic Diseases and Malaria, US Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - Matthew J Burton
- Clinical Research Department, London School of Hygiene & Tropical Medicine, London, UK
| | - Anthony W Solomon
- Clinical Research Department, London School of Hygiene & Tropical Medicine, London, UK
| | - David C W Mabey
- Clinical Research Department, London School of Hygiene & Tropical Medicine, London, UK
| | - Chrissy H Roberts
- Clinical Research Department, London School of Hygiene & Tropical Medicine, London, UK
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20
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Butcher R, Sokana O, Jack K, Sui L, Russell C, Last A, Martin DL, Burton MJ, Solomon AW, Mabey DC, Roberts CH. Clinical signs of trachoma are prevalent among Solomon Islanders who have no persistent markers of prior infection with Chlamydia trachomatis. Wellcome Open Res 2018; 3:14. [PMID: 29588922 PMCID: PMC5854984 DOI: 10.12688/wellcomeopenres.13423.1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/09/2018] [Indexed: 06/28/2024] Open
Abstract
Background: The low population-prevalence of trachomatous trichiasis and high prevalence of trachomatous inflammation-follicular (TF) provide contradictory estimates of the magnitude of the public health threat from trachoma in the Solomon Islands. Improved characterisation of the biology of trachoma in the region may support policy makers as they decide what interventions are required. Here, age-specific profiles of anti-Pgp3 antibodies and conjunctival scarring were examined to determine whether there is evidence of ongoing transmission and pathology from ocular Chlamydia trachomatis (Ct) infection. Methods: A total of 1511 individuals aged ≥1 year were enrolled from randomly selected households in 13 villages in which >10% of children aged 1-9 years had TF prior to a single round of azithromycin mass drug administration undertaken six months previously. Blood was collected to be screened for antibodies to the Ct antigen Pgp3. Tarsal conjunctival photographs were collected for analysis of scarring severity. Results: Anti-Pgp3 seropositivity was 18% in 1-9 year olds, sharply increasing around the age of sexual debut to reach 69% in those over 25 years. Anti-Pgp3 seropositivity did not increase significantly between the ages of 1-9 years and was not associated with TF (p=0.581) or scarring in children (p=0.472). Conjunctival scars were visible in 13.1% of photographs. Mild (p<0.0001) but not severe (p=0.149) scars increased in prevalence with age. Conclusions: Neither conjunctival scars nor lymphoid follicles were associated with antibodies to Ct, suggesting that they are unlikely to be a direct result of ocular Ct infection . Clinical signs of trachoma were prevalent in this population but were not indicative of the underlying rates of Ct infection. The current World Health Organization guidelines for trachoma elimination indicated that this population should receive intervention with mass distribution of antibiotics, but the data presented here suggest that this may not have been appropriate.
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Affiliation(s)
- Robert Butcher
- Clinical Research Department, London School of Hygiene & Tropical Medicine, London, UK
| | - Oliver Sokana
- Eye Department, Solomon Islands Ministry of Health and Medical Services, Honiara, Solomon Islands
| | - Kelvin Jack
- Eye Department, Solomon Islands Ministry of Health and Medical Services, Honiara, Solomon Islands
| | - Leslie Sui
- Primary Care Department, Lata Hospital, Lata, Solomon Islands
| | | | - Anna Last
- Clinical Research Department, London School of Hygiene & Tropical Medicine, London, UK
| | - Diana L. Martin
- Division of Parasitic Diseases and Malaria, US Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - Matthew J. Burton
- Clinical Research Department, London School of Hygiene & Tropical Medicine, London, UK
| | - Anthony W. Solomon
- Clinical Research Department, London School of Hygiene & Tropical Medicine, London, UK
| | - David C.W. Mabey
- Clinical Research Department, London School of Hygiene & Tropical Medicine, London, UK
| | - Chrissy h. Roberts
- Clinical Research Department, London School of Hygiene & Tropical Medicine, London, UK
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Vasileva H, Butcher R, Pickering H, Sokana O, Jack K, Solomon AW, Holland MJ, Roberts CH. Conjunctival transcriptome profiling of Solomon Islanders with active trachoma in the absence of Chlamydia trachomatis infection. Parasit Vectors 2018; 11:104. [PMID: 29467021 PMCID: PMC5822555 DOI: 10.1186/s13071-018-2682-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2017] [Accepted: 01/29/2018] [Indexed: 11/16/2022] Open
Abstract
BACKGROUND Clinical signs of active (inflammatory) trachoma are found in many children in the Solomon Islands, but the majority of these individuals have no serological evidence of previous infection with Chlamydia trachomatis. In Temotu and Rennell and Bellona provinces, ocular infections with C. trachomatis were seldom detected among children with active trachoma; a similar lack of association was seen between active trachoma and other common bacterial and viral causes of follicular conjunctivitis. Here, we set out to characterise patterns of gene expression at the conjunctivae of children in these provinces with and without clinical signs of trachomatous inflammation-follicular (TF) and C. trachomatis infection. METHODS Purified RNA from children with and without active trachoma was run on Affymetrix GeneChip Human Transcriptome Array 2.0 microarrays. Profiles were compared between individuals with ocular C. trachomatis infection and TF (group DI; n = 6), individuals with TF but no C. trachomatis infection (group D; n = 7), and individuals without TF or C. trachomatis infection (group N; n = 7). Differential gene expression and gene set enrichment for pathway membership were assessed. RESULTS Conjunctival gene expression profiles were more similar within-group than between-group. Principal components analysis indicated that the first and second principal components combined explained almost 50% of the variance in the dataset. When comparing the DI group to the N group, genes involved in T-cell proliferation, B-cell signalling and CD8+ T cell signalling pathways were differentially regulated. When comparing the DI group to the D group, CD8+ T-cell regulation, interferon-gamma and IL17 production pathways were enriched. Genes involved in RNA transcription and translation pathways were upregulated when comparing the D group to the N group. CONCLUSIONS Gene expression profiles in children in the Solomon Islands indicate immune responses consistent with bacterial infection when TF and C. trachomatis infection are concurrent. The transcriptomes of children with TF but without identified infection were not consistent with allergic or viral conjunctivitis.
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Affiliation(s)
- Hristina Vasileva
- Clinical Research Department, London School of Hygiene & Tropical Medicine, Keppel Street, London, WC1E 7HT UK
| | - Robert Butcher
- Clinical Research Department, London School of Hygiene & Tropical Medicine, Keppel Street, London, WC1E 7HT UK
| | - Harry Pickering
- Clinical Research Department, London School of Hygiene & Tropical Medicine, Keppel Street, London, WC1E 7HT UK
| | - Oliver Sokana
- Eye Department, Solomon Islands Ministry of Health and Medical Services, PO Box 349, Honiara, Solomon Islands
| | - Kelvin Jack
- Eye Department, Solomon Islands Ministry of Health and Medical Services, PO Box 349, Honiara, Solomon Islands
| | - Anthony W. Solomon
- Clinical Research Department, London School of Hygiene & Tropical Medicine, Keppel Street, London, WC1E 7HT UK
| | - Martin J. Holland
- Clinical Research Department, London School of Hygiene & Tropical Medicine, Keppel Street, London, WC1E 7HT UK
| | - Chrissy h. Roberts
- Clinical Research Department, London School of Hygiene & Tropical Medicine, Keppel Street, London, WC1E 7HT UK
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22
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Pickering H, Holland MJ, Last AR, Burton MJ, Burr SE. Evaluation of a Chlamydia trachomatis-specific, commercial, real-time PCR for use with ocular swabs. Parasit Vectors 2018; 11:102. [PMID: 29463279 PMCID: PMC5819642 DOI: 10.1186/s13071-018-2686-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2017] [Accepted: 01/30/2018] [Indexed: 12/02/2022] Open
Abstract
Background Trachoma, the leading infectious cause of blindness worldwide, is caused by conjunctival Chlamydia trachomatis infection. Trachoma is diagnosed clinically by observation of conjunctival inflammation and/or scarring; however, there is evidence that monitoring C. trachomatis infection may be required for elimination programmes. There are many commercial and ‘in-house’ nucleic acid amplification tests for the detection of C. trachomatis DNA, but the majority have not been validated for use with ocular swabs. This study evaluated a commercial assay, the Fast-Track Vaginal swab kit, using conjunctival samples from trachoma-endemic areas. An objective, biostatistical-based method for binary classification of continuous PCR data was developed, to limit potential user-bias in diagnostic settings. Methods The Fast-Track Vaginal swab assay was run on 210 ocular swab samples from Guinea-Bissau and Tanzania. Fit of individual amplification curves to exponential or sigmoid models, derivative and second derivative of the curves and final fluorescence value were examined for utility in thresholding for determining positivity. The results from the Fast-Track Vaginal swab assay were evaluated against a commercial test (Amplicor CT/NG) and a non-commercial test (in-house droplet digital PCR), both of whose performance has previously been evaluated. Results Significant evidence of exponential amplification (R2 > 0.99) and final fluorescence > 0.15 were combined for thresholding. This objective approach identified a population of positive samples, however there were a subset of samples that amplified towards the end of the cycling protocol (at or later than 35 cycles), which were less clearly defined. The Fast-Track Vaginal swab assay showed good sensitivity against the commercial (95.71) and non-commercial (97.18) tests. Specificity was lower against both (90.00 and 96.55, respectively). Conclusions This study defined a simple, automated protocol for binary classification of continuous, real-time qPCR data, for use in an end-point diagnostic test. This method identified a population of positive samples, however, as with manual thresholding, a subset of samples that amplified towards the end of the cycling program were less easily classified. When used with ocular swabs, the Fast-Track Vaginal swab assay had good sensitivity for C. trachomatis detection, but lower specificity than the commercial and non-commercial assays it was evaluated against, possibly leading to false positives.
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Affiliation(s)
| | | | - Anna R Last
- London School of Hygiene and Tropical Medicine, London, UK
| | | | - Sarah E Burr
- London School of Hygiene and Tropical Medicine, London, UK
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23
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Butcher RMR, Sokana O, Jack K, Kalae E, Sui L, Russell C, Houghton J, Palmer C, Holland MJ, Le Mesurier RT, Solomon AW, Mabey DCW, Roberts CH. Active Trachoma Cases in the Solomon Islands Have Varied Polymicrobial Community Structures but Do Not Associate with Individual Non-Chlamydial Pathogens of the Eye. Front Med (Lausanne) 2018; 4:251. [PMID: 29410954 PMCID: PMC5787070 DOI: 10.3389/fmed.2017.00251] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2017] [Accepted: 12/19/2017] [Indexed: 11/17/2022] Open
Abstract
BACKGROUND Several non-chlamydial microbial pathogens are associated with clinical signs of active trachoma in trachoma-endemic communities with a low prevalence of ocular Chlamydia trachomatis (Ct) infection. In the Solomon Islands, the prevalence of Ct among children is low despite the prevalence of active trachoma being moderate. Therefore, we set out to investigate whether active trachoma was associated with a common non-chlamydial infection or with a dominant polymicrobial community dysbiosis in the Solomon Islands. METHODS We studied DNA from conjunctival swabs collected from 257 Solomon Islanders with active trachoma and matched controls. Droplet digital PCR was used to test for pathogens suspected to be able to induce follicular conjunctivitis. Polymicrobial community diversity and composition were studied by sequencing of hypervariable regions of the 16S ribosomal ribonucleic acid gene in a subset of 54 cases and 53 controls. RESULTS Although Ct was associated with active trachoma, the number of infections was low (cases, 3.9%; controls, 0.4%). Estimated prevalence (cases and controls, respectively) of each non-chlamydial infection was as follows: Staphylococcus aureus: 1.9 and 1.9%, Adenoviridae: 1.2 and 1.2%, coagulase-negative Staphylococcus: 5.8 and 4.3%, Haemophilus influenzae: 7.4 and 11.7%, Moraxella catarrhalis: 2.3 and 4.7%, and Streptococcus pneumoniae: 7.0 and 6.2%. There was no statistically significant association between the clinical signs of trachoma and the presence or load of any of the non-Ct infections that were assayed. Interindividual variations in the conjunctival microbiome were characterized by differences in the levels of Corynebacterium, Propionibacterium, Helicobacter, and Paracoccus, but diversity and relative abundance of these specific genera did not differ significantly between cases and controls. DISCUSSION It is unlikely that the prevalent trachoma-like follicular conjunctivitis in this region of the Solomon Islands has a dominant bacterial etiology. Before implementing community-wide azithromycin distribution for trachoma, policy makers should consider that clinical signs of trachoma can be observed in the absence of any detectable azithromycin-susceptible organism.
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Affiliation(s)
- Robert M. R. Butcher
- Clinical Research Department, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Oliver Sokana
- Eye Department, Ministry of Health and Medical Services, Honiara, Solomon Islands
| | - Kelvin Jack
- Eye Department, Ministry of Health and Medical Services, Honiara, Solomon Islands
| | - Eric Kalae
- Primary Care Department, Lata Hospital, Santa Cruz Island, Solomon Islands
| | - Leslie Sui
- Primary Care Department, Lata Hospital, Santa Cruz Island, Solomon Islands
| | | | - Joanna Houghton
- Clinical Research Department, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Christine Palmer
- Clinical Research Department, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Martin J. Holland
- Clinical Research Department, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | | | - Anthony W. Solomon
- Clinical Research Department, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - David C. W. Mabey
- Clinical Research Department, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Chrissy h. Roberts
- Clinical Research Department, London School of Hygiene & Tropical Medicine, London, United Kingdom
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24
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Debrah O, Mensah EO, Senyonjo L, de Souza DK, Hervie TE, Agyemang D, Bakajika D, Marfo B, Ahorsu F, Wanye S, Bailey R, Koroma JB, Aboe A, Biritwum NK. Elimination of trachoma as a public health problem in Ghana: Providing evidence through a pre-validation survey. PLoS Negl Trop Dis 2017; 11:e0006099. [PMID: 29232708 PMCID: PMC5746280 DOI: 10.1371/journal.pntd.0006099] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2017] [Revised: 12/28/2017] [Accepted: 11/06/2017] [Indexed: 11/28/2022] Open
Abstract
Background In order to achieve elimination of trachoma, a country needs to demonstrate that the elimination prevalence thresholds have been achieved and then sustained for at least a two-year period. Ghana achieved the thresholds in 2008, and since 2011 has been implementing its trachoma surveillance strategy, which includes community and school screening for signs of follicular trachoma and trichiasis, in trachoma-endemic districts. In 2015–2016, the country conducted a district level population-based survey to validate elimination of trachoma as a public health problem. Methods As per WHO recommendations, a cross-sectional survey, employing a two-stage cluster random sampling methodology, was used across 18 previously trachoma endemic districts (evaluation units (EUs) in the Upper West and Northern Regions of Ghana. In each EU 24 villages were selected based on probability proportional to estimated size. A minimum of 40 households were targeted per village and all eligible residents were examined for clinical signs of trachoma, using the WHO simplified grading system. The number of trichiasis cases unknown to the health system was determined. Household environmental risk factors for trachoma were also assessed. Results Data from 45,660 individuals were examined from 11,099 households across 18 EUs, with 27,398 (60.0%) children aged 1–9 years and 16,610 (36.4%) individuals 15 years and above All EUs had shown to have maintained the WHO elimination threshold for Trachomatous inflammation-Follicular (TF) (<5.0% prevalence) in children aged 1–9 years old. The EU TF prevalence in children aged 1–9 years old ranged from between 0.09% to 1.20%. Only one EU (Yendi 0.36%; 95% CI: 0.0–1.01) failed to meet the WHO TT elimination threshold (< 0.2% prevalence in adults aged 15 and above). The EU prevalence of trichiasis (TT) unknown to the health system in adults aged ≥15 years, ranged from 0.00% to 0.36%. In this EU, the estimated TT backlog is 417 All TT patients identified in the study, as well as through on-going surveillance efforts will require further management. A total of 75.9% (95% CI 72.1–79.3, EU range 29.1–92.6) of households defecated in the open but many households had access to an improved water source 75.9% (95%CI: 71.5–79.8, EU range 47.4–90.1%), with 45.5% (95% CI 41.5–49.7%, EU range 28.4–61.8%) making a round trip of water collection < 30 minutes. Conclusion The findings from this survey indicate elimination thresholds have been maintained in Ghana in 17 of the 18 surveyed EUs. Only one EU, Yendi, did not achieve the TT elimination threshold. A scheduled house-by-house TT case search in this EU coupled with surgery to clear the backlog of cases is necessary in order for Ghana to request validation of elimination of trachoma as a public health problem. Trachoma is an eye disease caused by an infection with Chlamydia trachomatis. It is the leading cause of blindness due to infection globally. However, trachoma is both treatable and preventable through antibiotics and surgery, and may be preventable with basic hygiene improvements. Thus, the Surgery, Antibiotics, Facial cleanliness and Environmental modification (SAFE) strategy is endorsed by the World Health Organization for the implementation of interventions. Trachoma is a progressive disease. Clinically active trachoma, the follicular (trachomatous-inflammation follicular (TF)) and intense (trachomatous- inflammation intense (TI)) phases are most common in children aged 1–9 years old while complications such as in turned lashes and loss of vision are found mainly in adults. Globally, the disease is earmarked for elimination as a public health problem by the year 2020. In Ghana, studies conducted in 2000–2003 identified trachoma as endemic in the Upper West and Northern regions and by 2004 the elimination strategy based on Surgery, Antibiotics treatment, Face washing and Environmental improvement, was being implemented in all 18 districts in the two regions. Surveys conducted in 2008 indicated that the strategy had been successful with reduction of clinically active trachoma to elimination levels in all 18 districts. Ghana implemented a post-elimination surveillance phase from 2011–2014 and conducted a formal prevalence survey in 2015–2016 using WHO standard grading methodologies, the results of which are presented here. The results showed that TF prevalence was below the 5% elimination target in children aged 1–9 years old in all 18 districts, while TT was below 2 cases in every 1000 persons aged 15 and above in all 18 endemic districts except one (Yendi district). Ghana has put in place a TT case search of all persons 15 years and above in the Yendi district to identify persons with the complications and offer surgery to them. The outcomes of these investigations will enable Ghana to provide evidence for WHO dossier submission, to acknowledge validation of elimination of trachoma as public health problem.
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Affiliation(s)
| | | | - Laura Senyonjo
- Sightsavers International, UK Office, London, United Kingdom
- London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Dziedzom K. de Souza
- Noguchi Memorial Institute for Medical Research, University of Ghana, Accra, Ghana
| | - Tei E. Hervie
- Neglected Tropical Diseases Program, Ghana Health Service, Accra, Ghana
| | | | | | - Benjamin Marfo
- Neglected Tropical Diseases Program, Ghana Health Service, Accra, Ghana
| | | | - Seth Wanye
- Eye Care, Ghana Health Service, Accra, Ghana
| | - Robin Bailey
- London School of Hygiene and Tropical Medicine, London, United Kingdom
| | | | - Agatha Aboe
- Sightsavers International, Ghana Office, Accra, Ghana
| | - Nana-Kwadwo Biritwum
- Neglected Tropical Diseases Program, Ghana Health Service, Accra, Ghana
- * E-mail:
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25
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Migchelsen SJ, Sepúlveda N, Martin DL, Cooley G, Gwyn S, Pickering H, Joof H, Makalo P, Bailey R, Burr SE, Mabey DCW, Solomon AW, Roberts CH. Serology reflects a decline in the prevalence of trachoma in two regions of The Gambia. Sci Rep 2017; 7:15040. [PMID: 29118442 PMCID: PMC5678181 DOI: 10.1038/s41598-017-15056-7] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2017] [Accepted: 10/16/2017] [Indexed: 11/09/2022] Open
Abstract
Trachoma is caused by Chlamydia trachomatis (Ct). It is targeted for global elimination as a public health problem. In 2014, a population-based cross-sectional study was performed in two previously trachoma-endemic areas of The Gambia. Participants of all ages from Lower River Region (LRR) (N = 1028) and Upper River Region (URR) (N = 840) underwent examination for trachoma and had blood collected for detection of antibodies against the Ct antigen Pgp3, by ELISA. Overall, 30 (1.6%) individuals had active trachoma; the prevalence in children aged 1-9 years was 3.4% (25/742) with no statistically significant difference in prevalence between the regions. There was a significant difference in overall seroprevalence by region: 26.2% in LRR and 17.1% in URR (p < 0.0001). In children 1-9 years old, seroprevalence was 4.4% in LRR and 3.9% in URR. Reversible catalytic models using information on age-specific seroprevalence demonstrated a decrease in the transmission of Ct infection in both regions, possibly reflecting the impact of improved access to water, health and sanitation as well as mass drug administration campaigns. Serological testing for antibodies to Ct antigens is potentially useful for trachoma programmes, but consideration should be given to the co-endemicity of sexually transmitted Ct infections.
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Affiliation(s)
- Stephanie J Migchelsen
- Clinical Research Department, London School of Hygiene & Tropical Medicine, London, United Kingdom.
| | - Nuno Sepúlveda
- Clinical Research Department, London School of Hygiene & Tropical Medicine, London, United Kingdom
- Centro de Estatística e Aplicações, Faculdade de Ciências, Universidade de Lisboa, Lisboa, Portugal
| | - Diana L Martin
- Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, Atlanta, Georgia, USA
| | - Gretchen Cooley
- Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, Atlanta, Georgia, USA
| | - Sarah Gwyn
- IHRC, Inc., Centers for Disease Control and Prevention, Atlanta, Georgia, USA
| | - Harry Pickering
- Clinical Research Department, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Hassan Joof
- Disease Control and Elimination Theme, Medical Research Council, The Gambia Unit, Fajara, The Gambia
| | - Pateh Makalo
- Disease Control and Elimination Theme, Medical Research Council, The Gambia Unit, Fajara, The Gambia
| | - Robin Bailey
- Clinical Research Department, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Sarah E Burr
- Clinical Research Department, London School of Hygiene & Tropical Medicine, London, United Kingdom
- Disease Control and Elimination Theme, Medical Research Council, The Gambia Unit, Fajara, The Gambia
| | - David C W Mabey
- Clinical Research Department, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Anthony W Solomon
- Clinical Research Department, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Chrissy H Roberts
- Clinical Research Department, London School of Hygiene & Tropical Medicine, London, United Kingdom
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26
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Cama A, Müller A, Taoaba R, Butcher RMR, Itibita I, Migchelsen SJ, Kiauea T, Pickering H, Willis R, Roberts CH, Bakhtiari A, Le Mesurier RT, Alexander NDE, Martin DL, Tekeraoi R, Solomon AW. Prevalence of signs of trachoma, ocular Chlamydia trachomatis infection and antibodies to Pgp3 in residents of Kiritimati Island, Kiribati. PLoS Negl Trop Dis 2017; 11:e0005863. [PMID: 28898240 PMCID: PMC5609772 DOI: 10.1371/journal.pntd.0005863] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2017] [Revised: 09/22/2017] [Accepted: 08/08/2017] [Indexed: 11/18/2022] Open
Abstract
OBJECTIVE In some Pacific Island countries, such as Solomon Islands and Fiji, active trachoma is common, but ocular Chlamydia trachomatis (Ct) infection and trachomatous trichiasis (TT) are rare. On Tarawa, the most populous Kiribati island, both the active trachoma sign "trachomatous inflammation-follicular" (TF) and TT are present at prevalences warranting intervention. We sought to estimate prevalences of TF, TT, ocular Ct infection, and anti-Ct antibodies on Kiritimati Island, Kiribati, to assess local relationships between these parameters, and to help determine the need for interventions against trachoma on Kiribati islands other than Tarawa. METHODS As part of the Global Trachoma Mapping Project (GTMP), on Kiritimati, we examined 406 children aged 1-9 years for active trachoma. We collected conjunctival swabs (for droplet digital PCR against Ct plasmid targets) from 1-9-year-olds with active trachoma, and a systematic selection of 1-9-year-olds without active trachoma. We collected dried blood spots (for anti-Pgp3 ELISA) from all 1-9-year-old children. We also examined 416 adults aged ≥15 years for TT. Prevalence of TF and TT was adjusted for age (TF) or age and gender (TT) in five-year age bands. RESULTS The age-adjusted prevalence of TF in 1-9-year-olds was 28% (95% confidence interval [CI]: 24-35). The age- and gender-adjusted prevalence of TT in those aged ≥15 years was 0.2% (95% CI: 0.1-0.3%). Twenty-six (13.5%) of 193 swabs from children without active trachoma, and 58 (49.2%) of 118 swabs from children with active trachoma were positive for Ct DNA. Two hundred and ten (53%) of 397 children had anti-Pgp3 antibodies. Both infection (p<0.0001) and seropositivity (p<0.0001) were strongly associated with active trachoma. In 1-9-year-olds, the prevalence of anti-Pgp3 antibodies rose steeply with age. CONCLUSION Trachoma presents a public health problem on Kiritimati, where the high prevalence of ocular Ct infection and rapid increase in seropositivity with age suggest intense Ct transmission amongst young children. Interventions are required here to prevent future blindness.
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Affiliation(s)
- Anaseini Cama
- International Agency for the Prevention of Blindness, Western Pacific Region, Suva, Fiji
- The Fred Hollows Foundation, Sydney, Australia
| | - Andreas Müller
- Centre for Eye Research, University of Melbourne, Melbourne, Australia
| | - Raebwebwe Taoaba
- Eye Department, Ministry of Health and Medical Services, South Tarawa, Kiribati
| | - Robert M. R. Butcher
- Clinical Research Department, London School of Hygiene & Tropical Medicine, London, United Kingdom
- * E-mail:
| | - Iakoba Itibita
- Kiritimati Hospital, London, Kiritimati Island, Kiribati
| | - Stephanie J. Migchelsen
- Clinical Research Department, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | | | - Harry Pickering
- Clinical Research Department, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Rebecca Willis
- International Trachoma Initiative, Task Force for Global Health, Decatur, Georgia, United States of America
| | - Chrissy h. Roberts
- Clinical Research Department, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Ana Bakhtiari
- International Trachoma Initiative, Task Force for Global Health, Decatur, Georgia, United States of America
| | - Richard T. Le Mesurier
- International Agency for the Prevention of Blindness, Western Pacific Region, Suva, Fiji
- The Fred Hollows Foundation, Sydney, Australia
| | - Neal D. E. Alexander
- MRC Tropical Epidemiology Group, Infectious Disease Epidemiology Department, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Diana L. Martin
- Division of Parasitic Diseases and Malaria, Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America
| | - Rabebe Tekeraoi
- Eye Department, Ministry of Health and Medical Services, South Tarawa, Kiribati
| | - Anthony W. Solomon
- Clinical Research Department, London School of Hygiene & Tropical Medicine, London, United Kingdom
- Department of Control of Neglected Tropical Diseases, World Health Organization, Geneva, Switzerland
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27
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Butcher R, Houghton J, Derrick T, Ramadhani A, Herrera B, Last AR, Massae PA, Burton MJ, Holland MJ, Roberts CH. Reduced-cost Chlamydia trachomatis-specific multiplex real-time PCR diagnostic assay evaluated for ocular swabs and use by trachoma research programmes. J Microbiol Methods 2017; 139:95-102. [PMID: 28487054 PMCID: PMC5496587 DOI: 10.1016/j.mimet.2017.04.010] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2017] [Revised: 04/21/2017] [Accepted: 04/22/2017] [Indexed: 11/29/2022]
Abstract
INTRODUCTION Trachoma, caused by the intracellular bacterium Chlamydia trachomatis (Ct), is the leading infectious cause of preventable blindness. Many commercial platforms are available that provide highly sensitive and specific detection of Ct DNA. However, the majority of these commercial platforms are inaccessible for population-level surveys in resource-limited settings typical to trachoma control programmes. We developed two low-cost quantitative PCR (qPCR) tests for Ct using readily available reagents on standard real-time thermocyclers. METHODS Each multiplex qPCR test targets one genomic and one plasmid Ct target in addition to an endogenous positive control for Homo sapiens DNA. The quantitative performance of the qPCR assays in clinical samples was determined by comparison to a previously evaluated droplet digital PCR (ddPCR) test. The diagnostic performance of the qPCR assays were evaluated against a commercial assay (artus C. trachomatis Plus RG PCR, Qiagen) using molecular diagnostics quality control standards and clinical samples. We examined the yield of Ct DNA prepared from five different DNA extraction kits and a cold chain-free dry-sample preservation method using swabs spiked with fixed concentrations of human and Ct DNA. RESULTS The qPCR assay was highly reproducible (Ct plasmid and genomic targets mean total coefficients of variance 41.5% and 48.3%, respectively). The assay detected 8/8 core specimens upon testing of a quality control panel and performed well in comparison to commercially marketed comparator test (sensitivity and specificity>90%). Optimal extraction and sample preservation methods for research applications were identified. CONCLUSION We describe a pipeline from collection to diagnosis providing the most efficient sample preservation and extraction with significant per test cost savings over a commercial qPCR diagnostic assay. The assay and its evaluation should allow control programs wishing to conduct independent research within the context of trachoma control, access to an affordable test with defined performance characteristics.
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Affiliation(s)
- Robert Butcher
- Clinical Research Department, Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London WC1E 7HT, United Kingdom.
| | - Jo Houghton
- Clinical Research Department, Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London WC1E 7HT, United Kingdom
| | - Tamsyn Derrick
- Clinical Research Department, Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London WC1E 7HT, United Kingdom; Kilimanjaro Christian Medical Centre, Moshi, Tanzania
| | - Athumani Ramadhani
- Clinical Research Department, Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London WC1E 7HT, United Kingdom; Kilimanjaro Christian Medical Centre, Moshi, Tanzania
| | - Beatriz Herrera
- Clinical Research Department, Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London WC1E 7HT, United Kingdom
| | - Anna R Last
- Clinical Research Department, Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London WC1E 7HT, United Kingdom
| | | | - Matthew J Burton
- Clinical Research Department, Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London WC1E 7HT, United Kingdom
| | - Martin J Holland
- Clinical Research Department, Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London WC1E 7HT, United Kingdom
| | - Chrissy H Roberts
- Clinical Research Department, Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London WC1E 7HT, United Kingdom
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Feng L, Lu X, Yu Y, Wang T, Luo S, Sun Z, Duan Q, Wang N, Song L. Survey, Culture, and Genome Analysis of Ocular Chlamydia trachomatis in Tibetan Boarding Primary Schools in Qinghai Province, China. Front Cell Infect Microbiol 2017; 6:207. [PMID: 28119858 PMCID: PMC5220689 DOI: 10.3389/fcimb.2016.00207] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2016] [Accepted: 12/23/2016] [Indexed: 11/13/2022] Open
Abstract
Trachoma, the leading infectious cause of blindness worldwide, is an ancient human disease. Its existence in China can be traced back to as early as the twenty-seventh century BC. In modern China, the overall prevalence of trachoma has dramatically reduced, but trachoma is still endemic in many areas of the country. Here, we report that 26 (8%) of 322 students from two rural boarding schools of Qinghai province, west China, were identified as having ocular C. trachomatis infection; and 15 ocular C. trachomatis strains were isolated from these trachoma patients. Chlamydiae in 37 clinical samples were genotyped as type B based on ompA gene analyses. Three ompA variants with one or two in-between SNP differences in the second or fourth variable domain were found. C. trachomatis strains QH111L and QH111R were from the same patient's left and right conjunctival swabs, respectively, but their ompA genes have a non-synonymous base difference in the second variable domain. Moreover, this SNP only exists in this single sample, suggesting QH111L is a newly emerged ompA variant. Interestingly, chromosomal phylogeny analysis found QH111L clusters between a branch of two type B strains and a branch of both A and C strains, but is significantly divergent from both branches. Comparative chromosome analysis found that compared to sequences of reference B/TZ1A828/OT strain, 12 of 22 QH111L's chromosomal genes exhibiting more than nine SNPs have the best homology with reciprocal genes of UGT strains while 9 of 22 genes are closest to those of type C strains. Consistent with findings of UGT-type genetic features in the chromosome, the QH111L plasmid appears to be intermediate between UGT and classical ocular plasmids due to the existence of UGT-type SNPs in the QH111L plasmid. Moreover, the QH111L strain has a unique evolutionarily older cytotoxin region compared to cytotoxin regions of other C. trachomatis strains. The genome analyses suggest that the QH111L strain is derived from recombinations between UGT and classical ocular ancestors. This is the first study of culture and characterization of ocular C. trachomatis in Qinghai Tibetan areas.
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Affiliation(s)
- Le Feng
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology Beijing, China
| | - Xinxin Lu
- Beijing Institute of Ophthalmology, Beijing Tongren Hospital, Capital Medical University Beijing, China
| | - Yonghui Yu
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology Beijing, China
| | - Tao Wang
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology Beijing, China
| | - Shengdong Luo
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology Beijing, China
| | - Zhihui Sun
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology Beijing, China
| | - Qing Duan
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology Beijing, China
| | - Ningli Wang
- Beijing Institute of Ophthalmology, Beijing Tongren Hospital, Capital Medical University Beijing, China
| | - Lihua Song
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology Beijing, China
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Butcher RMR, Sokana O, Jack K, Macleod CK, Marks M, Kalae E, Sui L, Russell C, Tutill HJ, Williams RJ, Breuer J, Willis R, Le Mesurier RT, Mabey DCW, Solomon AW, Roberts CH. Correction: Low Prevalence of Conjunctival Infection with Chlamydia trachomatis in a Treatment-Naïve Trachoma-Endemic Region of the Solomon Islands. PLoS Negl Trop Dis 2016; 10:e0005051. [PMID: 27695076 PMCID: PMC5047450 DOI: 10.1371/journal.pntd.0005051] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
[This corrects the article DOI: 10.1371/journal.pntd.0004863.].
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