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Handley BL, Tchatchouang S, Grout L, Johnson RC, Tabah EN, Boua B, Boock AU, Koffi AP, Phanzu DM, Kotey NK, Rogers E, Dofitas B, Jung Y, Maweke T, Beiras CG, Maman I, Basing LA, Ngazoa SK, Houezo JG, Togbey K, Telan EF, Sarmento N, Marion E, Addo KK, Mitjà O, Asiedu K, Harding-Esch E, Marks M. Evaluating the yaws diagnostic gap: A survey to determine the capacity of and barriers to improving diagnostics in all yaws-endemic countries. FRONTIERS IN TROPICAL DISEASES 2022. [DOI: 10.3389/fitd.2022.969219] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
BackgroundYaws, caused by Treponema pallidum subsp. pertenue, is a skin neglected tropical disease. It is targeted for eradication by 2030, primarily using mass drug administration (MDA) with azithromycin. Traditionally, diagnosis of yaws has relied on clinical examination and serological testing. However, these approaches have poor diagnostic performance. To achieve eradication, more accurate diagnostics are required to determine whether MDA should be initiated or continued as well as for post-elimination surveillance. Molecular tools will be crucial for detecting antimicrobial resistant cases, which have the potential to derail eradication efforts. In order to determine the feasibility of introducing novel, more accurate, diagnostics for yaws surveillance purposes, it is necessary to understand current in-country diagnostic capacity. This study therefore aimed to understand the current capacity of, and challenges to, improving diagnostics for yaws in all yaws-endemic countries worldwide.Methodology/principal findingsAn online survey was sent to all 15 yaws-endemic countries in July 2021. The survey asked about past prevalence estimates, the availability of different diagnostic tools, and perceived barriers to enhancing capacity. Fourteen countries responded to the survey, four of which did not have a current National Policy for yaws eradication in place. Over 95% of reported that yaws cases from the past five years had not been confirmed with serological or molecular tools, largely due to the limited supply of rapid serological tests. Only four countries reported having operational laboratories for molecular yaws diagnosis, with only one of these having a validated assay to detect azithromycin resistance.Conclusions and significanceThis study highlights the diagnostic capacity constraints across all respondent countries. Countries are in need of access to a sustainable supply of serological tests, and development of molecular testing facilities. Sufficient sustainable funding should be made available to ensure that appropriate diagnostic tools are available and utilised.
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Becherer L, Knauf S, Marks M, Lueert S, Frischmann S, Borst N, von Stetten F, Bieb S, Adu-Sarkodie Y, Asiedu K, Mitjà O, Bakheit M. Multiplex Mediator Displacement Loop-Mediated Isothermal Amplification for Detection of Treponema pallidum and Haemophilus ducreyi. Emerg Infect Dis 2021; 26:282-288. [PMID: 31961303 PMCID: PMC6986840 DOI: 10.3201/eid2602.190505] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Yaws, a neglected tropical disease caused by the bacterium Treponema pallidum subspecies pertenue, manifests as ulcerative skin lesions. Nucleic acid amplification tests, like loop-mediated isothermal amplification (LAMP), are versatile tools to distinguish yaws from infections that cause similar skin lesions, primarily Haemophilus ducreyi. We developed a novel molecular test to simultaneously detect T. pallidum and H. ducreyi based on mediator displacement LAMP. We validated the T. pallidum and H. ducreyi LAMP (TPHD-LAMP) by testing 293 clinical samples from patients with yaws-like lesions. Compared with quantitative PCR, the TPHD-LAMP demonstrated high sensitivity and specificity for T. pallidum (84.7% sensitivity, 95.7% specificity) and H. ducreyi (91.6% sensitivity, 84.8% specificity). This novel assay provided rapid molecular confirmation of T. pallidum and H. ducreyi DNA and might be suitable for use at the point of care. TPHD-LAMP could support yaws eradication by improving access to molecular diagnostic tests at the district hospital level.
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Munson M, Creswell B, Kondobala K, Ganiwu B, Lomotey RD, Oppong P, Agyeman FO, Kotye N, Diwura M, Ako EP, Simpson SV, Addo KK, Pickering H, Handley BL, Houghton J, Kwakye C, Marks M. Optimising the use of molecular tools for the diagnosis of yaws. Trans R Soc Trop Med Hyg 2020; 113:776-780. [PMID: 31608961 DOI: 10.1093/trstmh/trz083] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2019] [Revised: 07/11/2019] [Accepted: 07/18/2019] [Indexed: 11/12/2022] Open
Abstract
BACKGROUND Yaws is a neglected tropical disease and results in lesions of skin, soft tissues and bones. PCR plays an important part in surveillance. METHODS Children suspected to have yaws were enrolled. From the largest lesion, paired swabs were collected, one in transport medium and one as a dry swab. In children with multiple lesions we collected additional swabs from up to four subsequent lesions. Swabs in transport medium were maintained in a cold chain while dry swabs were stored at ambient temperature. Swabs were tested by PCR for Treponema pallidum and Haemophilus ducreyi. RESULTS Of 55 individuals, 10 (18%) had at least one positive PCR for T. pallidum and 12 (22%) had at least one positive result for H. ducreyi. Concordance was 100% between swabs in transport medium and dry swabs. One patient had PCR-confirmed yaws on the swab of a third lesion when both the first and second lesions were PCR-negative. CONCLUSIONS Storing swabs in transport medium and transporting in a cold chain did not improve yield, however, detection of T. pallidum is increased by swabbing additional lesions. As the target for yaws is eradication, approaches to sample collection need revisiting to ensure cases are not missed.
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Affiliation(s)
- Morgan Munson
- Clinical Research Department, Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, Keppel Street, London, UK
| | - Benjamin Creswell
- Clinical Research Department, Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, Keppel Street, London, UK
| | | | | | | | | | | | | | | | | | - Shirley Victoria Simpson
- Department of Bacteriology, Noguchi Memorial Institute for Medical Research, University of Ghana, Legon, Ghana
| | - Kennedy Kwasi Addo
- Department of Bacteriology, Noguchi Memorial Institute for Medical Research, University of Ghana, Legon, Ghana
| | - Harry Pickering
- Clinical Research Department, Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, Keppel Street, London, UK
| | - Becca L Handley
- Clinical Research Department, Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, Keppel Street, London, UK
| | - Joanna Houghton
- Clinical Research Department, Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, Keppel Street, London, UK
| | | | - Michael Marks
- Clinical Research Department, Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, Keppel Street, London, UK.,Hospital for Tropical Diseases, Mortimer Market Centre, London, UK
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