LAMP4yaws:Treponema pallidum,Haemophilus ducreyiloop mediated isothermal amplification − protocol for a cross-sectional, observational, diagnostic accuracy study

Abstract

IntroductionYaws, caused by the bacterium Treponema pallidum subsp. pertenue, is a neglected tropical disease targeted for eradication by 2030. Improved diagnostics will be essential to meet this goal. Diagnosis of yaws has relied heavily on clinical and serological tools. However, the presence of coendemic cutaneous skin ulcer diseases, such as lesions caused by Haemophilus ducreyi (HD), means these techniques do not provide a reliable diagnosis. Thus, new diagnostic tools are needed. Molecular tools such as PCR are ideal, but often expensive as they require trained technicians and laboratory facilities, which are often not available to national yaws programmes.Methods and analysisThe LAMP4yaws project is a cross-sectional, observational, diagnostic accuracy study of a combined Treponema pallidum (TP) and HD loop mediated isothermal amplification (TPHD-LAMP) test performed under real world conditions in three endemic countries in West Africa. Individuals with serologically confirmed yaws will be recruited in Cameroon, Côte d’Ivoire and Ghana. Each participant will provide paired swabs, one of which will be sent to the respective national reference laboratory for yaws quantitative PCR and the other will be tested for both TP and HD using the TPHD-LAMP test at local district laboratories. Sensitivity and specificity of the TPHD-LAMP test will be calculated against the reference standard qPCR. We will also assess the acceptability, feasibility and cost-effectiveness of the test. We anticipate that results from this study will support the adoption of the TPHD-LAMP test for use in global yaws eradication efforts.Ethics and disseminationWe have received ethical approval from all relevant institutional and national ethical committees. All participants, or their parents or guardians, must provide written informed consent prior to study enrolment. Study results will be published in an open access journal and disseminated with partners and the World Health Organization.Trial registration numberNCT04753788.

An integrated active case search for skin-NTDs in yaws endemic health districts in Cameroon, Côte d’Ivoire and Ghana

“…Those reactive underwent a Chembio Dual Path Platform (DPP) test (Chembio Diagnostics, New York, USA) for simultaneous detection of both treponemal and non-treponemal antibodies, interpreted as serologically confirmed yaws case. Samples were then taken as part of the main study from participants as described elsewhere (39). Other skin diseases were recorded and referred to the health district for management following the national guidelines.…”

“…This approach was implemented by assessing burden of yaws in health districts from notifications of NTD national programs, training of health workers and village volunteers, conducting active case detection of skin conditions, clinical diagnosis and rapid tests for yaws, treating yaws cases and referring other skin conditions to healthcare centres (2). In each community visited, initial screening involved an examination to determine if participants had skin lesions as described in the study protocol (39).…”

“…The study was conducted in rural areas in 12 health districts in Cameroon, six in Côte d'Ivoire, and seven in Ghana (39). The characteristics of the study sites are summarised in Table 1.…”

“…Samples were then taken as part of the main study from participants as described elsewhere (39). Other skin diseases were recorded and referred to the health district for management following the national guidelines.…”

“…The LAMP4YAWS project in Cameroon, Côte d’Ivoire, and Ghana aimed to implement and evaluate a loop-mediated isothermal amplification test for yaws. As part of the project, field activities included active case searching of yaws using an integrated approach (39). Here we report data on skin conditions from active case searches in yaws-endemic health districts from all three countries.…”