Minimal training of fieldworkers in resource-poor settings for rapid assessment of scabies prevalence: a diagnostic accuracy study in Mopeia, Mozambique

Background Scabies is endemic in many tropical, resource-poor areas, causing significant morbidity. Our understanding of the true burden of scabies in Africa is very limited, and we lack tools to accurately assess its prevalence, given our reliance on highly qualified doctors and microscopy for diagnosis. The primary objective of this study was to assess the accuracy of minimally trained fieldworker diagnosis of scabies, compared to diagnosis by experienced medical doctors. Methodology We trained 62 fieldworkers with a minimum of secondary school education in the diagnosis of scabies (categorized as either clinical or suspected), and in terms of severity, based on lesion count. Immediately after the training, we assessed their knowledge based on written assessments. We also assessed the diagnostic accuracy of a sub-sample of the fieldworkers in the field compared to the reference standard (experienced medical doctors). 193 individuals were assessed for scabies. The sensitivity, specificity, PPV and NPV were calculated, as well as agreement (kappa coefficients) between medical doctors and between fieldworkers. Results The overall median results in written assessments were around 80%. Of the 193 people assessed for scabies, 27% were classified as having scabies according to the reference standard. The sensitivity of fieldworker diagnosis compared to the reference standard was 95% (95%CI 93 -100), and the specificity was 99% (95%CI 99-100). The sensitivity for severe scabies was lower at 64% (95%CI 51-75), and the mean specificity was 100%. Kappa coefficients were 1.00 between medical doctors and 0.95 between fieldworkers. Conclusions Fieldworkers without medical qualifications were capable of diagnosing scabies to a similar level of accuracy as experienced medical doctors, after a short period of focal training. This may facilitate rapid assessments of scabies prevalence for public health purposes and decisions about MDA implementation in similar settings. ### Competing Interest Statement The authors have declared no competing interest. ### Funding Statement This study was funded and supported by Unitaid under the BOHEMIA grant. ISGlobal acknowledges support from the Spanish Ministry of Science and Innovation through the Centro de Excelencia Severo Ochoa 2019-2023 Program (CEX2018-000806-S), and support from the Generalitat de Catalunya through the CERCA program. CISM is supported by the Government of Mozambique and the Spanish Agency for International Development Cooperation (AECID). ### Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes The details of the IRB/oversight body that provided approval or exemption for the research described are given below: The study protocol was approved by the Internal Scientific Committee and Institutional Review board from the Centro de Investigacao em Saude de Manhica (Ref: CIBS-CISM/004/2021), Hospital Clinic of Barcelona Clinical Research Ethics Committee (Ref: HCB/2019/0938) and The Ethics Research Committee of WHO (Protocol ID: ERC.0003265). I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable. Yes All data produced are available online at: https://dataverse.csuc.cat/dataset.xhtml?persistentId=doi:10.34810/data1100