Training of Field-Workers for Rapid Assessment of Scabies Prevalence: A Diagnostic Accuracy Study in Mozambique

Scabies is endemic in many resource-poor tropical areas, causing significant morbidity. However, our understanding of the true burden of scabies in Africa is limited, partly owing to limited capacity and challenges accessing the currently recommended diagnostic tools. The primary objective of this study was to assess the diagnostic accuracy of scabies assessments made by minimally trained field-workers. We trained field-workers with a minimum of secondary school education in the diagnosis of scabies. After the training, we assessed the diagnostic accuracy of assessments made by nine field-workers compared with the reference standard. In all, 193 individuals were assessed for scabies. The sensitivity, specificity, positive predictive value, and negative predictive value were calculated, as well as agreement (κ coefficients) between medical doctors and between field-workers. Of the 193 participants, 26% had scabies according to the reference standard. The sensitivity of field-worker diagnosis compared with the reference standard was 94% (95% CI: 90-99%), and the specificity was 96% (95% CI: 90-97%). The determination of severity by field-workers was less accurate; the sensitivity for severe scabies was 61% (95% CI: 48-74%), and the mean specificity was 97% (95% CI: 93-100%). This study demonstrated that field-workers 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 mass drug administration implementation in similar settings.