A preliminary report on the spill over effect of mass drug administration for Onchocerciasis on scabies control in Northern Ethiopia

Introduction: Scabies is a skin infestation caused by the mite Sarcoptes Scabiei var. hominis. WHO included the disease among the Neglected Tropical Diseases in the year 2017. Ethiopia bears a very high scabies burden and a series of scabies outbreaks have been recorded in the past few years. To respond to growing public health concern, the Ethiopian Federal Ministry of Health is looking for approaches to control the disease. In Ethiopia, Mass Drug Administration (MDA) with ivermectin has been taking place for the control of onchocerciasis since 2003 but its secondary effects on the transmission of scabies have not been evaluated. Aim: The aim of this study was to evaluate the effect of MDA for onchocerciasis on the transmission of scabies. Methods: A comparative cross-sectional study design with multi-stage sampling was used. Districts in Ethiopia, with varying time of onset of MDA were selected. Data were collected using a pretested structured interview questionnaire on the prevalence of scabies infestation, socioeconomic and socio-demographic variables, and health service utilization. The recently developed Consensus Criteria were used by the trained field data collectors (clinical nurses) and an experienced dermatologist to screen and identify clinical cases of scabies during a house-to-house survey. In one district, pre- and post- MDA data are being collected to measure the effectiveness of MDA. Results: To date, data from one district have been analyzed. This comprises household and individual level data from 402 households and 1400 individuals. The prevalence of scabies was estimated to be 15% (210 cases/1400 individuals). Half (105) of the cases have been re-evaluated by the dermatologist. Conclusion:Our preliminary findings suggest that prevalence of scabies in the district in which ivermectin MDA has been carried out since 2015 is still high. The agreement between clinical nurses and the dermatologist on scabies case identification was good. By finding out the impact of varying time of onset of ivermectin MDA on scabies, we anticipate formulating an improved control strategy for scabies, thereby reducing the burden of the disease.