Mass Drug Administration for Scabies Control in a Population with Endemic Disease.

BACKGROUND: Scabies is an underrecognized cause of illness in many developing countries. It is associated with impetigo, which can lead to serious systemic complications. We conducted a trial of mass drug administration for scabies control in Fiji. METHODS: We randomly assigned three island communities to one of three different interventions for scabies control: standard care involving the administration of permethrin to affected persons and their contacts (standard-care group), mass administration of permethrin (permethrin group), or mass administration of ivermectin (ivermectin group). The primary outcome was the change in the prevalence of scabies and of impetigo from baseline to 12 months. RESULTS: A total of 2051 participants were enrolled; 803 were in the standard-care group, 532 in the permethrin group, and 716 in the ivermectin group. From baseline to 12 months, the prevalence of scabies declined significantly in all groups, with the greatest reduction seen in the ivermectin group. The prevalence declined from 36.6% to 18.8% in the standard-care group (relative reduction in prevalence, 49%; 95% confidence interval [CI], 37 to 60), from 41.7% to 15.8% in the permethrin group (relative reduction, 62%; 95% CI, 49 to 75), and from 32.1% to 1.9% in the ivermectin group (relative reduction, 94%; 95% CI, 83 to 100). The prevalence of impetigo also declined in all groups, with the greatest reduction seen in the ivermectin group. The prevalence declined from 21.4% to 14.6% in the standard-care group (relative reduction, 32%; 95% CI, 14 to 50), from 24.6% to 11.4% in the permethrin group (relative reduction, 54%; 95% CI, 35 to 73), and from 24.6% to 8.0% in the ivermectin group (relative reduction, 67%; 95% CI, 52 to 83). Adverse events were mild and were reported more frequently in the ivermectin group than in the permethrin group (15.6% vs. 6.8%). CONCLUSIONS: Mass drug administration, particularly the administration of ivermectin, was efficacious for the control of scabies and impetigo. (Funded by the Australian National Health and Medical Research Council; Australian New Zealand Clinical Trials Registry number, ACTRN12613000474752.).

The Epidemiology of Scabies and Impetigo in Relation to Demographic and Residential Characteristics: Baseline Findings from the Skin Health Intervention Fiji Trial.

Scabies and associated impetigo are under-recognized causes of morbidity in many developing countries. To strengthen the evidence base for scabies control we undertook a trial of mass treatment for scabies. We report on the occurrence and predictors of scabies and impetigo in participants at baseline. Participants were recruited in six island communities and were examined for the presence of scabies and impetigo. In addition to descriptive analyses, logistic regression models were fit to assess the association between demographic variables and outcome of interest. The study enrolled 2051 participants. Scabies prevalence was 36.4% (95% confidence interval [CI] 34.3-38.5), highest in children 5-9 years (55.7%). Impetigo prevalence was 23.4% (95% CI 21.5-25.2) highest in children aged 10-14 (39.0%). People with scabies were 2.8× more likely to have impetigo. The population attributable risk of scabies as a cause of impetigo was 36.3% and 71.0% in children aged less than five years. Households with four or more people sharing the same room were more likely to have scabies and impetigo (odds ratios [OR] 1.6, 95% CI 1.2-2.2 and OR 2.3, 95% CI 1.6-3.2 respectively) compared to households with rooms occupied by a single individual. This study confirms the high burden of scabies and impetigo in Fiji and the association between these two conditions, particularly in young children. Overcrowding, young age, and clinical distribution of lesion are important risk factors for scabies and impetigo. Further studies are needed to investigate whether the decline of endemic scabies would translate into a definite reduction of the burden of associated complications.