Impact of an Ivermectin Mass Drug Administration on Scabies Prevalence in a Remote Australian Aboriginal Community

Background: scabies is endemic in many aboriginal and torres strait islander communities,with 69% of infants infected in the first year of life. we report the outcomes against scabies of two oral ivermectin mass drug administrations (mdas) delivered 12 months apart in a remote australian aboriginal community. methods: utilizing a before and after study design,we measured scabies prevalence through population census with sequential mdas at baseline and month 12. surveys at months 6 and 18 determined disease acquisition and treatment failures. scabies infestations were diagnosed clinically with additional laboratory investigations for crusted scabies. non-pregnant participants weighing ≥15 kg were administered a single 200 μg/kg ivermectin dose,repeated after 2–3 weeks if scabies was diagnosed,others followed a standard alternative algorithm. principal findings: we saw >1000 participants at each population census. scabies prevalence fell from 4% at baseline to 1% at month 6. prevalence rose to 9% at month 12 amongst the baseline cohort in association with an identified exposure to a presumptive crusted scabies case with a higher prevalence of 14% amongst new entries to the cohort. at month 18,scabies prevalence fell to 2%. scabies acquisitions six months after each mda were 1% and 2% whilst treatment failures were 6% and 5% respectively. conclusion: scabies prevalence reduced in the six months after each mda with a low risk of acquisition (1–2%). however,in a setting where living conditions are conducive to high scabies transmissibility,exposure to presumptive crusted scabies and population mobility,a sustained reduction in prevalence was not achieved. clinical trial registration: australian new zealand clinical trial register (actrn—12609000654257). © 2015 kearns et al.