Ivermectin mass drug administration program to treat endemic scabies and strongyloidiasis in a remote aboriginal community in northern Australia

Abstract

Background: In many Aboriginal communities in northern Australia 70% of children are clinically diagnosed with scabies before they reach 1 year of age and a high percentage of adults and children in the same communities are sero-positive for Strongyloides stercoralis. As both parasitic infections can be treated with ivermectin and mass drug administration (MDA) programs are recommended when helminth infections are £20% and scabies >5%, we hypothesised that an ivermectin MDA would reduce the endemic prevalence of these two infections.

Methods: A population census for prevalence and MDA was conducted at months 0 and 12 to be followed by cross sectional surveys for disease acquisition and treatment failures at months 6 and 18. Scabies was diagnosed clinically and strongyloidiasis by faecal microscopy and/or agar plate culture or by serology. Participants were administered a stat dose of 200 lg/kg ivermectin unless pregnant or their weight was <15 kg. All participants received one dose of ivermectin and those diagnosed with scabies and/or strongyloidiasis were given a 2nd dose after 2–3 weeks.

Results: There were 1011 (81%) participants enrolled from 127 (80%) houses and 7 (78%) surrounding homelands. Scabies prevalence reduced from 4% at month 0 to a point estimate of 1.8% at month 6 and strongyloidiasis from 21% to 6% over the same period. At month 6, disease acquisition of scabies was 1% and strongyloidiasis 3%, with treatment failures of 11% and 16% respectively. The 2nd population census and MDA#2 is currently underway and preliminary results will be presented at the congress.

Conclusion: These results are preliminary data from a study in progress however early indications for the success of the study are encouraging. A rigorously evaluated MDA has potential global ramifications for changing public health policy for the control of endemic scabies and strongyloidiasis.