Authors

M A Irvine¹; T D Hollingsworth¹;  ¹ University of Warwick

Discussion

Lymphatic Filariasis (LF) is a neglected tropical disease caused by filarial nematodes and prevalent in large parts of the tropics and sub-tropics. Currently 1 billion people are at risk of the disease and 40 million are currently infected. Current global efforts towards elimination are based on the use of mass drug administration to reduce the level of microfilariae (mf) in the population and thus break transmission. Currently there are three drugs used in combination: diethylcarbamazine, albendazole and ivermectin. A recently discovered drug regimen, known as IDA, involves the combination of all three and has been shown to produce 100% clearance of mf in all individuals surveyed. There remains open questions as to the efficacy of this regimen in reduced the number of rounds of MDA and ultimately breaking transmission. We modelled the intervention using three separate models of LF infection: EPIFIL, LYMFASIM and TRANSFIL. A variety of settings were compared including moderately endemic locations in Asia where Culex are the dominant mosquito vector and an African setting where Anopheles are dominant. We found that in lower prevalence settings, the use of the new regimen was only able to reduce the number of rounds by 2-4. However, for poor coverage and in higher prevalence settings, the IDA regimen was able to significantly reduce the number of rounds required, including reducing the number of rounds in the worst case scenarios compared to the standard regimen. This provides a first analysis on the likely impact of this novel regimen in the on-going global elimination programme.