Effect of single-dose ivermectin on Onchocerca volvulus: a systematic review and meta-analysis.
The broad-spectrum antiparasitic drug ivermectin was licensed for use against onchocerciasis in 1987, yet the mechanisms by which it exerts a fast decrease and long-lasting suppression of Onchocerca volvulus microfilaridermia, and inhibition of microfilarial release by female worms remain largely unknown. A better understanding of the effects of ivermectin on O volvulus microfilariae and macrofilariae is crucial to improve our ability to predict the long-term effect of treatment. We did a systematic review of individual and population-based ivermectin trials to investigate the temporal dynamics of the drug's microfilaricidal and embryostatic efficacy after administration of a single, standard dose (150 microg/kg). Meta-analyses on data from 26 microfilarial and 15 macrofilarial studies were linked by a mathematical model describing the dynamics of potentially fertile female parasites to skin microfilariae. The model predicts that after treatment, microfilaridermia would be reduced by half after 24 h, by 85% after 72 h, by 94% after 1 week, and by 98-99% after 1-2 months, the latter also corresponding to the time when the fraction of females harbouring live microfilariae is at its lowest (reduced by around 70% from its original value). Our results provide a baseline microfilarial skin repopulation curve against which to compare studies done after long-term treatment.
Basáñez
María-Gloria
MG
Department of Infectious Disease Epidemiology, Imperial College London, London, UK. m.basanez@imperial.ac.uk
Pion
Sébastien D S
SD
Boakes
Eve
E
Filipe
João A N
JA
Churcher
Thomas S
TS
Boussinesq
Michel
M
D000293:Adolescent; D000328:Adult; D000818:Animals; D002648:Child; D002675:Child, Preschool; D002986:Clinical Trials as Topic; D004305:Dose-Response Relationship, Drug; D005260:Female; D005369:Filaricides / Q000627:therapeutic use*; D006801:Humans; D007559:Ivermectin / Q000627:therapeutic use*; D008297:Male; D008433:Mathematics; D008875:Middle Aged; D017181:Onchocerca volvulus / Q000187:drug effects*; D009855:Onchocerciasis / Q000188:drug therapy* / Q000469:parasitology; D016032:Randomized Controlled Trials as Topic; D012867:Skin / Q000469:parasitology*; D016896:Treatment Outcome
D005369:Filaricides; D007559:Ivermectin