[Systemic action of ivermectin on Culex quinquefasciatus and Simulium squamosum]

The mortality of Culex quinquefasciatus mosquitoes having fed ten days earlier on a chicken treated by 2,000 micrograms/kg of ivermectin (about ten times the therapeutic dosage) is about 25% higher than the mortality recorded on mosquitoes having fed on a non treated chicken. This systemic effect occurs only if the blood meal takes place between 7 and 31 hours after the administration of the drug. However, no systemic effect is recorded either with the C. quinquefasciatus mosquito or with the Simulium squamosum black fly when they are fed on human beings treated at the therapeutic dose.