The 0.5% ivermectin topical cream formulation was not directly ovicidal to treated eggs of head lice, as hatchability was not decreased. Nevertheless, the percent of hatched lice from treated eggs that took a blood meal significantly decreased (80–95%) compared with lice that hatched from untreated eggs and all treated lice died within 48 h of hatching, including those that fed. Dilutions of ivermectin formulation of 0.15 and 0.2 µg/ml, which were topically applied to 0–8 d old eggs, were not lethal to lice at 24 h posteclosion. However, 9 and 16% less lice fed when hatched from these treated eggs, respectively. Total [3H] inulin ingested by untreated first instars significantly increased over a 48 h feeding interval but was significantly less in instars that hatched from eggs receiving the 0.15 (36% less) and 0.2 (55% less) µg/ml ivermectin treatments compared with placebo. The reduced feeding that occurred after the 0.15 and 0.2 µg/ml ivermectin treatments occurred in the absence of mortality and suggests a unique mode of action of ivermectin on feeding that is separate from the mode of action of ivermectin leading to mortality. Failure of hatched instars to take a blood meal after egg treatments with formulated ivermectin is likely responsible for its action as a posteclosion nymphicide.
How to translate text using browser tools
1 November 2011
Ivermectin Acts as a Posteclosion Nymphicide by Reducing Blood Feeding of Human Head Lice (Anoplura: Pediculidae) that Hatched from Treated Eggs
Joseph P. Strycharz,
Noah M. Berge,
Anna-Maria Alves,
J. Marshall Clark
ACCESS THE FULL ARTICLE
It is not available for individual sale.
This article is only available to subscribers.
It is not available for individual sale.
It is not available for individual sale.
Journal of Medical Entomology
Vol. 48 • No. 6
November 2011
Vol. 48 • No. 6
November 2011
human head louse
ivermectin formulation
Pediculus humanus capitis
posteclosion nymphicide