title: The use of ivermectin to kill ixodes scapularis ticks feeding on humans.
abstract: OBJECTIVE
  The purpose of this study was to determine whether 400 µg/kg oral ivermectin is able to kill Ixodes scapularis nymphs and adult female ticks feeding on humans.
  
  
  METHODS
  Ten study subjects each wore 2 ostomy bags, the one containing 24 I scapularis nymphs, and the other containing 24 I scapularis adult females. Twenty-four hours after the ostomy bags were attached, study subjects received either 400 µg/kg ivermectin or placebo. Thirty hours after the ivermectin or placebo was consumed, the ticks were removed, and mortality determined in a double-blinded manner.
  
  
  RESULTS
  Eleven percent of the I scapularis nymphs attached in the ivermectin group compared with 17% in the placebo. Mortality for the I scapularis nymphs that attached at the time of removal was 55% in the ivermectin group and 47% in the placebo group. Mortality for the I scapularis nymphs 5 days after removal was 92% in the ivermectin group and 88% for the placebo. Three percent of the I scapularis adults attached in the ivermectin group compared with 9% in the placebo group. Mortality for I scapularis adults was 0% on day 3 and 33% on day 8 for both the ivermectin and placebo groups. There were statistically insignificant differences in the mortality rates between I scapularis nymphs and adults exposed to ivermectin or placebo.
  
  
  CONCLUSIONS
  There were a high number of ticks that died in both groups but the data do not support our hypothesis that ivermectin can kill I scapularis. The study was not designed to determine whether it could prevent the transmission of tick-borne illness.
authors.affiliation: Department of Emergency Medicine, Eastern Virginia Medical School, Norfolk, VA (Drs Sheele, Tse, and Chidester, and Ms Ford). Electronic address: jsheele@gmail.com.
authors.forename: Johnathan M
authors.initials: JM
authors.lastname: Sheele
authors.affiliation: Department of Emergency Medicine, Eastern Virginia Medical School, Norfolk, VA (Drs Sheele, Tse, and Chidester, and Ms Ford).
authors.forename: Lucie R
authors.initials: LR
authors.lastname: Ford
authors.affiliation: Department of Emergency Medicine, Eastern Virginia Medical School, Norfolk, VA (Drs Sheele, Tse, and Chidester, and Ms Ford).
authors.forename: Adele
authors.initials: A
authors.lastname: Tse
authors.affiliation: Department of Emergency Medicine, Eastern Virginia Medical School, Norfolk, VA (Drs Sheele, Tse, and Chidester, and Ms Ford).
authors.forename: Benjamin
authors.initials: B
authors.lastname: Chidester
authors.affiliation: Emergency Medicine Physician, Presbyterian Healthcare Services, Albuquerque, NM (Dr Byers).
authors.forename: Peter A
authors.initials: PA
authors.lastname: Byers
authors.affiliation: Department of Biological Sciences, Old Dominion University, Norfolk, VA (Dr Sonenshine).
authors.forename: Daniel E
authors.initials: DE
authors.lastname: Sonenshine
mesh_terms: D000284:Administration, Oral; D000328:Adult; D000818:Animals; D005260:Female; D006801:Humans; D007559:Ivermectin / Q000008:administration & dosage / Q000494:pharmacology*; D018884:Ixodes / Q000187:drug effects*; D008297:Male; D009026:Mortality; D009758:Nymph / Q000187:drug effects; D055815:Young Adult
chemical_list: D007559:Ivermectin
keywords: Ixodes scapularis; Lyme disease; ivermectin; prevention; tick; tick-borne disease