title: Efficacy of ivermectin pour-on against Ostertagia ostertagi infection and residues in the American bison, Bison bison.
abstract: Sixteen American bison, Bison bison, were artificially infected with 10(5) infective stage larvae of Ostertagia ostertagi on 21 April 1993. At 42 days post-infection eight bison were treated with 0.5% ivermectin pour-on (500 micrograms/kg bodyweight) and eight treated with the carrier only. Bison were necropsied 17 and 18 days post-treatment (21 and 22 June 1993, respectively). Mean (+/- SE) of 5,413 (+/- 1,716) adults and 565 (+/- 305) immature O. ostertagi were recovered at necropsy from bison treated with the carrier. No O. ostertagi were detected in bison treated with ivermectin pour-on. Based on the levels of the ivermectin marker metabolite in liver and adipose tissue 18 days post-treatment, the established bovine withdrawal time of 48 days appears adequate to insure that violative residues do not occur.
authors.affiliation: Centers for Disease Control & Prevention, Parasitic Diseases Division, Atlanta, Georgia 30341, USA.
authors.forename: S E
authors.initials: SE
authors.lastname: Marley
authors.forename: S E
authors.initials: SE
authors.lastname: Knapp
authors.forename: M C
authors.initials: MC
authors.lastname: Rognlie
authors.forename: J R
authors.initials: JR
authors.lastname: Thompson
authors.forename: T M
authors.initials: TM
authors.lastname: Stoppa
authors.forename: S M
authors.initials: SM
authors.lastname: Button
authors.forename: S
authors.initials: S
authors.lastname: Wetzlich
authors.forename: T
authors.initials: T
authors.lastname: Arndt
authors.forename: A
authors.initials: A
authors.lastname: Craigmill
mesh_terms: D000273:Adipose Tissue / Q000737:chemistry; D000287:Administration, Topical; D000818:Animals; D000969:Antinematodal Agents / Q000008:administration & dosage / Q000032:analysis / Q000627:therapeutic use*; D016164:Bison / Q000469:parasitology*; D004350:Drug Residues / Q000032:analysis; D005243:Feces / Q000469:parasitology; D005260:Female; D007559:Ivermectin / Q000008:administration & dosage / Q000032:analysis / Q000627:therapeutic use*; D008099:Liver / Q000737:chemistry; D010029:Ostertagiasis / Q000188:drug therapy / Q000662:veterinary*; D010270:Parasite Egg Count / Q000662:veterinary; D010865:Pilot Projects; D011897:Random Allocation
chemical_list: D000969:Antinematodal Agents; D007559:Ivermectin