Comparison of the efficacy of ivermectin, oxibendazole, and pyrantel pamoate against 28-day Parascaris equorum larvae in the intestine of pony foals.
Sixteen helminth-free pony foals were inoculated with a mean (+/- SD) 2,000 (+/- 545.5) infective Parascaris equorum eggs (day 0). Foals were allocated to replicates of 4, and treatments within each replicate were assigned at random. Treatment administered on postinoculation day (PID) 28 included no treatment (control), 0.2 mg of ivermectin/kg of body weight, 10 mg of oxibendazole/kg, or 6.6 mg of pyrantel base (pamoate)/kg. Paste formulations of the anthelmintics were administered orally. The foals were euthanatized 14 days after treatment (PID 42) and examined for P equorum larvae in the small intestine. The mean +/- SD (and range) numbers of fourth-stage P equorum larvae recovered from nontreated foals and those treated with ivermectin, pyrantel, or oxibendazole were 1,603.8 +/- 1,026.8 (305 to 2,480), 29.3 +/- 55.8 (0 to 113), 413.0 +/- 568.1 (0 to 1,204), or 889.5 +/- 1,123.1 (1 to 2,345), respectively. Compared with the value for control (nontreated) foals, treatment with ivermectin, pyrantel, and oxibendazole was 98.2, 74.2, and 44.5% effective, respectively, when administered 28 days after experimentally induced infection with P equorum. Adverse reactions attributable to treatment were not observed.
Austin
S M
SM
Department of Veterinary Clinical Medicine, College of Veterinary Medicine, University of Illinois at Urbana-Champaign 61801.
DiPietro
J A
JA
Foreman
J H
JH
Baker
G J
GJ
Todd
K S
KS
D000818:Animals; D000871:Anthelmintics / Q000494:pharmacology / Q000627:therapeutic use*; D001199:Ascaridoidea / Q000187:drug effects*; D001562:Benzimidazoles / Q000494:pharmacology / Q000627:therapeutic use; D005260:Female; D006734:Horse Diseases / Q000188:drug therapy*; D006736:Horses; D007411:Intestinal Diseases, Parasitic / Q000188:drug therapy / Q000662:veterinary*; D007559:Ivermectin / Q000494:pharmacology / Q000627:therapeutic use; D007814:Larva / Q000187:drug effects; D008297:Male; D009349:Nematode Infections / Q000188:drug therapy / Q000662:veterinary*; D011716:Pyrantel Pamoate / Q000494:pharmacology / Q000627:therapeutic use
D000871:Anthelmintics; D001562:Benzimidazoles; C011321:oxibendazole; D007559:Ivermectin; D011716:Pyrantel Pamoate