Possible resistance of small strongyles from female ponies in The Netherlands against albendazole.
To determine resistance of small strongyles to albendazole, 3 female ponies (group 1) were grazed on a pasture from May to November 1985 and were treated with 7.5 mg of albendazole/kg of body weight, PO, 2 days before turnout in May and again in June and in July. Three other female ponies (group 2) grazed on a similar pasture from May to July, were treated with 7.5 mg of albendazole/kg, and were removed to another pasture until November. In December, ponies from both groups were treated with 7.5 mg of albendazole/kg, and 8 days later, they were euthanatized and necropsied for a critical test. Worm egg counts in the ponies' feces revealed that the May treatment of group 1 and the July treatment of group 2 were more effective than were later treatments. Numbers of small strongyles were higher in group 1 than in group 2. Efficacy of treatment against all developmental stages of small strongyles was higher in group 2 than in group 1. Efficacy was low in both groups against parasitic 3rd- and 4th-stage larvae. Fifteen species of small strongyles were identified at necropsy. Efficacy was limited against adult Cyathostomum coronatum, Cya labratum, Cylicostephanus calicatus, and Cyl poculatus in both groups; Cylicocyclus nassatus, Cyl minutus, and Cyl longibursatus in group 1; and Cya labiatum in group 2. Efficacy was 100% against Cya catinatum, Cyl goldi, and 5 other species that were found in low numbers.
Institute for Veterinary Parasitology and Parasitic Diseases, State University of Utrecht, The Netherlands.
M
M
Eysker
J H
JH
Boersema
F N
FN
Kooyman
P
P
Berghen
D015766:Albendazole; D000818:Animals; D001562:Benzimidazoles / Q000494:pharmacology / Q000627:therapeutic use*; D004351:Drug Resistance; D005243:Feces / Q000469:parasitology; D005260:Female; D006736:Horses; D009426:Netherlands; D010270:Parasite Egg Count / Q000662:veterinary; D013319:Strongyle Infections, Equine / Q000188:drug therapy* / Q000469:parasitology; D013320:Strongyloidea / Q000187:drug effects*; D013323:Strongylus / Q000187:drug effects*
D001562:Benzimidazoles; D015766:Albendazole