title: A study (1977-1992) of population dynamics of endoparasites featuring benzimidazole-resistant small strongyles (population S) in Shetland ponies.
abstract: Critical tests (91) were done between 1977 and 1992 in Shetland ponies to evaluate drug susceptibility and population dynamics (present paper) of endoparasites. The test ponies, most less than 1 year old, were from a herd where older animals were treated every 8 weeks initially with cambendazole (CBZ) (1974-1978) and then with oxibendazole (OBZ) (1978-1992). Previous field test data (1974-1992) on older ponies in the breeding herd indicated the presence of benzimidazole (BZ) resistant small strongyles. Data on population dynamics from the present critical tests indicated that 28 species of small strongyles persisted over the study period in spite of initial susceptibility and later refractiveness of six species to both CBZ and OBZ. Changes in intensities and other aspects were observed for the six BZ-resistant species (Cyathostomum catinatium, Cyathostomum coronatum, Cylicocyclus nassatus, Cylicostephanus calicatus, Cylicostephanus goldi, and Cylicostephanus longibursatus). Variabilities, some striking, were found in prevalence and intensity in bots, stomach worms, ascarids, eyeworms, large strongyles, pinworms and tapeworms.
authors.affiliation: Department of Veterinary Science, Gluck Equine Research Center, University of Kentucky, Lexington 40546-0099, USA.
authors.forename: E T
authors.initials: ET
authors.lastname: Lyons
authors.forename: S C
authors.initials: SC
authors.lastname: Tolliver
authors.forename: J H
authors.initials: JH
authors.lastname: Drudge
authors.forename: S
authors.initials: S
authors.lastname: Stamper
authors.forename: T W
authors.initials: TW
authors.lastname: Swerczek
authors.forename: D E
authors.initials: DE
authors.lastname: Granstrom
mesh_terms: D000818:Animals; D000871:Anthelmintics / Q000494:pharmacology* / Q000627:therapeutic use; D001562:Benzimidazoles / Q000494:pharmacology* / Q000627:therapeutic use; D004351:Drug Resistance; D006736:Horses; D007411:Intestinal Diseases, Parasitic / Q000188:drug therapy / Q000469:parasitology / Q000662:veterinary*; D011157:Population Dynamics; D013319:Strongyle Infections, Equine / Q000188:drug therapy / Q000469:parasitology*; D013320:Strongyloidea / Q000187:drug effects* / Q000254:growth & development
chemical_list: D000871:Anthelmintics; D001562:Benzimidazoles