title: Determination of the effective dose of an experimental fasciolicide in naturally and experimentally infected cattle.
abstract: The aim of the present study was to determine the effective dose of an experimental fasciolicide called compound alpha or 5-chloro-2-methylthio-6-(1-napthyloxy)1H-benzimidazole in experimentally and naturally infected cattle. In the first experiment, 24 fluke-free heifers were each infected with 800 metacercariae of Fasciola hepatica and re-infected on day 45 with other 600 cysts per animal. On day 75, when the animals had 4- and 10-week-old flukes respectively, they were divided into four groups (G) of six animals each according to fluke egg counts. Groups 1-3 received compound alpha at 10, 12 and 14 mg/kg/p.o., respectively. G4 remained as an untreated control. Twenty days after treatment, the animals were sacrificed for the recovery of flukes. Efficacy was assessed as a percentage of egg or fluke reduction relative to the untreated control. In the second experiment (naturally infected cattle), 24-year-old steers positive to F. hepatica eggs were blocked into four groups of five animals each. Groups 1-3 received compound alpha at 10, 12 and 14 mg/kg/p.o., respectively. Group 4 served as a non-treated control. All procedures to determine efficacy were carried out as mentioned in the first experiment. The results in the first study showed a percentage on egg reduction of 97.3, 100 and 100 and overall fluke reduction of 94.3, 100 and 100 for Groups 1-3, respectively. In the second study, the percentage of egg reduction was of 87.5, 99.1 and 100 and overall efficacy regarding fluke reduction was of 84.2, 99.6, and 100 for Groups 1-3, respectively. It is concluded that the effective dose selected for compound alpha was of 12 mg/kg/p.o. in cattle having an induced or natural F. hepatica infection.
authors.affiliation: Departamento de Parasitología, Fac. de Med. Vet. y Zoot., UNAM. Cd. Universitaria, 04510 Mexico, DF, Mexico. ibarraf@servidor.unam.mx
authors.forename: Froylán
authors.initials: F
authors.lastname: Ibarra
authors.forename: Yolanda
authors.initials: Y
authors.lastname: Vera
authors.forename: Héctor
authors.initials: H
authors.lastname: Quiroz
authors.forename: Jorge
authors.initials: J
authors.lastname: Cantó
authors.forename: Rafael
authors.initials: R
authors.lastname: Castillo
authors.forename: Alicia
authors.initials: A
authors.lastname: Hernández
authors.forename: Pedro
authors.initials: P
authors.lastname: Ochoa
mesh_terms: D000284:Administration, Oral; D000818:Animals; D000871:Anthelmintics / Q000008:administration & dosage*; D000909:Antibodies, Helminth / Q000032:analysis; D002417:Cattle; D002418:Cattle Diseases / Q000188:drug therapy* / Q000469:parasitology*; D004305:Dose-Response Relationship, Drug; D004797:Enzyme-Linked Immunosorbent Assay / Q000662:veterinary; D005210:Fasciola hepatica / Q000254:growth & development* / Q000378:metabolism; D005211:Fascioliasis / Q000188:drug therapy* / Q000469:parasitology / Q000662:veterinary*; D005243:Feces / Q000469:parasitology; D005260:Female; D007093:Imidazoles / Q000008:administration & dosage*; D008099:Liver / Q000469:parasitology; D008297:Male; D009281:Naphthalenes / Q000008:administration & dosage*; D010270:Parasite Egg Count / Q000662:veterinary; D018709:Statistics, Nonparametric
chemical_list: C468032:5-chloro-2-methylthio-6-(1-naphthyloxy)-1H-benzimidazole; D000871:Anthelmintics; D000909:Antibodies, Helminth; D007093:Imidazoles; D009281:Naphthalenes