title: In vivo assessment of closantel ovicidal activity in Fasciola hepatica eggs.
abstract: Anthelmintic resistance in livestock parasites is currently a worldwide problem. Fasciola hepatica is a cosmopolitan parasite which causes considerable loss in sheep and cattle production systems all over the world. Chemotherapy is currently the main tool available for its control. The intensive use of triclabendazole, the drug of choice for more than 20 years, has resulted in the development of resistant strains. The therapeutic options are adulticides such as closantel (salicylanilide anthelmintic that binds extensively to plasma albumin) to treat chronic fascioliasis in sheep, and cattle. In the present work, an Egg Hatch Assay (EHA) and morphometric studies were used to evaluate in vivo the ovicidal activity and morphology F. hepatica eggs, recovered from closantel treated sheep collected at different time intervals post treatment. Statistically significant differences (p < 0.0001) were observed in egg morphometry between the control and the treated groups in all the parameters studied. Eggs recovered from treated animals tend to be narrower and longer. Significant differences were found in the embryonation and hatching of eggs between 36 h post treatment (32, 5%) vs. approximately 85% in control, 12 h and 24 h post treatment. Our results confirm that closantel affects in vivo the normal development of the eggs. As one of the first effects, this drug affects the performance of the trematode's reproductive physiology. Even though closantel treated animals may still eliminate eggs in the first days post treatment, these are not viable.
authors.affiliation: Laboratorio de Biología Celular y Molecular, Centro de Investigación Veterinaria de Tandil (CIVETAN), CONICET, Facultad de Ciencias Veterinarias, UNCPBA, Tandil, Argentina. Electronic address: mvsolana@vet.unicen.edu.ar.
authors.forename: María Victoria
authors.initials: MV
authors.lastname: Solana
authors.affiliation: Centro de Investigación en Parasitología Regional (CIPAR), Universidad J.A. Maza, Guaymallén, Argentina.
authors.forename: Roberto
authors.initials: R
authors.lastname: Mera y Sierra
authors.affiliation: Laboratorio de Biología Celular y Molecular, Centro de Investigación Veterinaria de Tandil (CIVETAN), CONICET, Facultad de Ciencias Veterinarias, UNCPBA, Tandil, Argentina.
authors.forename: Silvana
authors.initials: S
authors.lastname: Scarcella
authors.affiliation: Centro de Investigación en Parasitología Regional (CIPAR), Universidad J.A. Maza, Guaymallén, Argentina.
authors.forename: Gisela
authors.initials: G
authors.lastname: Neira
authors.affiliation: Laboratorio de Biología Celular y Molecular, Centro de Investigación Veterinaria de Tandil (CIVETAN), CONICET, Facultad de Ciencias Veterinarias, UNCPBA, Tandil, Argentina.
authors.forename: Hugo Daniel
authors.initials: HD
authors.lastname: Solana
mesh_terms: D000284:Administration, Oral; D000818:Animals; D000871:Anthelmintics / Q000008:administration & dosage / Q000494:pharmacology*; D001646:Bile / Q000469:parasitology; D005210:Fasciola hepatica / Q000187:drug effects* / Q000254:growth & development / Q000502:physiology; D005211:Fascioliasis / Q000188:drug therapy* / Q000469:parasitology; D005704:Gallbladder / Q000469:parasitology; D007279:Injections, Subcutaneous; D010063:Ovum / Q000166:cytology / Q000187:drug effects; D012458:Salicylanilides / Q000008:administration & dosage / Q000494:pharmacology*; D012756:Sheep
chemical_list: D000871:Anthelmintics; D012458:Salicylanilides; C023342:closantel
keywords: Closantel; Egg hatch assay; Fasciola hepatica; Ovicidal activity