title: [Pathophysiology and immune response in sheep experimentally infected with Echinococcus granulosus].
abstract: The immune response to Echinococcus granulosus in sheep has not been extensively investigated. The objective of this study was to increase the information on the physiopathology of E. granulosus and the immune response elicited in sheep. Animals were experimentally inoculated with three different doses of E. granulosus eggs and the immune response was evaluated over 500 days using enzyme immunoassay with three antigenic preparations: total hydatid fluid, purified fraction of hydatid fluid and purified lipoprotein fraction. Sheep were slaughtered at different intervals to observe the macroscopic and microscopic development of the parasite. Immune response was detected at 10 days and was maintained throughout the observation period, being initially proportional to the load of inoculated eggs and then decreasing over time. Fertile cysts were identified 10 months after inoculation and live onchosphere 500 days after inoculation. Antibody response to E. granulosus in sheep preceded hydatid fluid formation and was generated by the mobility of the onchosphere. Early histological identification of fertile cysts indicates that feeding dogs with viscera of young sheep can produce cycles of infection. Furthermore, the presence of live onchosphere in the liver here found contributes to a better knowledge of the pathogenesis of this disease it could be hypothetically considered as a cause for the repeated surgeries necessary in man after the extirpation of a hydatid cyst.
authors.affiliation: Facultad de Veterinaria de la Universidad Nacional de La Pampa, Argentina. elarrieu@salud.rionegro.gov.ar
authors.forename: Edmundo
authors.initials: E
authors.lastname: Larrieu
authors.forename: Angela R
authors.initials: AR
authors.lastname: Alvarez
authors.forename: Antonio
authors.initials: A
authors.lastname: Gatti
authors.forename: Sergio
authors.initials: S
authors.lastname: Mancini
authors.forename: Ricardo
authors.initials: R
authors.lastname: Bigatti
authors.forename: Daniel
authors.initials: D
authors.lastname: Araya
authors.forename: Verónica
authors.initials: V
authors.lastname: Vespoli
authors.forename: Juan
authors.initials: J
authors.lastname: García Vinet
authors.forename: Mariela
authors.initials: M
authors.lastname: García Cacheau
authors.forename: Emiliano
authors.initials: E
authors.lastname: Alvarez
authors.forename: Laura
authors.initials: L
authors.lastname: Cavagion
mesh_terms: D000818:Animals; D000909:Antibodies, Helminth / Q000097:blood / Q000276:immunology*; D004195:Disease Models, Animal; D004285:Dogs; D004443:Echinococcosis / Q000276:immunology / Q000503:physiopathology / Q000662:veterinary*; D048209:Echinococcus granulosus / Q000254:growth & development* / Q000276:immunology; D007124:Immunoenzyme Techniques / Q000662:veterinary; D012756:Sheep; D012757:Sheep Diseases / Q000276:immunology* / Q000503:physiopathology; D013997:Time Factors
chemical_list: D000909:Antibodies, Helminth