title: Cryptosporidium parvum: an attempt at experimental infection in rainbow trout Oncorhynchus mykiss.
abstract: A study was carried out on rainbow trout Oncorhynchus mykiss fed with a commercial feed contaminated with bovine-isolated Cryptosporidium parvum oocysts whose viability and infectivity were previously tested by inoculation of oocysts to neonatal Swiss CD-1 mice. Histological examination of hematoxylin-eosin-stained gastrointestinal sections from control and C. parvum-exposed fish revealed no life-cycle stages of Cryptosporidium in any part of the apical border of the digestive tract. However, sections of the stomach and pyloric region from exposed fish displayed large numbers of 5-7-microm spherical structures located deep within the epithelial tissue. Under conditions of host stress, the number of these structures increased remarkably. An immunofluorescence antibody test with IgG and IgM anti-cryptosporidial antibodies revealed fluorescence reactivity in these structures. Simultaneously, wild trout were analyzed in order to detect natural cryptosporidial infections; Cryptosporidium oocyst-like bodies were found in the intestinal content of 10% of the specimens.
authors.affiliation: Departamento de Microbiología y Parasitología, Universidad de Santiago de Compostela, La Coruña, España.
authors.forename: F
authors.initials: F
authors.lastname: Freire-Santos
authors.forename: C A
authors.initials: CA
authors.lastname: Vergara-Castiblanco
authors.forename: J L
authors.initials: JL
authors.lastname: Tojo-Rodriguez
authors.forename: T
authors.initials: T
authors.lastname: Santamarina-Fernandez
authors.forename: E
authors.initials: E
authors.lastname: Ares-Mazas
mesh_terms: D000818:Animals; D000833:Animals, Suckling; D000913:Antibodies, Protozoan / Q000276:immunology; D002417:Cattle; D003457:Cryptosporidiosis / Q000469:parasitology*; D016785:Cryptosporidium parvum / Q000276:immunology / Q000502:physiology*; D005393:Fish Diseases / Q000469:parasitology*; D019084:Fluorescent Antibody Technique, Indirect / Q000662:veterinary; D051379:Mice; D017686:Oncorhynchus mykiss / Q000469:parasitology*; D013270:Stomach / Q000469:parasitology
chemical_list: D000913:Antibodies, Protozoan