Cryptosporidium parvum: an attempt at experimental infection in rainbow trout Oncorhynchus mykiss.
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.
Freire-Santos
F
F
Departamento de Microbiología y Parasitología, Universidad de Santiago de Compostela, La Coruña, España.
Vergara-Castiblanco
C A
CA
Tojo-Rodriguez
J L
JL
Santamarina-Fernandez
T
T
Ares-Mazas
E
E
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
D000913:Antibodies, Protozoan