title: Immunity in rainbow trout, Oncorhynchus mykiss, against the monogenean Discocotyle sagittata following primary infection.
abstract: Rainbow trout (Oncorhynchus mykiss) were experimentally infected by continuous or single exposure with the monogenean Discocotyle sagittata. To determine whether immunity follows primary infection, fish were exposed to a secondary challenge by one of two modes: (1) primary infections were cleared with praziquantel (PZQ) and hosts re-infected with 100 oncomiracidia; (2) parasites were allowed to reach maturity and hosts super-infected with 100 oncomiracidia. Fish challenged after initial continuous exposure developed significant partial resistance to re-infection, carrying burdens 35% lower than controls. PZQ treatment controls demonstrated that the drug did not account for the protection observed. Single exposure did not significantly modify the outcome of secondary challenges. Super-infection experiments suggested that no concomitant immunity develops. No correlation was found between initial burdens and the outcome of secondary challenges in the same individual. Significantly elevated anti-D. sagittata antibodies were detected in infected fish, but there was no correlation between immunoglobulin levels and parasite burdens.
authors.affiliation: School of Biological Sciences, University of Bristol, BS8 1UG, UK. mrubiogodoy@yahoo.com
authors.forename: Miguel
authors.initials: M
authors.lastname: Rubio-Godoy
authors.forename: Richard C
authors.initials: RC
authors.lastname: Tinsley
mesh_terms: D000818:Animals; D000909:Antibodies, Helminth / Q000097:blood; D000947:Antigens, Helminth / Q000276:immunology; D000980:Antiplatyhelmintic Agents / Q000627:therapeutic use; D005393:Fish Diseases / Q000188:drug therapy / Q000276:immunology*; D017686:Oncorhynchus mykiss / Q000276:immunology* / Q000469:parasitology*; D011223:Praziquantel / Q000627:therapeutic use; D015163:Superinfection; D014200:Trematoda / Q000276:immunology*; D014201:Trematode Infections / Q000188:drug therapy / Q000276:immunology / Q000662:veterinary*
chemical_list: D000909:Antibodies, Helminth; D000947:Antigens, Helminth; D000980:Antiplatyhelmintic Agents; D011223:Praziquantel