title: Scrapie infectivity is quickly cleared in tissues of orally-infected farmed fish.
abstract: BACKGROUND
  Scrapie and bovine spongiform encephalopathy (BSE) belongs to the group of animal transmissible spongiform encephalopathy (TSE). BSE epidemic in the UK and elsewhere in Europe has been linked to the use of bovine meat and bone meals (MBM) in the feeding of cattle. There is concern that pigs, poultry and fish bred for human consumption and fed with infected MBM would eventually develop BSE or carry residual infectivity without disease. Although there has been no evidence of infection in these species, experimental data on the susceptibility to the BSE agent of farm animals other than sheep and cow are limited only to pigs and domestic chicken. In the framework of a EU-granted project we have challenged two species of fish largely used in human food consumption, rainbow trout (Oncorhynchus mykiss) and turbot (Scophthalmus maximus), with a mouse-adapted TSE strain (scrapie 139A), to assess the risk related to oral consumption of TSE contaminated food. In trout, we also checked the "in vitro" ability of the pathological isoform of the mouse prion protein (PrPSc) to cross the intestinal epithelium when added to the mucosal side of everted intestine.
  
  
  RESULTS
  Fish challenged with a large amount of scrapie mouse brain homogenate by either oral or parenteral routes, showed the ability to clear the majority of infectivity load. None of the fish tissues taken at different time points after oral or parenteral inoculation was able to provoke scrapie disease after intracerebral inoculation in recipient mice. However, a few recipient mice were positive for PrPSc and spongiform lesions in the brain. We also showed a specific binding of PrPSc to the mucosal side of fish intestine in the absence of an active uptake of the prion protein through the intestinal wall.
  
  
  CONCLUSIONS
  These results indicate that scrapie 139A, and possibly BSE, is quickly removed from fish tissues despite evidence of a prion like protein in fish and of a specific binding of PrPSc to the mucosal side of fish intestine.
authors.affiliation: Istituto Superiore di Sanità, Department of Cellular Biology and Neuroscience, viale Regina Elena,299,00161 Rome, Italy. ingrosso@iss.it
authors.forename: Loredana
authors.initials: L
authors.lastname: Ingrosso
authors.forename: Beatriz
authors.initials: B
authors.lastname: Novoa
authors.forename: Andrea Z Dalla
authors.initials: AZ
authors.lastname: Valle
authors.forename: Franco
authors.initials: F
authors.lastname: Cardone
authors.forename: Raquel
authors.initials: R
authors.lastname: Aranguren
authors.forename: Marco
authors.initials: M
authors.lastname: Sbriccoli
authors.forename: Simona
authors.initials: S
authors.lastname: Bevivino
authors.forename: Marcello
authors.initials: M
authors.lastname: Iriti
authors.forename: Quanguo
authors.initials: Q
authors.lastname: Liu
authors.forename: Vito
authors.initials: V
authors.lastname: Vetrugno
authors.forename: Mei
authors.initials: M
authors.lastname: Lu
authors.forename: Franco
authors.initials: F
authors.lastname: Faoro
authors.forename: Salvatore
authors.initials: S
authors.lastname: Ciappellano
authors.forename: Antonio
authors.initials: A
authors.lastname: Figueras
authors.forename: Maurizio
authors.initials: M
authors.lastname: Pocchiari
mesh_terms: D000818:Animals; D001921:Brain / Q000473:pathology; D002432:Cecum / Q000378:metabolism / Q000473:pathology; D005412:Flatfishes / Q000378:metabolism*; D007413:Intestinal Mucosa / Q000378:metabolism; D007422:Intestines / Q000473:pathology; D051379:Mice; D017686:Oncorhynchus mykiss / Q000378:metabolism*; D018620:PrPSc Proteins / Q000378:metabolism*
chemical_list: D018620:PrPSc Proteins