NR AWCV
AU Cancedda,M.G.; Madau,L.; Uras,P.; Zucca,R.; Bandino,E.; Maestrale,C.; Saba,M.; Santucciu,C.; Demontis,F.; Patta,C.; Macciocu,G.; Demurtas,G.; Ligios,S.; Ligios,C.; Carta,A.
TI Clinical and sub-clinical scrapie occurrence in a natural infected Sarda breed sheep flock submitted to divergent selection for resistance
QU International Conference - Prion 2006: Strategies, advances and trends towards protection of society - 3.10.-6.10.2006, Torino, Italy, Lingotto Conference Centre - Poster sessions GEN-06
PT Konferenz-Poster
AB The occurrence of Scrapie in sheep is modulated by the polymorphisms at codons 136, 154 and 171 of the gene coding the prion protein (PrP). Combinations of the polymorphisms in these three codons, create different alleles, of which ARQ, AHQ and ARR are the most frequently found in Sarda breed sheep. So far, Scrapie in this breed affects animals with ARQ/ARQ, ARQ/AHQ, and AHQ/AHQ genotypes. In order to demonstrate that genetic control of population at the PrP locus can be a useful strategy in field conditions, a study on the effect of the introduction of resistant rams was planned, starting in 2001, in a natural-scrapie affected flock. A susceptible blood line (GS) and a resistant blood line (GR) of sheep were created in this flock, mating respectively, one group of sheep with an ARQ/ARQ rams and an other with an ARR/ARR rams. This procedure was also applied in the mating period of the three following years. The female born from each blood line in the period 2002 - 2004, were raised and also included, at 7 months of age, in the mentioned breeding program along with the dams. The two groups were kept in contact together in a barn, except during the mating period. Male offspring of each year was sacrificed at about 24 months of age. Appropriated western blotting and Sc immunohistochemical protocols for PrP detection in the Central Nervous System (CNS) and in the Lymphoreticular System (LRS) were carried out on the male offspring, sheep found with neurological signs, and sheep that died of non-scrapie-related conditions. In this period we found 29 sheep, of which 18 from the progenitor group and 11 from the offspring of the GS group, harbouring PrPsc in the CSN and/or the LRS. All infected animals carried the ARQ/ARQ or the ARQ/AHQ genotype. In our monitored flock of scrapie-affected Sarda breed sheep the genetic control of population at the PrP locus proved to be a useful strategy to avoid spreading the disease among the offspring. Indeed, the ARR allele is strongly associated with resistance to scrapie, in spite of the high infective pressure in the flock, since susceptible and resistant animals were kept together, even in the lambing period.
AD M.G. Cancedda, L. Madau, P. Uras, R. Zucca, E. Bandiono, C. Maestrale, M. Saba, C. Santucciu, F. Demontis, C. Pat6ta, G. Macciocu, G. Demurtas, C. Ligios: Istituto Zooprofilattico Sperimentale della Sardegna, Sassari, Italy; S. Ligios, A. Carta: Istituto Zootecnico Caseario della Sardegna, Olmedo, Italy. E-mail: ciriaco.ligios@izs-sardegna.it
SP englisch
PO Italien