PrP gene polymorphism in sheep breeds in Slovakia and susceptibility to scrapie
Tkáciková, L.; Rolková, G.; Bíres, J.; Novák, P.; Kontseková, E.; Imrichová, D.; Bhide, M.; Hanusovská, E.; Mikula, I.; Novák, M.
Acta Virologica 50(4): 257-261
We analyzed the prion protein (PrP) genotype based on the codons 136, 154 and 171 and assigned to five risk groups (R1-R5) in healthy and scrapie-affected sheep in Slovakia. In healthy (asymptomatic) population, 119 Merino, 106 Improved Valachian, 117 Tsigai, and 48 Suffolk breeds were tested. Among the asymptomatic sheep, the low-risk genotypes R1 and R2 were most abundant in Suffolk (94%) and Merino (84%) breeds, followed by Tsigai (58%) and Improved Valachian (40%) breeds. The medium-risk group R3 was most frequent in Improved Valachian (31%) breed, followed by Tsigai (21%), Merino (10%), and Suffolk (6%) breeds. The occurrence of high-risk groups R4 and R5 was none in Suffolk breed, followed by Merino (6%), Tsigai (21%), and Improved Valachian (30%) breeds. Since 2003, altogether 48 cases of scrapie have been confirmed in Tsigai (38), Merino (4), Improved Valachian (2), Improved Valachian x Tsigai (3), and Suffolk (1) breeds. Among sheep with scrapie, Merino breed belonged to the medium-risk group R3. The majority of scrapie-affected Tsigai sheep were classified into high-risk R5 (50%) and medium-risk R3 (42%) groups. We showed an association of scrapie with medium- and high-risk groups of PrP genotype in Slovakia. In particular, the glutamine at position 171 appears to be of major importance for the susceptibility to scrapie.