Περίληψη:
The allele and genotype frequency distributions of the prion protein
gene polymorphisms at codons 136, 154 and 171 were determined by
real-time PCR for 1,456 sheep from 7 classical scrapie-affected flocks
of Thessaloniki and Imathia, Central Macedonia, Greece. The blood
samples were collected by official veterinarians and were examined by
the National Reference Laboratory (NRL) for TSEs, Veterinary Laboratory
of Larisa, Greece, in the framework of the National Program for Scrapie
Surveillance and Control between 2009 and 2013. Among the 1,456 sheep,
340 were of Chios breed, 633 Chios crossbred and 483 crossbred. The
examined sheep showed high genotype variability, as a total of 7
haplotypes and 23 different genotypes were found. The predominant allele
and the predominant genotype were ARQ and ARQ/ARQ respectively, in all
breeds studied, followed by the ARR allele and the ARR/ARQ genotype. The
TRQ allele was frequent in Chios and Chios crossbred, while the VRQ
allele was rare for all the breeds. Interestingly, 3 genotypes (ARH/TRQ,
ARR/ARK and ARK/VRQ) were detected for the first time in Greece and two
of them (ARH/TRQ and ARK/VRQ) have, to our knowledge, never been
previously reported. Furthermore, it is emphasized that our country
outnumbers all European countries in classical scrapie cases of sheep
every year. Therefore, there is an urgent need to reduce the incidence
of classical scrapie through the implementation of selective breeding
programs. This is supported by the fact that the prevalence of classical
scrapie in the Greek sheep population is highly associated with the
predominant genotype ARQ/ARQ. Therefore, the elimination of the ARQ/ARQ
and the other susceptible genotypes (belonging to Risk Groups 3 and 5,
according to the National Scrapie Plan of Great Britain) would reduce
dramatically the incidence of classical scrapie in Greece.
Συγγραφείς:
Kioutsioukis, C.
Papadogiannakis, E.
Palaska, V
Kontos, V
and Papakostaki, D.
Paraskeva, S.
Vassalou, E.
