Prion protein gene polymorphisms and accumulation of pathogenic prion protein (PrPSc) in a herd with previously confirmed scrapie cases

Authors

  • Cristina Santos Sotomaior Pontifícia Universidade Católica do Paraná
  • David Driemeier Universidade Federal do Rio Grande do Sul
  • Juliano Leal Universidade Federal do Rio Grande do Sul
  • Rüdiger Daniel Ollhoff Pontifícia Universidade Católica do Paraná
  • Vanete Thomaz-Soccol Universidade Federal do Paraná

DOI:

https://doi.org/10.14393/BJ-v31n4a2015-26231

Keywords:

Ovis aries, PrPSc, PRNP polymorphisms, Genotyping, Affected flock.

Abstract

Scrapie in sheep is associated with at least three polymorphisms in the prion protein gene (PRNP) on codons 136, 154, and 171. Countries where scrapie is endemic have been using breeding programs based on selection for the most resistant alleles. There are some PRNP genotyping data on sheep in Brazil, and scrapie has sporadically been observed since 1978. Paraná is the Brazilian state where most of the cases of scrapie have been diagnosed. A flock that had three clinical scrapie cases in 2003 and 2004 was genotyped (128 sheep: 53 pure Hampshire Down and 75 crossbred) and slaughtered (111 sheep: 47 pure Hampshire Down and 64 crossbred) in 2006. Samples of lymphoid and central nervous tissues were examined by immunohistochemistry (IHC) for altered prion protein (PrPSc). Six genotypes were detected in the 128 genotyped animals: ARR/ARQ was the most frequent (45.3%), followed by ARQ/ARQ (28.1%), ARR/ARR (14.1%), and ARQ/VRQ (8.6%). ARR/VRQ and ARQ/AHQ showed less than 2.5% genotype frequency. IHC identified 16 positive sheep. Palatine tonsil tissue had the highest percentage of reactive samples: 81.25% of the total positive samples. Of these 16 positive animals, nine (56.25%) had genotype ARR/ARQ, five (31.25%) had genotype ARQ/ARQ, and the remaining two (12.5%) had genotype ARQ/VRQ. All the positive animals were clinically healthy, and therefore represented 14.14% of pre-clinical cases of scrapie in this flock.

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Published

2015-06-30

How to Cite

SOTOMAIOR, C.S., DRIEMEIER, D., LEAL, J., OLLHOFF, R.D. and THOMAZ-SOCCOL, V., 2015. Prion protein gene polymorphisms and accumulation of pathogenic prion protein (PrPSc) in a herd with previously confirmed scrapie cases . Bioscience Journal [online], vol. 31, no. 4, pp. 1189–1199. [Accessed30 November 2022]. DOI 10.14393/BJ-v31n4a2015-26231. Available from: https://seer.ufu.br/index.php/biosciencejournal/article/view/26231.

Issue

Section

Agricultural Sciences