Genetic, histochemical and biochemical studies on goat TSE cases from Cyprus.

Susanne Niedermeyer,Martin Eiden,Pavlos Toumazos,Alex Bossers,Penelope Papasavva-Stylianou,Martin H Groschup,Thorsten Kuczius,Cynthia Panagiotidis,Jan Langeveld,Martin Kaatz,Ioannis Ioannou,Theodoros Sklaviadis,Christine Fast

doi:10.1186/s13567-016-0379-0

Abstract

Scrapie and bovine spongiform encephalopathy (BSE) are transmissible spongiform encephalopathies (TSE’s) affecting sheep and goats. Susceptibility of goats to scrapie is influenced by polymorphisms of the prion protein gene (PRNP) of the host. Five polymorphisms are associated with reduced susceptibility to TSE’s. In the study presented here caprine samples from a scrapie eradication program on Cyprus were genotyped and further characterized using BioRad TeSeE rapid test, histological, immunohistochemical and biochemical methods. In total 42 goats from 20 flocks were necropsied from which 25 goats showed a positive result in the rapid test, a spongiform encephalopathy and an accumulation of pathological prion protein (PrPSc) in the obex. PrPSc deposits were demonstrated in the placenta, peripheral nervous and lymphoreticular system. Two animals showed PrPSc-accumulations in peripheral tissues only. By discriminatory immunoblots a scrapie infection could be confirmed for all cases. Nevertheless, slight deviations in the glycosylation pattern might indicate the presence of different scrapie strains. Furthermore scrapie samples from goats in the current study demonstrated less long term resistance to proteinase K than ovine or caprine BSE control samples. Reduced scrapie susceptibility according to the PRNP genotype was demonstrated (Fishers Exact test, p < 0.05) for the goats with at least one polymorphism (p = 0.023) at the six codons examined and in particular for those with polymorphisms at codon 146 (p = 0.016). This work characterizes scrapie in goats having implications for breeding and surveillance strategies.

Highlights

Transmissible spongiform encephalopathies (TSE’s) are progressive, fatal neurodegenerative diseases in humans and mammals
The transmissible spongiform encephalopathy (TSE) positive goats exhibited the I142N146R151R154R211Q222 genotype with one exception that showed a polymorphism at codon 154 (R154H)
The variability of genotypes was higher among the TSE negative goats, exhibiting in four animals single polymorphisms as N146S (n = 1), S146S (n = 1), N146D (n = 1) and M142 M (n = 1), respectively

Summary

Introduction

Transmissible spongiform encephalopathies (TSE’s) are progressive, fatal neurodegenerative diseases in humans and mammals. There is scrapie in sheep, goats and mufflons [2,3,4] and bovine spongiform encephalopathy which was first described in cattle in 1986 [5] being the only animal prion disease confirmed to affect human beings (Creutzfeldt–Jakob disease) and mammals [6]. As already described for sheep, the susceptibility of goats for scrapie is highly influenced by polymorphisms of the prion protein gene (PRNP). The polymorphisms I142M and R154H extend incubation period and for the latter partially protective effects had been described [12, 13, 15, 16].

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Results

Conclusion