The evolution of the prevalence of classical scrapie in sheep in Great Britain using surveillance data between 2005 and 2012

Arnold, Mark; Ortiz-Pelaez, Angel

doi:10.1016/j.prevetmed.2014.07.015

Cited by 21 publications

(21 citation statements)

References 22 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…If genetic testing to identify the PRNP alleles present in a population may be used to estimate our confidence in an antemortem test result, perhaps they could be used more proactively to foster resistance in farmed or otherwise managed herds-an approach that has already been used with success in sheep herds affected by scrapie (45)(46)(47). The caveat here is that, unlike with scrapie, a white-tailed deer PRNP allele has not yet been identified that completely prevents infection with the agent of CWD-though a number of putatively resistant alleles have been identified, including the 95H, 96S, 116G, and 226K alleles reevaluated here.…”

Section: Discussionmentioning

confidence: 99%

Antemortem Detection of Chronic Wasting Disease Prions in Nasal Brush Collections and Rectal Biopsy Specimens from White-Tailed Deer by Real-Time Quaking-Induced Conversion

et al. 2016

View full text Add to dashboard Cite

dChronic wasting disease (CWD), a transmissible spongiform encephalopathy of cervids, was first documented nearly 50 years ago in Colorado and Wyoming and has since spread to cervids in 23 states, two Canadian provinces, and the Republic of Korea. The expansion of this disease makes the development of sensitive diagnostic assays and antemortem sampling techniques crucial for the mitigation of its spread; this is especially true in cases of relocation/reintroduction of farmed or free-ranging deer and elk or surveillance studies of private or protected herds, where depopulation is contraindicated. This study sought to evaluate the sensitivity of the real-time quaking-induced conversion (RT-QuIC) assay by using recto-anal mucosa-associated lymphoid tissue (RAMALT) biopsy specimens and nasal brush samples collected antemortem from farmed white-tailed deer (n ‫؍‬ 409). Antemortem findings were then compared to results from ante-and postmortem samples (RAMALT, brainstem, and medial retropharyngeal lymph nodes) evaluated by using the current gold standard in vitro assay, immunohistochemistry (IHC) analysis. We hypothesized that the sensitivity of RT-QuIC would be comparable to IHC analysis in antemortem tissues and would correlate with both the genotype and the stage of clinical disease. Our results showed that RAMALT testing by RT-QuIC assay had the highest sensitivity (69.8%) compared to that of postmortem testing, with a specificity of >93.9%. These data suggest that RT-QuIC, like IHC analysis, is an effective assay for detection of PrP CWD in rectal biopsy specimens and other antemortem samples and, with further research to identify more sensitive tissues, bodily fluids, or experimental conditions, has potential for large-scale and rapid automated testing for CWD diagnosis. C hronic wasting disease (CWD) is an efficiently transmitted spongiform encephalopathy of cervids (e.g., deer, elk, and moose) and is the only known prion disease affecting both farmed and free-ranging, nondomestic animals. It is the only prion disease of animals the control and eradication of which, through movement restrictions, genotypic breeding schemes, or herd reduction/depopulation efforts, for example, are problematic (1, 2). While the origins of CWD are uncertain, the disease has been present in cervid populations of northern Colorado and southern Wyoming for nearly 50 years (3, 4) and has now been identified in both captive and free-ranging cervids in 23 states, two Canadian provinces, and the Republic of Korea (5, 6). With intensified national and international surveillance efforts, CWD continues to be identified in areas previously considered free of infection, including recent discoveries in Iowa, Texas, Pennsylvania, and Ohio (7, 8, 9, 10). The prevalence of CWD varies from 0 to 30% among free-ranging populations (11, 12) but may approach 80% in cervid farm operations under quarantine (13).The expanding distribution of CWD across North America can be considered to have followed two nearly distinct pathways: (i) gradual proliferatio...

show abstract

Section: Discussionmentioning

confidence: 99%

Antemortem Detection of Chronic Wasting Disease Prions in Nasal Brush Collections and Rectal Biopsy Specimens from White-Tailed Deer by Real-Time Quaking-Induced Conversion

et al. 2016

View full text Add to dashboard Cite

show abstract

“…Similar results were found in this study where homozygous QQ 211 and RR 211 were found resistant and highly susceptible respectively, while there was a very low prevalence of scrapie in RQ 211 heterozygous animals. Although, scrapie has not been seen in Canadian ARR/ARQ sheep to date, it has been detected in Europe sheep [ 31 – 33 ]. Statistical models have estimated that genotypes with ARR haplotypes were 1000× more resistant to the disease compared to homozygous ARQ [ 33 , 34 ].…”

Section: Discussionmentioning

confidence: 99%

Identification of amino acid variation in the prion protein associated with classical scrapie in Canadian dairy goats

2016

View full text Add to dashboard Cite

BackgroundA clear association of amino acid variation in the prion protein gene (PRNP) with susceptibility and resistance to classical scrapie exists in sheep, but not in goats. In this study we examined DNA sequence variation in the PRNP of 149 animals from two scrapie-infected herds of Saanen dairy goats, and identified 6 non-synonymous variants in the coding region.ResultsIn the larger herd, all of the 54 scrapie-affected goats tested had at least one allele with the arginine (R) codon at position 211, with 52 being homozygous for that variant. No animal homozygous for the glutamine (Q) codon at 211 were affected and only two heterozygotes (R/Q) were affected. A weak association was found at position 146 and no significant associations were found with amino acid variation at the remaining four variant positions (142, 143, 222 and 240), however, the allelic variation was low. Similar patterns were observed in the second scrapie-affected herd.ConclusionWe also evaluated previous studies on goat herds affected with scrapie and this relationship of R susceptibility and Q resistance at 211 was present independent of the genotypes at the other positions including 222. The fact that glutamine at 211 provides a significant protective property to scrapie irrespective of the other positions could be important for breeding strategies aimed at improving herd resistance to scrapie, while maintaining important productivity traits.

show abstract

“…[39][40][41] The latter finding has led to a multinational effort to breed sheep towards resistance to classical scrapie infection in areas where the disease is endemic, resulting in a significant decline and near-eradication of the disease in countries employing targeted breeding programs. [42][43][44] Polymorphisms in the PRNP gene of white-tailed deer, mule deer, elk, fallow deer and reindeer have all been found to influence susceptibility to CWD in wild, farmed, and experimental populations. [26,[45][46][47][48][49] The low prevalence of CWD in these populations has often made it difficult to adequately understand the role these polymorphisms may play in the disease process.…”

Section: Introductionmentioning

confidence: 99%

Estimating relative CWD susceptibility and disease progression in farmed white-tailed deer with rare PRNP alleles

et al. 2019

View full text Add to dashboard Cite

Chronic wasting disease is a prion disease affecting both free-ranging and farmed cervids in North America and Scandinavia. A range of cervid species have been found to be susceptible, each with variations in the gene for the normal prion protein, PRNP, reportedly influencing both disease susceptibility and progression in the respective hosts. Despite the finding of several different PRNP alleles in white-tailed deer, the majority of past research has focused on two of the more common alleles identified-the 96G and 96S alleles. In the present study, we evaluate both infection status and disease stage in nearly 2100 farmed deer depopulated in the United States and Canada, including 714 CWD-positive deer and correlate our findings with PRNP genotype, including the more rare 95H, 116G, and 226K alleles. We found significant differences in either likelihood of being found infected or disease stage (and in many cases both) at the time of depopulation in all genotypes present, relative to the most common 96GG genotype. Despite high prevalence in many of the herds examined, infection was not found in several of the reported genotypes. These findings suggest that additional research is necessary to more properly define the role that these genotypes may play in managing CWD in both farmed and free-ranging white-tailed deer, with consideration for factors including relative fitness levels, incubation periods, and the kinetics of shedding in animals with these rare genotypes.

show abstract

The evolution of the prevalence of classical scrapie in sheep in Great Britain using surveillance data between 2005 and 2012

Cited by 21 publications

References 22 publications

Antemortem Detection of Chronic Wasting Disease Prions in Nasal Brush Collections and Rectal Biopsy Specimens from White-Tailed Deer by Real-Time Quaking-Induced Conversion

Antemortem Detection of Chronic Wasting Disease Prions in Nasal Brush Collections and Rectal Biopsy Specimens from White-Tailed Deer by Real-Time Quaking-Induced Conversion

Identification of amino acid variation in the prion protein associated with classical scrapie in Canadian dairy goats

Estimating relative CWD susceptibility and disease progression in farmed white-tailed deer with rare PRNP alleles

Contact Info

Product

Resources

About