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1.  Immunohistochemical and biochemical characteristics of BSE and CWD in experimentally infected European red deer (Cervus elaphus elaphus) 
Background
The cause of the bovine spongiform encephalopathy (BSE) epidemic in the United Kingdom (UK) was the inclusion of contaminated meat and bone meal in the protein rations fed to cattle. Those rations were not restricted to cattle but were also fed to other livestock including farmed and free living deer. Although there are no reported cases to date of natural BSE in European deer, BSE has been shown to be naturally or experimentally transmissible to a wide range of different ungulate species. Moreover, several species of North America's cervids are highly susceptible to chronic wasting disease (CWD), a transmissible spongiform encephalopathy (TSE) that has become endemic. Should BSE infection have been introduced into the UK deer population, the CWD precedent could suggest that there is a danger for spread and maintenance of the disease in both free living and captive UK deer populations. This study compares the immunohistochemical and biochemical characteristics of BSE and CWD in experimentally-infected European red deer (Cervus elpahus elaphus).
Results
After intracerebral or alimentary challenge, BSE in red deer more closely resembled natural infection in cattle rather than experimental BSE in small ruminants, due to the lack of accumulation of abnormal PrP in lymphoid tissues. In this respect it was different from CWD, and although the neuropathological features of both diseases were similar, BSE could be clearly differentiated from CWD by immunohistochemical and Western blotting methods currently in routine use.
Conclusion
Red deer are susceptible to both BSE and CWD infection, but the resulting disease phenotypes are distinct and clearly distinguishable.
doi:10.1186/1746-6148-5-26
PMCID: PMC2724422  PMID: 19635142
2.  Idiopathic Brainstem Neuronal Chromatolysis (IBNC): a novel prion protein related disorder of cattle? 
Background
The epidemic form of Bovine Spongiform Encephalopathy (BSE) is generally considered to have been caused by a single prion strain but at least two strain variants of cattle prion disorders have recently been recognized. An additional neurodegenerative condition, idiopathic brainstem neuronal chromatolysis and hippocampal sclerosis (IBNC), a rare neurological disease of adult cattle, was also recognised in a sub-set of cattle submitted under the BSE Orders in which lesions of BSE were absent. Between the years of 1988 and 1991 IBNC occurred in Scotland with an incidence of 7 cases per 100,000 beef suckler cows over the age of 6 years.
Results
When the brains of 15 IBNC cases were each tested by immunohistochemistry, all showed abnormal labelling for prion protein (PrP). Immunohistological labelling for PrP was also present in the retina of a single case available for examination. The pattern of PrP labelling in brain is distinct from that seen in other ruminant prion diseases and is absent from brains with other inflammatory conditions and from normal control brains. Brains of IBNC cattle do not reveal abnormal PrP isoforms when tested by the commercial BioRad or Idexx test kits and do not reveal PrPres when tested by Western blotting using stringent proteinase digestion methods. However, some weakly protease resistant isoforms of PrP may be detected when tissues are examined using mild proteinase digestion techniques.
Conclusion
The study shows that a distinctive neurological disorder of cattle, which has some clinical similarities to BSE, is associated with abnormal PrP labelling in brain but the pathology and biochemistry of IBNC are distinct from BSE. The study is important either because it raises the possibility of a significant increase in the scope of prion disease or because it demonstrates that widespread and consistent PrP alterations may not be confined to prion diseases. Further studies, including transmission experiments, are needed to establish whether IBNC is a condition in which prion protein is abnormally regulated or it is yet a further example of an infectious cattle prion disease.
doi:10.1186/1746-6148-4-38
PMCID: PMC2569918  PMID: 18826563
3.  Experimental transmission of bovine spongiform encephalopathy to European red deer (Cervus elaphus elaphus) 
Background
Bovine spongiform encephalopathy (BSE), a member of the transmissible spongiform encephalopathies (TSE), primarily affects cattle. Transmission is via concentrate feed rations contaminated with infected meat and bone meal (MBM). In addition to cattle, other food animal species are susceptible to BSE and also pose a potential threat to human health as consumption of infected meat products is the cause of variant Creutzfeldt-Jakob disease in humans, which is invariably fatal. In the UK, farmed and free ranging deer were almost certainly exposed to BSE infected MBM in proprietary feeds prior to legislation banning its inclusion. Therefore, although BSE has never been diagnosed in any deer species, a possible risk to human health remains via ingestion of cervine products. Chronic wasting disease (CWD), also a TSE, naturally infects several cervid species in North America and is spreading rapidly in both captive and free-ranging populations.
Results
Here we show that European red deer (Cervus elaphus elaphus) are susceptible to intra-cerebral (i/c) challenge with BSE positive cattle brain pool material resulting in clinical neurological disease and weight loss by 794–1290 days and the clinical signs are indistinguishable to those reported in deer with CWD. Spongiform changes typical of TSE infections were present in brain and accumulation of the disease-associated abnormal prion protein (PrPd) was present in the central and peripheral nervous systems, but not in lymphoid or other tissues. Western immunoblot analysis of brain material showed a similar glycosylation pattern to that of BSE derived from infected cattle and experimentally infected sheep with respect to protease-resistant PrP isoforms. However, the di-, mono- and unglycosylated bands migrated significantly (p < 0.001) further in the samples from the clinically affected deer when compared to BSE infected brains of cattle and sheep.
Conclusion
This study shows that deer are susceptible to BSE by intra-cerebral inoculation and display clinical signs and vacuolar pathology that are similar to those of CWD. These findings highlight the importance of preventing the spread to Europe of CWD from North America as this may necessitate even more extensive testing of animal tissues destined for human consumption within the EU. Although the absence of PrPd in lymphoid and other non-neurological tissues potentially limits the risk of transmission to humans, the replication of TSE agents in peripheral tissues following intra-cerebral challenge is often limited. Thus the assessment of risk posed by cervine BSE as a human pathogen or for environmental contamination should await the outcome of ongoing oral challenge experiments.
doi:10.1186/1746-6148-4-17
PMCID: PMC2423184  PMID: 18507844
4.  Pruritus is a common feature in sheep infected with the BSE agent 
Background
The variability in the clinical or pathological presentation of transmissible spongiform encephalopathies (TSEs) in sheep, such as scrapie and bovine spongiform encephalopathy (BSE), has been attributed to prion protein genotype, strain, breed, clinical duration, dose, route and type of inoculum and the age at infection. The study aimed to describe the clinical signs in sheep infected with the BSE agent throughout its clinical course to determine whether the clinical signs were as variable as described for classical scrapie in sheep. The clinical signs were compared to BSE-negative sheep to assess if disease-specific clinical markers exist.
Results
Forty-seven (34%) of 139 sheep, which comprised 123 challenged sheep and 16 undosed controls, were positive for BSE. Affected sheep belonged to five different breeds and three different genotypes (ARQ/ARQ, VRQ/VRQ and AHQ/AHQ). None of the controls or BSE exposed sheep with ARR alleles were positive. Pruritus was present in 41 (87%) BSE positive sheep; the remaining six were judged to be pre-clinically infected. Testing of the response to scratching along the dorsum of a sheep proved to be a good indicator of clinical disease with a test sensitivity of 85% and specificity of 98% and usually coincided with weight loss. Clinical signs that were displayed significantly earlier in BSE positive cases compared to negative cases were behavioural changes, pruritic behaviour, a positive scratch test, alopecia, skin lesions, teeth grinding, tremor, ataxia, loss of weight and loss of body condition. The frequency and severity of each specific clinical sign usually increased with the progression of disease over a period of 16–20 weeks.
Conclusion
Our results suggest that BSE in sheep presents with relatively uniform clinical signs, with pruritus of increased severity and abnormalities in behaviour or movement as the disease progressed. Based on the studied sheep, these clinical features appear to be independent of breed, affected genotype, dose, route of inoculation and whether BSE was passed into sheep from cattle or from other sheep, suggesting that the clinical phenotype of BSE is influenced by the TSE strain more than by other factors. The clinical phenotype of BSE in the genotypes and breed studied was indistinguishable from that described for classical scrapie cases.
doi:10.1186/1746-6148-4-16
PMCID: PMC2390527  PMID: 18445253

Results 1-4 (4)