Approaches to investigating transmission of spongiform encephalopathies in domestic animals using BSE as an example

Simmons, Marion; Spiropoulos, John; Hawkins, S. A. C.; Bellworthy, S. J.; Tongue, Sue C.

doi:10.1051/vetres:2008011

Cited by 9 publications

(6 citation statements)

References 111 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Sections representing standardised levels of the fixed brain [3,5] were prepared from paraffin wax-embedded blocks using routine histological methods and stained with H&E for the detection of vacuolar changes as described previously [3]. Data generated from animals experimentally inoculated with C-type BSE by the intracerebral route in a previous study [52,53] were used for comparison. This same data was used previously as a comparator for experimental scrapie in cattle [9].…”

Section: Methodsmentioning

confidence: 99%

Experimental H-type and L-type bovine spongiform encephalopathy in cattle: observation of two clinical syndromes and diagnostic challenges

et al. 2012

View full text Add to dashboard Cite

BackgroundThe majority of atypical bovine spongiform encephalopathy (BSE) cases so far identified worldwide have been detected by active surveillance. Consequently the volume and quality of material available for detailed characterisation is very limiting. Here we report on a small transmission study of both atypical forms, H- and L-type BSE, in cattle to provide tissue for test evaluation and research, and to generate clinical, molecular and pathological data in a standardised way to enable more robust comparison of the two variants with particular reference to those aspects most relevant to case ascertainment and confirmatory diagnosis within existing regulated surveillance programmes.ResultsTwo groups of four cattle, intracerebrally inoculated with L-type or H-type BSE, all presented with a nervous disease form with some similarities to classical BSE, which progressed to a more dull form in one animal from each group. Difficulty rising was a consistent feature of both disease forms and not seen in two BSE-free, non-inoculated cattle that served as controls. The pathology and molecular characteristics were distinct from classical BSE, and broadly consistent with published data, but with some variation in the pathological characteristics. Both atypical BSE types were readily detectable as BSE by current confirmatory methods using the medulla brain region at the obex, but making a clear diagnostic distinction between the forms was not consistently straightforward in this brain region. Cerebellum proved a more reliable sample for discrimination when using immunohistochemistry.ConclusionsThe prominent feature of difficulty rising in atypical BSE cases may explain the detection of naturally occurring cases in emergency slaughter cattle and fallen stock. Current confirmatory diagnostic methods are effective for the detection of such atypical cases, but consistently and correctly identifying the variant forms may require modifications to the sampling regimes and methods that are currently in use.

show abstract

Section: Methodsmentioning

confidence: 99%

Experimental H-type and L-type bovine spongiform encephalopathy in cattle: observation of two clinical syndromes and diagnostic challenges

et al. 2012

View full text Add to dashboard Cite

show abstract

“…Each of 62 groups received a different pool of tissues or body fluids (1 ml of a 10% homogenate in saline solution) obtained from calves dosed orally with 100 g of titred BSE-affected brainstem homogenate and culled at various time points during the incubation period [16,18]. The remaining group received a pooled inoculum of nictitating membrane from naturally infected BSE cases [19]. Two groups of Friesian or Friesian crossbred male castrated cattle inoculated with saline solution served as controls.…”

Section: Methodsmentioning

confidence: 99%

Relationship between clinical signs and postmortem test status in cattle experimentally infected with the bovine spongiform encephalopathy agent

Konold

Sayers²,

Sach

et al. 2010

BMC Vet Res

View full text Add to dashboard Cite

BackgroundVarious clinical protocols have been developed to aid in the clinical diagnosis of classical bovine spongiform encephalopathy (BSE), which is confirmed by postmortem examinations based on vacuolation and accumulation of disease-associated prion protein (PrPd) in the brain. The present study investigated the occurrence and progression of sixty selected clinical signs and behaviour combinations in 513 experimentally exposed cattle subsequently categorised postmortem as confirmed or unconfirmed BSE cases. Appropriate undosed or saline inoculated controls were examined similarly and the data analysed to explore the possible occurrence of BSE-specific clinical expression in animals unconfirmed by postmortem examinations.ResultsBased on the display of selected behavioural, sensory and locomotor changes, 20 (67%) orally dosed and 17 (77%) intracerebrally inoculated pathologically confirmed BSE cases and 21 (13%) orally dosed and 18 (6%) intracerebrally inoculated but unconfirmed cases were considered clinical BSE suspects. None of 103 controls showed significant signs and were all negative on diagnostic postmortem examinations. Signs indicative of BSE suspects, particularly over-reactivity and ataxia, were more frequently displayed in confirmed cases with vacuolar changes in the brain. The display of several BSE-associated signs over time, including repeated startle responses and nervousness, was significantly more frequent in confirmed BSE cases compared to controls, but these two signs were also significantly more frequent in orally dosed cattle unconfirmed by postmortem examinations.ConclusionsThe findings confirm that in experimentally infected cattle clinical abnormalities indicative of BSE are accompanied by vacuolar changes and PrPd accumulation in the brainstem. The presence of more frequently expressed signs in cases with vacuolar changes is consistent with this pathology representing a more advanced stage of disease. That BSE-like signs or sign combinations occur in inoculated animals that were not confirmed as BSE cases by postmortem examinations requires further study to investigate the potential causal relationship with prion disease.

show abstract

“… a Cattle with BSE confirmed by postmortem tests. b BSE field suspects or cattle inoculated with tissue/body fluids from naturally infected BSE cases or from BSE/scrapie-challenged animals, which were not confirmed as BSE cases by postmortem tests. c Cattle inoculated with saline solution or BSE/scrapie-free tissue or not challenged.1 Cattle intracerebrally inoculated with various tissues collected from cattle orally dosed with classical BSE brainstem homogenate and saline-inoculated controls [45,46]. …”

Section: Introductionmentioning

confidence: 99%

“…1 Cattle intracerebrally inoculated with various tissues collected from cattle orally dosed with classical BSE brainstem homogenate and saline-inoculated controls [45,46]. …”

Section: Introductionmentioning

confidence: 99%

Time and frequency domain analysis of heart rate variability in cattle affected by bovine spongiform encephalopathy

2011

View full text Add to dashboard Cite

BackgroundHeart rate variability (HRV) analysis is a method to assess the function of the autonomic nervous system. Brainstem nuclei that influence HRV are affected by vacuolar changes and accumulation of disease-associated prion protein (PrPd) in bovine spongiform encephalopathy (BSE) resulting in clinical signs suggestive of an increased parasympathetic tone. It was hypothesised that BSE in cattle causes changes in the autonomic nervous system; this was tested by comparing HRV indices derived from 1048 electrocardiograms, which were recorded from 51 naturally or experimentally infected cattle with BSE confirmed by postmortem tests, 321 clinical suspect cases or cattle inoculated with potentially infectious tissue without disease confirmation and 78 BSE-free control cattle.FindingsStatistically significant differences were found for low or high frequency power, their normalised values and ratio when the last recording prior to cull or repeated recordings were compared but only between male and female cattle of the three groups and not between groups of the same gender, even though BSE cases of each gender appeared to be more nervous during the recording. The same findings were made for heart rate, deviation from the mean RR interval and vasovagal tonus index when repeated recordings were compared. BSE cases with severe vacuolar changes in the parasympathetic nucleus of the vagus nerve had a significantly lower low:high frequency power ratio but not a lower heart rate than BSE cases with mild vacuolation, whereas severity of vacuolar changes in the solitary tract nucleus or intensity of PrPd accumulation in both nuclei did not appear to have any affect on either index. Abnormalities in the electrocardiogram were detected in 3% of the recordings irrespective of the BSE status; sinus arrhythmia was present in 93% of the remaining recordings.ConclusionsHRV analysis was not useful to distinguish BSE-positive from BSE-negative cattle grouped by gender, and HRV indices appeared to be mainly influenced by gender. There is agreement with earlier studies that vacuolar changes in the brainstem may be associated with an increased parasympathetic tone in BSE and that abnormalities in an electrocardiogram can be detected in cattle without evidence of heart disease.

show abstract

Approaches to investigating transmission of spongiform encephalopathies in domestic animals using BSE as an example

Cited by 9 publications

References 111 publications

Experimental H-type and L-type bovine spongiform encephalopathy in cattle: observation of two clinical syndromes and diagnostic challenges

Experimental H-type and L-type bovine spongiform encephalopathy in cattle: observation of two clinical syndromes and diagnostic challenges

Relationship between clinical signs and postmortem test status in cattle experimentally infected with the bovine spongiform encephalopathy agent

Time and frequency domain analysis of heart rate variability in cattle affected by bovine spongiform encephalopathy

Contact Info

Product

Resources

About