TAFS1 Position Paper on BSE in small ruminants (January 2009)
TAFS INTERNATIONAL FORUM FOR TRANSMISSIBLE ANIMAL DISEASES AND FOOD SAFETY a non-profit Swiss Foundation
TAFS1 Position Paper on BSE in small ruminants
The recognition in 2004 that a French goat killed in 2002(25) was infected with BSE raised the profile of prion diseases in small ruminants in Europe, especially with respect to the risk that this may represent to consumers. Research into BSE in small ruminants, using experimental infections of sheep with BSE, were expanded and will inevitably add to our understanding of how BSE behaves in sheep and goats if infected. Meanwhile surveillance for prion diseases in small ruminants in Europe has identified scrapie cases in most countries, sometimes only in small numbers, but the evolving process of data analysis and scientific investigation is challenging past assumptions about the recognition and behaviour of prion infections of small ruminants. In particular, there is an intensification of the search for BSE amongst positive cases detected by surveillance, making use of newer discriminatory tools. This paper summarises recent results, both published or soon to be published, and their implications to both consumers and authorities who are responsible for ensuring the protection of consumers.
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When Atypical Scrapie cross species barriers
Andreoletti O., Herva M. H., Cassard H., Espinosa J. C., Lacroux C., Simon S., Padilla D., Benestad S. L., Lantier F., Schelcher F., Grassi J., Torres, J. M., UMR INRA ENVT 1225, Ecole Nationale Veterinaire de Toulouse.France; ICISA-INlA, Madrid, Spain; CEA, IBiTec-5, DSV, CEA/Saclay, Gif sur Yvette cedex, France; National Veterinary Institute, Postboks 750 Sentrum, 0106 Oslo, Norway, INRA IASP, Centre INRA de Tours, 3738O Nouzilly, France.
Atypical scrapie is a TSE occurring in small ruminants and harbouring peculiar clinical, epidemiological and biochemical properties. Currently this form of disease is identified in a large number of countries. In this study we report the transmission of an atypical scrapie isolate through different species barriers as modeled by transgenic mice (Tg) expressing different species PRP sequence.
The donor isolate was collected in 1995 in a French commercial sheep flock. inoculation into AHQ/AHQ sheep induced a disease which had all neuro-pathological and biochemical characteristics of atypical scrapie. Transmitted into Transgenic mice expressing either ovine or PrPc, the isolate retained all the described characteristics of atypical scrapie.
Surprisingly the TSE agent characteristics were dramatically different v/hen passaged into Tg bovine mice. The recovered TSE agent had biological and biochemical characteristics similar to those of atypical BSE L in the same mouse model. Moreover, whereas no other TSE agent than BSE were shown to transmit into Tg porcine mice, atypical scrapie was able to develop into this model, albeit with low attack rate on first passage.
Furthermore, after adaptation in the porcine mouse model this prion showed similar biological and biochemical characteristics than BSE adapted to this porcine mouse model. Altogether these data indicate.
(i) the unsuspected potential abilities of atypical scrapie to cross species barriers
(ii) the possible capacity of this agent to acquire new characteristics when crossing species barrier
These findings raise some interrogation on the concept of TSE strain and on the origin of the diversity of the TSE agents and could have consequences on field TSE control measures.
INFECTED AND SOURCE FLOCKS
There were 20 scrapie infected and source flocks with open statuses (Figure 3) as of April, 30, 2008. Twenty eight new infected and source flocks have been designated in FY 2008 (Figure 4); three source flocks were reported in April. ...snip
POSITIVE SCRAPIE CASES
As of April 30, 2008, 122 new scrapie cases have been confirmed and reported by the National Veterinary Services Laboratories (NVSL) in FY 2008 (Figure 6). Of these, 103 were field cases and 19* were Regulatory Scrapie Slaughter Surveillance (RSSS) cases (collected in FY 2008 and reported by May 20, 2008). Positive cases reported for April 2008 are depicted in Figure 7. Eighteen cases of scrapie in goats have been confirmed by NVSL since implementation of the regulatory changes in FY 2002 (Figure 8). The most recent positive goat case was confirmed in February 2008 and originated from the same herd in Michigan as the other FY 2008 goat cases. ...snip
CAPRINE SCRAPIE PREVALENCE STUDY (CSPS)
However, four positive goats have been identified this fiscal year through field investigations. One was a clinical suspect submitted for testing and the other three originated from the birth herd of the clinical case.
ANIMALS SAMPLED FOR SCRAPIE TESTING
As of April 30, 2008, 26,703 animals have been sampled for scrapie testing: 23,378 RSSS, 1,517 goats for the CSPS study, 1,466 regulatory field cases, 270 regulatory third eyelid biopsies, and 72 regulatory rectal biopsies (chart 8).
TESTING OF LYMPHOID TISSUE OBTAINED BY RECTAL BIOPSY WAS APPROVED BY USDA AS AN OFFICIAL LIVE-ANIMAL TEST ON JANUARY 11, 2008. ...
PLEASE NOTE, (FIGURE 6), Scrapie Confirmed Cases in FY 2008 MAP, PA 3, 1**, Two cases-state of ID UNKNOWN, 1 case Nor98-like**
Aspects of the Cerebellar Neuropathology in Nor98
Gavier-Widén, D1; Benestad, SL2; Ottander, L1; Westergren, E1 1National Veterinary Insitute, Sweden; 2National Veterinary Institute,
Norway Nor98 is a prion disease of old sheep and goats. This atypical form of scrapie was first described in Norway in 1998. Several features of Nor98 were shown to be different from classical scrapie including the distribution of disease associated prion protein (PrPd) accumulation in the brain. The cerebellum is generally the most affected brain area in Nor98. The study here presented aimed at adding information on the neuropathology in the cerebellum of Nor98 naturally affected sheep of various genotypes in Sweden and Norway. A panel of histochemical and immunohistochemical (IHC) stainings such as IHC for PrPd, synaptophysin, glial fibrillary acidic protein, amyloid, and cell markers for phagocytic cells were conducted. The type of histological lesions and tissue reactions were evaluated. The types of PrPd deposition were characterized. The cerebellar cortex was regularly affected, even though there was a variation in the severity of the lesions from case to case. Neuropil vacuolation was more marked in the molecular layer, but affected also the granular cell layer. There was a loss of granule cells. Punctate deposition of PrPd was characteristic. It was morphologically and in distribution identical with that of synaptophysin, suggesting that PrPd accumulates in the synaptic structures. PrPd was also observed in the granule cell layer and in the white matter. The pathology features of Nor98 in the cerebellum of the affected sheep showed similarities with those of sporadic Creutzfeldt-Jakob disease in humans.
***The pathology features of Nor98 in the cerebellum of the affected sheep showed similarities with those of sporadic Creutzfeldt-Jakob disease in humans.
Here we report that both Nor98 and discordant cases, including three sheep homozygous for the resistant PrPARR allele (A136R154R171), efficiently transmitted the disease to transgenic mice expressing ovine PrP, and that they shared unique biological and biochemical features upon propagation in mice. These observations support the view that a truly infectious TSE agent, unrecognized until recently, infects sheep and goat flocks and may have important implications in terms of scrapie control and public health.
Edited by Stanley B. Prusiner, University of California, San Francisco, CA, and approved September 12, 2005 (received for review March 21, 2005)
NOR-98 ATYPICAL SCRAPIE 5 cases documented in USA in 5 different states USA 007
Tuesday, June 3, 2008 SCRAPIE USA UPDATE JUNE 2008 NOR-98 REPORTED PA
Monday, December 1, 2008 When Atypical Scrapie cross species barriers
Saturday, January 24, 2009 Research Project: Detection of TSE Agents in Livestock, Wildlife, Agricultural Products, and the Environment Location: 2008 Annual Report