Five cases of scrapie with unusual features have been diagnosed in Norway since 1998. The affected sheep showed neurological signs dominated by ataxia, and had the PrP genotypes homozygous A136 H154 Q171/ A136H154Q171 or heterozygous A136H154Q171/A136R154Q171, which are rarely associated with scrapie. Brain histopathology revealed neuropil vacuolisation essentially in the cerebellar and cerebral cortices; vacuolation was less prominent in the brainstem, and no lesions were observed at the level of the obex. The deposits of PrPSc were mainly in the cortex of the cerebellum and cerebrum, and no PrPSC was detectable by immunohistochemistry and ELISA in the lymphoid tissues investigated. Western blot analysis showed that the glycotype was different from other known scrapie strains and from the BSE strain. From a diagnostic point of view, these features indicate that this type of scrapie, designated Nor98, could have been overlooked and may be of significance for sampling in scrapie surveillance programmes.

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Two-hundred and forty healthy sheep and 32 cases of natural scrapie in Norway were analysed for disease-linked polymorphisms in the prion protein (PrP) gene. Scrapie was strongly associated with the presence of a valine polymorphism at codon 136 (V 136 ), as 68n8 % of the cases were homozygous (VV 136 ) and 15n6 % were valine/alanine heterozygous (VA 136 ). All cases were homozygous arginine/arginine at codon 154 (RR 154 ), except two which were homozygous histidine/histidine (HH 154 ). All cases except two were homozygous glutamine/glutamine at codon 171 (QQ 171 ), the two exceptions being heterozygous glutamine/arginine (QR 171 ). More than 80 % of all scrapie cases in Norway have occurred in a Cheviot-related crossbred type of sheep called Rygja. This type of sheep, which is largely restricted to the south-western coast, carries the V 136 allele at a higher frequency than do other breeds of Norwegian sheep. Polymorphisms at codons 138 and 151 are also described.

Abstract. Within the framework of the active surveillance for transmissible spongiform encephalopathies in sheep in Sweden, 4 cases of the atypical form of scrapie, Nor98, were identified during 2003. Nor98 is a recently recognized and poorly understood variant of scrapie, first described in Norway. The cases were positive by the rapid test (enzyme-linked immunosorbent assay). Immunohistochemical staining showed diffuse thingranular staining of the cerebellar cortex. Western immunoblotting analysis of specimens of brain stem and cerebellum showed a light band of approximately 12 kDa. Typical scrapie was ruled out based on the confirmatory testing. The affected ewes were from 4 different flocks. They were between 7 and 9 years old. Two were of the ARQ/ARQ genotype, 1 ARR/ARQ, and 1 ARR/AHQ. Two ewes had shown ataxia, and the other 2 had no clinical signs. Whole-flock slaughter was applied, and testing of the flock mates did not reveal additional cases. Nor98 differs from typical scrapie in its epidemiology, frequency of genotypes of sheep affected, clinical signs, microscopic lesions, distribution of scrapie prion protein in the brain, and characteristics of the immunostaining and immunoblotting profiles.

Abstract. During a period of 1.5 months, a newly established pig herd experienced a high number of mummifications and stillbirths, a high neonatal mortality rate, and many piglets with congenital tremors or hind leg ataxia. After clinical and histological investigations, the submitted animals were divided into 4 groups: mummified or stillborn (N 5 6), live born with myocarditis (N 5 5) (average age 22.8 days), live born without myocarditis (N 5 14) (average age 20.0 days), and control animals from a different herd (N 5 5) (newborn). Statistically significant differences were observed in the mean porcine circovirus 2 (PCV2) load among the 4 groups in the liver (P , 0.0001). The presence of PCV2 antigen within the myocardial lesions was confirmed by immunohistochemistry. A high load of PCV2 DNA was observed in myocardium, liver, and spleen from mummified or stillborn piglets (.1 3 10 7 copies per 500 ng DNA), lower in piglets with myocarditis (.1 3 10 5 copies per 500 ng DNA), and even further lower in pigs without myocarditis (,1 3 10 5 copies per 500 ng DNA), whereas no PCV2 DNA was detected in the control animals. Myocardium, liver, and spleen were well suited for routine testing of fetuses and young piglets by quantitative real-time polymerase chain reaction. Neither porcine parvovirus nor encepaholomyocarditis virus was detected. These results indicate that the PCV2 infection might have been of etiological importance for the fetal deaths and piglet mortality observed in this herd.