BSE can propagate in sheep co-infected or pre-infected with scrapie

To understand the possible role of mixed-prion infections in disease presentation, the current study reports the co-infection of sheep with bovine spongiform encephalopathy (BSE) and scrapie. The bovine BSE agent was inoculated subcutaneously into sheep with ARQ/ARQ or VRQ/ARQ PRNP genotypes either at the same time as subcutaneous challenge with scrapie, or three months later. In addition, VRQ/VRQ sheep naturally infected with scrapie after being born into a scrapie-affected flock were challenged subcutaneously with BSE at eight or twenty one months-of-age. Sheep were analysed by incubation period/attack rate, and western blot of brain tissue determined the presence of BSE or scrapie-like PrPSc. Serial protein misfolding cyclic amplification (sPMCA) that can detect very low levels of BSE in the presence of an excess of scrapie agent was also applied to brain and lymphoreticular tissue. For VRQ/ARQ sheep challenged with mixed infections, scrapie-like incubation periods were produced, and no BSE agent was detected. However, whilst ARQ/ARQ sheep developed disease with BSE-like incubation periods, some animals had a dominant scrapie western blot phenotype in brain, but BSE was detected in these sheep by sPMCA. In addition, VRQ/VRQ animals challenged with BSE after natural exposure to scrapie had scrapie-like incubation periods and dominant scrapie PrPSc in brain, but one sheep had BSE detectable by sPMCA in the brain. Overall, the study demonstrates for the first time that for scrapie/BSE mixed infections, VRQ/ARQ sheep with experimental scrapie did not propagate BSE but VRQ/VRQ sheep with natural scrapie could propagate low levels of BSE, and whilst BSE readily propagated in ARQ/ARQ sheep it was not always the dominant PrPSc strain in brain tissue. Indeed, for several animals, a dominant scrapie biochemical phenotype in brain did not preclude the presence of BSE prion.

A study on evaluation of the role of fine-needle aspiration cytology in the etiology of lymphadenopathy in the rural population attending tertiary care hospital

Introduction: Lymph nodes are a site for organized collections of lymphoreticular tissue and arepink-gray bean-shaped encapsulated organs. Lymph nodes are among the commonly aspiratedorgans for diagnostic purposes. Lymphadenopathy is of great clinical significance as underlyingdiseases may range from a treatable infectious etiology to malignant neoplasms Fine needleaspiration cytology (FNAC) is a reliable as well as an inexpensive method used to diagnoselymphadenopathy of various sites. Aims: To evaluate the usefulness of FNAC as a diagnostic tool inthe etiological causes of lymphadenopathy and to study the cytomorphological features associatedwith various lymphadenopathies. Materials and Methods: The present prospective study wascarried out in the Department of Pathology at Maharajah's Institute of Medical Sciences,Vizianagaram, a Tertiary Care Centre. A total of 210 patients of all age groups underwent FNAC ofenlarged lymph nodes during this study period. Results: FNAC diagnosis was found to be as follows:tubercular lymphadenitis in 98 cases (46.67%) followed by reactive hyperplasia in 35 cases(16.67%), metastatic carcinoma 29 (13.8%), granulomatous lymphadenitis 27 (12.85%), non-specific lymphadenitis 8 (3.8%), acute suppurative lymphadenitis 7 (3.33%) and lymphoma 4 (1.8).Conclusion: FNAC of lymph nodes is an excellent first-line investigation to determine the nature ofthe lesion. It is quick, safe, minimally invasive, and reliable and is readily accepted by the patient.

Allelic variants at codon 146 in thePRNPgene show significant differences in the risk for natural scrapie in Cypriot goats

SUMMARYPrevious studies have shown the association between the polymorphisms serine (S) or aspartic acid (D) at codon 146 of thePRNPgene and resistance to scrapie. All goats aged >12 months (a total of 1075 animals) from four herds with the highest prevalence of scrapie in the country were culled and tested, of which 234 (21·7%) were positive by either the rapid test or immunohistochemistry (IHC) for any of the tissues tested. The odds of scrapie infection occurring in NN146goats was 101 [95% credible interval (CrI) 19–2938] times higher than for non-NN146or unknown genotypes. IHC applied to lymphoreticular tissue produced the highest sensitivity (94%, 95% CrI 90–97). The presence of putatively resistant non-NN146alleles in the Cypriot goat population, severely affected by scrapie, provides a potential tool to reduce/eradicate scrapie provided that coordinated nationwide breeding programmes are implemented and maintained over time.

Specified Risk Material and Topographical Distribution of Lymphoreticular Tissue of the Bovine Tongue

The elimination of specified risk material from food is crucial to restricting the risk to public health arising from bovine spongiform encephalopathy. The distribution of lymphoreticular tissue as potential specified risk material of the bovine lingual tonsil is described in relation to topographical anatomical landmarks. The definition of a proper landmark is a prerequisite for establishing adequate legal regulations concerning the removal of the lingual tonsil after slaughter. The main parameter to identify the lymphoreticular tissue in this study was the immunohistochemical identification of the follicular dendritic cells in the lingual tonsil. Lymph nodules were detected in areas up to 30 mm rostral of a given macroscopic landmark, i.e., the most caudal of the papillae vallatae. This area must therefore be adequately removed from the bovine tongue in the slaughterhouse. The current method for the removal of the lingual tonsil tissue according to Regulation (EC) 999/2001 at the slaughterhouse and alternatives to this method are discussed.

Central and peripheral pathology of kuru: pathological analysis of a recent case and comparison with other forms of human prion disease

While the neuropathology of kuru is well defined, there are few data concerning the distribution of disease-related prion protein in peripheral tissues. Here we report the investigation of brain and peripheral tissues from a kuru patient who died in 2003. Neuropathological findings were compared with those seen in classical (sporadic and iatrogenic) Creutzfeldt–Jakob disease (CJD) and variant CJD (vCJD). The neuropathological findings of the kuru patient showed all the stereotypical changes that define kuru, with the occurrence of prominent PrP plaques throughout the brain. Lymphoreticular tissue showed no evidence of prion colonization, suggesting that the peripheral pathogenesis of kuru is similar to that seen in classical CJD rather than vCJD. These findings now strongly suggest that the characteristic peripheral pathogenesis of vCJD is determined by prion strain type alone rather than route of infection.