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PPR is an acute, highly contagious and economically important viral disease of small ruminants. A polyclonal based indirect ELISA was developed for detection of antibodies to PPRV in the sheep sera samples using partially purified PPR viral antigen propagated in verocell lines. A cut-off value was set as twice the mean of negative population based on the distribution of known negative serum samples in respect of PPR viral antibodies in the test. The present assay had 100% specificity and 84% sensitivity and can be used as a good alternative to SNT for disease monitoring and serosurveillance. [ABSTRACT FROM AUTHOR]

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Sheep pox is a highly contagious, host specific viral infection and responsible for high morbidity and mortality. Three flocks consisting of 412 Madras Red sheep were examined for the presence of sheep pox at Arasankuppam and Vellakulam village of Thiruvannamalai district, Tamil Nadu. Overall morbidity and mortality of sheep pox was 14.94 and 43.73 %, respectively. The morbidity (53.85%) and mortality(42.85%) rates were higher in lambs than adult and young age groups. Among the sex, the morbidity and mortality rates were higher in females (15.69 and 40.90%) than males (8.00 and 50.00%), respectively. Clinical signs, postmortem lesions and histopathological findings were also reported and discussed. [ABSTRACT FROM AUTHOR]

The relevant information on the occurrence of Blue Tongue (BT) viral disease in sheep was analyzed on the economic losses, and their clinical management were studied. During 2012-13, 2013-14 and 2014-15 there were 10, 34 and 11 cases recorded in Nellore jodipi sheep at Livestock Research Station, Palamaner and the results indicated that the case fatality rate was 20, 23.53 and 18.18 and percent mortality were 0.26, 0.99 and 0.26. The reduction in the growth performance is the main concern and in some of the animals, reduced weights were noticed to a maximum of 7 kgs. The year wise monetary losses were Rs.26954, 103008 and 28232 observed during the respective years. [ABSTRACT FROM AUTHOR]

AIMS: To estimate the number of cases of scrapie that would occur in sheep of different prion protein (PrP) genotypes if scrapie was to become established in New Zealand, and to compare the performance of two commercially available, rapid ELISA kits using ovine retro-pharyngeal lymph nodes (RLN) from non-infected and infected sheep of different PrP genotypes. METHODS: Using published data on the distribution of PrP genotypes within the New Zealand sheep flock and the prevalence of cases of scrapie in these genotypes in the United Kingdom, the annual expected number of cases of scrapie per genotype was estimated, should scrapie become established in New Zealand, assuming a total population of 28 million sheep. A non-infected panel of RLN was collected from 737 sheep from New Zealand that had been culled, foundin extremisor died. Brain stem samples were also collected from 131 of these sheep. A second panel of infected samples comprised 218 and 117 RLN from confirmed scrapie cases that had originated in Europe and the United States of America, respectively. All samples were screened using two commercial, rapid, transmissible spongiform encephalopathy ELISA kits: Bio-Rad TeSeE ELISA (ELISA-BR), and IDEXX HerdChek BSE-Scrapie AG Test (ELISA-ID). RESULTS: If scrapie became established in New Zealand, an estimated 596 cases would occur per year; of these 234 (39%) and 271 (46%) would be in sheep carrying ARQ/ARQ and ARQ/VRQ PrP genotypes, respectively. For the non-infected samples from New Zealand the diagnostic specificity of both ELISA kits was 100%. When considering all infected samples, the diagnostic sensitivity was 70.4 (95% CI=65.3–75.3)% for ELISA-BR and 91.6 (95% CI=88.2–94.4)% for ELISA-ID. For the ARQ/ARQ genotype (n=195), sensitivity was 66.2% for ELISA-BR and 90.8% for ELISA-ID, and for the ARQ/VRQ genotype (n=107), sensitivity was 81.3% for ELISA-BR and 98.1% for ELISA-ID. CONCLUSIONS: In this study, the ELISA-ID kit demonstrated a higher diagnostic sensitivity for detecting scrapie in samples of RLN from sheep carrying scrapie-susceptible PrP genotypes than the ELISA-BR kit at comparable diagnostic specificity. CLINICAL RELEVANCE: The diagnostic performance of the ELISA-ID kit using ovine RLN merits the consideration of including this assay in the national scrapie surveillance programme in New Zealand. [ABSTRACT FROM PUBLISHER]

Summary: Ovine pulmonary adenocarcinoma (OPA) is a naturally occurring lung cancer of sheep caused by jaagsiekte sheep retrovirus (JSRV). This study examines immunohistochemically solitary lung nodules considered as early OPA lesions from 11 sheep infected naturally by JSRV. All 11 neoplastic nodules exhibited features of adenocarcinoma and in four of them mesenchymal growth was also observed. Both types of lesion were labelled with antibody specific for JSRV-Env. In two cases infiltrating lymphoreticular cells also contained JSRV-Env. All tumours had a high Ki67 labelling index and variably contained cells expressing CC10 (a marker of Clara cells (CCs)), SPC (a marker of type II pneumocytes), p63 and keratin 14 (markers for stem/progenitor cells of the lung airway epithelia). Tumours with mesenchymal growth had intense expression of vimentin and desmin, weak expression of smooth muscle actin and did not express pancytokeratin and p63. Both epithelial and mesenchymal proliferations did not express the stem cell markers CD90 and CD117, but some tumour infiltrating cells expressed CD133. Solitary OPA tumours can therefore be adenocarcinomas or mixed tumours and have a heterogeneous cellular composition, containing groups of cells expressing markers that characterize local progenitor cells involved in lung repair. [ABSTRACT FROM AUTHOR]

This study measured the clinical prevalence of peste des petits ruminants (PPR) among sheep and goats in India between 2003 and 2009 by analyzing clinical samples from suspected cases of PPR that were submitted to the Rinderpest and Allied Disease Laboratory, Division of Virology, IVRI, Mukteswar for PPR diagnosis. PPR outbreaks were confirmed by detecting PPR virus (PPRV)-specific antigen in the clinical samples. Clinical samples (blood, nasal swabs, spleen, lymph node, kidney, liver, intestine, and pooled tissue materials) were taken from a total of 592 sheep and 912 goats in different states of India and screened for the presence of PPRV antigen using a monoclonal antibody-based sandwich ELISA kit. A total of 20, 38, and 11 laboratory-confirmed PPR outbreaks occurred among sheep, goat, and combined sheep and goat populations, respectively. Our findings provide evidence of widespread PPR endemicity in India. The underlying reasons could be variations in husbandry practices in different geographical regions, agro-climatic conditions, and livestock migration. Furthermore, decrease in the number of PPR outbreaks over time might be due to the effectiveness of current live PPR vaccines and timely vaccination of target species. Vaccination against PPR has been practiced in India since 2002 to control this disease. [ABSTRACT FROM AUTHOR]

Summary: Dual infection of 26 fetal and neonatal small ruminants with border disease virus (BDV) and peste des petits ruminants virus (PPRV) is reported. The animals included five aborted lamb fetuses, 19 neonatal lambs and two neonatal kids from flocks in regions of the Black Sea and the Aegean region. BDV and PPRV antigens were detected immunohistochemically in the brain, oral mucosa, intestine and lung of infected animals. Reverse transcriptase-polymerase chain reaction was used to demonstrate PPRV and BDV in samples of the spleen, lymph node, lung and brain from infected animals. On the basis of observations made, it is concluded that brain damage following intrauterine infection with BDV facilitates the passage of PPRV to the brain and results in infection of neuronal and glial cells by PPRV. [Copyright &y& Elsevier]

The article describes the modification of the paraffin-embedded tissue (PET) blot for use as a tool to differentiate between classical scrapie and experimental bovine spongiform encephalopathy (BSE) in sheep. The method was developed by using medulla (obex) from 21 cases of classical scrapie and 6 cases of experimental ovine BSE. The success of the differential PET blot in differentiating between all of the scrapie and ovine BSE cases is also discussed.

The article discusses a research study on the identification of the prion protein associated with scrapie (PrPSc) in sheep affected by classical scrapie through a Western blot (WB) using formalin-fixed, paraffin-embedded (FFPE) tissue. Results show that protein-banding patterns from WB using FFPE tissue were similar to protein-banding patterns produced by WB assays using fresh tissues from the same animals. It is not recommended to treat brain tissue with formic acid prior to paraffin embedding for FFPE tissue WB.

The article presents a study which examines the genetic aspects of the prion protein gene (PRNP) at codons 136, 154, and 174 for scrapie-infected Canadian sheep between 1998-2008. For the study, researchers conducted genotyping analysis on 249 sheep diagnosed with classical scrapie infection. They found that the manifestation of scrapie symptons in the Canadian sheep was highly linked to the ARQ haplotype and the ARQ/AQR genotype.

Summary: Scrapie is the transmissible spongiform encephalopathy (TSE) that naturally affects sheep and goats; these species are also susceptible to experimental infection with the bovine spongiform encephalopathy (BSE) agent. Discrimination between different strains of sheep scrapie and ovine BSE has been achieved by descriptive and quantitative profiling of deposits of the disease-associated prion protein (PrPd) in different areas of the brain, but this process is time-consuming and difficult to standardize between laboratories. The present paper describes an alternative PrPd profiling method that is less demanding and addresses these difficulties. It is based on the scoring of similar 14 PrPd types in 11 precisely defined areas of the telencephalon. When applied to 48 archived cases of experimental sheep BSE, SSBP/1, CH1641 and natural scrapie, it gave comparable results to the original profiling method, previously conducted on the same brains, and allowed differentiation between the different infectious sources. This new ‘short PrPd profiling’ method has the advantages of being less time-consuming and easier to standardize, so that it can be readily adopted by different laboratories to provide comparable results. [Copyright &y& Elsevier]

The article discusses a study which identified three cases of atypical scrapie in Canadian sheep. Based on results obtained from independent enzyme-linked immunosorbent assays and investigation of the molecular profile of the isolate by Western blot analysis, the detected cases involved a clinically normal 6-year old, mixed breed ewe, a 5-8-year old Rambouillet ewe, and a sheep culled from a 650 animal commercial flock. The study differentiated the epidemiology, histopathology and biochemical characteristics of atypical scrapie from classic scrapie.

Summary: Blood transfusion practices have resulted in iatrogenic cases of variant Creutzfeldt–Jakob disease (vCJD) and it is known that sheep blood is also infectious in the pre-clinical stages of natural scrapie and experimentally induced bovine spongiform encephalopathy (BSE). Further investigations have also shown that the pathological phenotype of sheep BSE and human vCJD is maintained after blood transfusion. The present study describes the pathological phenotype, in terms of accumulation of the disease-associated prion protein in brain and lymphoreticular tissues, in sheep receiving blood from donors infected with natural scrapie. The immunohistochemical examinations undertaken showed a degree of phenotypic variability within and between scrapie donors and recipients, which might be attributable to the presence of more than one scrapie strain amongst the donor sheep or to a host adaptation process, or to the interaction of both, rather than to the influence of the route of infection. [Copyright &y& Elsevier]

The article discusses research on the existence of scrapie in sheep in Great Britain since at least 1987. Aside from scrapie, other forms of transmissible spongiform encephalopathies (TSE), which are a group of neurodegenerative diseases that affect both animals and humans, include bovine spongiform encephalopathy (BSE) and Creutzfeldt-Jakob disease (CJD). The diagnostic tool used in the study was immunohistochemistry (IHC).

Summary: Neuroinflammation elicited by PrPres (resistant prion protein [PrP]) deposits in the central nervous system (CNS) has been shown to involve cellular and oxidative stress responses in bovine spongiform encephalopathy (BSE) as well as in several murine models of transmissible spongiform encephalopathy (TSE). Additionally, deregulation of water homeostasis has been suggested to be a further component of the spongiform changes observed in TSEs. The aim of the present study was to characterize the pathogenic events occurring in the CNS of sheep with spontaneously arising classical scrapie. Brains from seven affected animals and two controls were subject to immunohistochemical and histochemical examinations. Semi-quantitative evaluation of PrPres deposits and spongiform changes throughout the encephalon confirmed that PrPres deposition elicits significant astroglial and microglial reactions, as evidenced by an increase in the number of glial cells and changes in glial cell morphology involving increased expression of vimentin. The altered expression of metallothionein and heat shock protein 25 (HSP25) suggested that this neuroinflammatory reaction entails cellular and oxidative stress responses. In contrast, there was no change in expression of the membrane-associated water channel aquaporin 1 when PrPres accumulated in the brain. [Copyright &y& Elsevier]

This article presents a study which investigated the pathologic changes and diagnostic results of the first six cases of Nor98 scrapie disease diagnosed in sheep of the U.S. It is noted that distinctions between classic scrapie and Nor98 scrapie are developed using histopathology and immunodiagnostic results. Results of the study indicate that sheep that have genotypes associated with resistance to classic scrapie are not spared from the disease.

The article presents a study which evaluated the use of enzyme-linked immunosorbent assay (ELISA) antigen detection for the diagnosis of Border disease virus (BDV) infection in fetuses, stillbirths and newborn lambs. The study notes that it is more suitable to analyze stillbirths and lambs with clinical symptoms by using reverse transcription polymerase chain reaction (RT-PCR) when confirming the presence of BDV. The study concludes that antigen ELISA is less efficient in determining viral presence in stillbirths and lambs.

The article describes the case of Ovine herpesvirus 2 (OvHV-2) infection in healthy cattle, swine, sheep and goats in Norwegian farms with a history of previous outbreaks of malignant catarrhal fever. A brief overview of malignant catarrhal fever is discussed. It explains the mode of transmission of OvHV-2 between small ruminants and susceptible cattle.

The article presents information on a study which investigated the development of TaqMan quantitative polymerase chain reaction (qPCR) and conventional PCR assays targeting the DNA polvmerase gene for the detection of Capripoxvirus DNA from clinical specimens of sheep and goats. It discusses the comparative efficacy of different assays in the detection of Sheeppox virus and Goatpox virus from suspected clinical samples. It reveals the results of suspected clinical samples tested for the detection of capripoxvirus by different assays.

The article presents information on a study which investigated oral transmission of U.S. origin scrapie, a transmissible spongiform encephalopathy (TSE), to neonatal sheep. The study documents incubation periods, pathologic findings, and distribution of abnormal prion proteins by immunohistochemistry and Western blot in tissues of genetically susceptible and resistant neonatal lambs inoculated with pooled brain homogenates from 13 U.S. origin scrapie-affected ewes. The study reveals that younger animals have increased susceptibility to scrapie, have higher attack rates, and require smaller doses of inoculum to induce disease compared with older animals.

Summary: Transmissible spongiform encephalopathies (TSEs) are a group of fatal neurodegenerative diseases characterized microscopically by spongiform lesions (vacuolation) in the neuropil, neuronal loss, and gliosis. Accumulation of the abnormal form of the prion protein (PrPSc) has been demonstrated in the retina of natural and non-natural TSE-affected hosts, with or without evidence of microscopically detectable retinal pathology. This study was conducted to investigate the effect of PrPSc accumulation on retinal neurons in a natural host lacking overt microscopical evidence of retinal degeneration by comparing the distribution of retinal cell type-specific markers in control and scrapie-affected sheep. In retinas with PrPSc-immunoreactivity, there was disruption of the normal immunoreactivity patterns of the alpha isoform of protein kinase C (PKCα) and vesicular glutamate transporter 1 (VGLUT1), markers of retinal bipolar cells. Altered immunoreactivity was also observed for microtubule-associated protein 2 (MAP2), a marker of a subset of retinal ganglion cells, and glutamine synthetase (GS), a marker of Müller glia. These results demonstrate alterations of immunoreactivity patterns for proteins associated with specific cell types in retinas with PrPSc accumulation, despite an absence of microscopical evidence of retinal degeneration. [Copyright &y& Elsevier]

Summary: Maedi-visna virus (MVV) in sheep, which infects mainly cells of the monocyte/macrophage lineage, produces changes in the lung, mammary gland, brain and joints. In this study, however, the liver and heart of six naturally infected sheep were examined for the presence of the virus. MVV proviral DNA was demonstrated by polymerase chain reaction (PCR) analysis, and immunohistochemical examination revealed viral antigens in the cytoplasm of hepatocytes and cardiac myocytes. Although histopathological examination showed mild to moderate, chronic lymphocytic cholangiohepatitis and myocarditis and the presence of small lymphoid aggregates, the typical maedi lymphoproliferative lesions (lymphoid follicle-like structures of considerable size with germinal centres) were not seen in the liver and heart. These novel findings suggest that, although the macrophage is the main cell for productive viral replication, the liver and heart represent additional MVV targets. [Copyright &y& Elsevier]

Summary: In an effort to find a structural explanation for the lack of direct transmission of scrapie from sheep to humans, secondary structure predictions are used to locate the segments of the prion sequence which may be involved in the transformation from the normal form of the prion protein, which has high helix content, to the pathogenic form, which has high β-sheet content. The Chou–Fasman algorithm, which calculates propensities for both helix and sheet formation, was used to predict the secondary structures of the scrapie-resistant and the scrapie-susceptible variants of the ovine prion protein. The scrapie-susceptible variant, which has a glutamine at residue position 168 (human prion protein numbering), is predicted to have a propensity for sheet formation in that region of the molecule, while the scrapie-resistant variant, which has an arginine at position 168, does not. The valine at position 133, additionally present in the ovine variant which is the most susceptible to scrapie, is predicted to result in even more sheet formation. When the predicted secondary structure of the human prion protein is compared to those of the ovine prion protein variants, the human protein is found to be most similar to the scrapie-resistant variant. This result is proposed to provide a possible explanation for the observation that scrapie is not directly transmitted from sheep to humans. [Copyright &y& Elsevier]

Summary: In the epizootic of bovine spongiform encephalopathy (BSE) in Great Britain, the cattle in which a positive diagnosis was made numbered almost 180 000, but strain characterization was performed on only a very small sample of these cases. This report describes the results of BSE transmission to Prnpa mice from 150 transmission experiments at the Veterinary Laboratories Agency (VLA) over the last decade. These data, derived from a large sample of BSE-affected cattle, confirmed previous reports that show no evidence for diversity in BSE isolates. The agent was readily transmitted to mice, with a mean incubation period of 408 days in the RIII strain. Because the incubation period was related to the titre of the inoculum, it is not a reliable characteristic of strain type on primary isolation. Consistent neuropathological changes associated with infection by the BSE agent in RIII and C57Bl mice included focal vacuolation in the dorsal cochlear nuclei, vacuolation of the granule cell layer of the cerebellum, absence of lesions in the hippocampus and in the molecular layer of the cerebellum, and a fine particulate distribution of disease-specific PrP (demonstrated immunohistochemically), with few or no amyloid plaques. These features, together with the conventional lesion profile, will be of use in distinguishing the agents of BSE and scrapie in sheep. [Copyright &y& Elsevier]

The present paper shares the results of genetic structure analysis of the PEN-P gene, carried out in an ovine nucleus of Merinos of Cluj breed. Biological samples (blood) were collected from 20 rams (Merinos of Cluj breed) from a herd in genetics conservation belonging to SDE Cluj-Napoca and were genotyped at the PRN-P locus by means of primer extension analysis, and the final products were analyzed on a Genetic Analyzer ABI Prism 3130 xl. The frequency of genes by haplotypes were identified, and the individuals were categorized in risk groups based on the frequency of the identified genotype, with a view to applying assisted selection at the molecular level. [ABSTRACT FROM AUTHOR]

The authors comment on a study published in this issue of the journal which examined commercial rapid screening tests for scrapie in sheep. Particular focus is given to transmissible spongiform encephalopathy (TSE) rapid tests. Topics discussed include the possible use of lymphoid tissue for diagnostic and surveillance purposes, scrapie surveillance approaches in New Zealand, and suggestions on collecting and testing lymphoid tissue.