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A total of 216 local crossbred sheep from 16 scrapie-affected Greek flocks and 210 purebred sheep of the milk breeds Chios and Karagouniko from healthy flocks were analysed for scrapie-linked polymorphisms in the prion protein (PrP) gene. Of the 216 sheep in this case-control study, 96 sheep were clinical cases, 25 subclinical cases (asymptomatic at the moment of euthanasia but positive by histopathology and/or ELISA detecting proteinase-resistant PrP) and 95 healthy controls (negative by all evaluations). Polymorphisms at codons 136, 154 and 171 were determined by denaturing gradient gel electrophoresis, followed by RFLP and sequencing. Scrapie, both clinical and subclinical, was associated with the genotypes ARQ/ARQ (88 of 110 sheep of that genotype), ARQ/TRQ (9 of 13), ARQ/AHQ (15 of 38) and VRQ/VRQ (9 of 17). Histopathological lesions were more severe in the clinical cases. Genotypes ARQ/ARR (26 sheep), ARQ/ARK (seven sheep), AHQ/ARR (one sheep), ARH/ARH (one sheep) and ARR/ARH (three sheep) were detected exclusively in healthy control sheep. In the purebred survey, four genotypes were present in the Chios sheep (ARQ/ARQ, ARQ/TRQ, ARQ/AHQ and ARQ/ARR) and four in the Karagouniko sheep (ARQ/ARQ, ARQ/AHQ, ARQ/ARR and ARQ/ARH). INTRODUCTIONScrapie is an infectious neurodegenerative fatal disease of sheep and goats belonging to the group of transmissible subacute spongiform encephalopathies (TSEs), along with bovine spongiform encephalopathy (BSE), chronic wasting disease and Creutzfeldt-Jakob disease. All TSEs are characterized by long incubation periods, disturbances in behaviour and movement, degeneration in tissues of the central nervous system (CNS) and accumulation of an abnormal isoform of the host-encoded cellular prion protein in tissues of the CNS. It has been hypothesized that these diseases are attributable to a conformational change in the prion protein (PrP), which results in a change from a predominantly a-helical protein to a b-sheet form (Prusiner, 1996). Normal PrP protein (PrP c ) is a cell-surface glycoprotein, the expression of which is necessary for the production of prions (Büeler et al., 1993;Prusiner et al., 1993). PrP c is expressed in most tissues of the body, with the nervous tissues showing the highest PrP c expression levels (Bendheim et al., 1992;Horiuchi et al., 1995).In several animal species and in humans, polymorphisms within the open reading frame of the PrP gene are associated with the occurrence and the pathological lesions of TSEs (Pocchiari, 1994). The incidence of natural scrapie is strongly influenced by alterations in the host gene that encodes the PrP (Hunter, 1997). Such polymorphisms may influence the conversion of PrP c into the pathogenic isoform . The mechanism by which the individual allelic variants lead to altered susceptibility or incubation periods has not been elucidated. It has been proposed that in humans PrP polymorphisms may be present at critical sites involved in the conformational transition from PrP c to PrP Sc (Glockshuber et al., 1999). The study o...

The last three years have seen remarkable progress in comprehending predisposing factors and upgrading our treatment arsenal concerning hepatocellular carcinoma (HCC). Until recently, there were no means to withstand the progression of viral hepatitis-associated liver cirrhosis to HCC. A deeper understanding of the molecular mechanism of the disease, the use of biomarkers, and the follow-up, allowed us to realize that conventional chemotherapy failing to increase survival in patients with advanced HCC tends to be exiled from clinical practice. Multi-kinase inhibitors (TKIs) such as sorafenib, lenvatinib targeting mainly the vascular endothelial growth factor receptors 1-3 VEGFRs 1-3 provided until recently the standard of care for these patients, as first-or second-line treatment. Since May 2020, the atezolizumab plus bevacizumab combination (immunotherapy plus anti-VEGF) has become the new reference standard in first-line HCC treatment. Additionally, anti-programmed cell death protein 1 (anti-PD-1) immunotherapy can be used as a secondline treatment following first-line treatment's failure. Phase III clinical trials have recently suggested the efficacy of novel anti-angiogenic factors such as cabozantinib and ramucirumab as a second-line treatment option. With considerations about toxicity arising, clinical trials are investigating combinations of the aforementioned targeted therapies with immunotherapy as first-line treatment. This paper aims to perform a systematic review describing the evolving treatment options for HCC over the last decades, ranging from neoadjuvant treatment to systemic therapy of advanced-stage HCC. With the landscape of HCC treatment shifting towards novel agents the forming of a new therapeutic algorithm for HCC seems to be imperative.

ObjectivesSerum samples, collected from 94 European wild boar (Sus scrofa) during the hunting seasons 2006 -2010 from different regions of Greece, were examined in order to estimate the role of these wildlife species as reservoir of pathogens important for livestock and/or public health.Materials and MethodsThe assays used for this purpose were commercial indirect ELISA for the detection of antibodies against porcine circovirus type 2 (PCV-2), porcine reproductive and respiratory syndrome (virus) (PRRSV), Aujeszky's disease virus (ADV), influenza A (IA) virus, Actinobacillus pleuropneumoniae, Mycoplasma hyopneumoniae, Salmonella species, Trichinella species and indirect immunofluorescence antibody test for the detection of antibodies against Toxoplasma gondii and Neospora caninum.ResultsAntibodies against PCV-2, PRRSV, ADV, IA virus,A. pleuropneumoniae, M. hyopneumoniae,Salmonella species, Trichinella species, T. gondii and N. caninum were detected in 19.1 per cent, 12.8 per cent, 35.1 per cent, 1.1 per cent, 57.4 per cent, 0 per cent, 4.3 per cent, 6.4 per cent, 5.2 per cent and 1.1 per cent of the samples, respectively. Cluster analysis revealed a hot spot of seropositivity near Bulgarian border; seropositivity to ADV was more common among female animals.ConclusionsThese results indicate exposure of wild boar to most of the above-mentioned pathogens, raising concern about the possibility that these species may pose a significant health risk for livestock and/or humans.

The major histocompatability complex (MHC) is a multigene family of receptors that bind and present antigenic peptides to T-cells. Genes of the MHC are characterized by an outstanding genetic polymorphism, which is considered to be maintained by positive selection. Sites involved in peptide binding form binding pockets (P) that are collectively termed the peptide-binding region (PBR). In this study, we examined the level of MHC genetic diversity within and among natural populations of brown hare (Lepus europaeus) from Europe and Anatolia choosing for analysis of the second exon of the DQA locus, one of the most polymorphic class II loci. We aimed at an integrated population genetic analysis of L. europeaus by (i) correlating MHC polymorphism to genetic variability and phylogenetic status estimated previously from maternally (mtDNA) and biparentally (allozymes, microsatellites) inherited loci; and (ii) comparing full-length exon amino acid polymorphism with functional polymorphism in the PBR and the binding pockets P1, P6 and P9. A substantial level of DQA exon 2 polymorphism was detected with two completely different set of alleles between the Anatolian and European populations. However, the phylogeny of full-length exon 2 Leeu-DQA alleles did not show a strong phylogeographic signal. The presence of balancing selection was supported by a statistically significant excess of nonsynonymous substitutions over synonymous in the PBR and a trans-species pattern of evolution detected after phylogenetic reconstruction. The differentiating patterns detected between genetic and functional polymorphism, i.e. the number and the distribution of pocket variants within and among populations, indicated a hierarchical action of selection pressures.

West Nile Virus (WNV) is the causative agent of a vector-borne, zoonotic disease with a worldwide distribution. Recent expansion and introduction of WNV into new areas, including southern Europe, has been associated with severe disease in humans and equids, and has increased concerns regarding the need to prevent and control future WNV outbreaks. Since 2010, 524 confirmed human cases of the disease have been reported in Greece with greater than 10% mortality. Infected mosquitoes, wild birds, equids, and chickens have been detected and associated with human disease. The aim of our study was to establish a monitoring system with wild birds and reported human cases data using Geographical Information System (GIS). Potential distribution of WNV was modelled by combining wild bird serological surveillance data with environmental factors (e.g. elevation, slope, land use, vegetation density, temperature, precipitation indices, and population density). Local factors including areas of low altitude and proximity to water were important predictors of appearance of both human and wild bird cases (Odds Ratio = 1,001 95%CI = 0,723–1,386). Using GIS analysis, the identified risk factors were applied across Greece identifying the northern part of Greece (Macedonia, Thrace) western Greece and a number of Greek islands as being at highest risk of future outbreaks. The results of the analysis were evaluated and confirmed using the 161 reported human cases of the 2012 outbreak predicting correctly (Odds = 130/31 = 4,194 95%CI = 2,841–6,189) and more areas were identified for potential dispersion in the following years. Our approach verified that WNV risk can be modelled in a fast cost-effective way indicating high risk areas where prevention measures should be implemented in order to reduce the disease incidence.

-Due to the probable role played by rodents as a reservoir for the transmission of the EMC virus to pigs, the experiment reported here was performed in order to assess the transmission rate of EMCV within a rat population. Twenty-five eight-week-old Wistar rats housed in individual plastic cages were experimentally infected either with a Greek myocardial EMCV strain (5 rats with a 0.2 × 10 6 TCID 50 dose per rat and 10 rats with a 0.5 × 10 4.5 TCID 50 dose per rat, oronasally) or a Belgian myocardial EMCV strain (10 rats with a 0.5 × 10 4.5 TCID 50 dose per rat, oronasally). Two to five days later, each inoculated rat was moved to a new clean cage and coupled with a contact rat to compare the pathogenicity of the two strains and to estimate the basic reproduction ratio R 0 , indicating the level of EMCV transmission. During the experiments, faecal virus excretion was measured as well as the serological response against EMCV. After euthanasia, virus isolation was attempted from different rat tissues. Neither strains produced mortality, nor clinical signs and only low titres of neutralising antibodies were found. All contact rats, however, were infected and the virus was isolated from their faeces and from various tissues. Both 10-pair experiments revealed a point estimate for the R 0 of (95%-CI for both the Greek and Belgian EMCV strains = 4.48 − ), as did the 5-pair experiment with a higher dose of the Greek strain (95%-CI = 1.83 − ). Combining the results from the two 10-pair experiments resulted in an estimate for R 0 of (95%-CI: 9.87 − ). These results indicate that the EMC virus can spread very easily within a rat population by horizontal rat-to-rat transmission (R 0 >> 1).

BackgroundAlthough orf is endemic around the world, there are few descriptions of Orf virus strains and comparisons of these strains. We report the sequence and phylogenetic analysis of the partial B2L gene of Orf virus from two outbreaks of the disease in Greece. The first was an outbreak of genital form of the disease in a flock imported from France, whilst the second was an outbreak of the disease in the udder skin of ewes and around the mouth of lambs in an indigenous flock.ResultsPhylogenetic analysis was performed on a part (498 bp) of the B2L gene of 35 Parapoxvirus isolates, including the two Orf virus isolates recovered from each of the two outbreaks in the present study. This analysis revealed that the maximum nucleotide and amino-acid variation amongst Orf virus strains worldwide (n = 33) was 8.1% and 9.6%, respectively. The homology of the nucleotide and amino-acid sequences between the two Greek isolates was 99.0% and 98.8%, respectively. The two Greek isolates clustered only with Orf virus strains.ConclusionsWe suggest that there can be differences between strains based on their geographical origin. However, differences in the origin of strains or in the clinical presentation of the disease may not be associated with their pathogenicity. More work is required to determine if differing clinical presentations are linked to viral strain differences or if other factors, e.g., flock immunity, method of exposure or genetic susceptibility, are more important to determine the clinical presentation of the infection.