George Valiakos

Prof. George Valiakos

Department of Microbiology and Parasitology, Veterinary Faculty, University of Thessaly,, Kardítsa, Thessalía, Greece
orcid
Associate Professor, Faculty of Veterinary Science, Universi...

Research Focus & Metrics

Academic Career Length

16Years (2011-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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1 December 2015 in Veterinary Microbiology
Verified
Journal Article
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VSV. Spyrou
V. Spyrou
George ValiakosGeorge Valiakos
George Valiakos

4 November 2021 in Veterinary Sciences
Verified
Journal Article
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George ValiakosGeorge Valiakos
George Valiakos
IKIoanna Kapna
Ioanna Kapna
The objective of this review is to collect and present the results of relevant studies on an international level, on the subject of colistin resistance due to mcr genes prevalence in livestock animals. After a literature search, and using PRISMA guidelines principles, a total of 40 swine, 16 bovine and 31 poultry studies were collected concerning mcr-1 gene; five swine, three bovine and three poultry studies referred to mcr-2 gene; eight swine, one bovine, two poultry studies were about mcr-3 gene; six swine, one bovine and one poultry manuscript studied mcr-4 gene; five swine manuscripts studied mcr-5 gene; one swine manuscript was about mcr-6, mcr-7, mcr-8, mcr-9 genes and one poultry study about mcr-10 gene was found. Information about colistin resistance in bacteria derived from animals and animal product foods is still considered limited and that should be continually enhanced; most of the information about clinical isolates are relative to enteropathogens Escherichia coli and Salmonella spp. This review demonstrates the widespread dispersion of mcr genes to livestock animals, indicating the need to further increase measures to control this important threat for public health issue.

28 August 2015 in Veterinary Record Open
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Journal Article
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ATA. Touloudi
A. Touloudi
George ValiakosGeorge Valiakos
George Valiakos
Labrini V. AthanasiouLabrini V. Athanasiou
Labrini V. Athanasiou
PBP. Birtsas
P. Birtsas
AGA. Giannakopoulos
A. Giannakopoulos
CBCharalambos Billinis
Charalambos Billinis
Objectives: Serum 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 Methods: The 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 . Results: Antibodies 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. Conclusions: These 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.

7 May 2014 in PLOS ONE
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Journal Article
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George ValiakosGeorge Valiakos
George Valiakos
KPKonstantinos Papaspyropoulos
Konstantinos Papaspyropoulos
AGAlexios Giannakopoulos
Alexios Giannakopoulos
PBPeriklis Birtsas
Periklis Birtsas
Sotirios TsiodrasSotirios Tsiodras
Sotirios Tsiodras
CBCharalambos Billinis
Charalambos Billinis
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.

AMAndriani Marka
Andriani Marka
ADAlexandros Diamantidis
Alexandros Diamantidis
APAnna Papa
Anna Papa
George ValiakosGeorge Valiakos
George Valiakos
Serafeim C. ChaintoutisSerafeim C. Chaintoutis
Serafeim C. Chaintoutis
DCDimosthenis Chochlakis
Dimosthenis Chochlakis
During the last three years Greece is experiencing the emergence of West Nile virus (WNV) epidemics. Within this framework, an integrated surveillance and control programme (MALWEST project) with thirteen associate partners was launched aiming to investigate the disease and suggest appropriate interventions. One out of seven work packages of the project is dedicated to the State of the Art report for WNV. Three expert working groups on humans, animals and mosquitoes were established. Medical databases (PubMed, Scopus) were searched together with websites: e.g., WHO, CDC, ECDC. In total, 1,092 relevant articles were initially identified and 258 of them were finally included as references regarding the current knowledge about WNV, along with 36 additional sources (conference papers, reports, book chapters). The review is divided in three sections according to the fields of interest: (1) WNV in humans (epidemiology, molecular characteristics, transmission, diagnosis, treatment, prevention, surveillance); (2) WNV in animals (epidemiological and transmission characteristics concerning birds, horses, reptiles and other animal species) and (3) WNV in mosquitoes (control, surveillance). Finally, some examples of integrated surveillance programmes are presented. The introduction and establishment of the disease in Greece and other European countries further emphasizes the need for thorough research and broadening of our knowledge on this viral pathogen.

12 November 2012 in Virology Journal
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Journal Article
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George ValiakosGeorge Valiakos
George Valiakos
ATAntonia Touloudi
Antonia Touloudi
Labrini V. AthanasiouLabrini V. Athanasiou
Labrini V. Athanasiou
AGAlexios Giannakopoulos
Alexios Giannakopoulos
CIChristos Iacovakis
Christos Iacovakis
CBCharalambos Billinis
Charalambos Billinis
Background: A West Nile virus (WNV) disease outbreak occurred in 2010 in northern Greece with a total of 262 laboratory-confirmed human cases and 35 deaths. A serological and molecular surveillance was conducted on samples of hunter-harvested wild birds prior to and during the outbreak. Findings: Serum and tissue samples from 295 resident and migratory wild birds, hunter-harvested during the 2009–2010 and 2010–2011 hunting seasons at the epicenter of the outbreak in northern Greece, were tested for the presence of WNV-specific antibodies by immunofluorescence assay and virus neutralization test. WNV neutralizing antibodies were detected in 53 avian samples. Fourteen positive sera were obtained from birds hunter-harvested up to 8 months prior to the human outbreak. Specific genetic determinants of virulence (His249Pro NS3 mutation, E-glycosylation motif) were recognized in a WNV lineage 2 strain isolated from a hunter-harvested Eurasian magpie and a nucleotide mismatch was revealed between this strain and a mosquito WNV strain isolated one month earlier in the same area. Conclusions: This is the first report regarding exposure of wild birds to WNV prior to the 2010 outbreak, in Greece. Results provide evidence of the implication of wild birds in a local enzootic cycle that could allow maintenance and amplification of the virus before and during the outbreak. Findings of past exposure of migratory birds to WNV upon their arrival in Greece during autumn migration, suggest avian species with similar migration traits as candidates for the introduction of WNV into Greece. The possibility that an endemic circulation of WNV could have caused the outbreak, after an amplification cycle due to favorable conditions cannot be excluded.