Publications by authors named "Spyridon Kritas"

Aujeszky's Disease, caused by the pseudorabies virus (PRV), is an acute, often fatal disease affecting mainly pigs and incidentally other animals. While eradicated in several countries, PRV persists in wild boar populations, posing a risk to domestic pigs. This study investigates PRV prevalence in wild boars in the region of Epirus, located in the northwest of Greece.

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Background: Cupriavidus gilardii is an aerobic, gram-negative, motile, glucose-nonfermenting bacillus, first described in 1999. Typically, it exhibits low pathogenicity in humans, causing opportunistic infections primarily in individuals with compromised immune systems. This bacterium has been also found in various environmental sources such as plants and contaminated soils.

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Mast cells (MCs) are derived from hematopoietic progenitors, mature in vascularized tissues, and participate in innate and acquired immunity. Neuroinflammation is a highly debated topic in the biomedical literature; however, the impact of tumor necrosis factor (TNF) and IL-33 on MCs in the brain has not been widely addressed. MCs can be activated by IgE binding to FcεRI, as well as by different antigens.

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West Nile Virus (WNV) is maintained in nature in a bird-mosquito cycle and human infections follow a seasonal pattern, favored by climatic conditions. Peloponnese Region, located in Southern Greece, initiated an active WNV surveillance program to protect public health during 2019-2020. The project included monitoring of avian hosts and mosquito vectors, while sampling locations were prioritized after consideration of WNV circulation in birds, mosquitos and humans during previous seasons.

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The present study investigates the pathogenicity of two recently isolated strains of Suid herpesvirus 1 (SuHV1), the Greek strain Hercules and the Chinese strain HeN1, in unvaccinated pigs and in pigs vaccinated with a Bartha-K61 strain. In an experiment performed in negative pressure kiosks (isolators), 45-day old seronegative pigs previously oronasally /intramuscularly vaccinated with the Bartha-K61 vaccine strain, along with unvaccinated controls, were challenged either with the Hercules strain or the HeN1 strain of SuHV1. All animals were observed daily for clinical signs and body temperature and nasal swabs, faeces, blood and bodyweight were collected up to a maximum period of 20 days post-challenge (dpc).

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Taking into consideration the essential contribution of farming, it is of rising importance to add knowledge regarding bacterial species occurrence in water samples from aquaculture zones from the point of view of both the organism and public health. In the present study, we investigated the bacterial community existing in water samples from six aquaculture areas in the Thermaikos gulf, northern Greece, that may provoke toxicity in aquatic organisms and humans and may indicate environmental pollution in mussel production as well as algal blooms. Bacterial species were identified molecularly by sequencing of a partial 16s rRNA segment and were analyzed phylogenetically for the confirmation of the bacterial taxonomy.

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Caliciviruses are single stranded RNA viruses, non-enveloped structurally, that are implicated in the non-bacterial gastroenteritis in various mammal species. Particularly in swine, viral gastroenteritis represents a major problem worldwide, responsible for significant economic losses for the pig industry. Among the wide range of viruses that are the proven or suspected etiological agents of gastroenteritis, the pathogenicity of the members of Caliciviridae family is among the less well understood.

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Article Synopsis
  • The study examined the presence of canine Astrovirus (CAstV), canine Norovirus (canine NoV), and canine Sapovirus (Canine SaV) in saliva and feces of 201 dogs across Greece, utilizing two molecular detection methods.
  • CAstV was detected in 7.5% to 15% of dogs, with higher prevalence found in young asymptomatic dogs; Canine SaV was found in 23% of the samples, while canine NoV was not detected.
  • The results indicate that CAstV and Canine SaV are circulating among Greek dogs, with SYBR-Green Real-time RT-PCR showing superior sensitivity for detection, and the CAstV strain identified through phylogen
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Pseudorabies virus (PRV) is the causative agent for Aujeszky's disease, a disease that mainly affects pigs and incidentally other domestic and wild animals. While PRV is almost always fatal, causing neurological disease independently of the age in non-porcine species, the development of neurological manifestation in its host species, the pig, highly depends on the age. In this study, an attempt was made to investigate the effect of nerve development on the outcome of virus infection and the effect of virus infection on the structure of nerves in piglets of various ages.

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Backround: Astrovirus, Norovirus and Sapovirus exhibit a wide distribution in swine pig herds worldwide. However, the association of porcine Astrovirus (PAstV), porcine Norovirus (PoNoV) and porcine Sapovirus (PoSaV) with disease in pigs remains uncertain. In this study, we investigated the prevalence of PAstV, PoNoV and PoSaV in Greek pig farms using both conventional RT-PCR and SYBR-Green Real-time RT-PCR in an effort to compare the sensitivity of the two methods.

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The purpose of this research was to characterize the antibiotic resistance patterns of spp. isolated from commercial farrow to finish farms in Greece, and analyze the relevant molecular resistance mechanisms among the resistant isolates. Susceptibility testing to five different classes of antibiotics was performed in 100 and 100 , previously isolated and identified.

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Background: Microcystins are emerging marine biotoxins, produced by potentially toxic cyanobacteria. Their presence has been reported in aquatic animals in Greek freshwater, while data are few in marine environments. Since the climate change induces eutrophication and harmful algal blooms in coastal marine ecosystems affecting the public health, further research on microcystins' presence in marine waters is required.

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Background: Brucellosis, caused by several Brucella species, such as the bacterium Brucella melitensis, is considered one of the most severe zoonotic diseases worldwide. Not only does it affect ruminant animal populations, leading to a substantial financial burden for stockbreeders, but also poses severe public health issues. For almost four decades in southern Europe and elsewhere, eradication of the disease has been based on ambiguously effective programs, rendering massive sanitation of livestock urgent and indispensable.

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We performed a survey aimed at analyzing milk samples collected from cows with mastitis for the presence of extended-spectrum β-lactamase (ESBL)-producing Escherichia coli. Single-quarter mastitic milk samples obtained from 400 cows in 23 Greek dairy herds with a history of E. coli mastitis were processed for the selective isolation of ESBL-producing E.

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Intracellular bacteria provoking zoonoses, such as those of the genus , present a host cell tropism mostly limited to the monocyte/macrophage lineage, leading to chronic inflammatory reactions, difficult-to-eradicate-infections, and widespread prevalence among ruminants. Eradication of brucellosis has been based on programs that translate into a substantial financial burden for both the authorities and stockbreeders, if not strictly followed. To this end, we sought to create an in vitro cell model that could be utilized as future reference for adequately measuring the number of engulfed brucellae/cell, using peripheral blood-derived sheep macrophages infected with at decimal multiplicities of infection (MOI = 5000-5), to simulate the host cell/microorganism interaction and monitor bacterial loads up to 6 days post-infection.

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Background: Q fever, caused by Coxiella burnetii, is a zoonosis that presents a worldwide distribution and affects both humans and animals. The route of dispersal of the pathogen by ruminants into the environment usually involves stages of abortion and parturition, nevertheless the agent can, also, be detected in other animal samples. Therefore it is considered as important in terms of proper diagnosis, as well as, for epidemiology and surveillance purposes, to genotype the pathogen.

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A number of bacteria provoking zoonotic diseases present intracellular survival and a host cell tropism limited to the monocyte/macrophage lineage. Thus, infection is rendered difficult to eradicate, causing chronic inflammatory reactions to the host and widespread prevalence. Although self-inactivating lentiviral vectors have been successfully tested in the clinic against virally-induced human infectious diseases, little is known about the transduction susceptibility of ruminant animal phagocytes that play a critical role in the outbreak of zoonotic diseases such as brucellosis.

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Mast cells (MCs) promote guest immune responses to parasites and play a critical role in allergic and inflammatory reactions. Once they have been activated, MCs release highly inflammatory compounds that can provoke serious pathologic signs that can lead to death. MCs generate a number of preformed, de novo synthesized compounds and inflammatory cytokine/chemokine synthesis in response to the high-affinity (Kd=10 M) immunoglobulin E receptor triggering.

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The objective of this study was to assess the effects of a probiotic strain Clostridium butyricumMIYAIRI 588 (CBM588) on broiler and weaned piglet health and zootechnical performance. Five field studies were carried out in broilers and five in weaned piglets under European feed additive guidelines. Each study followed a randomized blocked design with two treatments: Control (basal diet) and CBM588 supplemented groups.

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The host response to either exogenous or endogenous insults produces a series of changes, characterized by alterations in immunological functions and generation of mediators called cytokines which include the interleukin-1 (IL-1) family members. IL-1 acts as a hormone mediating the host responses to infection and inflammation. Blocking inflammatory IL-1 family members can be effective against inflammatory disorders, including allergies.

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In atherosclerosis lipoproteins stimulate the innate immune response, leading to the release of inflammatory cytokines and chemokines. Hypercholesterolemia may activate the synthesis and release of inflammatory cytokines such as IL-1, which induces TNF release in mast cells (MCs). IL-1 and IL-1 family members orchestrate a broadening list of inflammatory diseases, including atherosclerosis.

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Pseudorabies virus (species Suid herpesvirus 1) belongs to the genus Varicellovirus, subfamily Alphaherpesvirinae, family Herpesviridae, and is the causative agent of an acute and frequently fatal disease that affects mainly pigs. Here, we report the genome sequences of two strains of this virus isolated in Greece in 2010.

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The presence of Gram-negative bacteria species, other than Salmonella spp., in the gallbladder of pigs was examined. Isolated Gram-negative bacteria were assigned to species using the Microgen™ GnA+B-ID Systems.

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The minimum inhibitory concentrations (MICs) of enrofloxacin, ciprofloxacin, spectinomycin, tetracycline, spiramycin and erythromycin against 30 caprine Greek isolates of Mycoplasma agalactiae were determined using E test methodology. The E test strips were placed on Eaton's agar medium without antimicrobials and phenol red. MICs were then read by determining where the growth inhibition zone intersected with the MIC scale on the strip.

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