Publications by authors named "Gyozo L Kajan"

Article Synopsis
  • Turtles are unique reptiles facing endangerment, yet turtle adenoviruses are under-researched compared to other reptiles, prompting a study on their molecular diversity.
  • Researchers analyzed samples from turtles in Brazil and Hungary, employing nested PCR techniques and Sanger sequencing to detect and characterize adenoviruses and previously unreported circoviruses.
  • The study identified new strains of testadenoviruses, including the first adenovirus from a sea turtle, and suggests coevolutionary patterns between these viruses and their turtle hosts, revealing significant insights into turtle virology.
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Several bat-associated circoviruses and circular rep-encoding single-stranded DNA (CRESS DNA) viruses have been described, but the exact diversity and host species of these viruses are often unknown. Our goal was to describe the diversity of bat-associated circoviruses and cirliviruses, thus, 424 bat samples from more than 80 species were collected on four continents. The samples were screened for circoviruses using PCR and the resulting amino acid sequences were subjected to phylogenetic analysis.

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The present research aimed to evaluate the diversity of all monkeypox virus strains with a special focus on recently isolated ones by a comprehensive phylogenetic analysis of all available sequences, based on the concatenate of four viral genes. Almost all current strains from 2022 showed a high level of similarity to each other on the analyzed stretches: 218 strains shared identical sequence. Among all analyzed strains, the highest number of differences was counted compared to a RefSeq strain (Zaire-96-I-16) on the whole concatenate.

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To assess the prevalence of adenoviruses in psittacine birds kept in Slovenia, 258 cloacal swabs were collected from different psittacine species and screened by a nested PCR with degenerate, consensus primers targeting the adenoviral DNA polymerase gene. Forty-two samples were found to be positive. By sequencing, 28 samples from 10 different parrot species were identified as the formerly described siadenovirus, psittacine adenovirus 2 (PsAdV-2).

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In both a Eurasian blue tit (Cyanistes caeruleus) and a great tit (Parus major), found dead in North Rhine-Westphalia, Germany, intranuclear inclusion bodies were observed in the kidneys during the histologic examination. Siadenoviruses were detected in both samples, and the nucleotide sequence of the partial DNA polymerase, obtained from the blue tit, was almost identical with that of great tit adenovirus type 1, reported from Hungary previously. The sequence, derived from the German great tit sample was more similar to great tit adenovirus 2, yet divergent enough to forecast the possible establishment of a novel viral type and species.

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Wild birds are threatened by anthropic effects on a global scale, and their adenoviruses might contribute to their endangerment. Thus, it is important to reveal the real biodiversity of avian adenoviruses, as, unfortunately, this research topic is far from being prioritized. The turkey hemorrhagic enteritis is an economically important disease causing high mortalities, and its causative siadenoviral agent is only distantly related to other avian siadenoviruses in phylogenetic analyses.

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The family includes non-enveloped viruses with linear dsDNA genomes of 25-48 kb and medium-sized icosahedral capsids. Adenoviruses have been discovered in vertebrates from fish to humans. The family is divided into six genera, each of which is more common in certain animal groups.

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Fowl adenoviruses (FAdVs) are infectious agents, mainly of chickens, which cause economic losses to the poultry industry. Only a single serotype, namely FAdV-5, constitutes the species (FAdV-B); however, recently, phylogenetic analyses have identified divergent strains of the species, implicating a more complex scenario and possibly a novel serotype. Therefore, field isolates of the species were collected to investigate the contemporary diversification within FAdV-B, including traditional serotyping.

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Preexisting immune responses toward adenoviral vectors limit the use of a vector based on particular serotypes and its clinical applicability for gene therapy and/or vaccination. Therefore, there is a significant interest in vectorizing novel adenoviral types that have low seroprevalence in the human population. Here, we describe the discovery and vectorization of a chimeric human adenovirus, which we call HAdV-20-42-42.

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We studied the genetic variability of serine protease inhibitors (serpins) of Myxozoa, microscopic endoparasites of fish. Myxozoans affect the health of both farmed and wild fish populations, causing diseases and mortalities. Despite their global impact, no effective protection exists against these parasites.

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A novel lymphocystivirus causing typical signs of lymphocystis virus disease in whitemouth croaker (Micropogonias furnieri) on the coast of Uruguay was detected and described recently. Based on genetic analysis of some partially sequenced core genes, the virus seemed to differ from previously described members of the genus Lymphocystivirus. In this study, using next-generation sequencing, the whole genome of this virus was sequenced and analysed.

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Avian adenoviruses (AdVs) are a very diverse group of pathogens causing diseases in poultry and wild birds. Wild birds, endangered by habitat loss and habitat fragmentation in the tropical forests, are recognised to play a role in the transmission of various AdVs. In this study, two novel, hitherto unknown AdVs were described from faecal samples of smooth-billed ani and tropical screech owl.

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In the recent years, African swine fever has become the biggest animal health threat to the swine industry. To facilitate quick genetic analysis of its causative agent, the African swine fever virus (ASFV), we developed a simple and efficient method for next generation sequencing of the viral DNA. Execution of the protocol does not demand complicated virus purification steps, enrichment of the virus by ultracentrifugation or of the viral DNA by ASFV-specific PCRs, and minimizes the use of Sanger sequencing.

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Viruses have been infecting their host cells since the dawn of life, and this extremely long-term coevolution gave rise to some surprising consequences for the entire tree of life. It is hypothesised that viruses might have contributed to the formation of the first cellular life form, or that even the eukaryotic cell nucleus originates from an infection by a coated virus. The continuous struggle between viruses and their hosts to maintain at least a constant fitness level led to the development of an unceasing arms race, where weapons are often shuttled between the participants.

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In this work, we examined the diversity of fowl adenovirus (FAdV) types occurring in Hungary. From diseased chicken flocks in Eastern Hungary, 29 FAdV strains were isolated between 2011 and 2015. We performed molecular typing of the isolates based on their partial hexon sequences.

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Human adenoviruses (HAdVs) are common pathogens that can cause respiratory, gastrointestinal, urogenital, and ocular infections. They are divided into seven species containing 85 genotypes. Straightforward typing systems might help epidemiological investigations.

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A novel human adenovirus was isolated from a pediatric case of acute respiratory disease in Panama City, Panama in 2011. The clinical isolate was initially identified as an intertypic recombinant based on hexon and fiber gene sequencing. Based on the analysis of its complete genome sequence, the novel complex recombinant Human mastadenovirus D (HAdV-D) strain was classified into a new HAdV type: HAdV-84, and it was designated Adenovirus D human/PAN/P309886/2011/84[P43H17F84].

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Complete genomes of eight reference strains representing different serotypes within the species Fowl aviadenovirus D (FAdV-D) and Fowl aviadenovirus E (FAdV-E) were sequenced. The sequenced genomes of FAdV-D and FAdV-E members comprise 43 287 to 44 336  bp, and have a gene organization identical to that of an earlier sequenced FAdV-D member (strain A-2A). Highest diversity was noticed in the hexon and fiber genes and ORF19.

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Recombinant vectors based on human adenovirus serotype 5 (HAdV-5) have been extensively studied in preclinical models and clinical trials over the past two decades. However, the thorough understanding of the HAdV-5 interaction with human subjects has uncovered major concerns about its product applicability. High vector-associated toxicity and widespread preexisting immunity have been shown to significantly impede the effectiveness of HAdV-5-mediated gene transfer.

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Complete genomes of the first isolates of pigeon adenovirus 1 (PiAdV-1) and Muscovy duck adenovirus (duck adenovirus 2, DAdV-2) were sequenced. The PiAdV-1 genome is 45,480bp long, and has a gene organization most similar to turkey adenovirus 1. Near the left end of the genome, it lacks ORF0, ORF1A, ORF1B and ORF1C, and possesses ORF52, whereas six novel genes were found near the right end.

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Molecular typing of 26 recent fowl adenovirus (FAdV) isolates obtained in Eastern Hungary between 2006 and 2011 was performed. The viruses were isolated on primary chicken embryo liver cell cultures from carcasses of chickens, sent for diagnostic investigation. The isolates were subjected to a PCR to amplify a fragment from the hexon gene.

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Fowl adenoviruses (FAdVs) are grouped into five different species: Fowl adenovirus A through Fowl adenovirus E (FAdV-A to FAdV-E), and so far, complete nucleotide sequences are only available for the genomes of FAdV-A, FAdV-C, FAdV-D and FAdV-E members. The aim of this study was to sequence and analyze the complete genome of the reference strain representing FAdV-B (FAdV-5, strain 340). By applying Next Generation Sequencing, the genome was found to be 45,781 bp long with 56.

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We present, to our knowledge, the first complete genome sequence of a waterfowl aviadenovirus, goose adenovirus (GoAdV) strain P29, and an analysis of its genetic content in comparison with five published aviadenovirus genome sequences. Of the 35 genes predicted to encode functional proteins, the central region of the genome contains 19 (IVa2 to fiber-2) that were inherited from the ancestor of all known adenoviruses. Of the remaining genes, nine have orthologues only in aviadenoviruses and seven lack orthologues in any adenovirus.

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Adenoviruses are frequent infectious agents in different poultry species. The traditional, serological typing of new isolates by virus neutralisation tests is now in transition to be replaced by PCR and sequencing. The first PCRs, recommended for the detection of adenoviruses, had been designed to target the gene of the major capsid protein, the hexon.

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The complete genome sequence of an adenovirus, isolated from turkey and proposed to be turkey adenovirus type 1 (TAdV-1), was determined to extend our knowledge about the genome organisation and phylogeny of aviadenoviruses. The longest adenovirus genome, consisting of 45,412 bp, with the highest G+C content (of 67.55%) known to date, was found.

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