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  • Author or Editor: Ádám Dán x
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Equine herpesvirus-1 (EHV-1) can be classified into distinct groups by single nucleotide polymorphisms (SNPs) in their genomes. Only a few of these can be associated with a special attribute of the virus. Differences in the ORF30 region can determine the neuropathogenic potential, while by substitutions in the ORF68 region several strain groups can be made. In previous studies no connection was found between the neuropathogenic potential and the SNPs in ORF68, but the occurrence of members of distinct groups in different outbreaks can facilitate epidemiological investigations because the geographical distribution of a particular group is very often specific. The present study aimed at the molecular examination and grouping of 35 EHV-1 strains isolated from aborted equine fetuses in Hungary between 1977 and 2008. Genotyping was based on the comparison of nucleotide sequences of a polymorphic segment located in the ORF68 region, which had previously been found to be a useful tool for classification. After sequencing this region, the Hungarian EHV-1 isolates could be classified into seven groups. Only 23 of the 35 isolates belonged to the formerly described groups, while the SNPs of 12 isolates diverged, and four new groups could be set up. In addition, phylogenetic analysis was performed to compare the ORF68 sequences of the Hungarian strains with the sequences of isolates from Europe, America and Australia. The number of newly formed groups suggests that the further analysis of unknown EHV-1 isolates would involve the emergence of extended numbers of new groups, which can impair the usability of this grouping method.

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Porcine circovirus type 2 (PCV2) associated reproductive disease was diagnosed in a herd containing only gilts. A single case of abortion occurred and no other disorder was evident in the herd. PCV2 antigen and/or DNA were detected in two aborted fetuses. One of the fetuses, revealing both PCV2 DNA and antigen, presented multinucleated giant cells, severe vascular lesions (intramural oedema, fibrinoid necrosis, mild lympho-histiocytic vasculitis, fibrin thrombi) and mild non-suppurative inflammation in the lungs. Other abortifacient infections were not found. This is the only report of PCV2-induced abortion in Hungary since 1999, when PCV2-associated disease was first discovered in the country.

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Goose haemorrhagic polyomavirus (GHPV) provoke haemorrhagic nephritis and enteritis of domestic geese. Outbreaks were detected in European countries and caused economic losses for goose keepers. Domestic ducks may be infected with GHPV without any signs typical for geese. The genomic organisation of some isolates was described but the gene functions and the pathomechanisms of the virus was not precisely defined. Here we describe the genome sequence and structure of GHPV of a goose from a Hungarian goose flock showing characteristics of the haemorrhagic nephritis and enteritis. The GHPV genome investigated in this study was 5252 bp long and was very similar (99% nucleotide identity) to sequences deposited in the GenBank. All the whole GHPV genomes possess the same ORFs in length, including the VP1, VP2, VP3, ORF-X, t and T tumour antigens. Amino acid changes are detected mainly in the putative ORF-X region. Data about the GHPV genome imply a conserved genomic structure among isolates from different countries. Genomic and epidemiological studies may help vaccine development efforts and identify potential heterologous reservoirs of GHPV.

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Abstract

An epizootic caused by a new orthobunyavirus called Schmallenberg virus (SBV) was recognised in European ruminants in 2011 and 2012. The re-emergence of the infection was reported in several countries in the subsequent years. Although the main clinical sign of SBV infection is abortion, the impact of SBV in natural cases of abortion in domestic ruminants had not been systematically examined before this study. The aim of the study was to investigate the role of SBV infection and to compare it to the importance of other causes of abortion by examining 537 natural cases of abortion that had occurred between 2011 and 2017 in Hungary. The cause of abortion was determined in 165 (31%) cases. An infectious cause was proved in 88 (16%) cases. SBV infection was found only in a total of four cases (0.8%) using real-time polymerase chain reaction. Three of them proved to be inapparent SBV infection, and one case was attributed to SBV-induced abortion by detecting non-purulent encephalitis and SBV nucleoprotein by immunohistochemistry in a brain tissue sample. According to the results, SBV played a minor role in natural cases of domestic ruminant abortion in Hungary during the 7-year period following the first SBV outbreak in 2011.

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Acta Veterinaria Hungarica
Authors: Ákos Thuma, Ádám Dán, Éva Kaszanyitzky, Béla Fazekas, Ádám Tóth and Róbert Glávits

Two groups of one-day-old Peking ducklings (Groups I and II, 12 birds/group) were inoculated orally with Brachyspira pilosicoli and two groups with B. alvinipulli (Groups III and IV, 12 birds/group). T-2 toxin was added to the feed of Groups II and IV in a dose of 1 mg/kg of feed. Groups V and VI served as uninfected control groups (ducks of Group VI received T-2 toxin). The body weight gain of the ducks was measured and clinical signs were monitored continuously. The birds were sacrificed and necropsied on days 7, 14, 21, and 28 post infection (PI). The liver, spleen, kidney, thymus, bursa of Fabricius, ileum, caecum and colon were examined histologically. Culturing of Brachyspira spp. and immunohistochemistry were performed from the sampled parts of the intestines as well. No gross pathological or histological lesions that could be associated with B. pilosicoli or B. alvinipulli were detectable in the intestinal mucous membrane including the colonised intestinal glands. Mortality did not occur during the experimental period. Decrease in body weight gain was significant in the T-2-toxin-treated groups, and it was slight (not significant) in the Brachyspira-infected groups. Crust on the beaks, necrosis, crusting and ulceration in the mucous membrane of the oral cavity and on the skin of the feet, atrophy of the thymus and bursa of Fabricius due to the effect of T-2 toxin, accompanied by lymphocyte depletion, were observed. These lesions were most prominent on days 14 and 21 PI but were seen on day 28 PI as well. Immunohistochemical detection and reisolation of B. pilosicoli and B. alvinipulli were successful on days 7, 14, 21 and 28 days from different segments of the intestine of certain birds, but no significant difference was observed in the colonisation rate between the T-2-toxin-treated and the untreated groups.

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Acta Microbiologica et Immunologica Hungarica
Authors: Enikő Fehér, Szilvia Marton, Ádám György Tóth, Krisztina Ursu, Kerstin Wernike, Martin Beer, Ádám Dán and Krisztián Bányai

Since its emergence near the German–Dutch border in 2011, Schmallenberg virus (SBV) has been identified in many European countries. In this study, we determined the complete coding sequence of seven Hungarian SBV genomes to expand our knowledge about the genetic diversity of circulating field strains. The samples originated from the first case, an aborted cattle fetus without malformation collected in 2012, and from the blood samples of six adult cattle in 2014. The Hungarian SBV sequences shared ≥99.3% nucleotide (nt) and ≥97.8% amino acid (aa) identity with each other, and ≥98.9 nt and ≥96.7% aa identity with reference strains. Although phylogenetic analyses showed low resolution in general, the M sequences of cattle and sheep origin SBV strains seemed to cluster on different branches. Both common and unique mutation sites were observed in different groups of sequences that might help understanding the evolution of emerging SBV strains.

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Acta Veterinaria Hungarica
Authors: Éva Ivanics, Vilmos Palya, Béla Markos, Ádám Dán, Krisztina Ursu, Balázs Harrach, Győző Kaján and Róbert Glávits

Two outbreaks of severe acute disease characterised by hepatitis and hydropericardium were observed in young goslings on large-scale farms in Hungary. Histological examination revealed multifocal necrotic areas and two types of intranuclear inclusion bodies adjacent to necrotic areas in the liver. The most prominent type of inclusion bodies showed strong basophilic staining and completely filled the enlarged nucleus. The other type was eosinophilic and occupied the centre of the nucleus, which had margination of chromatin. In the heart, haemorrhage was associated with multifocal necrosis in the myocardium. The presence of fowl adenovirus DNA in different organs of the naturally infected goslings was detected by polymerase chain reaction (PCR). The virus was isolated, and identified as a goose adenovirus by genomic analysis. This is the first report on the involvement of a goose adenovirus in severe acute disease associated with hepatitis and hydropericardium.

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Acta Veterinaria Hungarica
Authors: Márta Lőrincz, Attila Cságola, Imre Biksi, Levente Szeredi, Ádám Dán and Tamás Tuboly

Porcine circoviruses (PCV) are present worldwide, infecting domestic pigs and wild boars alike. Studies under laboratory conditions indicated that PCV can be taken up by mice and the virus can replicate in these animals. The possible role of rodents in maintaining and transmitting PCV2 infection in the field has not been investigated yet. The present study reports the detection of PCV2, the pathogenic form of the virus, in mice and rats. A number of rodents, such as mice, rats and voles, were collected at PCV2-infected farms and also outside pig herds and tested for the presence of the virus by polymerase chain reaction (PCR). The results indicated that PCV2 can be present both in mice and rats (65.0% and 23.8% positivity, respectively) on the infected premises, but those rodents that were collected outside pig farms remained negative for PCV2.

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Acta Veterinaria Hungarica
Authors: Daniel Cadar, Attila Cságola, Marina Spinu, Ádám Dán, Krisztina Ursu, Márta Lőrincz and Tamás Tuboly

Porcine circoviruses (PCV) are widespread in domestic pigs worldwide and there is growing information about the presence of PCV in other suid species. Based on serological studies with sera of wild boars, it was established that PCV1 was present in these animals and antibodies specific to PCV2 were also detected in wild boars living in captivity or in sylvatic areas, both with or without clinical signs of PMWS. Studies including PCV2 genome or antigen detection confirmed the previous findings. This is the first report about the presence of PCV in Transylvanian wild boar populations. Four hundred and sixty-nine samples were collected and grouped according to geographic origin, tested for the presence of PCV DNA using a real-time quantitative polymerase chain reaction assay, and 13.52% of the animals proved to be positive for one or in three cases both of the PCV genotypes. PCV2 was detected in all of the PCV-positive samples.

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Acta Veterinaria Hungarica
Authors: Anna Valkó, András Marosi, Attila Cságola, Rózsa Farkas, Zsuzsanna Rónai and Ádám Dán

Enteric viral diseases of swine are one of the most frequent disorders causing huge economic losses in pork production. After the reappearance of an emerging enteropathogen, porcine epidemic diarrhoea virus (PEDV) in Hungary in 2016, an extensive survey was initiated in an attempt to identify diarrhoea-related porcine viruses, including adeno-, astro-, boca-, calici-, circo-, corona-, kobu-, rota- and Torque teno viruses. A total of 384 faecal samples collected during a twoyear period from diarrhoeic and asymptomatic pigs of various ages in 17 farms were screened by conventional and real-time PCR methods. Half of the samples contained at least one examined virus with the dominance of kobuvirus (55.1%) followed by bocaviruses (33.2%) and rotavirus groups A and C together (20.9%), while coronaviruses including PEDV were not found in this set of samples. Statistical analysis showed a highly significant difference (P < 0.0001) in the frequency of single infections compared to mixed ones with the exception of weaned pigs, in which group additionally most viruses were detected. The results of this study suggest that the complexity of this disease may vary with age, which makes the prevention of diarrhoea a challenge, especially in weaned pigs.

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