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  • Author or Editor: Levente Szeredi x
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Severe disease induced by porcine circovirus type 2 (PCV2) was observed in three pigs originating from a large herd affected by respiratory and digestive signs as well as wasting. Proliferative and necrotising pneumonia (PNP) was diagnosed in two animals, while severe acute interstitial pneumonia characterised by the presence of abundant hyaline membrane in the alveoli and fibrin in the bronchioles was found in one pig. In all cases, large amounts of PCV2 antigen were found in each tissue sample collected from the lungs and mediastinal lymph nodes. Neither porcine reproductive and respiratory syndrome virus (PRRSV) nor swine influenza virus (SIV) was detected, and no bacteria could be cultured in any of the cases. Vascular lesions, e.g. degeneration of endothelial cells, perivascular and intramural oedema, fibrinoid necrosis, vasculitis, perivasculitis, and vascular thrombi were observed in all cases, associated with the presence of PCV2 antigen. The viral antigen was present in the intravascular mononuclear cells, endothelial cells, myocytes and infiltrating inflammatory cells in lymph and blood vessels. In one case, obliterating thrombi in the lymph and blood vessels were directly connected to areas of tissue necrosis and were associated with abundant PCV2 antigen. The results further suggest the causative role of PCV2 infection in PNP, and the importance of the vascular system in the pathogenesis of PCV2-associated diseases of swine.

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A postweaning pig died in spite of antibiotic therapy showing wasting in a small herd. Postweaning multisystemic wasting syndrome (PMWS) was diagnosed on the basis of gross pathological and histological lesions and the presence of moderate amounts of porcine circovirus 2 (PCV2) antigen in tissue samples. Mycotic gastritis caused by Zygomycetes spp. was found on round areas with a diameter of 1 to 3 cm in the glandular mucosa of the stomach. Moderate amount of PCV2 viral antigen was detected almost evently in the stomach and mostly in the macrophages. In addition, acute uraemia, revealed by an ammonia-like stink of the gastric mucosa and the presence of acute erosions on the glandular mucosa of the stomach, was observed as a consequence of PCV2-induced interstitial nephritis. Only PCV2 infection could be identified as a cause of secondary mycotic gastritis. The results further support the immunosuppressive ability of PCV2 infection in PMWS-affected pigs.

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The infectious origin of fatal cases of calf pneumonia was studied in 48 calves from 27 different herds on postmortem examination. Lung tissue samples were examined by pathological, histological, bacterial culture, virus isolation and immunohistochemical methods for the detection of viral and bacterial infections. Pneumonia was diagnosed in 47/48 cases and infectious agents were found in 40/47 (85%) of those cases. The presence of multiple respiratory pathogens in 23/40 (57.5%) cases indicated the complex origin of fatal calf pneumonia. The most important respiratory pathogens were Mannheimia-Pasteurella in 36/40 (90%) cases, followed by Arcanobacterium pyogenes in 16/40 (40%) cases, Mycoplasma bovis in 12/40 (30%) cases, and bovine respiratory syncytial virus in 4/40 (10%) cases. Histophilus somni was detected in 2/40 (5%) cases, while bovine herpesvirus-1, bovine viral diarrhoea virus and parainfluenza virus-3 were each found in 1/40 (2.5%) case. Mastadenovirus, bovine coronavirus, influenza A virus or Chlamydiaceae were not detected.

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Klebsiella (K.) oxytoca infection induced the abortion of a female equine fetus in the 10th month of pregnancy. Bacteria were cultured from the liver, lung and stomach content. They were labelled with an anti- Mycobacterium bovis antibody in the thymus, liver and lungs and were stained with Giemsa and Brown-Brenn staining in the thymus and lung. The diffusely consolidated lungs contained numerous grey-whitish foci 2–4 mm in diameter, which corresponded to severe pyogranulomatous pneumonia characterised by numerous intraalveolar neutrophils and macrophages and multinucleated Langhans’ giant cells. K. oxytoca was located in the cytoplasm of these cells, and extracellularly in the lumen of alveoli, bronchioles and bronchi, in the capsule of thymus and in the sinusoids of the liver. The results indicate that K. oxytoca can cause sporadic equine abortion.

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Authors: Levente Szeredi, Attila Cságola, Ádám Dán and László Dencső

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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The applicability of an anti- Mycobacterium bovis (BCG) antibody-based immunohistochemistry (IHC) procedure was investigated using everyday veterinary pathological samples collected from 13 different animal species. Fifty-one formalin-fixed and paraffin-embedded tissue samples were selected for this study. Forty, 4 and 7 tissue samples contained different species of bacteria, fungi and protozoa, respectively. Three serial sections were prepared in each case. Two sections were pre-treated with enzyme and heat, respectively, while the last section was not pre-treated. In seven cases the sensitivity of histochemical staining (HSM), IHC and bacteriological culture were compared. Heating of the sections in a microwave oven was the most effective method in the case of almost all pathogens used. Strong or moderate positive reactions were observed for 26 bacterial species, all fungal and 2 protozoal species, while weak reactions occurred for 2 bacterial and 1 protozoal species. Only 4 protozoal and 12 bacterial species, including Leptospira and all the five Mycoplasma species examined, showed no reaction in this test. IHC had almost the same sensitivity as bacteriological culture and was more sensitive than HSM. The IHC method presented here should be preferred to HSM as a general screening tool in cases where pathological lesions suspicious for infections are evident and no microorganism can be cultured in vitro or only formalin-fixed tissue samples are available for the laboratory examination.

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Authors: Levente Szeredi, Ferenc Rausch, Zsófia Szeleczky and Szilárd Jánosi

The disease induced by Bibersteinia trehalosi usually occurs in lambs. It is triggered by certain stress factors and often emerges in the form of severe outbreaks. In adult sheep, only sporadic cases have been reported so far. This paper reports a B. trehalosi-induced high-mortality case occurring only in adult sheep. Seventy out of 628 adult sheep (11%) died in the affected pen during the six days of the outbreak. None of the 146 lambs kept in the neighbouring pen showed any clinical signs during that period. Several preceding events (shearing, vaccination and antiparasitic treatment) can be regarded as factors predisposing to the disease. Five adult sheep (4 females and 1 male) were sent for laboratory examination. Clinical, gross pathological, histological and bacteriological examinations revealed results corresponding to those reported previously in lambs that had died of a B. trehalosi-induced septicaemia.

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Authors: Levente Szeredi, Ádám Dán, Péter Malik, Szilárd Jánosi and Ákos Hornyák

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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Authors: Levente Szeredi, Ádám Dán, Péter Malik, Szilárd Jánosi and Ákos Hornyák

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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Authors: Barbara Ujvári, Levente Szeredi, László Pertl, Gergely Tóth, Károly Erdélyi, Szilárd Jánosi, Tamás Molnár and Tibor Magyar

This is the first report of Pasteurella multocida type B in Hungarian pigs. This disease was observed in backyard-raised pigs in three households within a small area. Neither the source of the infection nor the epidemiological connection between any of the premises could be determined. The most consistent lesion was dark red discolouration of the skin of the ventral neck and brisket, with accompanying oedema and haemorrhages. The morbidity was low and lethality relatively high, with three dead (50%) and two euthanised (33%) out of six affected animals. A total of three isolates of P. multocida (P55, P56 and P57) were cultured from these cases and examined in detail. These were identified as P. multocida ssp. multocida biovar 3. All were toxA negative and belonged to serotype B:2. Multilocus sequence typing was used to assign these to a new sequence type (ST61) that is closely related to other haemorrhagic septicaemia causing strains of P. multocida regardless of the host. M13 polymerase chain reaction and virulence-associated gene typing also show that type B strains form a highly homogeneous, distinct phylogenic group within P. multocida.

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