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ABSTRACT: The effect of bovine viral diarrhoea virus (BVDV) infection on early pregnant cows between 10 and 24days after virus inoculation at day 26 of pregnancy was determined. Four cows were inoculated intravenously with either BVDV (treated, n=3) or growth medium (control, n=1). The treated cows were euthanized on either day 10, 17 or 24 post-infection and the control cow was euthanized on day 24 post-infection. The level of serum 2-5A synthetase increased in all of the three treated cows. Progesterone levels decreased to below 1.0ng/ml between 10 and 22days after inoculation in two of the three treated cows and the embryos/foetuses of two cows died. Therefore, BVDV may be a cause of early embryonic or feotal loss in early pregnant cows and serum 2-5A synthetase may be useful as an indicator of viral infection in cows.
Research in Veterinary Science 12/2012; · 1.65 Impact Factor
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ABSTRACT: To investigate the effect of immunosuppression on porcine circovirus type 2 (PCV2) infection, hysterectomy-produced, colostrum-deprived piglets were inoculated with the virus by the intranasal or intraperitoneal route, with or without dexamethasone (DEX) treatment. Eleven piglets aged 8 days were divided into four groups, namely group A (four animals given PCV2), B (three given PCV2 with DEX), C (two given sterile medium with DEX) and D (two given sterile medium). No significant clinical signs were observed. Histopathological and immunohistochemical examination revealed granulomatous inflammation and PCV2 antigen in the lymphoid tissues of group B piglets, but not in the other three groups. Flow cytometric analysis of peripheral blood lymphocytes showed a reduced number of CD4+ T cells in DEX-treated piglets (groups A and C). No differences between groups were observed in respect of the number of B cells, serum IgG concentration, or PCV2 antibody titre. These results indicate that DEX influenced the pathogenic effects of PCV2 infection in lymphoid organs, and that suppression of cell-mediated immunity may play a role in the aetiology of postweaning multisystemic wasting syndrome.
Journal of Comparative Pathology 12/2003; 129(4):294-302. · 1.65 Impact Factor
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ABSTRACT: Pulsed field gel electrophoresis (PFGE) and random amplified polymorphic DNA (RAPD) methods were applied for molecular typing of 130 Mannheimia (Pasteurella) haemolytica serotype A1 isolates obtained from 13 prefectures in Japan. These isolates were divided into 15 ApaI PFGE profiles that formed six distinct clusters (clusters A-F). Fifty-three (40.7%) isolates were classified in cluster B, and 20.0, 13.8, 12.3, 6.9 and 6.1% of isolates were in clusters E, A, F, D and C, respectively. The isolates of cluster B were differentiated into seven subtypes (B1-B7) and subtype B5 contained 63% (34/53) of isolates. RAPD revealed four banding patterns (types I-IV), and among 130 isolates 60.7% (79/130) of isolates were RAPD type I. All of the RAPD type I isolates were grouped into clusters A-C by PFGE. There was no relationship between molecular typing and geographic origin of these isolates. These results indicate that isolates of M. haemolytica A1 strain with various molecular profiles have already spread in Japan and may have caused sporadic infections.
Epidemiology and Infection 11/2003; 131(2):939-46. · 2.84 Impact Factor
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ABSTRACT: The effects of immunosuppression were examined in 1.5-month-old calves that were given dexamethasone (DM) before endobronchial inoculation with bovine adenovirus type 3 (BAV-3). Immunohistopathologically, severe necrotizing bronchiolitis with eosinophilic and basophilic intranuclear inclusion bodies was observed both in DM-treated 1.5-month-old infected calves and in non-DM-treated 7-day-old infected calves. These inclusion bodies were correlated with the detection of BAV-3 antigen and viral particles. The presence of inclusion bodies in the desquamated epithelial cells or of BAV-3 antigen, or both, correlated well with the isolated level of BAV-3 in bronchoalveolar lavage (BAL) fluid. Few immunoglobulin (IgG, IgM, and IgA)-containing B lymphocytes or CD8+ T lymphocytes infiltrated the pneumonic lesion in both the 7-day-old and the DM-treated 1.5-month-old infected calves. Thus, depletion of CD8+ T lymphocytes in calves might influence the clearance of BAV-3 from respiratory tissues.
Veterinary Pathology 04/2003; 40(2):128-35. · 1.95 Impact Factor
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ABSTRACT: Three 1-week-old and three 3-month-old Holstein calves that had received colostrum were inoculated endobronchially with bovine adenovirus 3 (BAV-3). The gross and histologic lesions in these six infected calves were localized mainly in the right caudal lobe of the lung and were closely associated with the site of the deposition of the inoculum. The pneumonic lesions were severe necrotizing bronchitis, bronchiolitis, and alveolitis, accompanied by infiltration of inflammatory cells and proliferation of type 2 pneumocytes. Intranuclear inclusion bodies, BAV-3 antigen, and virus particles were detected in the degenerated epithelial cells in the 1-week-old but not the 3-month-old calves. After infection, the total cell count in the bronchoalveolar lavage (BAL) fluid cells was increased. The results of BAV-3 isolation from BAL fluid were correlated with the detection of intranuclear inclusion bodies in the desquamated epithelial cells in the BAL fluid cells from the right caudal lobe but not in cells from the left caudal lobe. CD8+ T lymphocytes in the pneumonic lesion were found only in the 3-month-old infected calves. The difference in the immunopathologic reactions between the 1-week-old and the 3-month-old infected calves may be attributed to differences in immune system development.
Veterinary Pathology 10/2002; 39(5):565-71. · 1.95 Impact Factor
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ABSTRACT: A total of 65 equine group A rotaviruses (GAR) isolated from diarrheal foals at 48 farms in Hokkaido, Japan, between 1996 (29 isolates) and 1997 (36 isolates) were characterized for their VP7 and VP4 serotypes by PCR, nucleotide sequencing, and virus neutralization (VN) tests. By PCR VP7 typing, all isolates were classified as G3 or G 14, and the predominant serotype in each year was G3 (86%) in 1996 and G14 (53%) in 1997. VN tests with these 20 isolates randomly selected confirmed the specificity of PCR on the bases of complete agreement of the results in these methods (9 G3 and 11 G14), and revealed that all 9 G3 isolates were subtype G3B. There were five differing amino acid residues in three VP7 antigenic regions between subtypes G3A and G3B. Antiserum to a baculovirus recombinant that expressed P[12] VP4 neutralized all isolates and P[12] reference strains. These results suggest that genotype P[12] GAR belong to a single VP4 serotype, and that one VP4 and two VP7 serotypes (G3B and G14) of GAR were predominant in the equine population in Japan.
Archives of Virology 11/2001; 146(10):1949-62. · 2.11 Impact Factor
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ABSTRACT: The assumption that sheep carry ovine herpesvirus-2 (OvHV-2), the causative agent of sheep-associated malignant catarrhal fever (SA-MCF), is widely accepted, albeit OvHV-2 has not been isolated. We attempted experimental contact transmission of MCF from Japanese sheep persistently infected with OvHV-2 to Japanese deer (Cervus nippon) and cattle. In Experiment 1, a deer was kept in close quarters with an infected ewe. In Experiment 2, a second deer was kept with the same ewe. In Experiment 3, two cows were each kept with two infected wethers. In Experiment 1, the deer developed clinical signs at 138 days after first contact and then died. OvHV-2 genes by polymerase chain reaction (PCR) and fluorescent antibodies to Alcelaphine herpesvirus-1 were detected in the affected deer. Moreover, sequences of PCR products (423bp), obtained by amplification of materials from the sheep and from the affected deer, coincided. These results clearly confirmed that the sheep was a carrier of OvHV-2, and that this virus had induced SA-MCF in a deer. In other experiments, no OvHV-2 infection occurred in deer and cattle during the 6-18 months periods of contact, though viral genes were detected in the nasal swabs and white blood cells of the sheep. To our knowledge, this is the first report on successful experimental transmission of MCF from OvHV-2-infected sheep to deer.
Veterinary Microbiology 04/2001; 79(1):83-90. · 3.33 Impact Factor
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ABSTRACT: We used an immunohistochemical method to investigate changes in macrophage and lymphocyte subpopulations in various lymphoid tissues of pigs in the acute phase of porcine reproductive and respiratory syndrome virus (PRRSV) infection. The numbers of CD8+ cells and B-cells varied among lymphoid tissues after PRRSV infection. In the infected pigs, numbers of CD8+ cells increased in systemic lymphoid tissues whereas numbers of B-cells increased in mucosa-associated lymphoid tissues. There was no difference in the distribution of virus-infected cells and macrophages between lymphoid tissues of the infected pigs. These changes may be associated with the establishment of virus persistence or the emergence of concurrent infection in mucosal organs.
Veterinary Immunology and Immunopathology 12/1999; 71(3-4):257-62. · 2.08 Impact Factor
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ABSTRACT: Nine pigs were inoculated endobronchially with Actinobacillus pleuropneumoniae serotype 1 (App-1) 6 days after infection with Aujeszky's disease virus (ADV); four died within 3 days and the remainder were killed after 1-6 days. Immunohistopathologically, there were two types of pneumonic lesion: pleuropneumonia, characterized by coagulative necrosis, oedema and fibrinous thrombosis; and necrotizing interstitial pneumonia, characterized by bronchitis, bronchiolitis and alveolitis. The former type of lesion was associated with App-1 antigen, and the latter with ADV antigen. These results indicated that a combined ADV and App-1 infection produced severe haemorrhagic pleuropneumonia; and that ADV and App-1 each produced a characteristic pneumonic lesion.
Journal of Comparative Pathology 08/1997; 117(1):25-33. · 1.65 Impact Factor
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ABSTRACT: Eleven field cases of a disease characterized by severe dyspnoea or abdominal breathing were examined post mortem. The affected pigs had antibody against porcine reproductive and respiratory syndrome virus (PRRSV). The predominant lung lesions were severe proliferative and interstitial pneumonia, and slight suppurative bronchopneumonia. The lesions were closely associated with the sites at which PRRSV and Mycoplasma hyorhinis antigens were detected. Four of five pigs inoculated with PRRSV developed slight pneumonitis. The fifth animal, which died of severe pneumonitis, yielded a heavy culture of M. hyorhinis. These findings demonstrate that dual infection with M. hyorhinis and PRRSV caused severe pulmonary lesions.
Journal of Comparative Pathology 05/1996; 114(3):315-23. · 1.65 Impact Factor
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ABSTRACT: Four 4-day-old gnotobiotic piglets infected intranasally with the Kanagawa/74 strain of hog cholera virus (HCV) did not develop severe illness over a period of 3 weeks. Large amounts of HCV were isolated from the lymphoid tissues and serum at necropsy. After the acute phase, hyperplasia of histiocytes and plasmacytopoiesis were observed in two pigs (killed 14 and 21 days after inoculation). The number of CD4+ and CD8+ T lymphocytes increased significantly and their location was consistent with the site of HCV replication. The results suggest that a CD8+ T-lymphocyte reaction is associated with persistent HCV infection.
Journal of Comparative Pathology 05/1996; 114(3):257-63. · 1.65 Impact Factor
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ABSTRACT: Abnormal changes of T-cell subpopulation were observed in the peripheral blood lymphocytes of pigs infected with porcine reproductive and respiratory syndrome (PRRS) virus. Pigs with naturally occurring PRRS revealed increases in CD2+ and CD8+ cells, and decreases in CD4+ cells and the ratios of CD4+/CD8+ cells. Specific-pathogen-free pigs inoculated with PRRS virus showed remarkable decreases in total lymphocytes, CD4+ and CD2+ cells on Postinoculation Day (PID) 3. The decline of CD4+ cells continued for at least 14 days, while CD2+ cells showed a tendency to increase thereafter. On the other hand,CD8+ cells slightly decreased in number on PID 3, and then increased remarkably; their number was significantly larger on PIDs 28 and 35 than on PID 0. The ratios of CD4+/CD8+ cells were significantly low between PIDs 3 and 28 as compared with PID 0. However, there were no differences in thymocyte subpopulations between infected and non-infected pigs, suggesting that the PRRS virus does not modulate intrathymic T-cell differentiation. In an experiment with peripheral blood mononuclear cell cultures, PRRS virus caused neither alteration of T-cell subpopulations nor cell proliferation, suggesting that the virus is not cytotoxic for CD4+ cells and not mitogenic for CD8+ cells.
Veterinary Immunology and Immunopathology 04/1996; 50(1-2):19-27. · 2.08 Impact Factor
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ABSTRACT: Seven pigs inoculated endobronchially with Actinobacillus pleuropneumoniae (App) serotype 1 developed acute and subacute necrotizing pleuropneumonia. When treated with high doses of atropine (0.25 mg per kg) and/or xylocaine spray using a bronchoscope, which suppressed mucus secretion and ciliary activity, the pigs showed severe pleuropneumonia and 2 treated pigs died within 36 hr after inoculating 320 colony forming units (CFU)/2ml of App serotype 1. Histopathologically, their lungs had alveolar and interlobular edema and intravascular fibrinous thrombosis. In the surviving pigs, the lymph nodes had App antigens in the germinal centers corresponding closely with activated follicular dendritic cells and increased in the number of IgG- and IgM-containing cells. The bacterial antigens were also observed as small sized granules in the cytoplasm of bronchoalveolar macrophages. These findings suggest that the attachment of App to the mucosal surface may be crucial in the development of pneumonic lesions.
Journal of Veterinary Medical Science 11/1995; 57(5):839-44. · 0.85 Impact Factor
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ABSTRACT: Six HPCD (hysterectomy-produced, colostrum-deprived) pigs were inoculated endobronchially with pseudorabies virus (PRV) in the right caudal lobe by means of a bronchoscope. Two pigs, killed on days 5 and 7, had severe purulent pneumonia in the right caudal lobe, associated with an accidental Haemophilus parasuis serovar 4 infection. The three surviving animals were treated with antibiotics. The pigs infected with PRV had necrotizing bronchiolitis and alveolitis. PRV antigen was closely associated with necrotic foci, and was sometimes surrounded by profuse H. parasuis antigen. PRV antigen and IgG- and IgA-containing cells were also detected in bronchioalveolar lavage fluid. These results suggested that the PRV infection destroyed respiratory epithelial cells and allowed H. parasuis to proliferate in the lungs.
Journal of Comparative Pathology 06/1994; 110(4):329-39. · 1.65 Impact Factor
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ABSTRACT: Pigs inoculated endobronchially (EB) with 2 ml of virus suspension containing 10(4) TCID50 per ml of the YS-81 strain of pseudorabies virus (PRV), by means of a bronchoscope, all developed viral pneumonia. No pneumonic lesions were observed in intranasally inoculated pigs. Macroscopical and microscopical lesions were localized to the middle to caudal parts of the right caudal lobe and were closely associated with the site at which the inoculum was deposited. PRV became attached to all types of cells and caused destruction of epithelial cells, and viral antigen persisted in the alveolar macrophages. After PRV infection, the total cell number in broncho-alveolar lavage (BAL) fluid was slightly increased and a high titre of PRV was found in the cells of BAL fluid in EB infected pigs. The findings suggest that PRV infection leads to dysfunction of alveolar macrophages before cell death is produced by virus replication.
Journal of Comparative Pathology 12/1993; 109(4):335-44. · 1.65 Impact Factor
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ABSTRACT: Seven hysterectomy-derived colostrum-deprived pigs aged 4 weeks were inoculated intranasally with 10(3) plaque-forming units (1 ml) of the Yamagata YS-81 strain of Aujeszky's disease virus. One pig died and five developed encephalomyelitis and trigeminal ganglionitis. Three pigs killed on days 12-16 showed prominent malacic degeneration. Associated with the malacic foci were many lysosome-positive cells. IgG- and IgM-containing cells in the perivascular cuffs and glial nodules were first detected on day 7, after which they increased in number. They were thought to be closely associated with the presence of neutralizing antibody. These findings suggest that inflammatory cells in the brain are of haematogenous origin.
Journal of Comparative Pathology 06/1993; 108(4):361-8. · 1.65 Impact Factor
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ABSTRACT: Pigs exposed to fluctuating temperatures (high, 30 +/- 2 degrees C; low, 4 +/- 1 degrees C) were intranasally inoculated with Aujeszky's disease virus (ADV). ADV-infected pigs, exposed to the fluctuating temperatures, showed severe clinical signs and ADV in the nasal secretions persisted longer than in the ADV-infected control pigs kept at the normal temperature (20 +/- 2 degrees C). High concentrations of ADV were isolated from nasal secretions on the 1st day after inoculation of the virus. Pathologically, all ADV-infected pigs had non-suppurative encephalitis and trigeminal ganglionitis. The lesions were more widely distributed in pigs exposed to fluctuating temperatures than in infected control pigs. Two infected pigs given the stress had severe malacic foci in the frontal lobe and four of them had prominent interstitial pneumonia. In the pigs exposed to fluctuating temperatures, a significant number of immunoglobulin-containing cells, especially IgM-containing cells, did not respond to ADV infection. A significant (P < 0.01) difference in the number of IgG- and IgM-containing cells was observed between the ADV-infected pigs exposed to the fluctuating temperature and ADV-infected control pigs, respectively. These results demonstrated that the stress of fluctuating temperatures enhanced the susceptibility to ADV infection.
Journal of Comparative Pathology 08/1992; 107(2):221-9. · 1.65 Impact Factor
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ABSTRACT: Three calves aged 1 week (group 1), three aged 6 weeks (group 2) and three aged 6 weeks (having been pretreated with dexamethasone) (group 3) were infected endobronchially with bovine adenovirus type 3 (BAV-3). All calves had received colostrum. The histopathological, immunohistochemical, ultrastructural and TUNEL features were examined on post-inoculation day (PID) 3, 5 and 7. Viral replication and intranuclear inclusions were frequently observed in groups 1 and 3, but not in group 2. The lesions became progressively severe on PID 5 and 7 in group 1. In group 3, however, the cellular injury caused by BAV-3 was of short duration and the lesions began to resolve at PID 7. Numerous apoptotic cells were seen in the PID 3 calves of all three groups, and in the PID 7 calves of groups 2 and 3; however, the PID 5 and 7 calves of group 1 showed only a few apoptotic cells in the alveolar septa. The results indicated that (1) the durability of BAV-3 infection in the lung was closely related to apoptosis, and (2) the host defence mechanism that induced apoptosis in infected cells was age-related.
Journal of Comparative Pathology 128(2-3):140-5. · 1.65 Impact Factor
