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1.
Mikami O Nakajima H Kawashima K Yoshii M Nakajima Y 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2005,67(7):735-738
Reproductive failure associated with porcine circovirus type 2 (PCV2) was observed in a farm, and a weak-born 8-day-old piglet was examined pathologically. Focal to locally extensive lesions, including infiltration of macrophages and lymphocytes, fibrosis and degeneration of the myocardium were observed in the heart. PCV2 antigens and nucleic acids were detected in degenerated cardiomyocytes and macrophages infiltrating the heart by immunohistochemical staining and in situ hybridization. Depletion of lymphocytes with occasional infiltration of multinucleated giant cells was seen in the lymphoid organs and PCV2 antigens were demonstrated in histiocytic cells. Crystalline arrays of viral particles were observed in infiltrated macrophages in the heart and, rarely, in cardiomyocytes by electron microscopy. Although myocarditis is a common finding in aborted or stillborn piglets in reproductive failure due to PCV2, it was also observed in the 8-day-old piglet with PCV2 association. 相似文献
2.
Pensaert MB Sanchez RE Ladekjaer-Mikkelsen AS Allan GM Nauwynck HJ 《Veterinary microbiology》2004,98(2):175-183
This publication reviews some pathogenetic features of the transplacental infection with porcine viruses in sows. Viremia either with virus freely circulating or associated to peripheral blood mononuclear cells (PBMC) is an essential part of such pathogenesis. Virus replication occurs either in fetal tissues only or both in fetal and maternal tissues and the outcome may be different.Since porcine circovirus 2 (PCV2) has been associated with reproductive failure in sows, the question was asked what type of viremia PCV2 causes and what the effect of PCV2 is on the pregnant uterus. Seronegative gilts were oronasally inoculated and plasma and PBMC were monitored for infectious virus and for quantity of viral DNA copies. Infectious virus was found in plasma only at 21 days post-inoculation (DPI). Virus associated to PBMC was detected between 14 and 49 DPI. Viral DNA was found in plasma between 14 and 49 DPI and associated to PBMC between 7 and 63 DPI (end of experiment). Direct intra-fetal inoculation at 57, 75 and 92 days of gestation and collection of fetuses 21 days later showed that the virus replicates highly in fetal tissues, particularly in the heart. Fetal death occurred in the 57 days sows while virus and antibodies were observed in the 75- and 92-day inoculated sows. Inoculation at 57 and 75 days of gestation and collection of the piglets at the end of pregnancy showed that intrauterine spread had occurred to fetuses adjacent to the inoculated ones and that fetal death occurred also in the presence of antibodies. The pregnancy was not interrupted.This study shows that PCV2 causes viremia which is largely cell-associated and that virus replication in fetuses causes fetal death with mummification. Whether such transplacental infection occurs in the immune sow population is questionable. 相似文献
3.
Porcine circovirus 2 infection in swine foetuses inoculated at different stages of gestation 总被引：11，自引：0，他引：11
The ability of porcine circovirus 2 (PCV2) to replicate and cause pathologic abnormalities in foetuses at selected time points of gestation was examined in this study. Two foetuses were inoculated in utero in each of two sows at 57, 75 and 92 days of gestation, respectively, with PCV2 (1121). The remaining foetuses were left uninoculated to assess whether intra-uterine spread occurred. Twenty-one days after inoculation, the foetuses were collected and examined for gross lesions and for virus and infected cells in different organs. Serum samples from all foetuses were tested for PCV2 antibodies. Virus replication was detected in all inoculated foetuses. Spread to non-inoculated foetuses did not occur. Virus replication was significantly higher in foetuses inoculated at 57 days compared to that inoculated at 75 and 92 days. The heart contained the highest virus titre and highest number of viral antigen positive cells. Gross lesions were observed only in foetuses inoculated at 57 days of age. PCV2 antibodies were detected only in foetuses inoculated at 75 and 92 days. This study shows the ability of PCV2 to replicate in foetuses at different stages of gestation and to cause pathologic abnormalities in foetuses inoculated at 57 gestational days. 相似文献
4.
Eight-week-old BALB/c mice were either sham inoculated (control mice) or were inoculated intraperitoneally (IP) and intranasally (IN) with a single (sPCV mice) or multiple (mPCV mice) doses of porcine circovirus 2 (PCV2). Four control mice and 4 sPCV mice were sacrificed 7, 14, 28, and 42 days postinoculation (PI). All 4 mPCV mice were sacrificed 42 days PI. In addition, 7-day and 14-day pregnant BALB/c mice were either sham inoculated (control mice) or were inoculated IP and IN with a single dose of PCV2. Newborn mice were euthanatized 1, 8, and 15 days after birth. Necropsies were performed on all euthanatized mice and tissues were collected for histopathology, electron microscopy, in situ hybridization, and polymerase chain reaction (PCR). PCV2 replicated in 8-week-old BALB/c mice that were inoculated with PCV2 and caused fetal infection when inoculated into pregnant BALB/c mice at 7 days and 14 days of gestation. PCV was detected by in situ hybridization and PCR in sPCV mice on days 7, 14, 28, and 42 PI; in mPCV mice on day 42 PI; and in newborn mice from mothers inoculated with PCV at 7 days and 14 days of gestation at 1, 8, and 15 days after birth, but not in control mice. No clinical signs or gross lesions were found in sPCV or mPCV mice during the study. Microscopic lesions in sPCV mice and mPCV mice were characterized by expansion of germinal centers in lymphoid organs with large numbers of histiocytic cells and lymphoblasts, apoptosis of histiocytic cells in germinal centers, and mild lymphoid depletion of the paracortex. PCV nucleic acid was detected in the nuclei and cytoplasm of histiocytes and apoptotic cells in germinal centers in lymphoid tissues as well as in the nuclei of hepatocytes in the liver, in the nuclei of renal tubular epithelial cells, and in the cytoplasm of single lymphocytes in the thymus. Congenitally infected mice only had PCV nucleic acid detected in putative Kupffer cells in livers. 相似文献
5.
The pathogenicity and pathogenesis of Lelystad virus was studied in six 6-day-old SPF piglets. A third passage of the agent was propagated on porcine alveolar macrophages and intranasally inoculated into pigs. Pigs were killed at hours 24, 48, 60, and 72, and on days 6 and 8 after inoculation. From day 2 on pigs developed diffuse interstitial pneumonia with focal areas of catarrhal pneumonia, and from this day on splenic red pulp macrophages were enlarged and vacuolated. Lelystad virus was re-isolated from the lungs of infected pigs from day 2 after inoculation. Lelystad virus antigens were detected by immunohistochemical techniques in bronchiolar epithelium and alveolar cells, and in spleen cells of infected pigs from day 2 after inoculation. Ultrastructural examination of tissues by electron microscopy revealed degenerating alveolar macrophages and epithelial cells in lungs and nasal mucosa, with excessive vacuolation of the endoplasmic reticulum. Although the respiratory tract seems to be the target organ for this virus, macrophages in other organs, such as the spleen, can also be infected. This preference for macrophages may impair immunological defences. 相似文献
6.
Romeo E Sanchez Peter Meerts Hans J Nauwynck John A Ellis Maurice B Pensaert 《Journal of veterinary diagnostic investigation》2004,16(3):175-185
In this study, the characteristics of porcine circovirus-2 (PCV2) replication (infectious virus titrations, distribution, and immunophenotyping of infected cells) in lymphoid organs were examined and related to the development of clinical signs and histological lesions in 26 piglets that had been inoculated with PCV2 either in utero or at 1 day of age. Piglets inoculated in utero at 92 or 104 gestational days (n = 12) were collected by Caesarean section at term and either sacrificed immediately or kept in isolators and allowed to live postnatally until 35 days postinoculation (PI). Caesarean-derived piglets inoculated at 1 day of age (n = 14) were sacrificed at 10, 21, 35, 42, and 49 days PI. Spleen and lymph nodes were collected for virologic and histopathological examinations. Clinical signs were not observed in any of the piglets. High virus titers (10(4.5-5.7) TCID50/g [TCID refers to tissue culture infectious dose]) were detected in 6 of the 26 piglets. Three of these 6 piglets were euthanized at 10 days PI, and infected cells of the monocyte-macrophage lineage (SWC3+, CD14+, and sialoadhesin [Sa]+ cells) and infected cells bearing lymphocyte markers (CD4+, CD8+, and immunoglobulin M+ cells) were identified by double-immunofluorescence labeling on serial cryostat sections. The other 3 piglets were euthanized at 21 and 35 days PI, and the majority of infected cells were SWC3+, CD14+, and Sa-. The absence of Sa in these infected cells, together with their localization in lymphocyte-dependent regions, suggests that they were infiltrating monocytic cells. Sialoadhesin is highly expressed in differentiated macrophages and not in peripheral blood mononuclear cells. In all 6 piglets with high virus titers, lymphocyte depletion and infiltration of monocytic cells were observed. In the remaining 20 piglets with virus titers less than 10(4.5) TCID50/g, the majority of infected cells were SWC3+, CD14+, and Sa+. In conclusion, it can be stated that high PCV2 titers in lymphoid organs may lead to the development of histological lesions similar to those observed in pigs with postweaning multisystemic wasting syndrome without causing disease. Furthermore, in lymphoid organs with high virus titers, infection occurs mainly in infiltrating monocytic cells and to a limited extent in cells bearing lymphocyte markers. 相似文献
7.
Summary The pathogenicity and pathogenesis of Lelystad virus was studied in six 6‐day‐old SPF piglets. A third passage of the agent was propagated on porcine alveolar macrophages and intranasally inoculated into pigs. Pigs were killed at hours 24, 48, 60, and 72, and on days 6 and 8 after inoculation. From day 2 on pigs developed diffuse interstitial pneumonia with focal areas of catarrhal pneumonia, and from this day on splenic red pulp macrophages were enlarged and vacuolated. Lelystad virus was re‐isolated from the lungs of infected pigs from day 2 after inoculation. Lelystad virus antigens were detected by immunohistochemical techniques in bronchiolar epithelium and alveolar cells, and in spleen cells of infected pigs from day 2 after inoculation. Ultrastructural examination of tissues by electron microscopy revealed degenerating alveolar macrophages and epithelial cells in lungs and nasal mucosa, with excessive vacuolation of the endoplasmic reticulum. Although the respiratory tract seems to be the target organ for this virus, macrophages in other organs, such as the spleen, can also be infected. This preference for macrophages may impair immunological defences. 相似文献
8.
9.
Rhesus monkey fetuses of either immune or nonimmune dams were inoculated in utero with Adenovirus SV-20 (AdSV-20), a virus capable of inducing fetal pneumonia, and studied immunologically at various intervals. AdSV-20 infection at 90–100 days gestational age resulted in absolute lymphopenia in a few fetuses, reduced numbers of peripheral blood lymphocytes (PBL) which formed rosettes with sheep erythrocytes (ERL) and reduced complement-receptor lymphocytes (CRL) in a majority, while Fc fragment-receptor lymphocytes (FcRL) were occasionally increased. There was a tendency for depression of ERL and CRL early in infection of 120–130-day fetuses, followed by stimulation of these populations and FcRL in later phases. Maternal immunity did not protect against these effects of AdSV-20 infection in fetuses. Immune and nonimmune dams were spared adverse clinical effects and had no changes in lymphoid cell populations following inoculation of their fetuses.Despite precocious production of circulating IgM, fetuses of nonimmune dams had little or no demonstrable anti-AdSV-20 serum neutralizing (SN) antibody, indicating that the ability to develop an effective immune response was suppressed or had not been acquired at the gestational ages studied. Nonimmune dams displayed little evidence of seroconversion following inoculation of their fetuses with AdSV-20, except in those dams whose fetuses died in utero, whereby there was a significant antibody response. SN antibody titers of immune dams were not boostered substantially subsequent to inoculation of their fetuses, and fetal SN titers were lower than maternal titers, suggesting absence of an active fetal antibody response in this group also. Direct inoculation of AdSV-20 into 90–130-day rhesus monkey fetuses provided a model system for immunologic study of fetal infection, probably involving complex fetal-maternal interactions, in a situation where the infected, viable fetus and its dam appeared to be microbiologically isolated from one another. 相似文献
10.
Virus localisation and lesions were studied in 14-one-week-old piglets following combined intranasal-oral inoculation with a British isolate of 'pneumotropic' porcine coronavirus (PCV) and were compared with the effects of transmissible gastroenteritis virus (TGEV) infection in five piglets. Unlike TGEV-infected piglets, all PCV-inoculated piglets remained clinically healthy. Seroconversion was detected at seven days after inoculation. Mild bronchointerstitial pneumonia involving terminal airways was consistently present at two days after infection and thereafter. Both PCV and TGEV infected bronchiolar epithelium and alveolar macrophages but, unlike TGEV, replication by PCV in villous enterocytes was limited and did not cause villous atrophy. 相似文献
11.
Myocarditis and abortion associated with intrauterine infection of sows with porcine circovirus 2. 总被引：24，自引：0，他引：24
K H West J M Bystrom C Wojnarowicz N Shantz M Jacobson G M Allan D M Haines E G Clark S Krakowka F McNeilly C Konoby K Martin J A Ellis 《Journal of veterinary diagnostic investigation》1999,11(6):530-532
Porcine circovirus 2 (PCV2) is a recently identified agent that has been associated with postweaning multisystemic wasting syndrome (PMWS) in swine populations. In this report, the potential spectrum of disease associated with PCV2 is expanded by evidence of vertical transmission and associated reproductive failure. PCV2 was isolated from a litter of aborted piglets from a farm experiencing late-term abortions and stillbirths. Severe, diffuse myocarditis was present in 1 piglet associated with extensive immunohistochemical staining for PCV2 antigen. Variable amounts of PCV2 antigen were also present in liver, lung, and kidney of multiple fetuses. The presence of other agents that have been associated with fetal lesions and abortion in swine, including porcine parvovirus, porcine reproductive respiratory syndrome virus, encephalomyocarditis virus, and enterovirus, could not be established. 相似文献
12.
Sixteen cesarean-derived, colostrum-deprived piglets were inoculated intranasally with porcine circovirus type 2 (PCV2), originally isolated from a pig affected with postweaning multisystemic wasting syndrome (PMWS). At 1 day postinoculation (PI), 3 of the 5 piglets in the uninoculated control group were moved to the room of inoculated piglets for contact exposure. Porcine circovirus type 2 was detected by polymerase chain reaction (PCR) in swabs from inoculated piglets from 1 day PI and from contact piglets from 2 days after cohabitation. Porcine circovirus type 2 was also detected in all serum samples but not in control piglets 7 days PI. Until the end of study, PCV2 was detected in swabs and serum samples by PCR but not in the control piglets. One inoculated piglet died suddenly without clinical signs 19 days PI. Beginning at 14 days PI, 5 piglets, including 1 contact piglet, had clinical signs of depression, anorexia, and icterus, and 1 inoculated piglet died 21 days PI. Most of the piglets exhibiting the above clinical signs became moribund and were necropsied 21 and 28 days PI. In the piglets that showed clinical signs, gross lesions, including icterus of liver and hemorrhage in stomach, and typical histopathological lesions of PMWS, such as lymphoid depletion and basophilic intracytoplasmic inclusion bodies in lymph nodes and other tissues, were observed. Porcine circovirus type 2 was detected by PCR in all tissue samples except in those of the control piglets. Porcine circovirus type 2 was recovered from several tissue samples of the piglets necropsied until 35 days PI. In particular, PCV2 was recovered in high titer from most of the tissue samples of the piglets exhibiting clinical signs. Serum antibody against PCV2 was mostly detected in inoculated piglets and in contact piglets 14 and 21 days PI by an indirect fluorescence antibody test but was not detected in the piglets exhibiting clinical signs until 28 days PI. These results indicate that PCV2 was able to induce clinical PMWS in the absence of other swine pathogens and that there were significant differences in both the quantitative PCV2 distribution in tissues and the antibody response between the piglets that were infected and developed PMWS and those that were infected but remained healthy. 相似文献
13.
Chang HW Jeng CR Liu JJ Lin TL Chang CC Chia MY Tsai YC Pang VF 《Veterinary microbiology》2005,108(3-4):167-177
Two common viral pathogens of swine, namely, porcine circovirus type 2 (PCV2) and porcine reproductive and respiratory syndrome virus (PRRSV), were investigated in regard to their effects on monolayer cultures of swine alveolar macrophages (AMs). The purpose was to identify selected cellular changes and responses potentially associated with the clinical reactions of pigs infected with either or both of these viruses. Measurements included the (1) absolute and relative numbers of infected, viable, and apoptotic cells; (2) distribution of viral antigens; (3) levels of interferon-alpha (IFN-alpha) and tumor necrosis factor-alpha (TNF-alpha) produced and their association with the extent of virus-induced cytopathology. Four groups of AMs were studied, including mock-infected, PCV2 alone-infected (PCV2-A), PRRSV alone-infected (PRRSV-A), and PCV2 and PRRSV dually infected (PCV2/PRRSV) groups. The AMs of PCV2-A group had high antigen-containing rate without cell death. There was a marked increase in cell death and apoptosis in PRRSV-A group. However, a lower PRRSV-induced infectious rate, cell death, and apoptosis were seen in PCV2/PRRSV group. High levels of IFN-alpha production were detected in PCV2-infected groups, but not in mock-infected and PRRSV-A groups. The PRRSV-induced cytopathic effect (CPE) on MARC-145 cells or swine AMs was markedly reduced by pre-incubation of the cells with UV-treated or non-UV-treated supernatants of PCV2-infected AMs. In addition, the reduction in CPE was abolished when the supernatants of PCV2-infected AMs were pre-treated with a mouse anti-recombinant porcine IFN-alpha antibody. The results suggest that swine AMs were an important reservoir of PCV2; PCV2 infection reduced PRRSV infection and PRRSV-associated CPE in PCV2/PRRSV AMs; the reduction of PRRSV infection in AMs was mediated by IFN-alpha generated by PCV2 infection. The reduced PRRSV-associated CPE in AMs and increased pro-inflammatory cytokine production may lead to a more severe pneumonic lesion in those dually infected pigs. 相似文献
14.
W L Castleman J C Lay E J Dubovi D O Slauson 《American journal of veterinary research》1985,46(3):547-553
Conventionally raised male Holstein calves, 1 month of age, were infected by intranasal and intratracheal inoculation with bovine respiratory syncytial virus. Viral antigen was identified by fluorescence microscopy most commonly in the cytoplasm of tracheal and bronchial epithelial cells 3 to 5 days after inoculation. Cytoplasmic viral antigen was identified also in nasal, nasopharyngeal, bronchiolar, and alveolar epithelial cells and in alveolar macrophages. Bronchitis and tracheitis, characterized in part by epithelial necrosis, formation of syncytial epithelial cells and epithelial hyperplasia, were the most common lesions observed histologically. Rhinitis, bronchiolitis, and interstitial pneumonia were observed less frequently. Alterations were not detected in the numbers of cells recovered by bronchoalveolar lavage after inoculation. An increase in the phagocytic rate of latex beads occurred in macrophages 5 days after inoculation. Viral-induced lesions were resolved by 30 days after inoculation. The results indicated that bovine respiratory syncytial virus inoculation of calves results in reversible alterations in airway epithelial structure and in the phagocytic function of alveolar macrophages. 相似文献
15.
为探讨猪圆环病毒2型（PCV2）对小鼠超微结构的病理损伤及其病毒在细胞内的复制,20只6周龄的昆明小鼠随机平均分成2组（即A组和B组）,A组小鼠经腹腔注射PCV2细胞培养物0.1mL/只（含病毒1 000TCID50）,B组以同样的方式和剂量注射无菌细胞培养液作为对照。于PCV2感染后14d,处死所有小鼠,取其组织做电镜观察和PCV2PCR检测。结果显示,在电镜下,所有PCV2感染鼠的超微结构病变基本一致,主要表现为淋巴器官、心脏、肝脏、肺脏、肾脏、脑、肠等脏器实质细胞凋亡或坏死,细胞内线粒体水肿、内质网扩张,间质毛细血管淤血、炎症细胞浸润,并在脾脏、胸腺、淋巴结的淋巴细、巨噬细胞,以及肝细胞,肾足细胞,脑神经细胞的胞浆或胞核内发现病毒包涵体。同时通过PCR检测,所有PCV2感染鼠的组织均可检出PCV2DNA。B组（对照组）小鼠除在淋巴结可见极少数淋巴细胞凋亡外,其他组织均无任何超微结构病变;同时,所有组织也未检出PCV2DNA。由此说明PCV2可在昆明小鼠多脏器实质细胞内复制,并诱导细胞凋亡。 相似文献
16.
Pregnant sows, immune against pseudorabies after vaccination, were inoculated at 70 days of gestation either with autologous blood mononuclear cells that had been infected in vitro with pseudorabies virus (PRV) or with cell-free PRV. The infected cells or cell-free PRV were inoculated surgically into the arteria uterina. Eight sows (A to H) had been vaccinated with an inactivated vaccine. The titer of seroneutralizing antibodies in their serum varied between 12 and 48. Five sows (A to E) were inoculated with autologous mononuclear cells, infected either with a Belgian PRV field strain or with the Northern Ireland PRV strain NIA3. These 5 sows aborted their fetuses: 2 of them (B and C) 3 days after inoculation, and the other 3 (A, D, and E) 10, 11, and 12 days after inoculation, respectively. Sows F, G, and H were inoculated with a cell-free PRV field strain. They farrowed healthy litters after normal gestation. Neutralizing antibodies were absent against PRV in the sera of the newborn pigs, which were obtained prior to the uptake of colostrum. The 23 fetuses that were aborted in sows B and C 3 days after the inoculation were homogeneous in appearance and size. Foci of necrosis were not detected in the liver. Viral antigens were located by immunofluorescence in individual cells in lungs, liver, and spleen of 15 fetuses. Virus was isolated from the liver, lungs, or body fluids of 12 fetuses. The 39 fetuses that were aborted in sows A, D, and E between 10 and 12 days after inoculation were of 2 types: 17 were mummified and 22 were normal-appearing.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
17.
Histomorphometric and scanning electron microscopic analyses were carried out on 74 embryos and fetuses and 20 sheep (early postnatal to adult age). Histodifferentiation of the rumen took place at 33 days of fetal life. Ruminal pillars were observed at 42 days, and at 61 days, ruminal papillae appeared as evaginations of the epithelial stratum basale. Neutral mucopolysaccharides first appeared in epithelial cells at 46 days of fetal life; thereafter, numbers decreased gradually and subsequently stabilized in postnatal life. Acid mucopolysaccharides, mucins, and mucoid compounds were not detected. Age and diet were recognized as factors that determine the structure of the ruminal mucosa. Growth curves and formulas were set out for each tissue layer. 相似文献
18.
The reproductive organs and fetuses of seven Norwegian Red heifers were investigated for the presence of bovine viral diarrhea virus (BVDV) antigen during the time of initial transplacental transmission of the virus. The heifers were inoculated with a noncytopathogenic BVDV at day 85/86 of gestation and were slaughtered at day 7, 10, 14, 18, or 22 postinoculation (pi). Cryostat sections of uterus, ovaries, placentomes, intercotyledonary fetal membranes, and fetal organs were examined using immunohistochemical techniques. A double immunofluorescence technique was used to identify cells that showed staining with antibodies against the leukocyte common antigen CD45 or the intermediate filament vimentin and BVDV antigens. The earliest stage of infection at which BVDV antigen could be detected in the fetuses was 14 days pi. At this stage, BVDV antigen was detected in cells of mesenchymal origin in the lungs and in large cells that morphologically resembled immature megakaryocytes in the liver. In the intercotyledonary fetal membranes and in the placentomes, BVDV antigen was not detected until 18 and 22 days pi, respectively. BVDV antigen was not detected in maternal tissue from any of the heifers. The present results indicate that fetal infection with BVDV can take place without preceding or simultaneous high concentrations of BVDV in uterus or placenta of acutely infected heifers. 相似文献
19.
Transmissible congenital demyelinating encephalopathy of lambs 总被引：2，自引：0，他引：2
Twenty-two fetal lambs were inoculated in utero with tissue suspension prepared from lambs born with weakness, incoordination and clonic tremor. Clinically, affected newborn lambs had clonic tremor, were generally weak and had abnormally pigmented hairy fleece. The inoculation resulted in a disseminated encephalomyelitis with secondary teratologic changes in a significant number of fetuses. The mononuclear inflammatory changes were most obvious 14 days after inoculation, after which there was rapid resolution. Changes seen at birth were chronic astrocytosis with neuron loss in the spinal cord and cerebellar dysplasia. Single radioimmunodiffusion studies showed consistently low IgG in infected fetuses and high IgG in lambs at birth. 相似文献
20.
Inger M Brunborg Christine M Jonassen Torfinn Moldal Bj?rn Bratberg Bj?rn Lium Frank Koenen Jürgen Sch?nheit 《Journal of veterinary diagnostic investigation》2007,19(4):368-375
During a period of 1.5 months, a newly established pig herd experienced a high number of mummifications and stillbirths, a high neonatal mortality rate, and many piglets with congenital tremors or hind leg ataxia. After clinical and histological investigations, the submitted animals were divided into 4 groups: mummified or stillborn (N = 6), live born with myocarditis (N = 5) (average age 22.8 days), live born without myocarditis (N = 14) (average age 20.0 days), and control animals from a different herd (N = 5) (newborn). Statistically significant differences were observed in the mean porcine circovirus 2 (PCV2) load among the 4 groups in the liver (P < 0.0001). The presence of PCV2 antigen within the myocardial lesions was confirmed by immunohistochemistry. A high load of PCV2 DNA was observed in myocardium, liver, and spleen from mummified or stillborn piglets (>1 x 10(7) copies per 500 ng DNA), lower in piglets with myocarditis (>1 x 10(5) copies per 500 ng DNA), and even further lower in pigs without myocarditis (<1 x 10(5) copies per 500 ng DNA), whereas no PCV2 DNA was detected in the control animals. Myocardium, liver, and spleen were well suited for routine testing of fetuses and young piglets by quantitative real-time polymerase chain reaction. Neither porcine parvovirus nor encepaholomyocarditis virus was detected. These results indicate that the PCV2 infection might have been of etiological importance for the fetal deaths and piglet mortality observed in this herd. 相似文献