共查询到20条相似文献，搜索用时 46 毫秒
1.
Histopathology and direct immunofluorescent antibody (DIFA) tests were compared for diagnoses of infectious laryngotracheitis (ILT) in 144 cases of spontaneous respiratory disease in chickens presented to the Georgia Poultry Laboratory during 1988. For the 48 cases in which ILT was diagnosed, correct histologic diagnoses were made 100% (48/48) of the time and correct DIFA diagnoses were made 96% (46/48) of the time. For the 96 cases in which ILT was not diagnosed, correct histologic and DIFA diagnoses were made in every case. A Kappa test showed that DIFA was as effective as histopathology for the diagnosis of ILT in chickens (P = 0.0). It was concluded that increased use of DIFA could be instrumental in the abatement of ILT in chickens. 相似文献
2.
During 2001, a mild infectious laryngotracheitis virus (ILTV) infection occurred in broiler flocks in the southeastern United States. Clinical signs included mild tracheitis, swollen sinuses, and conjunctivitis, with no increased mortality and minimal serologic response. Infrequent intranuclear inclusion bodies with or without syncytial cell formation were observed in eyelid, trachea, and larynx and in the chorioallantoic membrane of infected embryos. Immunohistochemistry and a nested infectious laryngotracheitis polymerase chain reaction (ILT PCR) were utilized to confirm the presence of ILTV nucleic acid in fixed tissues. In addition, 2-wk-old specific-pathogen-free (SPF) birds inoculated with field material exhibited the mild signs observed in broilers in the field. Tracheal swabs and tissues taken from these SPF birds were also positive by nested ILT PCR. Restriction fragment length polymorphism analysis of ILT PCR products indicated that ILT virus associated with mild respiratory disease in the southeast is related to the chicken embryo origin vaccine type strains. 相似文献
3.
Modified-live (ML) infectious laryngotracheitis (ILT) vaccine viruses, both tissue-culture-origin (TCO) and chicken-embryo-origin (CEO), were passaged 20 times in specific-pathogen-free chickens. After serial bird-to-bird passage, increased virulence was observed for CEO virus but not TCO virus. Increased mortality and increased severity and duration of respiratory disease were observed in chickens inoculated with chicken-passaged CEO viruses; only mild respiratory disease (no mortality) occurred in chickens inoculated with chicken-passaged TCO viruses. These findings suggest that ML ILT vaccine viruses may increase in virulence after bird-to-bird passage. 相似文献
4.
Detection of infectious laryngotracheitis virus in formalin-fixed, paraffin-embedded tissues by nested polymerase chain reaction 总被引：1，自引：0，他引：1
Infectious laryngotracheitis virus (ILTV) is routinely diagnosed by histopathologic examination of trachea, eyelid, and lung tissues. Lesions consistent with infectious laryngotracheitis (ILT) infection include syncytial cell formation with intranuclear inclusion bodies. These changes are present during the acute phase of infection. To increase the sensitivity of detecting ILT, a nested polymerase chain reaction (PCR) was developed for detection of ILTV DNA. Nested PCR assay was specific for the amplification of ILTV DNA and did not amplify a variety of other avian pathogens. To further validate the ability of this assay to detect ILT, nested PCR was performed in formalin-fixed, paraffin-embedded tissues from 35 cases of respiratory disease. Of the 35 cases, 12 were considered ILT suspects on the basis of initial clinical observation. Eleven of the 12 ILT-suspect cases were diagnosed as ILT, and the remaining 24 were diagnosed as nonspecific tracheitis (NST) by histopathologic examination. Histopathologically positive samples were confirmed by direct fluorescent antibody test and virus isolation. Of the 11 ILT-positive cases, 10 were positive by nested PCR. In addition, ILTV DNA was detected in 7 of the 24 samples diagnosed as NST upon histopathologic examination. Therefore, by nested PCR, ILTV DNA was detected in tissues independently of the presence of syncytial cells, intranuclear inclusions, or both. ILT nested PCR is a specific and sensitive assay capable of detecting ILT at different stages of infection and can be utilized in combination with histopathological examination to accelerate the diagnosis of ILT infection. 相似文献
5.
Twenty-nine female Angus cattle were monitored from birth until 24 months of age for infection with types 3 and 7 adenoviruses (AV3, AV7) and bovine viral diarrhea (BVD) virus by virus isolation and neutralization tests. Twenty-seven animals remained in the study for 450 days, whereas 16 animals remained at the conclusion of the tests. Viruses were not isolated from test animals. Seroepizootiologic examination indicated that there were 28 infections with AV3, 33 infections with AV7, and 13 infections with BVD virus. Of these infections, 5 with AV3, 6 with AV7, and 2 with BVD virus were reinfections. All but 1 primary AV3 infection had occurred between 180 and 360 days after parturition. Infection with AV7 occurred earlier than that with AV3, as shown by 6 seropositive animals by 180 days. Most adenovirus infections were documented after animals had left confinement and were turned out to pasture. Most BVD virus infections occurred within the first 90 days after parturition. At completion of the study, only 1 animal had not shown evidence of AV3 infection, 2 animals had not been infected with AV7, and 7 cows had remained free of BVD virus infection. 相似文献
6.
Infectious laryngotracheitis (ILT) virus strains were studied for their ability to infect chicken macrophages, lymphocytes, and kidney cells in vitro. Although macrophages were as susceptible as chicken kidney cells to infection, replication of most virus strains in macrophages was markedly restricted. Only a few isolates induced progressive infections in macrophages, and even with these the donor of the macrophages influenced replication. Thus, it appears that both cell genotype and virus genotype may help determine the extent of restriction of virus replication. Macrophages were more susceptible to an attenuated vaccine strain of ILT virus than to virulent virus strains. Spleen lymphocytes, peripheral blood lymphocytes, thymocytes, bursal lymphocytes, buffy coat leukocytes, and activated T-cells were nearly or totally refractory to infection by ILT virus. 相似文献
7.
Infectious laryngotracheitis (ILT) is a severe acute respiratory disease of chickens caused by ILT virus. To better understand the epidemiology of the disease, a polymerase chain reaction (PCR)-restriction fragment length polymorphism (RFLP) assay of the glycoprotein E gene has been developed and utilized to characterize vaccine strains and outbreak-related isolates. Enzymes EaeI and DdeI were used to differentiate the tissue culture origin (TCO) vaccine from chicken embryo origin (CEO) vaccines. Two RFLP patterns were observed with enzyme EaeI, one characteristic of the TCO vaccine and a second characteristic of all CEO vaccines. Three RFLP patterns were observed with enzyme DdeI. Patterns A and B were characterized as single patterns, whereas the type C pattern was a combination of patterns A and B. Analysis of vaccine strains showed the presence of patterns A and C. Pattern A was observed for the TCO vaccine and one CEO vaccine, whereas pattern C was observed for five of the six CEO vaccines analyzed. PCR-RFLP analysis of plaque-purified virus from pattern C CEO vaccine preparations demonstrated the presence of two populations (patterns A and B). Identification of molecularly different populations of viruses within currently used ILT vaccine is the first step to develop better molecular epidemiologic tools to track vaccine isolates in the field. 相似文献
8.
Specific-pathogen-free chickens were infected via the trachea when 4 weeks old with 2000 plaque-forming units (PFU) of the virulent Australian infectious laryngotracheitis (ILT) virus strain CSW-1. Titers of ILT virus in the trachea were greatest (10(7.0) PFU/ml in washings, 10(6.0) PFU/g of tissue) 2-4 days postinfection (PI). Infectivity then declined rapidly, to become undetectable by 7 days PI, although highly localized areas of ILT antigen in the tracheal epithelium were occasionally observed by fluorescent antibody staining at 7 and 8 days PI. Tracheal organ cultures established 7 and 8 days PI provided no evidence of latent ILT virus infection at this immediate post-acute stage of pathogenesis. ILT virus was not isolated from peripheral blood leukocytes or lymphoid organs (spleen, bursa, thymus). ILT virus was found in the trigeminal ganglia and/or brain in 14 of 36 chickens (40%) examined between 4 and 7 days after intratracheal inoculation, but it was not in these tissues in five chickens examined at 8 days PI. Virus was also detected at 6 days PI in the trigeminal ganglia in one of five chickens infected by the conjunctival route. These data indicate that the early pathogenesis of ILT (CSW-1) infection frequently involves the tissues of the nervous system. In acute ILT in 4-week-old chickens, interferon-alpha/beta activity was not detectable in serum or tracheal exudates within 14 days PI, but tracheal washings contained significant virus-neutralizing activity by 7 and 8 days PI. In 3-day-old chickens infected via the trachea with 200 PFU of ILT CSW-1, the clearance of ILT virus from the trachea was similar to that observed in 4-week-old chickens, but ILT virus spread systemically to the livers of 20% by 5-7 days PI. 相似文献
9.
Summary Seventy-three flocks of fowl were tested at regular intervals for the presence of precipitins to fowl adenovirus (AV) and infectious bronchitis virus (IBV), haem-agglutinating inhibiting antibodies to BC14 virus, and of agglutinins to Mycoplasma gallisepticum (M.g.) and Mycoplasma synoviae (M.s.). In all the eight flocks affected with Egg Drop Syndrome (EDS '76), egg production problems were associated with increasing numbers of BCI4 virus reactors and AV reactors. In flocks showing production problems other than EDS '76 without any apparent cause, the average percentage of AV reactors increased significantly after the rearing period; this was not true of IBV reactors. BC14 reactors were either absent or present only once, in small numbers and with low titres, during the test period. The average percentage of AV reactors did not increase after the rearing period either in normally producing flocks or in flocks with production problems for which other diseases or dietary errors plausibly accounted for these problems. All this suggests a pathogenic role of AV in production problems. One can conclude from the high percentage of reactors in all groups of flocks that sub-clinical IBV infections are common. The percentage of IBV reactors during the laying period of flocks with EDS '76 was significantly higher than that of normally producing flocks. It is therefore suggested that subclinical IBV infection could be among the factors causing stress, acting as a trigger for EDS '76. All M.g.-infected flocks showed production problems; M.s. infections could not be related to egg production disturbances. 相似文献
10.
Infectious laryngotracheitis (ILT) is caused by an alphaherpesvirus, and latency can be produced by previous exposure to vaccine virus. The main sites of latency for the ILT virus have been shown to be the trigeminal ganglion and the trachea. Reactivation of latent virus is one factor related to the production of clinical signs. The development of a genetically engineered ILT vaccine has been suggested for many years as a tool to eliminate viral latency. Several approaches have been suggested. Included among them is the development of a thymidine kinase-deficient mutant or the insertion of ILT viral glycoproteins into a viral vector such as a poxvirus. A commercially available, live, fowlpox-vectored infectious laryngotracheitis + avian encephalomyelitis (FP-LT+AE) vaccine was used in field trials in leghorn pullet flocks and evaluated by tracheal challenge in a laboratory setting with the use of the National Veterinary Services Laboratory (Ames, IA) ILT challenge virus. Interference of the pigeon pox vaccine, which is often administered concurrently with fowlpox vaccine, was also evaluated when given in conjunction with the FP-LT+AE vaccine. Overall, the results indicate that the FP-LT+AE vaccine provides adequate protection against ILT viral challenge. Proper administration is essential. In one flock, inadequate protection was most likely a result of either poor vaccine administration or previous exposure to pox virus. In addition, the simultaneous administration of pigeon pox vaccine did not appear to interfere with protection against ILT viral challenge. 相似文献
11.
Six modified-live (ML) infectious laryngotracheitis (ILT) vaccine viruses, three reference strains, and 18 field isolates were compared by restriction endonuclease analysis of their DNA. Viral DNA digestion patterns were established for vaccine viruses using restriction endonucleases PstI, BamHI, KpnI, and HindIII. Using these enzymes, five of six ML vaccine viruses had identical restriction endonuclease cleavage patterns. Vaccine viruses had distinct patterns compared with ILT virus reference strains Illinois-N71851, Cover, and NVSL. Restriction endonuclease cleavage patterns of 18 field isolates of ILT virus, obtained from ILT outbreaks in North Carolina, were indistinguishable from vaccine viruses. These results suggest a possible role of vaccine or vaccine-like viruses in recent ILT outbreaks. 相似文献
12.
Seven restriction endonucleases (REs) were used to cleave the DNA from seven vaccine strains of infectious laryngotracheitis (ILT) virus and from six Georgia field isolates of ILT virus. After electrophoresis of the resulting RE fragments, the patterns were compared in order to differentiate strains of ILT virus. The six chicken-embryo-origin (CEO) vaccines were identical with each RE, but the tissue-culture-origin (TCO) vaccine strain differed from the CEO vaccines using five of the REs. Four of the six field isolates were identical by each RE, but two field isolates differed from each other and from the four identical field isolates on the basis of patterns produced by some but not all of the REs. The four identical field isolates could not be differentiated from the CEO vaccine strains by any RE, but the other two field isolates were not identical to either strain of vaccine virus. This work demonstrates that differentiable strains of ILT virus exist in the United States and that viruses other than vaccine viruses are involved in field outbreaks of ILT. 相似文献
13.
Blacker HP Kirkpatrick NC Rubite A O'Rourke D Noormohammadi AH 《Australian veterinary journal》2011,89(3):89-94
Objective Over the past 3 years, numerous outbreaks of infectious laryngotracheitis (ILT) have occurred in poultry in Australia. The objectives of this study were to identify the viral strains involved in the recent outbreaks and to determine possible epidemiological links between these outbreaks. Procedure A combination of polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLP) analyses of several genes of the ILT virus was used to identify genetic differences in field/vaccine ILT virus isolates. In a previous study, these procedures had demonstrated five classes (1–5) in Australia. Results Analysis of 92 field ILT viruses demonstrated four new classes: 6, 7, 8 and 9. Class 6 was responsible for four outbreaks in one Victorian broiler company and demonstrated to be distinct from other Australian strains of ILT. Class 7 was the Nobilis ILT vaccine (Intervet Pty Ltd). Class 8 was responsible for the majority of the outbreaks in New South Wales and was phylogenetically close to class 7. On one occasion, classes 7 and 8 were identified in an outbreak on a Victorian farm that had used the Nobilis ILT vaccine. Class 9, also phylogenetically close to classes 7 and 8, was found only in New South Wales. The previously identified class 2 was also found to be responsible for a large number of outbreaks, mainly in Victoria. Conclusion The results demonstrate that, epidemiologically, most outbreaks of ILT in New South Wales are unrelated to those in Victoria and suggest a link between classes 8 and 9 and the Nobilis ILT vaccine (class 7). 相似文献
14.
Summary Seventy‐three flocks of fowl were tested at regular intervals for the presence of precipitins to fowl adenovirus (AV) and infectious bronchitis virus (IBV), haem‐agglutinating inhibiting antibodies to BC14 virus, and of agglutinins to Mycoplasma gallisepticum (M.g.) and Mycoplasma synoviae (M.s.). In all the eight flocks affected with Egg Drop Syndrome (EDS ‘76), egg production problems were associated with increasing numbers of BCI4 virus reactors and AV reactors. In flocks showing production problems other than EDS ‘76 without any apparent cause, the average percentage of AV reactors increased significantly after the rearing period; this was not true of IBV reactors. BC14 reactors were either absent or present only once, in small numbers and with low titres, during the test period. The average percentage of AV reactors did not increase after the rearing period either in normally producing flocks or in flocks with production problems for which other diseases or dietary errors plausibly accounted for these problems. All this suggests a pathogenic role of AV in production problems. One can conclude from the high percentage of reactors in all groups of flocks that sub‐clinical IBV infections are common. The percentage of IBV reactors during the laying period of flocks with EDS ‘76 was significantly higher than that of normally producing flocks. It is therefore suggested that subclinical IBV infection could be among the factors causing stress, acting as a trigger for EDS ‘76. All M.g.‐infected flocks showed production problems; M.s. infections could not be related to egg production disturbances. 相似文献
15.
Clinically normal adult dogs and pups 8 to 24 weeks of age were monitored for 2nd-degree atrioventricular (AV) heart block. Radiotelemetry was used to obtain the electrocardiogram (ECG) of resting, unanesthetized, unrestrained dogs. Second-degree AV heart block was detected in 64% of 11 adult dogs and 100% of 12 pups between 8 and 11 weeks of age. The dropped beats, prolonged P-R intervals, and prolonged P-P intervals appeared to be associated with the respiratory cycle. Atropine quickly reduced the frequence of dropped beats. It was concluded that occasional dropped ventricular beats due to 2nd-degree AV heart block may be normal in dogs, especially young dogs. 相似文献
16.
Effects of certain stress factors on the re-excretion of infectious laryngotracheitis virus from latently infected carrier birds 总被引：1，自引：0，他引：1
C S Hughes R M Gaskell R C Jones J M Bradbury F T Jordan 《Research in veterinary science》1989,46(2):274-276
Experiments were set up to assess the effects of 'natural' and 'artificial' stresses on the re-excretion of infectious laryngotracheitis (ILT) virus in latently infected chickens recovered from the acute phase of the disease. The stresses were rehousing with the addition of ILT-free contact birds, corticosteroid treatment and the onset of lay. The contact birds were also monitored for transmission of the virus from the carrier birds. Rehousing with unfamiliar birds induced ILT virus shedding in one of five birds and there was evidence of transmission from this bird to its mate. The onset of lay had a significant effect on the overall shedding rates of the carrier birds. Nine of 10 birds shed virus after onset of lay compared with only two in the three-and-a-half weeks before, and there was a highly significant increase (P less than 0.001) in the overall number of virus isolations during this period. Corticosteroid treatment did not affect virus shedding. These results may explain some of the apparently spontaneous outbreaks of ILT which occur in the field. 相似文献
17.
Labeled avidin-biotin enzyme-linked immunosorbent assay for detecting antibody to infectious laryngotracheitis virus in chickens 总被引：1，自引：0，他引：1
A labeled avidin-biotin enzyme-linked immunosorbent assay (LAB-ELISA) for detecting antibody to infectious laryngotracheitis (ILT) virus in chicken sera was developed and compared with ordinary ELISA. Purified ILT virus, biotin-labeled anti-chicken IgG rabbit IgG conjugate, and horseradish-peroxidase-labeled avidin were used in the LAB-ELISA. When sera from farm chickens were tested by serum neutralization (SN) and two kinds of ELISA, the correlation rate between SN and LAB-ELISA was 50/50 (100%), and that between SN and ordinary ELISA was 39/50 (78%). In LAB-ELISA, all of the sera that were antibody-negative by SN had low absorbance (A) values (below 0.05), and the A values were closely correlated with the SN indexes. In ordinary ELISA, however, the sera antibody-negative by SN had various A values ranging from 0.06 to 0.32. LAB-ELISA had much lower nonspecific reactions than ordinary ELISA against sera from ILT-negative chickens, even when chickens were 30 weeks old. ILT antibody production after ILT vaccination could be detected by LAB-ELISA. A values peaked 5 weeks postinoculation and were maintained for 17 weeks. 相似文献
18.
试验旨在建立简易、快速、高效的鸡传染性喉气管炎病毒(infectious laryngotracheitis virus,ILTV)检测和诊断方法。根据GenBank上公布的ILTV TK基因序列,设计检测ILTV的特异性环介导的等温扩增(loop media-ted isothermal amplification,LAMP)技术反应引物,通过对LAMP反应体系和反应条件的优化,以及特异性、敏感性和临床样品的检测,建立了ILTV LAMP检测方法。结果显示,以内引物ILT9-FIP和ILT9-BIP、外引物ILT9-F3和ILT9-B3、环引物ILT9-LB和ILT9-LF为LAMP反应引物,反应温度为66℃时,所建立的LAMP检测方法反应效率最高;所建立的LAMP检测方法能够特异性地检测ILTV(匈牙利株和王岗株),不与新城疫病毒(NDV,B株)、鸡传染性支气管炎病毒(IBV,H52株和H120株)、大肠杆菌、鸡副嗜血杆菌、巴氏杆菌等发生交叉反应,且能够检测到的病毒最低浓度达到0.06pg/μL,其灵敏度是普通PCR方法的100倍;采用建立LAMP方法对50个临床样本进行检测,阳性率为14%,且与PCR检测结果的符合率达96%。本研究建立了特异性强、灵敏度高、操作简单的LAMP检测方法,适用于临床上ILTV的快速检测和诊断。 相似文献
19.
在甘肃省60个特种禽类养殖场,采集了17个品种禽类的非免疫血清953份、免疫血清51份、脏器等病料83份,进行了实验室检验和监测,结果表明鸽感染了ND、A I、IB、ILT、AL、FP、IBD 7种疫病,鸭感染ND、A I、ILT、FP、VA、PD 6种疫病,鹧鸪感染了A I、IB、ILT、IBD 4种疫病,珍珠鸡感染了IB、ILT、AL 3种疫病,鸵鸟感染了ND,乌鸡感染了IB、ILT、IBD、M D、VA、IC,贵妇鸡感染了M D、AL、IC。从病料中检出了大肠杆菌、都柏林沙门氏菌和念珠菌、组织滴虫和球虫虫卵等病原。ND、A I、IB、IBD、ILT、FP 6种疫病的免疫抗体水平普遍较低。 相似文献
20.
A Taneno T Honda E Sakai T Kawai Y Tokuyama M Eto 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》1991,53(4):671-676
The safety and efficacy of the cell-associated (C-A) vaccine prepared by chicken embryo fibroblast (CEF) cells infected with the tissue-culture-modified strain of infectious laryngotracheitis (ILT) virus were studied in chickens. Over seventy percent of chickens inoculated with the C-A vaccine by the subcutaneous (S.C.) or intramuscular (I.M.) route at 1 day of age was protected against challenge with a virulent strain of ILT virus without any clinical signs. Chickens vaccinated with the C-A vaccine at 1 day of age acquired immunity within 6 days after vaccination, and the protection rate maintained more than 60% until 10 weeks post-vaccination. The C-A vaccine was invariably effective for chickens at various age. There was no evidence that the development of immunity was hindered by further vaccination with Newcastle disease and infectious bronchitis combined live vaccine. In addition, the C-A vaccine was safe when chickens were inoculated with 10 doses. In the field trials of the C-A vaccine, no adverse reaction was observed, and over 65% of vaccinated chickens was protected against the challenge of the virulent ILT virus at 8 weeks after vaccination. 相似文献