Evaluation of the rabbit as a laboratory model for infectious bovine rhinotracheitis virus infection

Experimental infection of rabbits with infectious bovine rhinotracheitis virus (IBRV) produced diverse manifestations of disease which included abortion, conjunctivitis, dermatitis, vulvovaginitis, systemic infection, neonatal death and respiratory tract infection. Each disease syndrome was studied using virus isolation, fluorescent antibody examination and histologic examination. Conjunctivitis, dermatitis and vulvovaginitis lesions were characterized by edema, infiltration of mucosa and submucosa with inflammatory cells and ulceration of epithelium. Systemic infection resulted in severe necrosis of liver and adrenal glands with large numbers of cells containing intranuclear inculsions. Pregnant rabbits aborted within 48 hours following inoculation of IBRV. Virus infection and viral lesions were not demonstrated in aborted fetuses.     

Detection of bovine rhinotracheitis virus antibody by neutralizing test and ELISA in experimentally infected rabbits.

The antibody response of rabbit to infectious bovine rhinotracheitis (IBR) virus was examined. Two rabbits were inoculated with IBR virus strain Los Angeles into the trachea and intravenously, and intravenously two times, respectively. The patterns of antibody titers in the rabbits measured by neutralization test and ELISA were similar to those in the case of bovine. The antibody was detected after the inoculation, and much more antibody was detected after the second inoculation. The fact suggests that rabbits are a very useful laboratory animal for IBR virus infection studies.     

Experimental infectious bovine rhinotracheitis virus infections of English ferrets (Mustela putorius furo L).

Intranasal and intraperitoneal exposure of English ferrets (Mustela putorius furo L) to infectious bovine rhinotracheitis virus caused acute and chronic infections of the respiratory tract. The clinical syndrome was characterized by sneezing, coughing, and anorexia from postexposure days (PED) 3 to 7. Mucopurulent exudate was observed in the posterior nares and pharyngeal area of ferrets euthanatized on PED 4 and 8. The virus was readily recovered from the turbinates, respiratory tract epithelium of the pharynx, retropharyngeal lymph nodes, trachea, lungs, and spleen of animals euthanatized on PED 4, but only from the respiratory tract epithelium of the pharynx in ferrets euthanatized on PED 8 and 12. Results of histopathologic studies revealed an acute suppurative pharyngitis in animals euthanatized on PED 4 and 8. Recrudescence of chronic infection could be elicited by daily intraperitoneal injections of 4.0 mg of dexamethasone. However, daily administration of 2.0 mg of dexamethasone intraperitoneally did not cause more severe clinical disease. Results of serologic studies revealed serum antibody profiles comparable with those expected in experimentally exposed cattle.     

Protection from parainfluenza-3 virus and persistence of infectious bovine rhinotracheitis virus in sheep vaccinated with a modified live IBR-PI-3 vaccine.

Ewes (N = 7) and their lambs (N = 12) were vaccinated with a commercial modified live infectious bovine rhinotracheitis-parainfluenza type 3 virus vaccine. Both the vaccinated ewes and lambs and a group of unvaccinated ewes (N = 8) and their lambs (N = 13) were subsequently challenged with virulent parainfluenza type 3 virus. Although absolute immunity to infection and clinical response was not conferred, the clinical response was less severe in vaccinated lambs. Vaccinated animals also shed parainfluenza type 3 virus in nasal secretions for a shorter time than nonvaccinated animals. Some vaccinated lambs developed a persistent infectious bovine rhinotracheitis virus infection that was recrudesced by treatment with dexamethasone. It was concluded that vaccination was of benefit in reducing the severity of infection with parainfluenza type 3 virus. However, the inclusion of infectious bovine rhinotracheitis virus in a vaccine for sheep respiratory tract disease is highly questionable as it might increase the risk factor associated with vaccination. The consequences of the persistence of infectious bovine rhinotracheitis virus are now known.     

Effect of human leukocyte A interferon on prevention of infectious bovine rhinotracheitis virus infection of cattle

Human leukocyte A interferon was evaluated for its ability to prevent infectious bovine rhinotracheitis virus-induced respiratory tract disease in cattle. Weanling calves were treated daily for 1 week with 50 X 10(6) U of interferon, intranasally (by nebulization) and IM, and inoculated with infectious bovine rhinotracheitis virus on the first day of treatment. Respiratory tract disease was less severe in treated as compared with nontreated calves which were given only infectious bovine rhinotracheitis virus, and infection in the treated calves occurred later than in the untreated calves. Viral shedding and appearance of viral neutralizing antibodies occurred later in treated calves than in calves given only virus. Because several calves in a treatment group were housed together, whether the late appearance of infection in some interferon-treated calves was due to emergence of suppressed virus or to horizontal transmission from calves shedding virus could not be determined. One calf in the interferon-treated group developed antibody to human interferon and a few treated calves had transient elevation of hepatic enzymes. Interferon-treated calves developed a high temperature which subsided on termination of treatment. Production of disease was considerably dependent on the amount of virus and interferon given, since calves given 300 times more virus and approximately half as much interferon showed no evidence of protection against infection.     

四川部分地区牦牛传染性鼻气管炎血清学检测报告

[目的]为了解四川省牦牛传染性鼻气管炎感染的流行情况。[方法]应用酶联免疫吸附试验对在2012年间采自对四川省甘孜藏族自治州和红原县共377份牦牛血清进行牛传染性鼻气管炎病毒抗体检测。[结果]检出阳性血清样品共105份,阳性率为27.9%。[结论]表明四川省牦牛群中均存在牛传染性鼻气管炎病毒的感染。该研究为该地区牦牛传染性鼻气管防治提供依据。     

牛传染性鼻气管炎诊断和防治

牛传染性鼻气管炎又被称为坏死性皮鼻炎,是由牛传染性鼻气管炎病毒感染引发的一种急性呼吸道疾病。不同年龄的牛感染传染性鼻气管炎病毒后表现的临床症状存在一定差异,年龄较小的牛会表现为明显的临床症状,年龄较大的牛呈现隐性感染或持续性感染,患病牛长时间或终生携带病毒,污染周围环境后造成病情反复流行,病情难以控制、难以消灭。牛传染性鼻气管炎造成的死亡率相对较低,但是会严重影响牛群正常生长与采食,需要掌握该类传染性疾病的流行特点,并进行严格诊断,然后构建有效的防控措施,降低发病率。该文分析牛传染性鼻气管炎的流行病学、临床症状、病理变化、诊断方法和防治措施。     

牛传染性鼻气管炎病毒内蒙古分离株gG基因的PCR扩增

参考牛传染性鼻气管炎病毒全基因序列(GenBank)设计1对特异性引物,以牛传染性鼻气管炎病毒内蒙古分离株提取的总DNA为模板,运用PCR方法成功地扩增出牛传染性鼻气管炎病毒内蒙古分离株gG基因,并用琼脂糖凝胶电泳检测扩增产物。     

Effect of maternal antibody upon vaccination with infectious bovine rhinotracheitis and bovine virus diarrhea vaccines.

This report presents the normal rate of decay of maternal antibody and the influence of maternal antibody on responses to a single vaccination with modified-live bovine virus diarrhea and infectious bovine rhinotracheitis virus vaccines at 196 days of age and on response to vaccinations with the same vaccines given twice at 84 and 196 days of age. Passive immunity decreased to near zero over the first six months of life for both bovine virus diarrhea and infectious bovine rhinotracheitis controls. All calves seroconverted to bovine virus diarrhea vaccine at 84 days of age, even though high levels (greater than 1:32) of maternal antibodies were present. These calves did not seroconvert to infectious bovine rhinotracheitis vaccine at 84 days of age when high levels (less than 1:16) of maternal antibodies were present. Calves responded well to bovine virus diarrhea and infectious bovine rhinotracheitis vaccines given only once at 196 days of age after passive immunity disappeared. Calves which were revaccinated with infectious bovine rhinotracheitis seroconverted showing a more rapid response than the single vaccinates. Those revaccinated with bovine virus diarrhea showed an immediate response of small magnitude.     

Isolement du virus de la rhino-trachéite infectieuse bovine à partir du liquide synovial du tarse d''un taureau

Isolation of infectious bovine rhinotracheitis virus from the tarsal joint of a bullInfectious bovine rhinotracheitis virus was isolated from the right tarsal joint of a bull who was showing signs of a systemic viral infection. The clinical signs manifested by 16 bulls of this herd are described, the laboratory methods used are listed and the results are analysed and discussed.     

The association between serological titers in infectious bovine rhinotracheitis virus, bovine virus diarrhea virus, parainfluenza-3 virus, respiratory syncytial virus and treatment for respiratory disease in Ontario feedlot calves.

A seroepidemiological study of the association between antibody titers to infectious bovine rhinotracheitis, parainfluenza-3, bovine virus diarrhea and bovine respiratory syncytial viruses, and treatment for bovine respiratory disease was conducted. A total of 322 calves from five different groups were bled on arrival, then one month later all cases (cattle treated for bovine respiratory disease) were rebled together with an equal number of controls (cattle not treated for any disease). Titers to these viruses varied significantly from group to group. Based on seroconversion, infectious bovine rhinotracheitis virus was active in 4.4%, bovine virus diarrhea virus in 24%, parainfluenza-3 virus in 69.5% and bovine respiratory syncytial virus in 71.3% of the cattle. Cattle with low titers to infectious bovine rhinotracheitis and/or bovine respiratory syncytial viruses on arrival, were at increased risk of subsequent treatment for bovine respiratory disease. Treated cattle also had significantly greater increases to parainfluenza-3 and/or bovine virus diarrhea viruses than control calves. Treatment rates varied considerably from group to group and were not strongly correlated with weight gain in the postarrival period.     

Investigation of possible vaccine-induced epizootics of infectious bovine rhinotracheitis, using restriction endonuclease analysis of viral DNA

Viral DNA was extracted from each of 14 modified-live (ML) bovine herpesvirus 1 vaccines, representing all of the ML infectious bovine rhinotracheitis virus (IBRV) vaccines licensed by the US Department of Agriculture for use in cattle. Restriction endonucleases Pst I and Bgl II were used to establish restriction enzyme patterns for the vaccinal viruses. Viral DNA from isolates obtained from 6 field samples of IBRV (1 from Colorado, 1 from West Virginia, 3 from Wisconsin, 1 from South Dakota) were digested with restriction endonucleases, and patterns were compared to evaluate the role of vaccinal virus in these field epizootics of infectious bovine rhinotracheitis. Animals from which field samples were obtained had been vaccinated with ML IBRV vaccine before the epizootic of infectious bovine rhinotracheitis occurred in the herds. In 2 of the 6 field samples, DNA restriction endonuclease analyses patterns from the isolates were indistinguishable from the pattern for the vaccinal viruses used. In the remaining 4 field samples, DNA restriction endonuclease analyses patterns of the IBRV from isolates were different from those of the vaccinal viruses.     

Some lesions observed in calves born to cows exposed to the virus of infectious bovine rhinotracheitis in the last trimester of gestation.

Sixteen pregnant cows were challenged with infectious bovine rhinotracheitis virus intranasally. One had a mummified fetus, four aborted, one calf was stillborn, two live fetuses were taken at the abattoir and eight calves were born alive. Of the eight born alive, five were dead by 12 days of age. Four of these had the usual lesions of infectious bovine rhinotracheitis as well as lesions in the intestine and peritoneum and two of the four had a fibrinous pneumonia thought to be caused by aspiration of milk. The lesions, results of virus isolation and fluorescent antibody testing are recorded in these four calves. Attention is drawn to the intestinal lesions, the peritonitis and fibrinous pneumonia and the ease with which the underlying infectious bovine rhinotracheitis infection may be overlooked.     

Demonstration of infectious bovine rhinotracheitis virus antigen in paraffin sections

Nine pregnant heifers were inoculated intravenously with infectious bovine rhinotracheitis virus (IBRV) in the sixth month of pregnancy. Tissues were collected from the fetus of a heifer killed 13 days postinoculation (PI), from fetuses of 6 heifers that aborted 16-27 days PI, and from mummified fetuses of 2 heifers that aborted 53 and 85 days PI, respectively. Control tissues were obtained from the fetus of a non-inoculated heifer that was killed in the seventh month of gestation. Tissues were fixed in 10% formalin, embedded in paraffin, and examined for viral antigen by immunohistochemistry, using biotinylated second antibody and alkaline phosphatase-labeled avidin-biotin complex. Antigen was detected in at least 1 tissue from the fetus of each inoculated heifer. Positive tissues included lung, liver, spleen, kidney, adrenal, and placenta. In several fetuses, antigen was identified in tissues from which virus was not isolated in cell culture. This appeared to occur when tissues had only a few small foci of infection or when tissues were severely autolyzed. The observation of viral antigen in tissues from mummified fetuses indicates that this technique may be useful in diagnostic laboratories to detect IBRV infection in tissues that are not suitable for virus isolation or for examination by the cryostat tissue section-fluorescent antibody technique.     

Interferon, Antibody Responses and Protection Induced by an Intranasal Infectious Bovine Rhinotracheitis Vaccine

The interferon and antibody response induced by an intranasal infectious bovine rhinotracheitis vaccine was followed in 22 calves over a nine month period and the ability of these vaccinated calves to withstand challenge with virulent infectious bovine rhinotracheitis virus was assessed.Interferon was detected two to three days post-vaccination and disappeared by the tenth day. Nasal and serum antibodies appeared by day 7 and persisted for nine months.The calves challenged three days postvaccination came down with disease typical of infectious bovine rhinotracheitis, whereas calves challenged three weeks, three months or nine months postvaccination resisted infection.     

Evidence for defective neutrophil function in lungs of calves exposed to infectious bovine rhinotracheitis virus

Calves were exposed to an aerosol of infectious bovine rhinotracheitis (IBR) virus followed five days later by an aerosol of Pasteurella haemolytica. The animals were subjected to bronchoalveolar lavage before IBR and four days after, and again at 0, 4, 24, and 48 hours following Pasteurella haemolytica challenge. The results of these experiments suggest that neutrophil infiltration into the lung, in response to the presence of the bacteria was delayed thereby allowing the bacteria to become established in the lung. Neutrophils in infected animals displayed little random migration in vitro and did not respond to a chemotactic stimulus. It was also found that alveolar macrophages from virus-infected animals were not able to produce neutrophil chemotactic factors. These data suggest that the decrease in neutrophil chemotaxis and the lack of chemotactic factor production by the alveolar macrophage following infection with infectious bovine rhinotracheitis virus may predispose infected cattle to a secondary bacterial infection.     

Clinical and experimental modifications of plasma iron and zinc concentrations in cattle

Plasma iron and zinc concentrations were studied in pyrexic cattle or in cattle experimentally infected with infectious bovine rhinotracheitis virus or Escherichia coli endotoxin. Plasma iron and zinc levels tended to decline in the animals given endotoxin and in the pyrexic cattle, but the plasma iron level was only modified after experimental infectious bovine rhinotracheitis infection. These changes were not always related to pyrexia. Plasma iron and zinc concentrations taken together may be used as an indicator of infection.     

Effect of temperature, relative humidity and medium on the aerosol stability of infectious bovine rhinotracheitis virus.

Aerosols of infectious bovine rhinotracheitis virus were generated with a Devilbiss 40 nebulizer from Eagle's minimum essential medium, nasal secretion from a noninfected calf and nasal secretion from a calf artificially infected with infectious bovine rhinotracheitis virus and aged in a rotating drum at temperatures of 6 degrees C or 32 degrees C and relative humidities of 30% or 90%. The aerosols were sampled at seven minutes after start of spraying, one hour, two hours and three hours with an all glass impinger (AGI-30) and titrated for infectivity in cell cultures. Physical decay was determined by a rhodamine B tracer technique. During spraying (seven minutes from start of spraying), the virus was usually more stable in aerosols of nasal secretion from a noninfected calf and at 90% relative humidity. In nasal secretion from a noninfected calf the virus survived best at 90% relative humidity when the temperature was 6 degrees C and best at 30% relative humidity when the temperature was 32 degrees C. During aging, biological decay was greater at the higher temperature, and at 6 degrees C, the highest decay rates occurred at 30% relative humidity in Eagle's minimum essential medium and at 90% relative humidity in nasal secretion from a noninfected calf. The stability of infectious bovine rhinotracheitis virus infected nasal secretion was not widely different from that in noninfected nasal secretion, although under certain conditions greater survival occurred in the noninfected secretion.     

In utero infection of swine fetuses with infectious bovine rhinotracheitis virus (bovine herpesvirus-1)

The pathogenesis of infectious bovine rhinotracheitis (IBR) virus (bovine herpesvirus-1) was studied in porcine fetuses after in utero inoculation. Laparotomies were performed on 8 seronegative pregnant sows at 34 to 86 days of gestation, and all fetuses in 1 uterine horn of each sow were exposed to IBR virus via inoculation into the amniotic sacs. Fetuses in the other horn served as controls. Clinical signs of infection were not observed in the sows, except for 2 sows that aborted at postinoculation days (PID) 11 and 15. Fetuses of the remaining 6 sows were collected at slaughter on PID 15 to 28. Fetuses were examined for gross abnormalities, presence of IBR virus in tissues, and the formation of neutralizing antibodies to IBR virus. Of 33 inoculated fetuses from 6 sows, 10 were mummified, 11 were hemorrhagic and/or edematous, and 12 were alive. Necrotic lesions were observed on the skin and in the liver of dead and live fetuses. Virus was recovered from 29 of 33 inoculated fetuses. Infectious bovine rhinotracheitis virus was isolated from fetal skin, liver, lungs, kidney, spleen, stomach contents, brain, amniotic fluid, and placenta. Virus was isolated from 4 of 11 fetuses recovered from 1 aborting sow. Antibodies to IBR virus were not detected in sera from the sows. However, antibodies were detected in 6 of 15 fetuses inoculated at 63 to 86 days of gestation and collected at slaughter at 86 to 112 days of gestation. The youngest fetus with detectable IBR antibody was estimated to be 74 days of gestation by measuring crown-rump length of the fetus.     

Detection of African malignant catarrhal fever virus antigens in cell cultures by immunofluorescence

A fluorescent antibody (FA) test for antigens of African bovine wildebeest-derived malignant catarrhal fever virus was developed. Serum from one of the few survivors of the experimental disease in steers was used to prepare the conjugate. Both a virulent and an attenuated strain of malignant catarrhal fever virus were used to infect bovine thyroid cell cultures. Cells infected with both strains were readily detected by FA staining as early as 24 h post infection, whereas cytopathic effect could be observed by bright-field microscopy only after days 5 or 6 post infection. Controls consisting of normal bovine thyroid cells or infected cells treated with conjugated normal globulins did not show autofluorescence. The reaction was blocked by treatment of infected cells with homologous positive antisera but not by treatment with normal bovine serum or antisera to foot-and-mouth disease, rinderpest, bovine virus diarrhea, Ibaraki, infectious bovine rhinotracheitis, or bovine herpes mammilitis viruses. Treated with African malgnant catarrhal fever virus conjugate did not react.