Ovarian lesions induced in heifers by intravenous inoculation with modified-live infectious bovine rhinotracheitis virus on the day after breeding

Four commercially available vaccine strains of modified-live infectious bovine rhinotracheitis virus were passaged once in embryonic bovine kidney cells. Heifers were inoculated IV on the day after breeding with 5.0 ml of nondiluted cell culture fluid of each of the 4 strains. Virus was reisolated from nasal swabs and blood collected during the week after inoculation. The heifers were killed 9 to 14 days after inoculation. Mild-to-marked inflammatory and necrotic lesions were seen in the corpora lutea and ovaries of the heifers. The lesions were similar to, and almost as severe as, those resulting from the inoculation of virulent strains of infectious bovine rhinotracheitis virus. Adrenal lesions were also found in all heifers examined. Virus was reisolated from the ovaries of only 4 of the 8 heifers. However, virus was confirmed in the ovaries of all 8 heifers, using immunofluorescent or ultrastructural studies. Heifers with severe luteal damage had abnormally low plasma progesterone concentrations.     

Rapid onset of protection against infectious bovine rhinotracheitis with a modified-live virus multivalent vaccine

This study provides evidence that subcutaneous vaccination of cattle with a commercially available modified-live virus combination vaccine can help reduce clinical signs associated with infectious bovine rhinotracheitis infections in feedlot animals vaccinated at the time of arrival. Calves vaccinated 72 or 96 hours before challenge had reduced clinical signs, lower body temperatures, lower virus titers, and 39% to 76% greater weight gains compared with nonvaccinated controls.     

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.     

Ovarian lesions in heifers exposed to infectious bovine rhinotracheitis virus by non-genital routes on the day after breeding

Twelve heifers were exposed to either a Colorado infectious bovine rhinotracheitis (IBR) virus isolate or an Iowa IBR isolate obtained from a bovine respiratory disease outbreak. All inoculations were made on the day after the heifers had been in estrus and bred by an IBR virus-negative bull. Pairs of heifers were inoculated with each virus isolate intravenously, intramuscularly or exposed by aerosol. The heifers were killed 11-15 days after inoculation and their reproductive tracts and ovaries subjected to virological and pathological study. Virus was isolated from the ovaries of all 4 heifers inoculated intravenously and from 3 of the 4 heifers inoculated intramuscularly, but not from the ovaries of heifers exposed by aerosol. Virus isolations and lesions were, with only 1 exception, confined to the ovary containing the corpus luteum. In ovaries from which IBR virus was isolated, lesions in the corpus luteum ranged from focal necrosis and infiltration of mononuclear cells to diffuse hemorrhage and necrosis. Most of these ovaries also had necrotic follicles and a diffuse mononuclear cell accumulation in the stroma. Lesions were not found in ovaries from which IBR virus was not isolated. It was concluded that lesions are readily induced in the ovaries of post-estrus heifers as a result of hematogenous spread of IBR virus and suggest that the differences in lesion development observed with the 3 routes are related to whether or not a viremia occurred.     

Nitrogen metabolism of calves inoculated with bovine adenovirus-3 or with infectious bovine rhinotracheitis virus

Beef calves were inoculated with bovine adenovirus-3 or infectious bovine rhinotracheitis virus. After inoculation, plasma fibrinogen increased, serum phosphorus decreased, and nitrogen and phosphorus digestibility decreased compared with preinoculation values. Urinary N excretion increased when calves developed rectal temperatures greater than 39.7 C. Results indicated that clinical infection of calves with infectious bovine rhinotracheitis virus increases urinary N excretion and reduces N and phosphorus balance, and that clinical and subclinical infections with either virus reduce dietary N digestibility.     

Reproductive tract lesions in heifers after intrauterine inoculation with infectious bovine rhinotracheitis virus

Cross-breed heifers given infectious bovine rhinotracheitis virus by intrauterine inoculation 1 day after natural mating with a noninfected bull were killed on postinoculation days 4 to 14. When reproductive organs were examined for gross and microscopic lesions and for virus infection, the most severe uterine lesions were found in the body and caudal portions of the uterine horns of heifers killed between postinoculation days 4 and 9. Primary pathologic features were necrosis, edema, hemorrhage, and a diffuse accumulation of mononuclear cells, mostly lymphocytes; numerous lymphocytes were in mitosis. In cranial parts of uterine horns, the only lesions observed were a few small lymphocytic foci in the endometrial lamina propria. Lesions were not seen in the oviducts. In many heifers, the ovarian corpus luteum (CL) was cystic. In a few of these heifers, the cyst had a necrotic wall that was bordered by a zone of proliferating mononuclear cells. Focal necrosis and lymphoid proliferation were common in the parenchyma of cystic and noncystic CL. Similar necrotizing lesions were sometimes present in non-CL ovarian tissue. Infectious bovine rhinotracheitis virus was most frequently isolated from the uterine body, the internal os of the cervix, and the CL. Isolations were not made from blood samples taken at the time of necropsy. Isolation of virus from the CL correlated with the detection of luteal inflammation by light microscopy, but did not correlate with the presence of cysts. There also was no correlation between cystic CL and the severity of uterine lesions.     

Necrotic oophoritis in heifers vaccinated intravenously with infectious bovine rhinotracheitis virus vaccine during estrus

Twenty-two Hereford heifers were injected IM with prostaglandin F2 alpha a, 11 days apart to synchronize estrous cycles. Twelve of 14 heifers that had signs of estrus were inoculated IV with 1 of 3 modified-live infectious bovine rhinotracheitis virus vaccines, and 2 were assigned to a nonvaccinated control group. Also, 6 of the 8 anestrous heifers were inoculated IV with 1 of the 3 vaccines on the fourth day after the last prostaglandin injection and the other 2 were assigned to the nonvaccinated group. Vaccine virus was isolated from the blood and nasal and vaginal secretions from the vaccinated heifers on postvaccination days 4, 7, and 9. On postvaccination day 9, all heifers were ovariectomized and ovarian tissues were processed for virus isolation and histologic examination. Vaccine virus was isolation and histologic examination. Vaccine virus was isolated from ovarian tissues of some heifers in each of the vaccine groups. Necrotic oophoritis characterized by multifocal areas of ovarian tissue necrosis, hemorrhage, and mononuclear lymphocytic infiltration was observed. The corpora lutea and surrounding ovarian tissues taken from vaccinated heifers in each group had varying amounts of necrotic and inflammatory change, but the changes appeared to be more severe in 1 group than in the other 2. Virus also was isolated from 2 of the controls; these heifers apparently became infected with vaccine virus that had been excreted from the vaccinated animals.     

Efficacy of bovine herpesvirus-1 inactivated vaccine against abortion and stillbirth in pregnant heifers

OBJECTIVE: To evaluate the efficacy of an inactivated bovine herpesvirus-1 (BHV-1) vaccine to protect against BHV-1 challenge-induced abortion and stillbirth. DESIGN: Prospective study. ANIMALS: 35 beef heifers. PROCEDURES: Before breeding, heifers were vaccinated with a commercially available BHV-1 inactivated vaccine SC or IM. The estrous cycle was then synchronized, and heifers were artificially inseminated 30 to 60 days after vaccination. Heifers (n = 21) were challenge inoculated IV at approximately 180 days of gestation with virulent BHV-1. Fourteen control heifers were not vaccinated. Clinical signs of BHV-1 infection were monitored for 10 days following challenge; serologic status and occurrence of abortion or stillbirth were evaluated until time of calving. RESULTS: 18 of 21 (85.7%) heifers that received vaccine were protected from abortion following challenge, whereas all 14 control heifers aborted. CONCLUSIONS AND CLINICAL RELEVANCE: Results indicated that an inactivated BHV-1 vaccine can protect against abortion resulting from a substantial challenge infection, with efficacy similar to that of modified-live BHV-1 vaccines.     

Fatal, generalized bovine herpesvirus type-1 infection associated with a modified-live infectious bovine rhinotracheitis parainfluenza-3 vaccine administered to neonatal calves.

Generalized bovine herpesvirus 1 (BHV-1) infection was diagnosed in six Salers calves from the same herd. The calves had received an intramuscular injection of modified-live infectious bovine rhinotracheitis parainfluenza-3 vaccine between birth and three days of age. The purpose of this study was to determine if the outbreak was associated with the vaccine strain of BHV-1. Analysis of epidemiological data and BHV-1 DNA for restriction fragment length polymorphism was undertaken. Multifocal necrosis in multiple organs was observed on pathological examination, and the presence of BHV-1 in tissues was confirmed by immunohistochemistry. Forty-three calves (aged birth to thirty days) were vaccinated over an 11-day interval. The 10 deaths recorded for vaccinated calves were clustered over a subsequent 14-day interval. Mortality in calves vaccinated between birth and three days of age was significantly higher than in nonvaccinated calves (chi-square test; p < or = 0.025), and this mortality was characterized by a greater age at death and duration of illness for vaccinated calves (t test; p < or = 0.001). The patterns of the restriction fragments, generated by six restriction endonucleases, of BHV-1 isolated from a necropsied calf and from the vaccine were identical, and different from that of a laboratory strain of BHV-1 (P8-2). These findings support the conclusion that newborn calves were susceptible to an intramuscularly injected vaccine strain of BHV-1, and that administration of an intramuscular modified-live infectious bovine rhinotracheitis parainfluenza-3 vaccine to neonatal calves may not be an innocuous procedure.     

Transmission of a vaccinal strain of infectious bovine rhinotracheitis virus from intranasally vaccinated steers commingled with nonvaccinated steers

Ninety-seven feeder steers, averaging 7 months of age, were allotted to 3 groups. Group I (n = 33) was vaccinated intranasally with an infectious bovine rhinotracheitis virus (IBRV) vaccine on postinoculation day (PID) 0; group II (n = 31) was not vaccinated on PID 0 but was commingled with group I; and group III (n = 33) served as controls housed in the same facility, but was physically separated from groups I and II. On PID 20, all steers were given a modified-live IBRV vaccine IM. Virus isolation attempts from nasal swab specimens collected on PID 10 resulted in IBRV isolation from 19 (57.6%) of group I, 4 (12.9%) of group II, and 0 of group III. By PID 20, geometric mean titer for serum antibody to IBRV had increased in group I but had decreased in groups II and III. By PID 40, geometric mean titer for serum antibody to IBRV had increased in the 3 groups in response to IM vaccination given on PID 20. Seemingly, transmission of a vaccinal strain of IBRV to nonvaccinated steers did not take place at a frequency that elicited a humoral immune response similar to that of vaccinated steers.     

Comparison of humoral immune responses in dairy heifers vaccinated with 3 different commercial vaccines against bovine viral diarrhea virus and bovine herpesvirus-1

A randomized clinical trial was conducted to compare the humoral immune response to 3 different commercial vaccines in dairy heifers housed in 3 different dairy farms in Quebec. All heifers were seronegative to type 1 bovine viral diarrhea virus (BVDV) (Singer strain), type 2 BVDV (NVSL 125c strain), and bovine herpesvirus-1 (BHV-1) at the beginning of the trial. In addition, control heifers in group 1 remained seronegative to the 2 viruses till the end of the trial. Significant differences in humoral immune responses occurred among the 3 commercial vaccines at 4 weeks and 6 months following vaccination. The vaccine in group 2 elicited higher mean antibody titers and seroconversion rates to both type 1 and type 2 BVDV than that in groups 3 or 4. Vaccines in groups 2 and 3 induced higher mean antibody titers to BHV-1 than did the vaccine in group 4.     

青海省牛传染性鼻气管炎及病毒性腹泻黏膜病血清学调查

从青海省互助、玛多、海晏、玉树、贵德、德令哈、共和等14个地区采集牛血清样品420份,应用酶联免疫吸附试验（ELISA）调查了青海省牛传染性鼻气管炎和病毒性腹泻黏膜病的感染情况。结果在被检牛血清420份样品中,共检出阳性血清样品228份,平均阳性率为50.67%（228/420）;在被检牦牛血清180份样品中,共检出阳性血清样品1份,平均阳性率0.56%（1/180）。     

Propagation of infectious bovine rhinotracheitis (bovine herpes-1) virus in murine primary cell cultures

Virus synthesis in BALB/C mouse lung and kidney primary cultures infected with infectious bovine rhinotracheitis (IBR) virus started between 6 and 8 hours after virus inoculation and reached a maximum titer of 5.5 log₁₀ plaque forming units (PFU) at 48 hours postinfection (PI). Cytopathic effect (CPE) in cell cultures occurred at 8–10 hours and over 90% of the cells had CPE by 48 to 72 hours PI. The bulk of the newly replicated virus (60–80%) was cell-associated as determined by plaque assay of extracellular and intracellular virus. Pulse-chase experiments demonstrated incorporation of radioactive precursors into viral DNA and protein macromolecules. Viral DNA synthesis was initiated between 2 and 4 hours PI and was maximum at 4 to 6 hours. Viral proteins were detected at 4 hours and peaked between 6 and 8 hours PI. Enzyme-linked immunosorbant assay (ELISA) confirmed synthesis of specific viral proteins, which gradually increased during the virus growth cycle. Abstract in French is given at the end of the article.

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Resume La synthèse du virus de la rhinotrachéite infectieuse bovine (virus IBR) sur des cultures primaires de poumon et de reins de souris (souche Balb/C) commençait entre 6 et 8 heures après inoculation du virus et atteignait un titre maximal de 5.5 log PFU (Plaque Forming Unit) 48 heures après infection. L'effet cytopathogenic (CPE) sur ces cultures cellulaires apparaissaient en 8 à 10 heures et plus de 90% des cellules montraient un CPE en 48 à 72 heures après infection. La détermination par la méthode des plages sous agarose, du virus extracellulaire et du virus intracellulaire, indiquait que 60–80% du virus synthétisé était associé avec les cellules. Les expériences de pulsechase demontraient l'incorporation des précurseurs radioactifs dans les protèines et ADN viraux. La synthèse virale d'ADN était initiée entre 2 et 4 heures après infection et était maximale en 4 à 6 heures. Les protéines virales étaient détectées en 4 heures avec un maximum de synthèse entre 6 et 8 heures après infection. Enzyme-linked immunosorbant assay (ELISA) confirmait la synthèse de protéines virales spécifiques qui montrait une augmentation graduelle pendant le cycle de replication du virus.

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Supported in part by grants 0831 from the Cooperative State Research Service of the US Department of Agriculture and published as contribution 85-160-J, Kansas Agricultural Experiment Station.