Prevalence of antibodies to infectious bovine rhinotracheitis, parainfluenza 3, bovine respiratory syncytial, and bovine viral diarrhea viruses in cattle in Saskatchewan and Alberta

A total of 1745 healthy cattle from 295 farms in Saskatchewan and Alberta was tested by ELISA for antibodies to four viruses. Antibodies to infectious bovine rhinotracheitis (IBR) virus were found in 37.8% of sera (59.5% of properties), to parainfluenza 3 (PI3) virus in 93.9% of sera (99.7% of properties), to bovine respiratory syncytial (BRS) virus in 78.5% of sera (86.6% of properties), and to bovine viral diarrhea (BVD) virus in 40.6% of sera (66.7% of properties)

The prevalence of PI3 viral antibodies among Saskatchewan cattle was not affected by district of origin, breed, sex, age, or vaccination practices, though BRS viral antibodies appeared less frequent in young, male, and unvaccinated animals. Antibodies to IBR and BVD viruses were less prevalent in the Prince Albert/Tisdale districts and in young, male, and unvaccinated animals, but were more common in Holstein cattle. Antibodies to IBR virus appeared less frequent in Herefords. Antibodies were more prevalent in cattle which had been vaccinated against IBR, BRS, and BVD virus infections.

The relatively small number of cattle sampled from Alberta had a similar prevalence of antibodies to PI3 and BRS viruses to that seen in cattle in Saskatchewan, though IBR and BVD prevalence rates were lower.

     

Investigation of causative agents of bovine respiratory tract disease in a beef cow-calf herd with an early weaning program.

Serum samples were collected from early weaned fall calves shortly after the onset of respiratory tract disease. Antibody titers to infectious bovine rhinotracheitis (IBR) virus, parainfluenza type 3 (PI-3) virus, bovine viral diarrhea (BVD) virus, bovine adenovirus type 3 (BAV-3), and bovine respiratory syncytial virus (BRSV) were determined on paired (acute and convalescent) serums. Seroconversion rate (a fourfold or greater rise in antibody titer) for IBR virus was 4.3%, PI-3 virus--16.3%, BVD virus--9.6%, and BAV-3--2.2%. Seroconversion for BRSV was 45.4%. An increased rate of seroconversion for IBR, PI-3, and BVD viruses and BAV-3 was observed in the presence of BRSV seroconversion. These results suggest that BRSV may facilitate infection by other viruses. Results of virus isolation procedures from these calves were negative.     

Demonstration and quantitation of immunoglobulins in bovine serum, follicular fluid, and uterine and vaginal secretions with reference to bovine viral diarrhea and infectious bovine rhinotracheitis.

Immunoglobulin concentrations (IgG, IgM, and IgA) in bovine serum, follicular fluid, and uterine and vaginal secretions were determined. The specificities of IgG, IgM, and IgA for virus-neutralizing antibody against bovine viral diarrhea (BVD) and infectious bovine rhinotracheitis (IBR) viruses were also examined. High concentrations of IgG were present in both serum and follicular fluid. The IgG, IgM, and IgA concentrations were low in uterine and vaginal secretions. There was more IgG in the uterus during estrus than at any other time. Virus-neutralizing antibodies against BVD and IBR in serum of cows were mainly the IgG class. There was positive correlation between serum and follicular fluid virus-neutralizing antibody titers fro BVD and IBR. These antibodies may provide some protection for recently ovulated ova.     

A Controlled Field Study Using Live Virus Vaccines and an Antiserum in a Preconditioning Program

Thirty-five vaccinates and 29 control beef calves from five farms were studied. Vaccinates in group 1 received a modified live virus vaccine against infectious bovine rhinotracheitis (IBR) and bovine virus diarrhea (BVD) 30 days after shipment; vaccinates in groups 2, 3 and 4 received live virus vaccines agains IBR and bovine parainfluenza 3 (PI3) seven to 17 days before shipment. Half of group 5 were given bovine origin antiserum containing antibodies against IBR, BVD and PI3. Three weeks later, the animals that had received serum were given a live modified vaccine containing IBR, BVD and PI3. In group 1, WBC counts were lower in the vaccinates than in the controls for two weeks after vaccination. WBC counts in groups 3 and 4 were higher in vaccinates than in controls after addition to the feedlot. Seroconversions to BVD virus occured in all groups. Clinical disease apparently due to BVD affected one vaccinated calf in group 2 and eight calves in group 5. Combined weight gains were significantly higher in three groups of calves vaccinated before shipment compared to unvaccinated control animals after addition to the feedlot. Vaccination with IBR and PI3 live virus vaccines should be given at least 17 days before shipment to feedlots containing infected cattle. Antiserum containing antibodies against the three viruses showed no apparent advantage in preventing clinical respiratory disease over control calves not receiving the serum.     

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.     

Active and Passive Immunity to Bovine Viral Respiratory Diseases in Beef Calves After Shipment

Fifteen steers were vaccinated after shipment with a modified live virus vaccine containing infectious bovine rhinotracheitis (IBR), bovine virus diarrhea (BVD), and bovine myxovirus parainfluenza-3 (PI3), and 16 unvaccinated steers were kept as controls. Geometric mean titers one month after vaccination were highest to BVD, followed by PI3 and IBR. Weight gains were higher during 30 days after vaccination in the controls. One case of acute respiratory disease developed in one vaccinated calf. Revaccination 79 days after the first dose increased antibody to PI3 and BVD virus but not IBR. In a second trial, no clinical respiratory disease developed after shipment of 13 heifers that received an antibacterial-antiviral antiserum or in the 12 controls. Weight gains 30 days after shipment were identical in both groups.     

Maternal immunity to infectious bovine rhinotracheitis and bovine viral diarrhea viruses: duration and effect on vaccination in young calves.

The immune response to modified live-virus bovine viral diarrhea (BVD) vaccine and infectious bovine rhinotracheitis (IBR) vaccine was examined in calves that had received passive maternal antibodies to these viruses. Blood serum samples from vaccinated and control (nonvaccinated) calves were examined for more than 1 year to determine the rate of decline of passive anti-BVD and anti-IBR antibodies and the effect that vaccination had on these antibody titers. The control calves lost their antibodies to BVD and IBR viruses at the rate of one half their remaining antibody titer every 21 days. Calves serologically responded to BVD vaccine at a time when maternal antibody titers remained between 1:96 and 1:20. However, animals did not seroconvert to the IBR vaccine until maternal antibodies had decreased and become undetectable. Evidence is presented to show that although passive immunity will inhibit IBR vaccination, priming for a secondary response will occur so that on subsequent vaccination, at a time when maternal antibodies have disappeared, the animals will respond anamnestically to IBR vaccination.     

Viral aetiologies for bovine respiratory disease

Extract

Bovine respiratory disease (BRD) is a major health problem of cattle all over the world. Financial losses arise from the loss in production, cost of treatment and mortality. Incidence varies with seasons, the highest occurring in autumn and winter. Virus infections such as infectious bovine rhinotracheitis (IBR), parainfluenza 3 (P13) and bovine respiratory syncytial (BRS) viruses have all been incriminated as causes for BRD. It has been suggested that bovine viral diarrhoea (BVD) virus may also contribute to BRD because of its immunosuppressive effects, thus increasing the susceptibility of the host to other respiratory pathogens.     

Analysis of symptoms associated with bovine herpesvirus 1 vaccination

Between 1 May 1998 and 22 February 1999, it was compulsory for Dutch cattle farmers to take measures against bovine herpesvirus 1 (BHV1). Cattle on farms that were not certified as infectious bovine rhinotracheitis (IBR)-free had to be vaccinated twice a year. During the vaccination programme, both farmers and veterinarians reported side-effects of the vaccine. These reports were collected by the Stichting IBR/BVD Schade (SIS; Foundation for IBR/BVD Damage) in order to draw up a damage report. In 1999 in total 6977 cattle farmers lodged complaints which they considered to be related to the vaccination against BHV1. On these farms, 15,150 herd vaccinations had been performed, 10,269 of which were associated with one or more symptoms. During the compulsory vaccination period, 13% of the herd vaccinations led to symptoms and complaints. In March 1999, a number of vaccine batches were found to be contaminated with bovine virus diarrhoea (BVD) virus. For the purposes of this analysis, a 'known contaminated' herd vaccination was defined as one in which at least one 'known contaminated' batch or lot of vaccine was used. In total, 987 of 1007 herds vaccinated with 'known contaminated' vaccines developed one or more symptoms compatible with acute BVD. There were no commonly seen combinations of symptoms. For this reason, and because the start and end dates were not reported for 55% of the symptoms, it was not possible to detect a symptom pattern. Therefore there were no 'suspect' batches of vaccine which, although not contaminated with BVD virus, gave rise to symptoms. The number of BVD symptoms was determined for those herds with vaccination-related symptoms. There was no difference in the distribution frequency between batch numbers or between 'known contaminated' batches and 'non-suspect' batches. The farmers' definition of chronic wasting was used in this investigation, with the inevitable large differences in definition. The symptom chronic 'wasting' was reported for 3209 of the 10,269 herds with vaccination-related symptoms. On 161 farms (164 herd vaccinations) 'chronic wasting' accounted for more than 20% of the symptoms. As expected, other symptoms were reported in addition to wasting. The symptom 'chronic wasting' was reported more often on forms where a 'known contaminated' vaccine was used. Inactivated vaccine was used for 154 herd vaccinations. In 34 cases, one or more symptoms of acute BVD were reported. The frequency was the same as that for live vaccines. The frequency of reported symptoms tended to be lower with the inactivated vaccine. On the basis of the SIS data, no relationship was found between vaccine batch and reported symptoms. This may be because (i) the classification of a vaccine as 'known contaminated', 'non-suspect', and 'not known' may not have been in keeping with the real status of the vaccine, (ii) farmers may have reported symptoms selectively, and (iii) there is no relationship with vaccination against BHV1.     

Experimental transmission of bovine viral diseases by insemination with contaminated semen or during embryo transfer

Three experimental approaches were used to study transmission of blue tongue (BT), infectious bovine rhinotracheitis (IBR) and bovine virus diarrhoea (BVD) viruses. These were insemination with contaminated semen, experimental infection of embryo donor cows, or transfer of embryos experimentally exposed to virus in vitro to normal recipients. Parameters assessed included number and quality of embryos produced, virus detection (isolation and electron microscopy), serology and histopathology. All superovulated sesceptible cows inseminated with semen containing blue tongue virus (BTV) (n = 2) or infectious bovine rhinotracheitis virus (IBRV) (n = 2) became infected. One cow inseminated with semen containing BTV produced seven virus-free seven-day-old embryos; the second cow failed to produce any embryos. One of two cows inseminated with semen containing IBRV produced two underdeveloped, virus-free embryos while no embryos were produced by the second cow. One of two cows inseminated with semen containing bovine viral diarrhoea virus (BVDV) became infected. Two poorly developed, virus-free seven-day-old embryos were recovered from one of these cows. Superovulated susceptible cows inoculated either intramuscularly with BTV (n = 3) or intranasally with IBR virus (n = 2) became infected. Virus was isolated from some tissues of two BTV-infected cows, neither of which produced embryos. A third BTV-infected cow produced two virus-free embryos collected at necropsy five days after inoculation. One of two cows experimentally infected with IBR virus, produced three embryos but virus was not detected either by electron microscopy (1 embryo) or in cell culture by cytopathic alterations (1 embryo).(ABSTRACT TRUNCATED AT 400 WORDS)     

Preliminary serological characterization of bovine viral diarrhoea virus strains using monoclonal antibodies

Five monoclonal antibodies against the bovine viral diarrhoea (BVD) viral strain NADL were isolated and characterized by an indirect immunofluorescence assay. Extensive cross-reactions were detected when the antibodies were tested with 12 heterologous BVD and four hog cholera (HC) viral strains. One antibody reacted with all strains tested. Two antibodies were specific for cytopathogenic BVD viruses, but failed to react with HC virus. The other antibodies reacted to varying degrees with BVD and HC viral strains.     

BVD approach: vaccination and eradication

The vulnerability of cattle populations that do not have adequate levels of antibodies against the bovine virus diarrhoea (BVD) virus was demonstrated in February 1999, when a contaminated vaccine against infectious bovine rhinotracheitis (IBR) was accidentally used. Only cattle with antibodies against BVD survived this unintentional challenge. A BVD infection can be detected easily with currently available laboratory techniques, but the virus is less easy to eliminate. The risk of financial loss is small, and the costs are limited, if mainly seronegative cattle, selected on the basis of sampling, are given the live vaccine. Over the last 7 years this approach has been applied to about twenty dairy farms. This approach would be compatible with a BVD eradication programme.     

In vitro interferon production by bovine tissues: induction with infectious bovine rhinotracheitis virus.

The interferon-inducing ability of infectious bovine rhinotracheitis (IBR) virus was determined in tissue cultures of bovine origin inoculated with untreated and ultraviolet (UV) irradiated IBR viruses. Interferon was assayed by the plaque-reduction method in bovine fetal kidney (BFK) cell cultures, using vesicular stomatitis virus as challenge virus. Highest interferon concentrations were produced by cultures of bovine fetal (BF) spleen cells and aveolar macrophage cultures derived from adult cattle. Moderate interferon concentrations were produced by peripheral blood leukocyte (PBL) suspension cultures from adult cattle with serum-neutralizing antibodies against IBR virus. Cultures of PBL from 1 cow without detectable serum-neutralizing antibodies against IBR virus did not produce detectable interferon in response to IBR virus. Cultures of PBL from cattle with or without detectable serum-neutralizing antibodies against IBR virus produced interferon when stimulated with phytohemagglutinin (PHA). Low levles of viral inhibitors were detected infrequently in monolayer cultures of BFK and BF nasal mucosa inoculated with UV-irradiated IBR virus and in BF tracheal organ cultures inoculated with untreated IBR virus. Interferon was not detected in fluids collected from IBR virus-exposed monolayer cultures of primary and secondary BF lung, secondary BF tracheal mucosa, secondary BF liver, secondary BF adrenal, and PBL in the 4th and 7th passages. The antiviral inhibitors from BF spleen, bovine alveolar macrophage, and PBL cultures induced with IBR virus, as well as inhibitors from PBL cultures induced with PHA, had the usual properties of interferon.     

Serological survey concerning the IBR, CHV2, BVD, PI3, BRS and rinderpest viruses in small ruminants in Zaire

More than 400 small ruminant sera from Za?re were screened for antibodies to IBR, CHV2, BVD, bovine and ovine PI3, BRS and rinderpest viruses. Sera from local animals were negative for BVD, PI3 and rinderpest viruses: 8% of sera were positive for IBR virus, all with higher titers to CHV2; 31% of sera were positive to BRS virus.     

A study of some infectious causes of reproductive disorders in cattle owned by resource-poor farmers in Gauteng Province, South Africa

Two hundred and thirty-nine cattle from Gauteng Province in South Africa were tested for various pathogens causing reproductive diseases includingbovine viral diarrhoea/mucosal disease (BVD/MD) virus, infectious bovine rhinotracheitis/infectious pustular vulvovaginitis (IBR/IPV) virus, Neospora caninum and Brucella abortus usingvarious tests. For BVD/MD virus, 49.37% tested positive, 74.47% for IBR/IPV virus, 8.96% for Neospora caninum and 3.8% for Brucella abortus. The result for Brucella abortus is higher than the national average, possibly due to the small sample size. A high seroprevalence of antibodies to both BVD/MD virus and IBR/IPV virus was evident. These 2 viruses should be considered, in addition to Brucella abortus, when trying to establish causes of abortion in cattle. The clinical significance of Neospora caninum as a cause of abortion in Gauteng needs further investigation. One hundred and forty-three bulls were tested for Campylobacter fetus and Trichomonas fetus, and a low prevalence of 1.4% and 2.1% respectively was found in this study. The clinical implications of these findings are discussed.     

A field trial with a multicomponent inactivated respiratory viral vaccine.

An inactivated virus vaccine containing strains of parainfluenza type 3 (PI3), bovine adenovirus type 3, reovirus type 1, bovine virus diarrhoea (BVD) and infectious bovine rhinotracheitis (IBR) viruses was tested in a group of 58 calves reared in a semi-intensive management system. Following vaccination, 1/30, 14/30 and 17/30, showed significant rises in antibody titre to reovirus type 1, adenovirus type 3 and IBR respectively. None of the animals showed significant serological response to PI 3 and BVD. In the control group, 2/28, 1/28, 6/28 and 3/28 developed antibody responses to reovirus type 1, BVD, adenovirus type 3 and IBR respectively. Microbiological examination revealed the presence of a wide variety of commensal bacteria and Mycoplasma bovirhinis in both groups. Analysis of the records of clinical examinations indicated that the respiratory tract infections occurred among the calves at between 50 and 80 days after arrival at the farm, and that there was no significant difference between the test and the control groups. A number of animals had maternal antibodies to the various components of the vaccine present before the trial commenced and these antibodies appeared to interfere with the subsequent serological response to the antigen challenge. The vaccination schedule recommended by the manufacturer does not entirely circumvent this problem.     

In vitro interactions of cytokines and bovine viral diarrhea virus in phytohemagglutinin-stimulated bovine mononuclear cells

Bovine viral diarrhea (BVD) virus inhibited phytohemagglutinin (PHA)-stimulated bovine peripheral blood mononuclear cell (PBMC) proliferation and bovine interleukin-2 (IL-2) production. In the controls, the heat-inactivated BVD virus was not capable of suppressing the PHA-stimulated PBMC proliferation. Presence of exogenous cytokines, such as purified human IL-2, recombinant bovine interleukin-1 (rbovIL-1), recombinant bovine IL-2, and recombinant human IL-6 failed to reverse the BVD virus-induced immunosuppression. Also, we found that the BVD virus inhibited PHA and IL-2 induced proliferation of bovine PBMC in the early and late stages of activation. In summary, our data suggest that BVD virus induced immunosuppression was not due to destruction of the PBMC but may be inhibiting one or more of the important intracellular enzymes that may regulate PBMC proliferation.     

Response of cattle persistently infected with noncytopathic bovine viral diarrhea virus to vaccination for bovine viral diarrhea and to subsequent challenge exposure with cytopathic bovine viral diarrhea virus

Nine steers persistently infected with noncytopathic bovine viral diarrhea (BVD) virus were allotted into 3 groups (3 cattle/group). Cattle in group A were vaccinated with a modified-live BVD virus vaccine of porcine cell origin, cattle in group B with a modified-live BVD virus vaccine of bovine cell origin, and cattle in group C with a killed BVD virus vaccine of bovine cell origin. Detrimental effects due to vaccination were not seen. Six weeks after vaccination, the steers were challenge exposed with a cytopathic BVD virus. All steers developed mucosal disease after challenge exposure, produced antibodies that neutralized various isolates of BVD virus, and remained persistently infected until death. Steers given killed virus vaccine had a minimal neutralizing-antibody response and developed mucosal disease as quickly as reported for challenge-exposed, nonvaccinated, persistently infected cattle. Steers given modified-live virus vaccines had higher neutralizing-antibody response and longer intervals from challenge exposure to development of mucosal disease. The specificity of the neutralizing-antibody response differed between groups of vaccinated cattle.     

Effects in calves of mixed infections with bovine viral diarrhea virus and several other bovine viruses

The objective of this study was to verify whether a mixed infection in calves with bovine viral diarrhea virus (BVDV) and other bovine viruses, such as bovid herpesvirus-4 (BHV-4), parainfluenza-3 (PI-3) and infectious bovine rhinotracheitis (IBR) virus, would influence the pathogenesis of the BVDV infection sufficiently to result in the typical form of mucosal disease being produced.

Accordingly, two experiments were undertaken. In one experiment calves were first infected with BVDV and subsequently with BHV-4 and IBR virus, respectively. The second experiment consisted in a simultaneous infection of calves with BVDV and PI-3 virus or BVDV and IBR virus.

From the first experiment it seems that BVDV infection can be reactivated in calves by BHV-4 and IBR virus. Evidence of this is that BVDV, at least the cytopathic (CP) strain, was recovered from calves following superinfection. Moreover, following such superinfection the calves showed signs which could most likely be ascribed to the pathogenetic activity of BVDV. Superinfection, especially by IBR virus, created a more severe clinical response in calves that were initially infected with CP BVDV, than in those previously given the non-cytopathic (NCP) biotype of the virus. Simultaneous infection with PI-3 virus did not seem to modify to any significant extent the pathogenesis of the experimentally induced BVDV infection whereas a severe clinical response was observed in calves when simultaneous infection was made with BVDV and IBR virus.     

ELISA detection of bovine viral diarrhoea virus specific antibodies using recombinant antigen and monoclonal antibodies

A panel of monoclonal antibodies was prepared by immunization of BALB/c mice with Moredun (BD) virus strains. These antibodies were characterized by immunofluorescence and seroneutralization against BD, BVD and hog cholera (HC) virus strains, and radioimmunoprecipitation of BVD-infected cells extracts. The MAbs reacting with the majority of the Pestivirus strains recognize the 80 kDa antigen of the BVD cytophathic strains. The 80 kDa antigen of the BVD/Osloss virus strain has been cloned and expressed in E. coli as a fusion protein with beta-galactosidase. The fusion protein has been purified from inclusion bodies and used successfully as an antigen for ELISA detection of BVDV specific antibodies in bovine sera. A competitive ELISA using MAbs is more specific than a direct assay. These results compare well with the ones obtained with antigen extracted from BVDV-infected cells.