Antibody prevalence against respiratory viruses in sheep and goats in North-Western Turkey

Respiratory viruses may infect both small and large ruminant species, and can be transmitted among those of species. Present study reports presence and serological distribution of bovine respiratory viral infections in sheep and goats in Marmara region of Turkey. Total of 388 sera, 228 from sheep and 160 from goats collected from 4 provinces were analysed. Neutralising antibodies specific to BVDV, BHV-1, BRSV, PI-3, BAV-1 and BAV-3 were investigated. Among 388 serum samples 32.1% were positive for BVDV, 23.0% for BHV-1, 72.9% for BRSV, 13.2% for PI-3, 86.0% for BAV-1 and 93.0% for BAV-3. There were significant differences observed between seroprevalence rates detected in neighbouring provinces. Prevalence of BVDV specific antibodies was extremely higher (p = 0.0009) in sheep, however, BHV-1 (p = 0.0001) and PI-3 (p = 0.0038) were more prevalent in goats. BRSV antibody prevalence was closely related to data obtained from cattle. This study demonstrates that, like in cattle herds, BRSV and adenoviruses are the possible common reason of respiratory diseases in small ruminants in the region.     

Serological evaluation of relationship between viral pathogens (BHV-1, BVDV,BRSV, PI-3V,and Adeno3) and dairy calf pneumonia by indirect ELISA

In this study, viral pathogens associated with nine outbreaks of naturally occurring dairy calf pneumonia in Mashhad area of Khorasan Razavi province from September 2008 to May 2009 were assessed. Five diseased calves from each farm were chosen for examination. Acute and convalescent serum samples were taken from calves with signs of respiratory disease. Sera were analyzed for antibodies to bovine viral diarrhea virus (BVDV), bovine herpesvirus type 1 (BHV-1), bovine respiratory syncytial virus (BRSV), parainfluenza virus type 3 (PI-3V), and bovine adenovirus-3 (BAV-3) by indirect ELISA kits. Among 42 serum samples collected at sample 1, seroprevalence values for viruses BHV-1, BVDV, BRSV, PI-3V, and BAV-3 were 61.9% (26), 57.1% (24), 64.2% (27), 90% (38), and 61.9% (26), respectively. Seroconversion to BVDV, BRSV, PI-3V, and BAV-3 occurred in 11.9% (5), 16.6% (7), 26.1% (11), and 21.4% (9) of animals, and 52.3% (22) had generated antibodies against one or more viral infections at sample 2. In addition, no significant relationship between seroprevalence of BHV-1, BVDV, BRSV, PI-3V, and BAV-3 and dairy herd size was observed (P > 0.05). According to serological findings, BHV-1, BVDV, BRSV, PI-3V, and BAV-3 are common pathogens of the dairy calf pneumonia in dairy herds in Mashhad area of Khorasan Razavi province, Iran.     

A preliminary serological survey of viral antibodies in Peruvian sheep

This study reports the sero-prevalence of viral infections in sheep in Peru. Serum samples were collected from 34 mature healthy rams located in 3 different geographic regions of the country (north, central and south). The sera were tested for antibodies to the following viruses: respiratory syncytial virus (RSV); parainfluenza 3 (PI-3) virus; bovine viral diarrhea/border disease (BVD/BD) virus; bovine herpesvirus 1 (BHV-1); bluetongue (BT) virus; ovine progressive pneumoniae (OPP) virus; bovine leukosis virus (BLV). The serological studies showed that 47% were positive for RSV; 82% for PI-3; 3% for BVD/BD virus; 49% for BT virus; 13% for OPP virus. Antibodies were not detected to bovine herpesvirus 1 or to bovine leukosis virus.     

Seroprevalence of bovine respiratory viruses in North-Western Turkey

Bovine respiratory disease complex is a very important health problem around the world. Present study describes serological distribution of bovine major respiratory viruses in non -vaccinated cattle population of Marmara region in north-western Turkey. Neutralising antibodies specific to bovine viral diarrhoea virus (BVDV), bovine herpesvirus 1 (BHV-1), bovine respiratory syncytial virus (BRSV), bovine parainfluenza virus 3 (PI-3), bovine adenovirus serotype 1 (BAV-1) and serotype 3 (BAV-3) were investigated. Among 584 serum samples collected from 39 establishments in 7 provinces, 41.4% were positive for BVDV, 17.1% for BHV-1, 73.0% for BRSV, 43.0% for PI-3, 89.5% for BAV-1 and 92.3% for BAV-3. There were significant differences observed between seroprevalence rates detected in neighbouring provinces. Serological prevalence of BVDV, BHV-1 and BRSV were extremely higher in large capacity dairy farms than of small capacity farms (p < 0.0001). This study demonstrates that herd capacity is a very important risk factor for respiratory viruses and, on the other hand bovine adenoviruses and BRSV are the common reason of respiratory diseases in the region.     

Evaluation of an antigen-capture ELISA for the detection of bovine herpesvirus type 1 shedding from feedlot cattle

A total of 457 nasal swab specimens from cases of respiratory disease in 2 feed lots were evaluated for the detection of bovine herpesvirus Type 1 (BHV-1) by ELISA. Thirty-three were found to be positive for BHV-1 by the recovery of infectious virus and 21 of these were positive by ELISA, yielding a sensitivity of 64%. Fifteen other virus isolations were made and included bovine viral diarrhea viruses, rhinoviruses and parainfluenza Type 3 viruses; none of these cases were positive with the BHV-1 ELISA. Specificity of the ELISA was 100%. Eighty percent of the specimens with BHV-1 titers greater than 10(5) TCID50 were detected by ELISA; the median amount of virus in positive specimens that were detected by ELISA was 7 X 10(5) TCID50 and the median amount of virus in specimens not detected was 1.5 X 10(4) TCID50. BHV-1 infection was most frequently diagnosed in feedlot cattle that had been in the feedlot for 40-80 days. Approximately half of the infected cattle were carrying virus-neutralizing antibodies in their serum.     

Bovine viral diarrhea viral infections in feeder calves with respiratory disease: interactions with Pasteurella spp., parainfluenza-3 virus, and bovine respiratory syncytial virus.

The prevalence of bovine viral diarrhea virus (BVDV) infections was determined in a group of stocker calves suffering from acute respiratory disease. The calves were assembled after purchase from Tennessee auctions and transported to western Texas. Of the 120 calves, 105 (87.5%) were treated for respiratory disease. Sixteen calves died during the study (13.3%). The calves received a modified live virus BHV-1 vaccine on day 0 of the study. During the study, approximately 5 wk in duration, sera from the cattle, collected at weekly intervals, were tested for BVDV by cell culture. Sera were also tested for neutralizing antibodies to BVDV types 1 and 2, bovine herpesvirus-1 (BHV-1), parainfluenza-3 virus (PI-3V), and bovine respiratory syncytial virus (BRSV). The lungs from the 16 calves that died during the study were collected and examined by histopathology, and lung homogenates were inoculated onto cell cultures for virus isolation. There were no calves persistently infected with BVDV detected in the study, as no animals were viremic on day 0, nor were any animals viremic at the 2 subsequent serum collections. There were, however, 4 animals with BVDV type 1 noncytopathic (NCP) strains in the sera from subsequent collections. Viruses were isolated from 9 lungs: 7 with PI-3V, 1 with NCP BVDV type 1, and 1 with both BVHV-1 and BVDV. The predominant bacterial species isolated from these lungs was Pasteurella haemolytica serotype 1. There was serologic evidence of infection with BVDV types 1 and 2, PI-3V, and BRSV, as noted by seroconversion (> or = 4-fold rise in antibody titer) in day 0 to day 34 samples collected from the 104 survivors: 40/104 (38.5%) to BVDV type 1; 29/104 (27.9%) to BVDV type 2; 71/104 (68.3%) to PI-3V; and 81/104 (77.9%) to BRSV. In several cases, the BVDV type 2 antibody titers may have been due to crossreacting BVDV type 1 antibodies; however, in 7 calves the BVDV type 2 antibodies were higher, indicating BVDV type 2 infection. At the outset of the study, the 120 calves were at risk (susceptible to viral infections) on day 0 because they were seronegative to the viruses: 98/120 (81.7%), < 1:4 to BVDV type 1; 104/120 (86.7%) < 1:4 to BVDV type 2; 86/120 (71.7%) < 1:4 to PI-3V; 87/120 (72.5%) < 1:4 to BRSV; and 111/120 (92.5%) < 1:10 to BHV-1. The results of this study indicate that BVDV types 1 and 2 are involved in acute respiratory disease of calves with pneumonic pasteurellosis. The BVDV may be detected by virus isolation from sera and/or lung tissues and by serology. The BVDV infections occurred in conjunction with infections by other viruses associated with respiratory disease, namely, PI-3V and BRSV. These other viruses may occur singly or in combination with each other. Also, the study indicates that purchased calves may be highly susceptible, after weaning, to infections by BHV-1, BVDV types 1 and 2, PI-3V, and BRSV early in the marketing channel.     

Bovine herpesvirus-1 (BHV-1), bovine leukemia virus (BLV) and bovine viral diarrhea virus (BVDV) infections in Algerian dromedary camels (<Emphasis Type="Italic">Camelus dromaderius</Emphasis>)

This study was performed to investigate the presence of bovine herpesvirus-1 (BHV-1), bovine leukemia virus (BLV) and bovine viral diarrhea virus (BVDV) infections in dromedary camels (Camelus dromaderius) kept in mixed herds with sheep and goats in Algeria, since the prevalence of BHV-1, BVDV, and BLV infections among dromedary camels in Algeria is unknown. Totally, 111 camel sera were collected from two provinces (Laghouat and Ghardaia) in Algeria. The sera were analyzed for BHV-1 specific antibodies, BVDV specific antibodies and BVDV antigen using the ELISA, and BLV nucleic acid using PCR. The seropositivity rate was 9.0% for BVDV-specific antibody, although 41.4% of camels tested were positive for BVDV antigen. Moreover, there was no evidence of BHV-1 and BLV infections. The results indicated that camels might represent an important source for BVDV infection in all ruminants, including cattle, sheep, and goats bred in mixed herds in Algeria, since they had a higher BVDV prevalence rates. Therefore, the prevention and control measures for BVDV infection should put in place in camel populations to limit the spread of BVDV infection to ruminant populations in Algeria.     

Viral antibodies in bovine fetuses in Argentina

In order to establish the prevalence of viral infections of the bovine fetus in Argentina, a serological survey for antibodies against viral agents currently affecting cattle in this country was conducted. Antibodies against foot-and-mouth disease virus (FMDV), bovine herpesvirus-1 (BHV-1), bovine leukaemia virus (BLV), bovine rotavirus (BRV), bovine coronavirus (BCV), bovine viral diarrhoea virus (BVDV) and parainfluenza-3 (PI-3) were investigated in a total of 315 fetal serum samples. Conventional techniques were used: indirect immunofluorescence (FMDV, BHV-1, BVDv and BCV), radial immunodiffusion (BLV), ELISA (BRV) and haemagglutination inhibition (PI-3). Antibodies against BHV-1, BVDV and PI-3 were detected in samples from fetuses in the second and third trimester of gestation, with a prevalence of 1·21 per cent (two of 165), 2·03 per cent (four of 197) and 5·08 per cent (nine of 177), respectively. Either antibodies or non-antibody factors able to bind to BRV and Bcv antigens were detected with a prevalence of 2·44 per cent (five of 205) and 4·54 per cent (five of 110), respectively. In addition, 14·68 per cent of non-specific inhibitors of PI-3 mediated haemagglutination were found. No seropositives against FMDV and BLV were detected.     

Prevalence of bovine herpesvirus-1, bovine oral diarrhea, parainfluenza-3, bovine adenoviruses-3 and -7, and goat respiratory syncytial viral antibodies in goats

Sera from healthy goats were collected during October 1979 through October 1980. These sera were tested for bovine herpesvirus-1 (BHV-1), bovine viral diarrhea virus (BVDV), parainfluenza-3 (PI-3) virus, bovine adenoviruses (BAV) -3 and -7, and goat respiratory syncytial virus (GRSV) antibodies by microtitration virus-neutralization test. The number of herds with seropositive goats for each virus were: 5/38 (13.2%) for BHV-1; 9/38 (23.7%) for BVDV; 8/38 (21.1%) for PI-3 virus; 1/38 (2.6%) for BAV-3; 15/38 (39.5%) for BAV-7; and 26/34 (76.5%) for GRSV. Seropositive rates for each virus for the individual goats tested were: 6/502 (1.2%) for BHV-1; 9/498 (1.8%) for BVDV; 49/458 (10.75) for PI-3 virus; 1/487 (0.025) for BAV-3; 40/448 (8.9%) for BAV-7; and 166/332 (50.0%) for GRSV.     

Prevalence of serum antibodies to bovine herpesvirus-1 and bovine viral diarrhea virus in beef cattle in Uruguay

Our objective was to determine the prevalence of serum antibodies to bovine herpesvirus-1 (BHV-1) and bovine viral diarrhea (BVD) virus in beef cattle in Uruguay. A random sample of 230 herds selected with probability proportional to population size based on the number of cattle was chosen from a list frame of all registered livestock farms as of June 1999. Sera from up to 10 heifers, cows and bulls (up to 30 sera total per herd) were collected on selected farms between March 2000 and March 2001 and evaluated by means of enzyme-linked immunosorbent assays (ELISAs). Overall, 6358 serum samples were evaluated. We also collected data on previous diagnosis of BHV-1 or BVD infections and on the use of vaccines against these agents.

The estimated prevalence of exposure to BHV-1 and BVD at the herd level for the Uruguayan beef population was 99% and 100%, respectively. Approximately 37% of beef cattle in Uruguay have been exposed to BHV-1 and 69% to BVD virus. Only 3% of beef herds in Uruguay regularly (typically, annually) use vaccines against either of these agents.     

Prevalence of bovid herpesvirus-4 and its antibody in cattle in Minnesota

Serologic analyses and virus isolation studies were carried out to determine the role of bovid herpesvirus-4 (BHV-4) in infections in cattle, principally those of the reproductive tract. Serologic analyses were performed, using an indirect fluorescent antibody test on thoracic fluid specimens from aborted fetuses and on sera from 3 sources of adult cattle. Virus isolation was attempted from field cases of abortion, early embryo death, and postpartum vulvovaginitis/metritis, using uterine discharge and buffy coat preparations obtained from cows and tissues obtained from aborted fetuses. Of 420 fetal thoracic fluid specimens examined, 5 were positive for BHV-4 antibodies. Seventeen percent of adult cattle from 2 sources ie, clinically normal herds and abattoir cattle, were seropositive for BHV-4 antibodies. Cattle from a third source, 4 herds with high incidence of reproductive tract disorders, had a seroprevalence rate between 36 and 88%. Two isolates of BHV-4 were also obtained from this group. The overall incidence of BHV-4 antibodies in clinically normal cattle was higher than previously recognized, with relatively higher prevalence in herds having reproductive problems (chi 2 = 156.5, P less than 0.005). At least 10% of the BHV-4 antibody-positive sera did not have neutralizing antibody against bovine viral diarrhea virus and/or bovid herpesvirus-1, both important causes of bovine reproductive tract disorders.     

Important virus infections of the respiratory tract in cattle from the clinical point of view

The etiological participation of different viruses in the pneumonia complex of cattle is undisputed. The significance of the individual viruses in the genesis of disease symptoms is still mostly unclear. Since the pneumonia complex of cattle is a multifactorial syndrome, vaccination programs as the only measure of prophylaxis in most cases do not show the desired effect. Against those viral agents causing self-standing diseases of the respiratory tract, specific vaccinations are applicable with success. Prerequisite for their effectiveness, however, is the exact etiological clarification of the cause of disease or of the existing infections respectively in the herd. The frequency of possible viral agents in infections of the respiratory tract in cattle from herds of the province of Schleswig-Holstein found in routine diagnostic work during the last four years is presented in addition.     

Association of bovine viral diarrhea virus with multiple viral infections in bovine respiratory disease outbreaks

We investigated eleven outbreaks of naturally occurring bovine respiratory diseases in calves and adult animals in the St-Hyacinthe area of Quebec. Specific antibodies to bovine herpesvirus-1, bovine viral diarrhea virus, respiratory syncytial virus, parainfluenza type 3 virus, reovirus type 3, and serotypes 1 to 7 of bovine adenovirus were found in paired sera from diseased animals. Several bovine viruses with respiratory tropism were involved concomitantly in herds during an outbreak of bovine respiratory disease. In addition, concomitant fourfold rises of antibody titers were frequently observed to two or more viral agents in seroconverted calves (61%) or adult animals (38%). Bovine viral diarrhea virus was found to be the most frequent viral agent associated with multiple viral infection in calves only (92%).     

Prevalence of bovine herpesvirus-1, bovine viral diarrhea, parainfluenza-3, goat respiratory syncytial, bovine leukemia, and bluetongue viral antibodies in sheep

Sera from healthy sheep were collected in January and March 1982 from flocks of sheep located in southwestern and southeastern Louisiana. These sera were tested for bovine herpesvirus-1 (BHV-1), bovine viral diarrhea virus (BVDV), parainfluenza-3 (PI-3) virus, and goat respiratory syncytial virus (GRSV) antibodies by microtitration virus-neutralization test. The sera were tested also for bovine leukemia virus (BLV) and bluetongue virus (BTV) antibodies by immunodiffusion tests. The number of flocks with seropositive sheep for each virus were: 2/8 (25%) for BVDV; 8/8 (100%) for PI-3 virus; 7/8 (87.5%) for GRSV; and 6/8 (75%) for BTV. Seropositive rates for each virus for the individual sheep tested were: 4/158 (2.5%) for BVDV; 117/158 (74.1%) for PI-3 virus; 77/158 (48.7%) for GRSV; and 21/158 (13.3%) for BTV. All sheep were seronegative for BHV-1 and BLV.     

Survey of desert bighorn sheep in California for exposure to selected infectious diseases

From February 1983 to June 1985, 188 desert bighorn sheep (Ovis canadensis nelsoni, = 161 and Oc cremnobates, = 27) from 18 herds in 17 mountain ranges and one captive herd were caught, marked, and had blood, fecal, and nasal mucus samples collected. Nasal swab specimens were cultured bacteriologically and virologically specifically for parainfluenza-3 (PI-3) virus. Bacterial flora differed from herd to herd. Pathogenic pneumophilic bacteria (eg, Pasteurella sp) seldom were found. Parainfluenza-3 virus was isolated from 6 bighorn sheep in 3 herds. Fecal specimens were examined for parasite ova and low numbers of lungworm (Protostrongylus sp) larvae were found in feces from 2 herds. Sera were evaluated for antibodies against respiratory syncytial virus, ovine progressive pneumonia, infectious bovine rhinotracheitis, PI-3, bovine viral diarrhea, brucellosis, leptospirosis, contagious ecthyma, bluetongue, and epizootic hemorrhagic disease. Blood clots were cultured virologically for bluetongue and epizootic hemorrhagic disease. Serologic evidence of bluetongue and/or epizootic hemorrhagic disease was found in 9 herds, and bluetongue virus (serotypes 10,11,13 and 17) was isolated from 3 herds. Antibody titers against PI-3 and respiratory syncytial virus were found in 9 and 13 herds, respectively. Evidence of bovine viral diarrhea infection was found in 6 herds, whereas infectious bovine rhinotracheitis was found in only 1 herd. Antibody titers against contagious ecthyma were found in 9 of 18 herds in California, and active lesions were seen occasionally. Evidence of ovine progressive pneumonia, leptospirosis, or brucellosis was not found.     

Association of herd BHV-1 seroprevalence with respiratory disease in youngstock in Estonian dairy cattle

The associations between herd bovine herpesvirus 1 (BHV-1) seroprevalence, along with other infectious and farm management factors with bovine respiratory disease (BRD) in dairy calves and heifers, were investigated. Serum samples from 103 dairy cattle herds were analyzed for antibodies against BHV-1, bovine respiratory syncytial virus (BRSV), bovine viral diarrhea virus (BVDV), and Mycoplasma bovis (M. bovis). A questionnaire was used to record herd management practices. A high occurrence of respiratory disease in unweaned calves was associated with low to moderate and high prevalence of BHV-1 among cows (OR=14.8, p=0.005 and OR=19.2, p=0.002, respectively) and positive BVDV status of a herd (OR=5.1, p=0.02). The presence of BVDV in a herd was related to a high incidence of respiratory disease in heifers 3-16 months old (OR=4.3, p=0.027). Based on the results of multiple correspondence analysis, holding youngstock separately from cows until pregnancy, introducing new animals and the activities of on-farm employees may contribute to a higher incidence of BRD.     

Testing for BTV, BVDV and BHV-1 in blood samples of new world camelids kept in middle Germany

The susceptibility of camelids for infectious agents which may result in severe economic losses or which are strictly regulated for epidemiological reasons in farm animals potentially causes a mutual risk of transmission. This study aimed to investigate the presence of antibodies against bovine herpesvirus 1 (BHV-1), bluetongue virus (BTV) and bovine viral diarrhoea virus (BVDV) as well as the presence of pestivirus antigen in new world camelids in Central Germany. Therefore 107 serum samples from 93 alpacas and lamas from this region which had been obtained from 2007 to 2009 were examined using ELISA, serum neutralisation test, RT-PCR and a pestivirus specific gene probe. All sample were negative for BHV-1 antibodies. Antibodies against BVDV-1 could be detected in four animals, titres reaching from 1:64 to > 1:256. One animal was positive for BTV antibodies in the year 2008. This animal had been tested negative for BTV antibodies in 2007. It can be concluded that up to now, these viruses seem to be of minor importance as pathogens in new world camelids in Central Germany. Therefore the risk of infection originating from new world camelids for production animals could be considered to be rather low in this region at the moment. However, it must be taken into consideration that these animals due to lack of antibodies are fully susceptible in case of occurrence of one of these viruses. For maintenance and improvement of the present status, general hygienic precautions should be applied; direct and indirect contact between animals from different herds must be avoided and virological diagnostic and quarantine should be required trading these animals.     

Indications of a relationship between buying-in policy and infectious diseases on dairy farms in Wales

During the period February to May 2008, bulk milk samples were collected from 57 dairy farms throughout Wales in the framework of a voluntary somatic cell count project. Bulk milk samples were tested for antibodies to bovine viral diarrhoea virus (BVDV), bovine herpesvirus type 1 (BHV-1) and Leptospira Hardjo, and samples were also tested for the presence of BVDV antigen by PCR. A questionnaire was used to determine whether the herd was open or closed, what the vaccination status was, and to obtain general farm information such as the herd size and average milk yield. Vaccination against BVD, infectious bovine rhinotracheitis and leptospirosis was practised on 37, 12 and 35 per cent of the farms, respectively. The presence of bulk milk antibodies on farms that did not use vaccination was 75 per cent for BVDV, 54 per cent for BHV-2 and 76 per cent for L Hardjo. Open herds had 10 times the odds (95 per cent confidence interval [CI] 1.7 to 59.4)of having bulk milk antibodies for BVDV and 16.7 times the odds (95 per cent CI 2.0 to 49.7) of having bulk milk antibodies to BHV-1 compared with closed herds. A farm with bulk milk antibodies to one disease had significantly higher odds of having bulk milk antibodies to a second disease (P<0.05).     

An acute outbreak of teat lesions affecting 38% of a dairy herd in Northland

Extract

Teat lesions are common in dairy cattle in New Zealand. Most of the infectious cases are caused by pseudocowpox virus, but lesions similar to those caused by bovine herpesvirus (BHV)-2 have been described clinically and confirmed serologically in New Zealand (Horner and Raynel 1988). BHV-2 and BHV-4 cause an acute viral disease in cattle known as bovine herpes mammillitis or ulcerative mammillitis (Hillerton et al 2001). Presumptive cases have been reported in New Zealand based on the nature and distribution of lesions (Daniel 1970). The disease is probably endemic in New Zealand but is poorly documented and generally considered to be mild and sporadic. The main differential diagnosis is pseudocowpox, which is often also present in herds affected with bovine herpes mammillitis, and dual infections of individual cattle have been reported (Gibbs et al 1972). To my knowledge, neither BHV-2 nor BHV-4 have yet been isolated in New Zealand.     

Transmission of Bovine viral diarrhea virus 1b to susceptible and vaccinated calves by exposure to persistently infected calves

Bovine viral diarrhea virus (BVDV) persistently infected (PI) calves represent significant sources of infection to susceptible cattle. The objectives of this study were to determine if PI calves transmitted infection to vaccinated and unvaccinated calves, to determine if BVDV vaccine strains could be differentiated from the PI field strains by subtyping molecular techniques, and if there were different rates of recovery from peripheral blood leukocytes (PBL) versus serums for acutely infected calves. Calves PI with BVDV1b were placed in pens with nonvaccinated and vaccinated calves for 35 d. Peripheral blood leukocytes, serums, and nasal swabs were collected for viral isolation and serology. In addition, transmission of Bovine herpes virus 1 (BHV-1), Parainfluenza-3 virus (PI-3V), and Bovine respiratory syncytial virus (BRSV) was monitored during the 35 d observation period. Bovine viral diarrhea virus subtype 1b was transmitted to both vaccinated and nonvaccinated calves, including BVDV1b seronegative and seropositive calves, after exposure to PI calves. There was evidence of transmission by viral isolation from PBL, nasal swabs, or both, and seroconversions to BVDV1b. For the unvaccinated calves, 83.2% seroconverted to BVDV1b. The high level of transmission by PI calves is illustrated by seroconversion rates of nonvaccinated calves in individual pens: 70% to 100% seroconversion to the BVDV1b. Bovine viral diarrhea virus was isolated from 45 out of 202 calves in this study. These included BVDV1b in ranch and order buyer (OB) calves, plus BVDV strains identified as vaccinal strains that were in modified live virus (MLV) vaccines given to half the OB calves 3 d prior to the study. The BVDV1b isolates in exposed calves were detected between collection days 7 and 21 after exposure to PI calves. Bovine viral diarrhea virus was recovered more frequently from PBL than serum in acutely infected calves. Bovine viral diarrhea virus was also isolated from the lungs of 2 of 7 calves that were dying with pulmonary lesions. Two of the calves dying with pneumonic lesions in the study had been BVDV1b viremic prior to death. Bovine viral diarrhea virus 1b was isolated from both calves that received the killed or MLV vaccines. There were cytopathic (CP) strains isolated from MLV vaccinated calves during the same time frame as the BVDV1b isolations. These viruses were typed by polymerase chain reaction (PCR) and genetic sequencing, and most CP were confirmed as vaccinal origin. A BVDV2 NCP strain was found in only 1 OB calf, on multiple collections, and the calf seroconverted to BVDV2. This virus was not identical to the BVDV2 CP 296 vaccine strain. The use of subtyping is required to differentiate vaccinal strains from the field strains. This study detected 2 different vaccine strains, the BVDV1b in PI calves and infected contact calves, and a heterologous BVDV2 subtype brought in as an acutely infected calf. The MLV vaccination, with BVDV1a and BVDV2 components, administered 3 d prior to exposure to PI calves did not protect 100% against BVDV1b viremias or nasal shedding. There were other agents associated with the bovine respiratory disease signs and lesions in this study including Mannheimia haemolytica, Mycoplasma spp., PI-3V, BRSV, and BHV-1.