No vaccine interference between bovine coronavirus and bovine herpesvirus-1 in a randomized trial when coadministrating two intranasal modified-live viral vaccines to neonatal calves.

OBJECTIVE: Compare immune responses induced by 2 commercial intranasal (IN) modified-live viral (MLV) vaccines given individually or coadministered and evaluate prevention of infection and lung pathology following bovine herpesvirus-1 (BHV-1) challenge. ANIMALS: 36 male Holstein calves (ages, 5 to 12 days). METHODS: In a randomized complete block design, each calf received an IN injection of either vaccine diluent (Placebo), an MLV vaccine containing bovine herpesvirus-1 (BHV-1; N3), bovine coronavirus vaccine (BC), or both N3 and BC (BC + N3) with a booster 4 weeks later. Nasal secretions and blood were collected weekly. Three weeks after the booster, the calves were challenged with BHV-1, sampled for virus shedding, and euthanized 10 days later to quantify lung pathology. The study period was September 7, 2020, to April 6, 2021. RESULTS: Calves were seropositive for BHV-1 and BC before vaccination. No significant difference in BC-specific serum immunoglobin G and nasal immunoglobin A antibody responses in the BC versus BC + N3 group or BHV-1-specific serum immunoglobin G and nasal immunoglobin A antibody responses in the N3 versus BC + N3 group. Cytokine responses to BHV-1 and BC did not differ among groups. BHV-1 shedding after challenge was significantly reduced in N3 groups versus Placebo and BC. There was a significant reduction in lung pathology in the N3 + BC group versus Placebo. CLINICAL RELEVANCE: This study provides evidence an MLV vaccine containing BHV-1 and an MLV BC vaccine can be coadministered to neonatal calves without significantly altering immune responses to the 2 viruses or compromising the prevention of BHV-1 respiratory disease. Calves receiving the BC + N3 vaccine had a significant reduction in lung pathology after BHV-1 aerosol challenge.

Intranasal booster vaccination of beef steers reduces clinical signs following experimental coinfection with BRSV and BHV-1 without reducing shedding of BRD-associated bacteria.

OBJECTIVE: To determine the efficacy of primary or booster intranasal vaccination of beef steers on clinical protection and pathogen detection following simultaneous challenge with bovine respiratory syncytial virus and bovine herpes virus 1. METHODS: 30 beef steers were randomly allocated to 3 different treatment groups starting at 2 months of age. Group A (n = 10) was administered a single dose of a parenteral modified-live vaccine and was moved to a separate pasture. Groups B (n = 10) and C (10) remained unvaccinated. At 6 months of age, all steers were weaned and transported. Subsequently, groups A and B received a single dose of an intranasal modified-live vaccine vaccine while group C remained unvaccinated. Group C was housed separately until challenge. Two days following vaccination, all steers were challenged with bovine respiratory syncytial virus and bovine herpes virus 1 and housed in a single pen. Clinical and antibody response outcomes and the presence of nasal pathogens were evaluated. RESULTS: The odds of clinical disease were lower in group A compared with group C on day 7 postchallenge; however, antibody responses and pathogen detection were not significantly different between groups before and following viral challenge. All calves remained negative for Histophilus somni and Mycoplasma bovis; however, significantly greater loads of Mannheimia haemolytica and Pasteurella multocida were detected on day 7 postchallenge compared with day -2 prechallenge. CLINICAL RELEVANCE: Intranasal booster vaccination of beef steers at 6 months of age reduced clinical disease early after viral challenge. Weaning, transport, and viral infection promoted increased detection rates of M haemolytica and P multocida regardless of vaccination status.

The immunogenicity and efficacy of acommercially available Infectious Bovine Rhinotracheitis (IBR) virus vaccine against a Pakistani field IBR strain.

Infectious bovine rhinotracheitis (IBR) is a highly communicable disease of cattle and wild ruminants that is caused by Bovine alphaherpesvirus 1 (BoHV­1). For IBR control, several developed countries have adopted the immunization and eradication programs focusing on IBR­positive animals. In Pakistan, livestock producers are importing commercially available vaccine of BoHV­1, but no studies on the efficacy of these commercial vaccines against local isolates are available. Therefore, the present study was aimed to evaluate the efficacy of a commercially available vaccine of BoHV­1 against local field isolates of virus. The rabbit model was used and the vaccine was evaluated for immunogenicity and protection after challenge with a highly virulent strain of a field virus. The immune response was measured by virus neutralization titers (VNT). This vaccine induced a humoral response in rabbits but that was not sufficient to completely protect the vaccinated animals against the wild­type BoHV­1 strain challenge. While a low virus titer compared to control rabbits was observed in the vaccinated rabbits (p<0.05), there was no sterilizing immunity or freedom from infection. However, complete freedom from disease, for example, the absence of pyrexia was noticed in the vaccinated group. In conclusion, the present study demonstrated that imported vaccine stock provoked only a partial protection against indigenous isolated of BoHV­1. However, tests performed on rabbits are preliminary, as only those performed on the source species can determine more reliable results.

A retrospective evaluation of pooled serum ELISA testing in the frame of the French eradication program for infectious bovine rhinotracheitis.

Pooled serum testing using whole-virus indirect ELISA has been recently recognized as an official method for surveillance of bovine herpesvirus 1 (BoHV1) in cattle herds in Europe. In this study, a retrospective analysis of data from the French BoHV1 surveillance campaign 2018-2019, including 7434 BoHV1-free certified herds and 157 infected herds, was performed in order to evaluate the diagnostic specificity and sensitivity of two pooled serum indirect ELISAs (from IDEXX and IDVet), in comparison with individual testing by blocking ELISAs targeting the gB and gE proteins. Pooled serum testing showed a relative specificity higher than 97.5% and a detection rate of 100% since all gB+/gE+ samples were found in positive pools. At the herd level, no more than one false positive pool was observed in most of BoHV1-free certified herds, leading to a herd relative specificity of 85.1% and 86.0% for the IDEXX and IDVet pooled serum ELISAs, respectively. Among infected herds tested by pool sizes up to 10 sera (n = 122), 46% of herds were detected through pools of size 10 containing a single positive sample, 23% through pools of size 10 containing at least two positive samples, and 31% through pools of smaller sizes. A complementary study based on manually constituted pools revealed that at least one positive sample in 100% and 93.4% of herds could be detected individually by pools of size 10 with the IDEXX and IDVet ELISAs, respectively. However, pooled serum ELISAs were influenced by the level of individual reactivity, since pools composed of either one weak-positive sample or one gB+/gE- sample could yield negative results. Altogether, these results provided the first evidence that pooled serum testing (pool size up to 10) is a suitable strategy for surveillance of BoHV1-free cattle farms.

Characterization and expression of domains of Alphaherpesvirus bovine 1/5 envelope glycoproteins B in Komagataella phaffi.

BACKGROUND: Bovine herpes virus (BoHV 1 and BoHV-5) are the causative agents of infectious bovine rhinotracheitis (IBR). IBR is responsible for important economic losses in the cattle industry. The envelope glycoprotein B (gB) is essential for BoHV infection of cattle's upper respiratory and genital tract. gB is one of the main candidate antigens for a potential recombinant vaccine since it induces a strong and persistent immune response. RESULTS: In this study, gB of BoHV-1 and BoHV-5 was characterized in terms of function, structure, and antigenicity through bioinformatics tools. gB showed conserved sequence and structure, so, both domains named PH Like 1 and 2 domains of each virus were selected for the design of a bivalent vaccine candidate. The immunoinformatic study showed that these two domains have epitopes recognizable by B and T lymphocytes, followed by this, the cDNA domains from BoHV-1/5 gB (Domains-gB) were transformed into the yeast Komagataella phaffii GS115 (previously known as Pichia pastoris). A recombinant protein with molecular weight of about 110 kDa was obtained from the culture media. The vaccine candidate protein (Domains-gB) was recognized by a monoclonal antibody from a commercial ELISA kit used for IBR diagnostic, which may suggest that the epitopes are conserved of the entire infectious virus. CONCLUSION: Overall, it was shown that the recombinant domains of BoHV-1/5 gB have antigenic and immunogenic properties similar to the native gB. This vaccine candidate is promising to be used in future studies to assess its immunogenicity in an animal model.

Subunit vaccine based on glycoprotein B protects pattern animal guinea pigs from tissue damage caused by infectious bovine rhinotracheitis virus.

Infectious bovine rhinotracheitis (IBR) is caused by Bovine herpesvirus type 1 (BoHV-1), which seriously threatens the global cattle industry. Only vaccination to improve immunity is the most direct and effective means to prevent IBR. Attempts are being made to use subunit vaccines, deleted or recombinant viral vaccines to reduce or eradicate IBR. For investigating the immunological characteristics of glycoprotein B subunit vaccine in pattern animal guinea pigs, the partial glycoprotein B (gB) of BoHV-1 with dominant antigenic characteristic was selected. A recombinant prokaryotic expression vector pET-32a-gB with the truncated gB gene was constructed, expressed, identified and the purified proteins were used to immunize guinea pigs. The immune effect of the subunit vaccine was assessed by monitoring clinical symptoms, viral load, antibody secretion, and histopathological changes. The results indicated that guinea pigs immunized with the gB subunit vaccine produced high levels of anti-gB antibodies and virus-neutralizing antibodies. The gB subunit vaccine significantly reduced viral shedding and lung tissue damage after IBRV challenge. The animals inoculated the gB subunit vaccine also had less virus reactivation. Its protective effect on viral shedding and tissue damage was similar to that of inactivated BoHV-1 vaccine. This work is a proof-of-concept study of subunit vaccine-induced protection against BoHV-1. And it is expected to be a candidate vaccine for the prevention of IBR.

TLR activation, immune response and viral protection elicited in cattle by a commercial vaccine against Bovine Herpesvirus-1.

The innate and acquired immune response induced by a commercial inactivated vaccine against Bovine Herpesvirus-1 (BoHV-1) and protection conferred against the virus were analyzed in cattle. Vaccination induced high levels of BoHV-1 antibodies at 30, 60, and 90 days post-vaccination (dpv). IgG1 and IgG2 isotypes were detected at 90 dpv, as well as virus-neutralizing antibodies. An increase of anti-BoHV-1 IgG1 in nasal swabs was detected 6 days post-challenge in vaccinated animals. After viral challenge, lower virus excretion and lower clinical score were observed in vaccinated as compared to unvaccinated animals, as well as BoHV-1-specific proliferation of lymphocytes and production of IFNγ, TNFα, and IL-4. Downregulation of the expression of endosome Toll-like receptors 8-9 was detected after booster vaccination. This is the first thorough study of the immunity generated by a commercial vaccine against BoHV-1 in cattle.

A large-scale epidemiological model of BoHV-1 spread in the Irish cattle population to support decision-making in conformity with the European Animal Health Law.

We present a new modelling framework to address the evaluation of national control/surveillance programs planned in line with the European Animal Health Law (AHL) for livestock diseases. Our modelling framework is applied to the cattle sector in Ireland where there is need for policy support to design an optimal programme to achieve bovine herpesvirus type 1 (BoHV-1) free status under the AHL. In this contribution, we show how our framework establishes a regional model that is able to mechanistically reproduce the demography, management practices and transport patterns of an entire cattle population without being dependent on continuous livestock registry data. An innovative feature of our model is the inclusion of herd typing, thereby extending these beyond the categories of dairy, beef and mixed herds that are frequently considered in other regional modelling studies. This detailed representation of herd type-specific management facilitates comparative assessment of BoHV-1 eradication strategies targeting different production types with individual strategy protocols. Finally, we apply our model to support current discussions regarding the structure and implementation of a potential national BoHV-1 eradication programme in Ireland.

Control programs for infectious bovine rhinotracheitis (IBR) in European countries: an overview.

Infectious bovine rhinotracheitis (IBR), caused by Bovine alphaherpesvirus 1 (BoHV-1), is a disease of cattle responsible for significant economic losses worldwide. IBR is under certain communitarian regulations. Every member state can approve its own national IBR control program for the entire territory - or part of it - and can demand additional guarantees for bovids destined to its territory; therefore, every member state can be officially declared as entirely or partly IBR-free. The aim of this review is to provide an overview of IBR control and eradication programs in European countries. BoHV-1 control schemes were first introduced in the late 1970s, mainly in Northern and Central Europe. Depending on the seroprevalence rate, control strategies rely on identification and removal of seropositive animals or the use of glycoprotein E (gE)-deleted marker vaccines in infected herds. The implementation of a novel law for disease eradication at the EU level and of a European IBR data flow could make the goal of IBR eradication in all European countries easier to achieve.

Effect of administering activated lymphocytes originated from the dam on the immune cell reaction in Holstein calves.

Injection of lymphokine activated killer (LAK) cells is known as useful for activation of cellular immune system. Although the effect of LAK cells has been clarified in human or mice, this effect on function of immune cells has not been examined in calves. Healthy ten Holstein calves were injected with the LAK cells 2 days after birth (LAK Group), and another eight calves were observed as controls (Control Group). All calves received the colostrum formulation on the day of birth, and then, were inoculated with a live attenuated vaccine of bovine herpesvirus (BHV)-1 at 2 (the first vaccination) and 6 (the second vaccination) weeks after birth. Peripheral blood of their dam obtained 3 weeks before calving was used for preparation of LAK cells. Blood samples were taken prior to vaccine inoculation and 3 days after the first inoculation, as well as 3 and 6 days after the second vaccination from all calves. Numbers of CD8+ and CD21+ cells increased significantly after the second vaccination in the LAK Group compared with Control Group. The present study suggested the improved effect of injecting LAK cells originated from dams on immune cells function of young calves after BHV-1 live vaccine.

Immune memory induced by intranasal vaccination with a modified-live viral vaccine delivered to colostrum fed neonatal calves.

Bovine respiratory disease (BRD) remains a major health problem despite extensive use of vaccines during the post-weaning period. Apparent vaccine failure is attributed, in part, to primary vaccination during the period of greatest risk for BRD, providing inadequate time for onset of protective immunity. The current study investigated whether intranasal (IN) vaccination of 3-6 week old calves with a modified-live viral (MLV) vaccine induced sufficient immune memory to prevent respiratory disease and accelerate onset of protective immunity 5 months later. Vaccine groups included naïve controls, a single IN vaccination at 3-6 weeks of age, primary IN vaccination at 6 months, and either an IN or subcutaneous (SC) booster vaccination at 6 months (n = 10/group). All calves were challenged with BHV-1 four days after vaccination at 6 months of age. Primary IN vaccination at 6 months did not significantly reduce clinical disease but significantly (P < 0.01) reduced virus shedding. A single IN vaccination at 3-6 weeks of age significantly (P < 0.05) reduced weight loss but did not reduce fever or virus shedding. Both IN and SC booster vaccinations, significantly (P < 0.01) reduced clinical disease but virus shedding was significantly (P < 0.001) reduced only by IN booster vaccination. Reduction in virus shedding was significantly (P < 0.01) greater following booster versus primary IN vaccination at 6 months. All vaccination regimes significantly (P < 0.01) reduced secondary bacterial pneumonia and altered interferon responses relative to naïve controls. Only IN booster vaccination significantly (P < 0.05) increased BHV-1 specific IgA in nasal secretions. These results confirm primary MLV IN vaccination at 3 to 6 weeks of age, when virus neutralizing maternal antibody was present, induced immune memory with a 5 month duration. This immune memory supported rapid onset of protective immunity four days after an IN booster vaccination.

Improvement of eradication program for infectious bovine rhinotracheitis in France inferred by serological monitoring of singleton reactors in certified BoHV1-free herds.

Within the framework of the national voluntary eradication program for Bovine alphaherpesvirus 1 (BoHV1) in France, the proportion of certified-free herds which experienced no more than two positive animals (termed singleton reactors) steadily increased to reach up to 95% in 2015. The aim of this study was to collate and evaluate serological data to gain insight into these epidemiological questionable BoHV1 seropositive animals. Preliminary evaluation of the performances of BoHV1 ELISA kits using a collection of 997 field sera with well-defined status revealed a relatively low specificity of the two gB blocking ELISAs most used in France for confirmatory testing (93.2% and 97.5% for gB-IDVet and gB-Idexx, respectively). In both ELISAs, the suboptimal specificity was associated with the presence of antibodies against BoHV2. Reassessment of the cut-offs led to a specificity and a sensitivity higher than 99.3%. Consequently, a comprehensive analysis of gB-positive sera from 2551 singleton reactors was performed by using gB ELISAs with optimized cut-offs, combined with viral neutralization test (campaign 2014-2015) or gE ELISA (campaign 2015-2016). Fifty percent of the 728 sera collected in 2014-2015 reacted below the optimized cut-offs in both gB ELISAs. Analysis of new blood samples collected at a minimum 6-week interval showed that these weak-positive reactions did not increase with time and could not be confirmed by confirmatory tests. Among the 1823 sera collected in 2015-2016, only 84 samples tested positive by gE ELISA, most of them corresponding to sera with reactivity above the optimized cut-offs in gB ELISAs. Screening for BoHV2 antibodies revealed a significantly increased prevalence among herds with singleton reactors, compared with the between-herd prevalence in French cattle herds. Altogether, these results provided suitable analytical strategies to limit the occurrence of false-positive BoHV1 reactions and inappropriate withdrawal of the BoHV1-free status, without alteration of diagnostic costs and reliability of eradication programs.

Pre-weaning plane of nutrition and Mannheimia haemolytica dose influence inflammatory responses to a bovine herpesvirus-1 and Mannheimia haemolytica challenge in post-weaning Holstein calves.

The objectives of this study were to determine whether plane of nutrition (PON) of milk replacer previously provided to calves, and dosage level of Mannheimia haemolytica (MH), influenced inflammatory responses to a combined viral-bacterial respiratory challenge. Holstein calves (1 d of age; n = 30) were assigned to treatments in a 2 × 3 factorial with pre-weaning PON and MH dose as main effects (n = 5 per treatment). Calves were fed either a low (LPN; n = 15) or a high PON (HPN; n = 15) from birth through weaning. Calves fed LPN were fed 436 g of dry matter (DM) per day of milk replacer until weaning, and HPN calves were fed 797 g of DM per day of milk replacer from d 1 to 10 and 1,080 g of DM per day from d 11 until weaning. Calf starter and water were offered ad libitum. Calves were step-down weaned beginning at d 54 and moved into an enclosed barn at d 70. Indwelling rectal temperature (RT) recording devices and jugular catheters were inserted at d 80. Calves were challenged with 1.5 × 108 plaque-forming units (pfu) per mL of bovine herpesvirus-1 (BHV-1) in each nostril at d 81 and with either 106, 107, or 108 cfu of MH at d 84. Blood samples were collected at varying intervals relative to BHV-1 and MH challenges. Four LPN calves either died or were euthanized soon after the 144-h observation period, whereas all HPN calves survived the entire observation period. As dosage of MH administered increased, acute and systemic inflammatory responses increased. Higher doses of MH resulted in increased leukocyte, neutrophil, and haptoglobin concentrations in infected calves. Data from the current study suggest that the highest dose, 108 cfu, triggered weaned calves' acute disease response, whereas the lower doses, 106 and 107 cfu, caused more moderate inflammation and disease. The effects of PON on inflammation responses to the disease challenge indicated that calves previously fed the LPN diet had more severe pathophysiological responses. Calves fed LPN showed higher peripheral neutrophil and leukocyte counts and serum haptoglobin concentrations following the BHV-1 challenge. Additionally, following the MH challenge, LPN calves had higher peripheral neutrophil counts, neutrophil-to-lymphocyte ratios, and serum tumor necrosis factor-α concentrations. These data demonstrate that higher doses of MH increase the acute inflammatory response and prolong inflammation, and that calves previously fed LPN responded more severely to the combined viral-bacterial respiratory challenge.

Influence of a bovine respiratory disease vaccine with a temperature-sensitive modified live or killed infectious bovine rhinotracheitis component on oestrous cycle parameters and anti-Müllerian hormone concentration in nulliparous heifers.

The objective of this study was to examine the impact of a bovine respiratory disease complex (BRDC) vaccine with a temperature-sensitive modified live vaccine (MLV) infectious bovine rhinotracheitis (IBR) component on oestrous cycle parameters and the follicular pool. Twenty-four Holstein heifers (12.4 ± 0.5 months) previously calfhood vaccinated with an IBR MLV component were enrolled in two replicates (Spring; n = 10 and Fall; n = 14) and were blocked by pre-vaccination bovine viral diarrhoea (BVD) serum neutralizing (SN) titres. Upon enrolment, heifers were oestrous synchronized with sampling beginning at detected oestrus. At their second heat, heifers were vaccinated with a BRDC calfhood vaccine with a MLV (MLV; n = 12) or killed (K; n = 12) IBR component and sampled for two additional cycles. Serum samples for oestrogen (E2) and progesterone (P4) as well as ultrasound data of ovarian structures were collected every other day. Serum samples for anti-Müllerian hormone (AMH) were collected at oestrus and mid-cycle for each cycle, and serum for titres was collected prior to and following vaccination. Data were analysed with the PROC MIXED and GLM procedures of SAS. There was no difference in pre- or post-vaccination titres between MLV and K heifers (p > .5). Vaccination had no impact on P4 concentrations, P4 area under the curve, luteal tissue area, peak E2 production or oestrous cycle length (p > .05). Cycle number did impact AMH concentration (p < .05). In MLV heifers, AMH concentration was highest in cycle 1 (p < .05) while cycles 2 and 3 did not differ (p > .05). This was also true for the K heifers in the Fall replicate (p < .05). Within cycle 2, AMH concentrations were numerically lower between vaccine types (K = 308.22 ± 33.3 pg/ml, MLV = 181.13 ± 32.9 pg/ml; p > .05). Although no differences were seen in overall cycle parameters, differences in AMH concentrations may indicate a reduction of the follicular pool following vaccination and requires further investigation.

Antibody Responses to Bovine Alphaherpesvirus 1 (BoHV-1) in Passively Immunized Calves.

To date, in countries where infectious bovine rhinotracheitis (IBR) is widespread, its control is associated with deleted marker vaccines. These products lack one or more genes responsible for the synthesis of glycoproteins or enzymes. In Europe, the most widely used marker vaccine is one in which glycoprotein E (gE-) is deleted, and it is marketed in a killed or modified-live form. Using this type of immunization, it is possible to differentiate vaccinated animals (gE-) from those infected or injected with non-deleted (gE+) products using diagnostic tests specific for gE. The disadvantage of using modified-live gE-products is that they may remain latent in immunized animals and be reactivated or excreted following an immunosuppressive stimulus. For this reason, in the last few years, a new marker vaccine became commercially available containing a double deletion related to genes coding for gE and the synthesis of the thymidine-kinase (tk) enzyme, the latter being associated with the reduction of the neurotropism, latency, and reactivation of the vaccine virus. Intramuscularly and intranasally administered marker products induce a humoral immune response; however, the mother-to-calf antibody kinetics after vaccination with marker vaccines is poorly understood. This review discusses several published articles on this topic.

Field application of an indirect gE ELISA on pooled milk samples for the control of IBR in free and marker vaccinated dairy herds.

BACKGROUND: The aim of the present study was to assess the reliability of a new strategy for monitoring the serological response against Bovine Herpesvirus 1 (BoHV1), the causative agent of infectious bovine rhinotracheitis (IBR). Bulk milk samples have already been identified as cost effective diagnostic matrices for monitoring purposes. Nevertheless, most eradication programs are still based on individual standard assays. In a region of northwestern Italy (Piedmont), the voluntary eradication program for IBR has become economically unsustainable. Being the prevalence of infection still high, glycoprotein E-deleted marker vaccines are commonly used but gE blocking ELISAs are less sensitive on bulk milk samples compared to blood serum. RESULTS: A recently developed indirect gE ELISA showed high versatility when applied to a wide range of matrices. In this study, we applied a faster, cost effective system for the concentration of IgG from pooled milk samples. The IgG enriched fractions were tested using a gE indirect ELISA for monitoring purposes in IBR-positive and IBR-marker-vaccinated herds. Official diagnostic tests were used as gold standard. During a 3 years study, a total 250 herds were involved, including more than 34,500 lactating cows. The proposed method showed a very good agreement with official diagnostic protocols and very good diagnostic performances: only 37 positive animals were not detected across the entire study. CONCLUSIONS: The results highlighted the ability of the proposed method to support the surveillance of IBR in the Piedmont region, reducing the costs without affecting the diagnostic performances.

Field trial to evaluate the effect of an intranasal respiratory vaccine protocol on calf health, ultrasonographic lung consolidation, and growth in Holstein dairy calves.

The objective of this field trial was to evaluate the effect of a vaccine protocol using a commercially available trivalent vaccine designed for intranasal use. Experimental challenge studies have demonstrated varying efficacies of vaccines administered via the intranasal route. A total of 468 calves from 3 herds were enrolled and randomized into 3 treatment groups (positive control, PC, n = 211; intranasal vaccine, IN, n = 215; negative control, NC, n = 42) and followed for 8 to 12 wk. The PC consisted of one dose of commercially available multivalent injectable vaccine against bovine respiratory syncytial virus, infectious bovine rhinotracheitis, parainfluenza 3, and bovine viral diarrhea administered subcutaneously at 6 wk of age. The IN was administered at enrollment and 6 wk of age, and contained antigen against bovine respiratory syncytial virus, infectious bovine rhinotracheitis, and parainfluenza 3. The NC was sterile saline administered intranasally and subcutaneously at enrollment and 6 wk of age. Clinical illness was assessed using systematic respiratory scoring, and thoracic ultrasonography was used to identify the lung consolidation associated with pneumonia. Rib fractures were identified in 6% of calves, and an association was observed between rib fractures and calving ease. Overall, 54% of the calves had at least one episode of an abnormal respiratory score (ILL). Vaccination protocol did not affect the occurrence of ILL. Similarly, 54% of the calves had at least one episode of lung consolidation ≥3 cm (CON). Vaccine protocol affected the odds of CON. The odds of CON in PC were 1.63 (95% confidence interval: 1.04-2.56) times the odds of CON in IN, and 0.38 (95% confidence interval: 0.16-0.93) times the odds of CON in NC. The odds of CON in IN were 0.23 (95% confidence interval: 0.09-0.59) times the odds of CON in NC. The outcomes ILL and CON were associated; however, the measure of agreement was only fair (kappa = 0.38). Multivariable linear regression revealed an interaction between vaccine protocol and herd on average daily gain (ADG); therefore, these data were stratified. In herd 1, IN (0.53 ± 0.03 kg/d) decreased ADG compared with PC (0.63 ± 0.03 kg/d). In herd 2, IN increased ADG (0.41 ± 0.03 kg/d) compared with PC (0.38 ± 0.03 kg/d). In contrast, none of the protocols affected ADG at herd 3. In conclusion, this commercially available trivalent IN vaccine protocol did not alter the incidence of ILL, reduced the risk of lung lesions associated with pneumonia, and improved the ADG of the calves in one of the commercial study herds.

Long-term study (2005-2010) on the vaccination with BoHV-1 glycoprotein E-deleted marker vaccine in selected two dairy herds in Turkey.

A follow-up study from 2005 to 2010 was carried out in two herds where eradication programme for the bovine herpes virus-1 (BoHV-1) infection depends on the vaccination with inactivated glycoprotein E-deleted vaccine that was started in 2001 following the vaccination with inactivated conventional vaccine between 1999 and 2001. For serological screening, a total of 12,976 sera sampled over several sampling times approximately 6 months of interval during 5 years (2005-2010) were tested for glycoprotein E (gE)- and glycoprotein B-specific antibodies using ELISA. According to the serological evidence, the long-term persistence of BoHV-1 antibodies, success of marker vaccine, first vaccination time of the calves in herds regularly vaccinated, etc. were discussed in this paper. In conclusion, the vaccination programme using gE (-) marker vaccines, with making efforts to prevent the other factors about transmission of infection, was suggested for the eradication of BoHV-1 infection in Turkey as many EU countries. This is the first report on the BoHV-1 eradication programme in some dairy cattle in Turkey.

Virus detection by PCR following vaccination of naive calves with intranasal or injectable multivalent modified-live viral vaccines.

We evaluated duration of PCR-positive results following administration of modified-live viral (MLV) vaccines to beef calves. Twenty beef calves were randomly assigned to either group 1 and vaccinated intranasally with a MLV vaccine containing bovine alphaherpesvirus 1 (BoHV-1), bovine respiratory syncytial virus (BRSV), and bovine parainfluenza virus 3 (BPIV-3), or to group 2 and vaccinated subcutaneously with a MLV vaccine containing bovine viral diarrhea virus 1 and 2 (BVDV-1, -2), BoHV-1, BRSV, and BPIV-3. Deep nasopharyngeal swabs (NPS) and transtracheal washes (TTW) were collected from all calves, and whole blood was collected from group 2 calves and tested by PCR. In group 1, the proportions of calves that tested PCR-positive to BVDV, BoHV-1, BRSV, and BPIV-3 on any sample at any time were 0%, 100%, 100%, and 10%, respectively. In group 1 calves, 100% of calves became PCR-positive for BoHV-1 by day 3 post-vaccination and 100% of calves became PCR-positive for BRSV by day 7 post-vaccination. In group 2, the proportions of calves that tested positive to BVDV, BoHV-1, BRSV, and BPIV-3 on any sample at any time were 50%, 40%, 10%, and 0%, respectively. All threshold cycle (Ct) values were >30 in group 2 calves, irrespective of virus; however, Ct values <25 were observed in group 1 calves from PCR-positive results for BoHV-1 and BRSV. All calves were PCR-negative for all viruses after day 28. Following intranasal MLV viral vaccination, PCR results and Ct values for BRSV and BoHV-1 suggest that attempts to differentiate vaccine virus from natural infection is unreliable.

Surveillance of Infectious Bovine Rhinotracheitis in marker-vaccinated dairy herds: Application of a recombinant gE ELISA on bulk milk samples.

Infectious Bovine Rhinotracheitis (IBR) occurs worldwide, requiring significant resources for eradication programs or surveillance purposes. The status of infection is usually detected by serological methods using the virus neutralization test (VNT) or enzyme-linked immunosorbent assay (ELISA) on individual sera. The gE DIVA (Differentiating Infected from Vaccinated Animals) vaccines approach, adopted in order to reduce the virus circulation and prevent clinical signs, have tightened the range of available methods for the serological diagnosis. Different gE blocking ELISA could be performed to detect specific antibodies in sera of infected or whole virus-vaccinated animals but with less sensitivity if applied to bulk milk samples, especially in marker-vaccinated herds. A new rec-gE ELISA was recently developed in Italy and applied with good performances on blood serum samples. The present paper focuses on the application of a rapid protocol for purification/concentration of immunoglobulin G (IgG) from bulk milk and on the use of the new rec-gE indirect ELISA. The study involved three different partners and 225 herds (12,800 lactating cows) with different official IBR diagnostic statuses. The diagnostic specificity of the method was demonstrated closed to 100% while the diagnostic sensitivity was strictly related to the herd-seroprevalence. Considering 2.5% as the limit of detection of within-herd seropositivity prevalence, the diagnostic sensitivity showed by the proposed method was equal to 100%. A single reactivation of a whole strain vaccine in an old cow was detected inside a group of 67 lactating cows, showing the field applicability of the method.