Bovine Respiratory Syncytial Virus Research Articles

Serological investigation of antibodies against respiratory viruses in calves from Brazilian family farming and their relation to clinical signs of bovine respiratory disease

ABSTRACT: Bovine respiratory disease (BRD) is responsible for economic losses in cattle production. Viruses are categorized as primary etiological agents. The aims of this study were to evaluate the presence of antibodies against bovine viral diarrhea virus (BVDV), bovine herpes virus type 1 (BoHV-1), and bovine respiratory syncytial virus (BRSV) in healthy and BRD calves from family farming in relation to clinical signs of BRD. Hundred and forty-five calves were randomly selected and physical examination was performed. Only 123 animals were classified as healthy and BRD calves. Antibodies were evaluated by virus neutralization test. Person’s Chi-square test and Fisher’s exact test were performed as univariate analysis. Binary Logistic Regression was applied as multivariate analysis. Variables with P<0.10 were considered statistically significant. Variables with 0.15<P<0.10 were considered as statistical tendencies. Antibodies against BoHV-1, BVDV, and BRSV were detected in 32%, 23% and 37% animals. Antibodies against both three viruses were detected in 26.8% of calves. The presence of antibodies against BRSV were associated to normal heart rates (P=0.018) and unilateral airflow (P=0.035). Tendency was observed to unilateral airflow (P=0.06) Statistical tendencies were observed to Ab-BoHV-1 and body temperature (P=0.119) and breathing pattern (P=0.123). The profile of antibodies against respiratory viruses in calves from Brazilian family farming was firstly described. The results confirmed the importance of some clinical signs to viral infection.

Evaluation of a multiplex immunoassay for bovine respiratory syncytial virus and bovine coronavirus antibodies in bulk tank milk against two indirect ELISAs using latent class analysis

Bovine respiratory syncytial virus (BRSV) and bovine coronavirus (BCV) are responsible for respiratory disease and diarrhea in cattle worldwide. The Norwegian control program against these infections is based on herd-level diagnosis using a new multiplex immunoassay. The objective of this study was to estimate sensitivity and specificity across different cut-off values for the MVD-Enferplex BCV/BRSV multiplex, by comparing them to a commercially available ELISA, the SVANOVIR® BCV-Ab and SVANOVIR® BRSV-Ab, respectively. We analyzed bulk tank milk samples from 360 herds in a low- and 360 herds in a high-prevalence area. As none of the tests were considered perfect, estimation of test characteristics was performed using Bayesian latent class models. At the manufacturers’ recommended cut-off values, the median sensitivity for the BRSV multiplex and the BRSV ELISA was 94.4 [89.8–98.7 95% Posterior Credibility Interval (PCI)] and 99.8 [98.7–100 95% PCI], respectively. The median specificity for the BRSV multiplex was 90.6 [85.5–94.4 95% PCI], but only 57.4 [50.5–64.4 95% PCI] for the BRSV ELISA. However, increasing the cut-off of the BRSV ELISA increased specificity without compromising sensitivity. For the BCV multiplex we found that by using only one of the three antigens included in the test, the specificity increased, without concurrent loss in sensitivity. At the recommended cut-off this resulted in a sensitivity of 99.9 [99.3–100 95% PCI] and specificity of 93.7 [88.8–97.8 95% PCI] for the multiplex and a sensitivity of 99.5 [98.1–100 95% PCI] and a specificity of 99.6 [97.6–100 95% PCI] for the BCV ELISA.

Preliminary serological and molecular investigation of selected viral pathogens in Croatian cervid species

Abstract A total of 131 blood samples and 175 spleen samples were collected from three cervid species: roe deer (Capreolus capreolus), red deer (Cervus elaphus) and fallow deer (Dama dama) inhabiting the continental part of Croatia. Serum samples were tested for antibodies against bovine herpesvirus 1, parainfluenza-3 virus, bluetongue virus, bovine respiratory syncytial virus, hepatitis E virus, bovine viral diarrhoea virus and enzootic bovine leukosis virus. The tested sera were negative for bovine viral diarrhoea virus, enzootic bovine leukosis virus, bluetongue virus, bovine respiratory syncytial virus and hepatitis E virus antybodies. The antibody prevalence in roe deer and red deer samples was 21.11% for bovine herpesvirus 1 and 75.55% for parainfluenza-3 virus. Sera from bovine herpesvirus 1 positive animals were subsequenty tested with comparative virus neutralization test and bovine herpesvirus 1 neutralising antibodies were found in 18 (out of 19) sera. In fallow deer, no antibodies against any of the viral pathogens were detected. All spleen samples tested for bovine viral diarrhoea virus and enzootic bovine leukosis virus came back negative, except for one red deer spleen sample found to be weakly diarrhoea virus-positive. Our findings provide the first information on the exposure of Croatia-inhabiting cervid species to viral pathogens, and could serve as valuable baseline data for future investigations regarding deer exposure to various pathogens and the distribution of diseases shared between wildlife and livestock. As of now, the epidemiology of these viruses in the Croatian cervid population has been only poorly understood, so that further research is recommended.

Efficacy of mucosal polyanhydride nanovaccine against respiratory syncytial virus infection in the neonatal calf

Human respiratory syncytial virus (HRSV) is a leading cause of severe acute lower respiratory tract infection in infants and children worldwide. Bovine RSV (BRSV) is closely related to HRSV and a significant cause of morbidity in young cattle. BRSV infection in calves displays many similarities to RSV infection in humans, including similar age dependency and disease pathogenesis. Polyanhydride nanoparticle-based vaccines (i.e., nanovaccines) have shown promise as adjuvants and vaccine delivery vehicles due to their ability to promote enhanced immunogenicity through the route of administration, provide sustained antigen exposure, and induce both antibody- and cell-mediated immunity. Here, we developed a novel, mucosal nanovaccine that encapsulates the post-fusion F and G glycoproteins from BRSV into polyanhydride nanoparticles and determined the efficacy of the vaccine against RSV infection using a neonatal calf model. Calves receiving the BRSV-F/G nanovaccine exhibited reduced pathology in the lungs, reduced viral burden, and decreased virus shedding compared to unvaccinated control calves, which correlated with BRSV-specific immune responses in the respiratory tract and peripheral blood. Our results indicate that the BRSV-F/G nanovaccine is highly immunogenic and, with optimization, has the potential to significantly reduce the disease burden associated with RSV infection in both humans and animals.

Seroprevalence and risk factors for selected respiratory and reproductive tract pathogen exposure in European bison (Bison bonasus) in Poland

After the complete extinction from the wild of European bison (Bison bonasus) at the beginning of the twentieth century, the worldwide species population was restored to approximately 5500 individuals, with the species however remaining endangered. Despite numerous studies on the ecology and genetics of European bison, the threats of infectious diseases have been largely unexamined. The aim of this study was to screen the exposure of the world’s largest population of European bison to the pathogens, which may influence the condition and development of the endangered species. A total of 240 free-ranging and captive European bison from eight main Polish populations sampled were tested for the presence of specific antibodies against ten different viruses, bacteria or protozoan. The samples were collected from chemically immobilized, selectively culled or found dead animals. Based on serology, the exposure to bovine viral diarrhea virus (BVDV), bovine herpesvirus type 1 (BoHV-1), Mycoplasma and Brucella spp. was determined as rather accidental. Using gamma-interferon assay followed by Mycobacterium tuberculosis subs. caprae detection in tissues, diagnosis of bovine tuberculosis was made for 6 out of 78 (7.7%) bison from one captive herd. The highest seroprevalence was found for bovine adenovirus type 3 (BAdV-3) −60.2% and bovine parainfluenza type 3 (PIV-3) −34.0%, while the antibodies against bovine respiratory syncytial virus (BRSV), Toxoplasma gondii and Leptospira spp. were found in 10.4%, 10.4% and 8.7% of samples, respectively. In the multivariable statistical analysis using generalized linear mixed models (GLMMS), the risk factors for PIV-3 seropositivity included population type (free-living/captive), age and health status (apparently healthy/eliminated due to the poor condition). Higher risk of BAdV-3 seropositive result was observed in free-living female European bison. The high BAdV-3 and PIV-3 seroprevalences may suggest involvement of these pathogens in the most frequently observed respiratory disorders in European bison. Moreover, this is the first study demonstrating BAdV-3 exposure in the species.

Temporary carriage of bovine coronavirus and bovine respiratory syncytial virus by fomites and human nasal mucosa after exposure to infected calves

BackgroundIn order to prevent spread of the endemic pathogens bovine coronavirus (BCoV) and bovine respiratory syncytial virus (BRSV) between herds, knowledge of indirect transmission by personnel and fomites is fundamental. The aims of the study were to determine the duration of viral RNA carriage and the infectivity of viral particles on fomites and human nasal mucosa after exposure to BCoV and BRSV. During two animal infection experiments, swabs were collected from personnel (nasal mucosa) and their clothes, boots and equipment after contact with calves shedding either virus. Viral RNA was quantified by RT-qPCR or droplet digital RT-PCR (RT-ddPCR), and selected samples with high levels of viral RNA were tested by cell culture for infectivity.ResultsFor BCoV, 46% (n = 80) of the swabs from human nasal mucosa collected 30 min after exposure were positive by RT-qPCR. After two, four and six hours, 15%, 5% and 0% of the swabs were positive, respectively. Infective virions were not detected in mucosal swabs (n = 2). A high viral RNA load was detected on 97% (n = 44) of the fomites 24 h after exposure, and infective virions were detected in two of three swabs. For BRSV, 35% (n = 26) of the human nasal mucosa swabs collected 30 min after exposure, were positive by RT-ddPCR, but none were positive for infective virions. Of the fomites, 89% (n = 38) were positive for BRSV RNA 24 h after exposure, but all were negative for infective viruses.ConclusionsThe results indicate that human nasal mucosa can carry both BCoV and BRSV RNA after exposure to virus shedding calves, but the carriage seems short-lived and the transmission potential is likely limited. High viral loads on contaminates fomites 24 h after exposure to infected animals, and detection of infective BCoV, indicate that contaminated fomites represent a significant risk for indirect transmission between herds.

Performance, health and physiological responses of newly weaned feedlot cattle supplemented with feed-grade antibiotics or alternative feed ingredients

With increased regulations regarding the use of feed-grade antimicrobials in livestock systems, alternative strategies to enhance growth and immunity of feedlot cattle are warranted. Hence, this experiment compared performance, health and physiological responses of cattle supplemented with feed-grade antibiotics or alternative feed ingredients during the initial 60 days in the feedlot. Angus×Hereford calves (63 steers+42 heifers) originating from two cow–calf ranches were weaned on day −3, obtained from an auction yard on day −2 and road-transported (800 km; 12 h) to the feedlot. Upon arrival on day −1, shrunk BW was recorded. On day 0, calves were ranked by sex, source and shrunk BW, and allocated to one of 21 pens. Pens were assigned to receive (7 pens/treatment) a free-choice total mixed ration containing: (1) lasalocid (360 mg/calf daily of Bovatec; Zoetis, Florham Park, NJ, USA)+chlortetracycline (350 mg/calf of Aureomycin at cycles of 5-day inclusion and 2-day removal from diet; Zoetis) from days 0 to 32, and monensin only (360 mg/calf daily of Rumensin; Elanco Animal Health, Greenfield, IN, USA) from days 33 to 60 (PC), (2) sodium saccharin-based sweetener (Sucram at 0.04 g/kg of diet dry matter; Pancosma SA; Geneva, Switzerland)+plant extracts containing eugenol, cinnamaldehyde and capsicum (800 mg/calf daily of XTRACT Ruminants 7065; Pancosma SA) from days 0 to 32 and XTRACT only (800 mg/calf daily) from days 33 to 60 (EG) or (3) no supplemental ingredients (CON; days 0 to 60). Calves were assessed for bovine respiratory disease (BRD) signs and dry matter intake was recorded from each pen daily. Calves were vaccinated against BRD pathogens on days 0 and 22. Shrunk BW was recorded on day 61, and blood samples collected on days 0, 6, 11, 22, 33, 43 and 60. Calf ADG was greater (P=0.04) in PC v. EG and tended (P=0.09) to be greater in PC v. CON. Feed efficiency also tended (P=0.09) to be greater in PC v. CON, although main treatment effect for this response was not significant (P=0.23). Mean serum titers against bovine respiratory syncytial virus were greater in EG v. PC (P=0.04) and CON (tendency; P=0.08). Collectively, the inclusion of alternative feed ingredients prevented the decrease in feed efficiency when chlortetracycline and ionophores were not added to the initial feedlot diet, and improved antibody response to vaccination against the bovine respiratory syncytial virus in newly weaned cattle.

Besi sığırlarında solunum sistemi virüslerinin seroprevalansı ve persiste BVD virüs enfeksiyonu tespiti

Sigir solunum sistemi enfeksiyonlari tum dunyada besi ve sut sigiri isletmelerindeki en onemli problemlerden birisidir. Bu calismada, buyuk kapasiteli bir besi sigiri isletmesinde bulunan uc farkli yas grubundaki (6-8 aylik; 9-11 aylik; 12-15 aylik) hayvanlarda solunum sistemi viruslerinin serolojik dagilimi incelenmistir. Bu kapsamda orneklenen hayvanlarda, bovine viral diarrhoea virus (BVDV), bovine herpesvirus-1 (BHV-1), bovine respiratorik sinsityal virus (BRSV) ve bovine parainfluenza -3 (PI-3) virusleri icin spesifik antikor varligi arastirilarak, bireysel ve coklu solunum sistemi enfeksiyonlarinin degerlendirmesi yapildi. Arastirma kapsaminda ele alinan her yas grubundan 80 adet olmak uzere toplam 240 adet kan serumu ornegi toplandi. Virus notralizasyon yontemiyle yapilan analizler sonucunda BVDV, BHV-1, BRSV ve PI-3 icin seropozitiflik degerleri sirasiyla 6-8 aylik grup icin %96.3; %98.8; %100; %100; 9-11 aylik grup icin %88.8; %100; %97.5; %98.8 ve 12-15 aylik grup icin %71.3; %95; %93.8; %96.3 olarak tespit edildi. Elde edilen verilere gore 6-8 aylik ve 9-11 aylik hayvanlarin test edilen tum etkenlere karsi yuksek seropozitiflige sahip oldugu gorulurken 12-15 aylik hayvanlarda bu oranin azalmaya basladigi belirlendi. Ayrica ornekleme yapilan besi sigirlarinin tumunun test edilen viruslerden en az iki veya daha fazlasina karsi seropozitif bulunmasi coklu enfeksiyon varliginin yuksek oranda seyrettigini gosterdi. Seropozitif hayvanlarin yas gruplari arasindaki dagiliminin BVDV enfeksiyonu icin 6-8 aylik ile 12-15 aylik ve 9-11 aylik ile 12-15 aylik yaslar arasinda istatistiki olarak onemli duzeyde farkli oldugu goruldu (P<0.05)

Effect of passive transfer status on response to a glycoprotein E (gE)-negative bovine herpesvirus type 1 (BoHV-1) and bovine respiratory syncytial virus (BRSV) vaccine and weaning stress in pre-weaned dairy calves

ABSTRACTThe study objectives were to: 1) examine how calves of divergent immune status respond to BRSV vaccination at 3 weeks of age; 2) trace glycoprotein E negative BoHV-1 antibodies from vaccinated dams to calf sera and to investigate how passive transfer affects response to live BoHV-1 vaccine at 6 weeks of age; 3) explore the impact of passive transfer status on blood metabolites around weaning. Thirty seven Holstein cows and their calves were included in the study. All cows were immunised with a commercial marker vaccine against BoHV-1(gE-) administered intra-muscularly at 4 month prior to the start of calving. Calves were assigned to 1 of 2 colostrum treatment groups: 1) 5% of BW in colostrum fed at birth, or 2) 10% of BW in colostrum fed at birth. Calves were also immunised at 3 weeks of age with a respiratory commercial vaccine, and a booster administered 4 weeks later. Calves were also immunised against BoHV-1 at 6 weeks of age, using one dose of a live commercial vaccine. The results demonstrated that level of passive immunity had no effect on immune response to vaccination and the importance of feeding colostrum from vaccinated BoHV-1 gE- dams to provide calves with passive protection against IBRV.

Phylogenetic Analysis of Bovine Respiratory Syncytial Virus from Calves with Respiratory Disorders

Phylogenetic Analysis of Bovine Respiratory Syncytial Virus from Calves with Respiratory Disorders

Detecting the Effect of Umckaloabo/EPs®7630 Liquid Extract after its Therapeutic Purposed Usage in Calves Showing Symptoms of Respiratory Tract Infection

Background: Respiratory tract diseases are commonly seen in beef cattle. Young calves are affected with many respiratory pathogens. Viral pathogens are particularly seen. There are many causative factors, e.g. environmental conditions, immune system of calves. Therefore, alternative treatments are needed for viral respiratory infections. The purpose of the current study was to investigate effectiveness of Umckaloabo/EPs®7630 liquid extract in some bovine viral pathogens of young beef calves.Materials, Methods &amp; Results: Antibody presence in terms of bovine herpesvirus type 1 (BHV-1), bovine viral diarrhea virus (BVDV), bovine parainfluenza virus type 3 (BPIV-3), bovine respiratory syncytial virus (BRSV) and bovine adenovirus type 3 (BAV-3) was searched in blood serum samples of 40 Holstein calves aged 6 months and over showing respiratory tract infection symptoms. All animals were found seronegative in terms of other factors except BRSV. Out of 20 BRSV seropositive calves, 10 of them were classified as control group and the other ten as testing group. BRSV antibody titers were also detected in blood samples of both groups on day 0. Umckaloabo/EPs®7630 liquid extract was given through oral route to animals in testing group according to their weights for 14 days morning, noon and night. No application was performed on animals in control group. BRSV antibody titers were detected in blood samples of animals in both groups taken on days 1st, 3rd, 5th, 7th, 10th and 14th. At the end of day 14th, BRSV antibody titer increased in 9 out of 10 animals (90%) in testing group that were given Umckaloabo/EPs® 7630 liquid extract while one of them (10%) showed no variability. BRSV antibody titer increased in 6 out of 10 animals (60%) in control group while it decreased in one of them (10%) and 3 of them (30%) showed no variability. In testing group, BRSV antibody titer started to increase on day 3rd in 6 out of 10 animals (60%), on day 5th in one (10%), on day 10th in one (10%) and on day 14th in another (10%). In control group, BRSV antibody titer started to increase on day 3rd in 3 out of 10 animals (30%) and on day 5th in 3 of them (30%). When haematologic values of blood samples taken from animals in testing and control groups on day 14th were studied comparatively, no statistical importance (P &lt; 0.01 or P &lt; 0.05) and difference was detected. As a result, in stock calves showing respiratory tract infection symptoms, applying Umckaloabo/EPs® 7630 liquid extract helped BRSV antibody titer to increase and symptoms decreased. The increase in antibody titers started from day 3rd especially after applying Umckaloabo/EPs® 7630 liquid extract.Discussion: Respiratory system infections are contagious and fatal in calves. Respiratory tract bacterial and viral vaccinations are applied in order to prevent losses of calves due to these problems. However, these vaccinations are not sufficient most of the time and antibiotics+supportive treatment applications follow afterwards. Therefore, we advise to use a herbal product, Umckaloabo/ EPs®7630 liquid extract, that has both an antiviral efficiency and a feature of supporting immune system in order to prevent mortalities in stock calves, to stop the infection from spreading on all the herd and to decrease the symptoms of respiratory system. We believe that the obtained data should be supported with more examples and more wide-ranging studies.

Development of a recombinase polymerase amplification combined with lateral-flow dipstick assay for detection of bovine ephemeral fever virus

Bovine ephemeral fever virus (BEFV), identified as the causative pathogen of bovine ephemeral fever (BEF), is responsible for increasing numbers of epidemics/outbreaks and has a significant harmful effect on the livestock industry. Therefore, a rapid detection assay is imperative for BEFV diagnosis. In this study, we described the development of lateral-flow dipstick isothermal recombinase polymerase amplification (LFD-RPA) assays for detection of BEFV. RPA primers and LF probes were designed by targeting the specific G gene, and the amplification product can be visualized on a simple lateral flow dipstick with the naked eyes. The amplification reaction was performed at 38 °C for 20 min and LFD incubation time within 5 min. The detection limit of this assay was 8 copies per reaction, and there was no cross-reactivity with other bovine infectious viruses such as bovine viral diarrhea virus, infectious bovine rhinotracheitis virus, bovine respiratory syncytial virus, bovine coronavirus, bovine parainfluenza virus type 3, bovine vesicular stomatitis virus. In addition, the assay was performed with total 128 clinical specimens and the diagnostic results were compared with conventional RT-PCR, real-time quantative(q) PCR. The result showed that the coincidence rate of BEFV LFD-RPA and real-time qPCR was 96.09% (123/128), which was higher than conventional RT-PCR. The RPA combined with LFD assay probably provides a rapid and sensitive alternative for diagnosis of BEFV infections outbreak.

Genetic characterization of bovine respiratory syncytial virus strains isolated in Italy: evidence for the circulation of new divergent clades.

Bovine respiratory syncytial virus (BRSV) is circulating in cattle in Europe. Although vaccination helps control the disease, its prevalence within and among herds remains high. Previous genetic characterization studies revealed a strict geographic correlation between viral variants; on the other hand, they showed the emergence of new variants in northern Europe. Few studies have described BRSV distribution, and little is known about the genetic features of BRSV strains circulating in Italy. We studied sample-positive tests for BRSV, and sequenced the coding regions of the G and N proteins to determine the presence of divergent variants. Two different sets of sequences were found, including in samples from animals from vaccinated herds. The 2 groups of sequences correspond to 2 time periods and suggest an active role of herd immunity in preventing the spread of infection. Our findings that different strains of BRSV are circulating in Italy and that the virus is evolving rapidly highlight the importance of updating vaccination strategies.

Bovine respiratory syncytial virus seroprevalence and risk factors in feedlot cattle from Córdoba and Santa Fe, Argentina

Bovine respiratory syncytial virus (BRSV) is one of the causative agents of respiratory disease in cattle all over the world, leading to important economic losses. The aim of this work was to determine the seroprevalence of BRSV in feedlot cattle of Argentina and the risk factors associated with the disease. Results showed a high individual seroprevalence of 78.64% (95% confidence interval adjusted [CI]=66.55–90.75%) against the virus. Positive association was found between the presence of high BRSV neutralizing antibody titers, and the following risk factors: cattle age, source of animals, presence of clinical respiratory signs and herd size. This work contributes to updating the understanding of its epidemiology in Argentinean feedlots and poses the need for reevaluating vaccination strategies against this virus in order to control infection and its impact on productivity.

Tissue Tropism in Host Transcriptional Response to Members of the Bovine Respiratory Disease Complex

Bovine respiratory disease (BRD) is the most common infectious disease of beef and dairy cattle and is characterized by a complex infectious etiology that includes a variety of viral and bacterial pathogens. We examined the global changes in mRNA abundance in healthy lung and lung lesions and in the lymphoid tissues bronchial lymph node, retropharyngeal lymph node, nasopharyngeal lymph node and pharyngeal tonsil collected at the peak of clinical disease from beef cattle experimentally challenged with either bovine respiratory syncytial virus, infectious bovine rhinotracheitis, bovine viral diarrhea virus, Mannheimia haemolytica or Mycoplasma bovis. We identified signatures of tissue-specific transcriptional responses indicative of tropism in the coordination of host’s immune tissue responses to infection by viral or bacterial infections. Furthermore, our study shows that this tissue tropism in host transcriptional response to BRD pathogens results in the activation of different networks of response genes. The differential crosstalk among genes expressed in lymphoid tissues was predicted to be orchestrated by specific immune genes that act as ‘key players’ within expression networks. The results of this study serve as a basis for the development of innovative therapeutic strategies and for the selection of cattle with enhanced resistance to BRD.

A survey of recommended practices made by veterinary practitioners to cow-calf operations in the United States and Canada

Practicing veterinarians (n = 148) who service commercial beef cow-calf herds responded to a survey describing general recommendations made to their clients in terms of vaccine protocol, health, and production practices. Responding veterinarians represented 35 states in the United States and 3 provinces in Canada. More than 50% of responding veterinarians devote over 50% of their practice to service commercial cow-calf producers. The largest group (33%) of veterinarians have been in practice for over 30 yr. Thirty-nine percent of responding veterinarians serviced more than 10,000 cows. Genetic advice is provided by 54% of practicing veterinarians. When vaccinating at branding, the most common recommended vaccines are clostridial (96%), infectious bovine rhinotracheitis (IBR; 94%), bovine respiratory syncytial virus (BRSV; 91%), parainfluenza-3 (PI-3; 90%), and bovine viral diarrhea (BVD) Types 1 and 2 (78 and 77%, respectively). When vaccinating before weaning, the most common recommended vaccines are IBR (99%), BRSV (98%), BVD Types 1 and 2 (96%), PI-3 (93%), clostridial (77%), and Mannheimia haemolytica (77%). When vaccinating after weaning, the most common recommended vaccines are BVD Type 2 (97%), IBR (97%), BVD Type 1 (96%), BRSV (96%), and PI-3 (91%). Over 60% of responding veterinarians recommended that the last preventative vaccine should be administered to cattle 7 to 21 d before shipping. The largest number of respondents (38%) recommended that the earliest age their clients should wean their calves is 90 to 120 d. Castrating bull calves at an age of 0 to 7 d was recommended by 34% of respondents. Calf nutrition is considered as extremely important during a preconditioning program by 82% of responding veterinarians.

Molecular survey of infectious agents associated with bovine respiratory disease in a beef cattle feedlot in southern Brazil.

We investigated the occurrence of infectious pathogens during an outbreak of bovine respiratory disease (BRD) in a beef cattle feedlot in southern Brazil that has a high risk of developing BRD. Nasopharyngeal swabs were randomly collected from steers ( n = 23) and assessed for the presence of infectious agents of BRD by PCR and/or RT-PCR assays. These included: Histophilus somni, Mannheimia haemolytica, Pasteurella multocida, Mycoplasma bovis, bovine respiratory syncytial virus (BRSV), bovine coronavirus (BCoV), bovine viral diarrhea virus (BVDV), bovine alphaherpesvirus 1 (BoHV-1), and bovine parainfluenza virus 3 (BPIV-3). Pulmonary sections of one steer that died with clinical BRD were submitted for pathology and molecular testing. The frequencies of the pathogens identified from the nasopharyngeal swabs were: H. somni 39% (9 of 23), BRSV 35% (8 of 23), BCoV 22% (5 of 23), and M. haemolytica 13% (3 of 23). PCR or RT-PCR assays did not identify P. multocida, M. bovis, BoHV-1, BVDV, or BPIV-3 from the nasopharyngeal swabs. Single and concomitant associations of infectious agents of BRD were identified. Fibrinous bronchopneumonia was diagnosed in one steer that died; samples were positive for H. somni and M. haemolytica by PCR. H. somni, BRSV, and BCoV are important disease pathogens of BRD in feedlot cattle in Brazil, but H. somni and BCoV are probably under-reported.

Adjuvants and the vaccine response to the DS-Cav1-stabilized fusion glycoprotein of respiratory syncytial virus.

Appropriate adjuvant selection may be essential to optimize the potency and to tailor the immune response of subunit vaccines. To induce protective responses against respiratory syncytial virus (RSV)—a highly prevalent childhood pathogen without a licensed vaccine—we previously engineered a pre-fusion-stabilized trimeric RSV F (pre-F) “DS-Cav1” immunogen, which induced high titer RSV-neutralizing antibodies, in mice and non-human primates, when formulated with adjuvants Poly (I:C) and Poly (IC:LC), respectively. To assess the impact of different adjuvants, here we formulated RSV F DS-Cav1 with multiple adjuvants and assessed immune responses. Very high RSV-neutralizing antibody responses (19,006 EC50) were observed in naïve mice immunized with 2 doses of DS-Cav1 adjuvanted with Sigma adjuvant system (SAS), an oil-in-water adjuvant, plus Carbopol; high responses (3658–7108) were observed with DS-Cav1 adjuvanted with Alum, SAS alone, Adjuplex, Poly (I:C) and Poly (IC:LC); and moderate responses (1251–2129) were observed with DS-Cav1 adjuvanted with the TLR4 agonist MPLA, Alum plus MPLA or AddaVax. In contrast, DS-Cav1 without adjuvant induced low-level responses (6). A balanced IgG1 and IgG2a (Th2/Th1) immune response was elicited in most of the high to very high response groups (all but Alum and Adjuplex). We also tested the immune response induced by DS-Cav1 in elderly mice with pre-existing DS-Cav1 immunity; we observed that DS-Cav1 adjuvanted with SAS plus Carbopol boosted the response 2-3-fold, whereas DS-Cav1 adjuvanted with alum boosted the response 5-fold. Finally, we tested whether a mixture of ISA 71 VG and Carbopol would enhanced the antibody response in DS-Cav1 immunized calves. While pre-F-stabilized bovine RSV F induced very high titers in mice when adjuvanted with SAS plus Carbopol, the addition of Carbopol to ISA 71 VG did not enhance immune responses in calves. The vaccine response to pre-F-stabilized RSV F is augmented by adjuvant, but the degree of adjuvant-induced enhancement appears to be both context-dependent and species-specific.

Pre-fusion RSV F strongly boosts pre-fusion specific neutralizing responses in cattle pre-exposed to bovine RSV

Human respiratory syncytial virus (hRSV) is responsible for serious lower respiratory tract disease in infants and in older adults, and remains an important vaccine need. RSV fusion (F) glycoprotein is a key target for neutralizing antibodies. RSV F stabilized in its pre-fusion conformation (DS-Cav1 F) induces high neutralizing antibody titers in naïve animals, but it remains unknown to what extent pre-fusion F can boost pre-existing neutralizing responses in RSV seropositive adults. We here assess DS-Cav1 F immunogenicity in seropositive cattle pre-exposed to bovine RSV, a virus closely related to hRSV. A single immunization with non-adjuvanted DS-Cav1 F strongly boosts RSV neutralizing responses, directed towards pre-fusion F-specific epitopes, whereas a post-fusion F is unable to do so. Vaccination with pre-fusion F thus represents a promising strategy for maternal immunization and for other RSV vaccine target populations such as older adults.

Proteome analysis of bronchoalveolar lavage from calves infected with bovine respiratory syncytial virus-Insights in pathogenesis and perspectives for new treatments.

Human and bovine respiratory syncytial viruses (HRSV/BRSV) are major causes of severe lower respiratory tract infections in children and calves, respectively. Shared epidemiological, clinical, pathological and genetic characteristics of these viruses make comparative research highly relevant. To characterise the host response against BRSV infection, bronchoalveolar lavage supernatant (BAL) from i) non-vaccinated, BRSV-infected ii) vaccinated, BRSV-infected and iii) non-infected calves was analysed by tandem mass spectrometry. Proteins were semi-quantified and protein expression was validated by immunoblotting. Correlations between selected proteins and pathology, clinical signs and virus shedding were investigated. Calves with BRSV-induced disease had increased total protein concentrations and a decreased number of proteins identified in BAL. The protein profile was characterised by neutrophil activation and a reduction in identified antioxidant enzymes. The presence of neutrophils in alveolar septa, the expression level of neutrophil-related or antioxidant proteins and LZTFL1 correlated significantly with disease. Citrullinated histone 3, an indicator of extracellular traps (ETs), was only detected in non-vaccinated, BRSV-infected animals. By bringing disequilibrium in the release and detoxification of reactive oxygen species, generating ETs and causing elastine degradation, exaggerated neutrophil responses might exacerbate RSV-induced disease. Neutrophil-mitigating or antioxidant treatments should be further explored.