Search Results (50)

The seasonal patterns of viral diseases in farm animals present significant challenges to global livestock productivity, with cold stress emerging as a potential modulator of host–pathogen interactions. This review synthesizes current knowledge on the expression dynamics of heat shock protein 70 (HSP70) in farm animals under cold-stress conditions and its potential roles as (1) a viral replication facilitator and (2) an immune response regulator. This review highlights cold-induced HSP70 overexpression in essential organs, as well as its effects on significant virus life cycles, such as porcine epidemic diarrhea virus (PEDV), porcine reproductive and respiratory syndrome virus (PRRSV), and bovine viral diarrhea virus (BVDV), through processes like viral protein chaperoning, replication complex stabilization, and host defense modulation. By integrating insights from thermophysiology, virology, and immunology, we suggest that HSP70 serves as a crucial link between environmental stress and viral disease seasonality. We also discuss translational opportunities targeting HSP70 pathways to break the cycle of seasonal outbreaks, while addressing key knowledge gaps requiring further investigation. This article provides a framework for understanding climate-driven disease patterns and developing seasonally adjusted intervention strategies. Full article

Bovine respiratory disease complex (BRDC) is one of the primary causes of morbidity, mortality, and economic loss in cattle worldwide. Accurate and rapid identification of causative pathogenic agents is essential for effective disease management and control. In this study, a novel multiplex fluorescence-based quantitative polymerase chain reaction (qPCR) assay was developed for the simultaneous detection of eight major pathogens associated with BRDC. The targeted pathogens included the following: bovine viral diarrhea virus (BVDV), bovine parainfluenza virus type 3 (BPIV3), bovine respiratory syncytial virus (BRSV), bovine coronavirus (BcoV), Mycoplasma bovis (M.bovis), Pasteurella multocida (PM), Mannheimia haemolytica (MH), and infectious bovine rhinotracheitis virus (IBRV). The assay was rigorously optimized to ensure high specificity with no cross-reactivity among targets. The limit of detection (LOD) was determined to be as low as 5 copies per reaction for all target pathogens. The coefficient of variation (CVs) for both intra-assay and inter-assay measurements were consistently below 2%, demonstrating excellent reproducibility. To validate the clinical utility of the assay, a total of 1012 field samples were tested, including 504 nasal swabs from Farm A and 508 from Farm B in Jiangsu Province. BVDV, BcoV, PM, and MH were detected from Farm A, with a BVDV-positive rate of 21.63% (109/504), BcoV-positive rate of 26.79% (135/504), PM-positive rate of 28.77% (145/504), and MH-positive rate of 15.08% (76/504). Also, BcoV, PM, MH, and IBRV were detected from Farm B, with a BcoV-positive rate of 2.36% (12/508), PM-positive rate of 1.38% (7/508), MH-positive rate of 14.76% (75/508), and IBRV-positive rate of 5.51% (28/508). Notably, a significant proportion of samples showed evidence of mixed infections, underscoring the complexity of BRDC etiology and the importance of a multiplex diagnostic approach. In conclusion, the developed multiplex qPCR assay provides a reliable, rapid, and cost-effective tool for simultaneous detection of multiple BRDC-associated pathogens, which will hold great promise for enhancing disease surveillance, early diagnosis, and targeted intervention strategies, ultimately contributing to improved BRDC management and cattle health outcomes. Full article

Serum beta-hydroxybutyrate (BHB) and non-esterified fatty acids (NEFAs) are biomarkers of situations of negative energetic balance in bovine. However, knowledge about their possible measurement and use in saliva is limited. In this report, two commercially available methods for the measurement of BHB and NEFAs were validated for use in bovine saliva. Both methods showed good precision and accuracy. The BHB concentrations were correlated between the saliva and the serum, but not the NEFA concentrations. The cows with hyperketonemia (n = 17) had increased salivary BHB compared to the cows with no clinical signs and no hyperketonemia (n = 34) and those with clinical signs of metritis (n = 17). The salivary NEFA concentration increased in newborn calves (n = 10) on days 1 and 2 of life compared to the day of birth before colostrum intake. The calves with symptomatic bovine respiratory disease complex (BRD, n = 7) showed higher salivary NEFA concentrations than those without clinical symptoms (n = 6). Thus, BHB and NEFAs can be reliably measured in bovine saliva using easily automatable colorimetric methods. Salivary BHB increased in hyperketonemia and could be a potential biomarker of this condition. Further studies should be undertaken to clarify the mechanism and possible use of salivary NEFAs as biomarkers. Full article

The ovine respiratory complex significantly affects lamb welfare and production efficiency, necessitating accurate diagnostic methods for pulmonary lesions. This study explores the relationship between clinical scoring, auscultation, ultrasonography, and macroscopic post-mortem evaluation to assess respiratory disease in 111 lambs. A standardized clinical scoring system, adapted from bovine models, evaluated ocular and nasal discharge, head tilt, cough, and rectal temperature. Auscultation categorized pulmonary sounds, while ultrasonography identified lung abnormalities, including B-lines, consolidations, pleural effusion, and abscesses. Macroscopic post-mortem examinations confirmed lesion extent. Kendall–Tau-B correlation coefficient analysis revealed significant associations between the methods (p < 0.01), with a high correlation between auscultation and clinical scoring τ of 0.634 (95% CI: 0.489 to 0.765), auscultation and ultrasonography τ of 0.611 (95% CI: 0.500 to 0.710), and ultrasonography and post-mortem findings τ 0.608 (95% CI: 0.460 to 0.731). While auscultation and clinical scoring provided useful insights, ultrasonography exhibited superior sensitivity in detecting subclinical and early-stage lesions, aligning closely with post-mortem evaluations. These findings emphasize ultrasonography as an effective tool for diagnosing respiratory disease in lambs, improving diagnostic accuracy and enabling timely interventions to mitigate disease impact and reduce antimicrobial use. Full article

Background: Bovine respiratory syncytial virus (BRSV) is a major pathogen of the bovine respiratory disease complex and causes regular severe winter outbreaks of respiratory disease in cattle. It is therefore responsible for important economic losses for the farming industry. In this study, the genetic diversity of the circulating BRSV strains in Belgium, which has not been assessed since the end of the 1990s, was investigated. Methods: We analyzed 51 BRSV-positive samples collected from 2015 to 2023. This study is the first report on the circulation of BRSV subgroup VIII in Belgium. Furthermore, co-circulation of subgroups II and III was recorded in the same period. Four commercially available vaccine strains marketed in Belgium were also included in the analysis and they clustered with subgroup II or III. Results: Our findings indicate that different strains of BRSV are circulating in Belgium, including those from subgroups II and VIII, with the subgroup VIII strains being particularly distant from the commercially available vaccine strains. Conclusions: These results highlight the importance of ensuring that the available vaccines efficiently protect against strains from circulating subgroups and assessing the potential circulation of attenuated vaccine strains. Full article

Mycoplasma spp. are facultative pathogens that contribute to the pathogenesis of multiple bovine diseases, including the bovine respiratory disease complex, and have been shown to form biofilms. Biofilm formation is associated with increased antibiotic resistance in many organisms, but accurate determination of antimicrobial susceptibility in biofilms is challenging. In Mycoplasma spp., antimicrobial susceptibility is routinely determined using metabolic pH-dependent color change. However, biofilm formation can lead to reduced metabolism, making interpretation of metabolic readouts difficult. Therefore, we developed and optimized a new flow cytometry-based method for antimicrobial susceptibility testing in biofilm-forming Mycoplasma, termed the live/dead antimicrobial susceptibility test (LD-AST). The LD-AST measures the proportion of live bacteria upon exposure to antibiotics, works robustly with both planktonic and biofilm cultures, and enables the determination of the minimum bactericidal concentration (MBC) for a given antibiotic. We used two strains of Mycoplasma bovis (Donetta PG45 and Madison) and two clinical Mycoplasma bovoculi isolates (MVDL1 and MVDL2) to determine the impact of biofilm growth on antimicrobial susceptibility for gentamicin, enrofloxacin, or tetracycline. All Mycoplasma strains were susceptible to all antibiotics when cultured as planktonic cells, with MBCs in the expected range. However, three out of four strains (Donetta PG45, MVDL1, and MVDL2) were completely resistant to all three antibiotics when newly adhered biofilms were analyzed, whereas M. bovis Madison gave variable results. For mature biofilms that were cultured for 4–5 days before antibiotic exposure, results also were variable, with some strains showing an increased resistance with certain antibiotics and a decreased resistance with others. Overall, these results are consistent with earlier reports that biofilms can exhibit increased antimicrobial resistance. Full article

The bovine respiratory disease complex (BRD) is a multifactorial disease caused by various bacterial and viral pathogens. Using rapid pathogen detection techniques is helpful for tailoring therapeutic and preventive strategies in affected animals and herds. The objective of this study was to report the frequency of 10 pathogens by multiplex RT-qPCR on samples submitted for BRD diagnosis to a diagnostic laboratory (Biovet Inc., QC, Canada) in the Province of Quebec, Eastern Canada. From the 1st of January 2019 to the 31st of December 2023, a total of 1875 samples were analyzed. Most samples collected were individual samples (1547 of 1860 samples for which information was available (83.17%)), and the rest were from pooled samples of 2 (8.55%, n = 159) or ≥3 specimens (8.28%, n = 154). In 19.3% of the samples (n = 362), no pathogen was found, whereas 54.1% of samples had two or more different pathogens. Among the viruses, bovine coronavirus (BCV) was the most commonly found (27.5% of samples, n = 516), followed by bovine respiratory syncytial virus (BRSV) (17.7%, n = 332), whereas, for bacteria, Pasteurella multocida (50.1%, n = 940) and Mannheimia haemolytica (26.9%, n = 505) were the most common. The frequency of samples positive for Histophilus somni, Mycoplasmopsis bovis, influenza type D virus (IDV), bovine parainfluenza virus type 3 (BPI3V), bovine herpesvirus type 1 (BHV1), and bovine viral diarrhea virus (BVDV) was 22.6%, 22.4%, 4.6%, 4.3%, 2.7%, and 0.9%, respectively. In the multivariable Poisson regression model, the total number of pathogens increased with the number of animals in the pool, with an incidence risk ratio (IRR) of 1.15 (95% CI 1.02–1.29) and 1.32 (1.18–1.47) for 2 individuals in the pool and ≥3 individuals vs. individual samples, respectively. An increased number of pathogens were isolated in the winter season (IRR = 1.28 (95% CI 1.17–1.40)) compared to fall, and a lower number of pathogens were isolated in the summer compared to fall (IRR = 0.82 (95% CI 0.73–0.92)). These seasonal differences were mostly driven by the number of viruses isolated. This study gives interesting insights on the circulation of BRD pathogens in cattle from Eastern Canada. Full article

Influenza D virus (IDV) is a newly emerged zoonotic virus increasingly reported worldwide. Cattle are considered the main reservoir of IDV, although it was first isolated from pigs. IDV infects multiple animal species and contributes to the bovine respiratory disease complex (BRDC). To date, there has been no report on the presence and frequency of IDV among cattle herds in Pakistan. In this study, we collected nasal swabs from cattle and performed virological surveillance of IDV via qRT-PCR. Among 376 swab samples, IDV was detected in 9 samples (2.4%). Four dairy cattle farms were positive for IDV; two IDV-positive samples (two/nine, 22.2%) belonged to asymptomatic cattle, while seven IDV-positive samples (seven/nine, 77.8%) were from cattle showing respiratory clinical signs, including two with a recent history of abortion and mastitis. Partial sequences of the hemagglutinin–esterase-fusion gene of IDV were obtained from nine qRT-PCR-positive samples. Notably, all IDV strains in this study clustered within the D/OK lineages in phylogenetic analysis. A 98.8–99.6% genetic identity to its European and US counterparts indicates that the IDVs are closely related. The D/OK lineage of IDV was previously unreported in Pakistan. This is the first report of IDV in Pakistan. We confirmed that IDV is circulating among cattle herds in Pakistan. This study underscores the importance of virological surveillance to monitor the ecology of IDV for better animal and public health. The continued spread of IDV and its adaptation to various hosts necessitate further epidemiological studies. Full article

Bovine respiratory disease (BRD) is a multifactorial disease complex commonly affecting beef and dairy operations. Vaccination against major BRD-related pathogens is routinely performed for disease prevention; however, uniform reporting of health and performance outcomes is infrequent. Our objective was to evaluate the effect of commercially available BRD-pathogen vaccination on titer response with respect to health or performance in beef and dairy cattle. This study was conducted under Prisma 2020 guidelines for systematic reviews and PRESS guidelines utilizing five databases. Criteria for study inclusion were as follows: research conducted in the USA or Canada, between 1982 and 10 October 2022, on beef or dairy cattle, using a commercially available vaccine labeled for a respiratory pathogen of interest, which evaluated antibody titers alongside either performance or morbidity. A total of 3020 records underwent title and abstract evaluation. Full-text analysis was conducted on 466 reports; 101 studies were included in the final review. Approximately 74% of included studies were beef cattle-based versus 26% dairy cattle-based. This review aimed to assess how vaccination titer responses affect beef and dairy cattle health and performance, but varying study methods made comparisons difficult, highlighting the need for consistent reporting. Full article

Bovine respiratory disease (BRD) inflicts significant losses in cattle farming worldwide and is caused by the co-occurrence of various infectious agents which is often compounded by environmental factors. It is well known that microorganisms of the Mollicutes class are responsible for respiratory disorders in cattle, including BRD. This review highlights the current role of these microorganisms, in particular Mycoplasma bovis and Mycoplasma dispar, in the etiology of this disease complex, which has recently shifted toward a primary or predominant cause of the disease. Full article

Bovine respiratory syncytial virus (BRSV) is an economically important pathogen of cattle and contributes to the bovine respiratory disease complex (BRDC). Despite individual studies investigating BRSV prevalence, risk factors, and detection methodologies, a systematic review and meta-analysis have been lacking. The aim of the current study was to conduct a systematic review and meta-analysis to determine the prevalence and detection rate of BRSV and identify associated risk factors. Additionally, the study aimed to explore the variability in BRSV prevalence based on different detection methods and associated risk factors. Adhering to PRISMA guidelines, data from three databases—Web of Science, PubMed, and Scopus—were systematically retrieved, screened and extracted. Out of 2790 initial studies, 110 met the inclusion criteria. The study found that prevalence and detection rates varied based on the detection methods used (antibody, antigen, and nucleic acid), study populations, production systems, and geographic locations. Findings were reported as a pooled proportion. The pooled proportion, hereafter referred to as prevalence or detection rate, was determined by calculating the ratio of cattle that tested positive for BRSV to the total number of cattle tested. Key findings include a pooled prevalence of 0.62 for antibody-based methods, 0.05 for antigen-based methods, and 0.09 (adjusted to 0.03) for nucleic acid-based methods. Detection rates in BRDC cases also varied, with antibody methods showing a rate of 0.34, antigen methods 0.16, and nucleic acid methods 0.13. The certainty of evidence of the meta-analysis results, assessed using GRADE, was moderate for antibody detection methods and low for antigen and nucleic acid methods. The study identified significant risk factors and trends affecting BRSV prevalence, such as geographical location, herd size, age, and co-infections. The results of the current study showed the complexity of understanding BRSV prevalence in different settings. The variability in BRSV prevalence based on detection methods and associated risk factors, such as geographic location and herd size, highlights the need for tailored approaches to detect and manage BRSV accurately. Full article

Supplementing trace minerals is common in managing bovine respiratory disease (BRD) in post-weaned cattle; however, its influence on host immunity and metabolism in high-risk cattle remains unclear. We aimed to assess the impact of three supplementation programs on liver and serum trace element concentrations and blood gene expression. Fifty-six high-risk beef steers were randomly assigned to one of three groups over 60 days: (1) sulfate-sourced Cu, Co, Mn, and Zn (INR), (2) amino acid-complexed Cu, Mn, Co, and Zn (AAC), or (3) AAC plus trace mineral and vitamin drench (COMBO). Serum and liver biopsies for Cu, Co, Mn, and Zn at d0, d28, and d60 were analyzed from cattle free of BRD (n = 9 INR; n = 6 AAC; n = 10 COMBO). Differences and correlations of mineral concentrations were analyzed via generalized linear mixed models and Spearman’s rank coefficients, respectively (p < 0.05). Whole blood RNA samples from healthy cattle (n = 4 INR; n = 4 AAC; n = 4 COMBO) at d0, d13, d28, d45, and d60 were sequenced and analyzed for differentially expressed genes (DEGs) via glmmSeq (FDR < 0.05), edgeR (FDR < 0.10), and Trendy (p < 0.10). Serum and liver Cu and Co concentrations increased over time in all groups, with higher liver Cu in COMBO (487.985 μg/g) versus AAC (392.043 μg/g) at d60 (p = 0.013). Serum and liver Cu concentrations (ρ = 0.579, p = 6.59 × 10⁻⁸) and serum and liver Co concentrations (ρ = 0.466, p = 2.80 × 10⁻⁵) were linearly correlated. Minimal gene expression differences were found between AAC versus COMBO (n = 2 DEGs) and INR versus COMBO (n = 0 DEGs) over time. AAC versus INR revealed 107 DEGs (d13–d60) with increased traits in AAC including metabolism of carbohydrates/fat-soluble vitamins, antigen presentation, ATPase activity, and B- and T-cell activation, while osteoclast differentiation and neutrophil degranulation decreased in AAC compared to INR. Our study identifies gene expression differences in high-risk cattle fed inorganic or amino acid-complexed mineral supplements, revealing adaptive immune and metabolic mechanisms that may be improved by organically sourced supplementation. Full article

This study aimed to enhance our understanding of the agreement between two sampling methods for the detection of bovine respiratory disease (BRD) pathogens in calves using high-throughput real-time qPCR (ht-RT-qPCR). In total, 233 paired nasal swab (NS) and non-endoscopic bronchoalveolar lavage (nBAL) samples were collected from 152 calves from 12 Danish cattle herds. In 202 of the observations, the calves were examined using a standardized clinical protocol. Samples were tested for three viruses (bovine respiratory syncytial virus, bovine corona virus, and influenza D virus) and six bacteria (Histophilus somni, Mannheimia haemolytica, Mycoplasma bovis, Mycoplasma species, Pasteurella multocida, and Truepurella pyogenes). The results showed age-related differences in disease and pathogen occurrence, with the highest detection rates in calves aged 35 days or older. Poor to moderate agreement was found between the NS and nBAL results. The presence of Mannheimia haemolytica in both NS and nBAL in younger calves and in nBAL in older calves was associated with clinical BRD. There was a potential link between BRD and influenza D virus in older calves, although it was only found in one herd in a small sample size. Overall, NS was a relatively poor predictor of pathogens in the lower respiratory tract. The present study confirms the complexity of pathogen detection in BRD, with marked influences of age and the sampling method on pathogen detection and disease associations. Full article

Bovine respiratory disease complex, a complex respiratory ailment in cattle, results from a combination of viral and bacterial factors, compounded by environmental stressors such as overcrowding, transportation, and adverse weather conditions. Its impact extends beyond mere health concerns, posing significant economic threats to the cattle industry. This study presents an extensive investigation into viral pathogens associated with BRDC in Serbian cattle, utilizing serum samples and nasal swabs. A cross-sectional study was conducted in 2024 across 65 randomly selected dairy farms in Serbia, excluding farms with vaccinated cattle. The farms were categorized by their livestock count: small (≤50 animals), medium (51–200 animals), and large (>200 animals). Serum samples from adult cattle older than 24 months were tested for antibodies against BVDV, BHV-1, BRSV, and BPIV3. Nasal swab samples from the animals with respiratory signs were tested using PCR for viral genome detection. The results showed seropositivity for all four viruses across all of the farms, with BPIV3 exhibiting universal seropositivity. Medium-sized and large farms demonstrated higher levels of seropositivity for BRSV and BHV-1 compared to small farms (p < 0.05). Our true seroprevalence estimates at the animal level were 84.29% for BRSV, 54.08% for BVDV, 90.61% for BHV-1, and 84.59% for BPIV3. A PCR analysis of the nasal swabs revealed positive detections for BRSV (20%), BHV-1 (1.7%), BVDV (8%), and BPIV3 (10.9%). Influenza D virus was not found in any of the samples. This study provides critical insights into the prevalence and circulation of viral pathogens associated with BRDC in Serbian cattle, emphasizing the importance of surveillance and control measures to mitigate the impact of respiratory diseases in cattle populations. Full article

Bovine parainfluenza virus type 3 (BPIV-3) is one of the major pathogens of the bovine respiratory disease complex (BRDC). BPIV-3 surveillance in China has been quite limited. In this study, we used PCR to test 302 cattle in China, and found that the positive rate was 4.64% and the herd-level positive rate was 13.16%. Six BPIV-3C strains were isolated and confirmed by electron microscopy, and their titers were determined. Three were sequenced by next-generation sequencing (NGS). Phylogenetic analyses showed that all isolates were most closely related to strain NX49 from Ningxia; the genetic diversity of genotype C strains was lower than strains of genotypes A and B; the HN, P, and N genes were more suitable for genotyping and evolutionary analyses of BPIV-3. Protein variation analyses showed that all isolates had mutations at amino acid sites in the proteins HN, M, F, and L. Genetic recombination analyses provided evidence for homologous recombination of BPIV-3 of bovine origin. The virulence experiment indicated that strain Hubei-03 had the highest pathogenicity and could be used as a vaccine candidate. These findings apply an important basis for the precise control of BPIV-3 in China. Full article