Acute phase protein changes in calves during an outbreak of respiratory disease caused by bovine respiratory syncytial virus.
ABSTRACT Bovine acute phase proteins (APPs), lipopolysaccharide binding protein (LBP), serum amyloid A (SAA), haptoglobin (Hp) and alpha(1)-acid glycoprotein (AGP) were evaluated as inflammatory markers during an outbreak of bovine respiratory disease (BRD) caused by bovine respiratory syncytial virus (BRSV). Calves (n = 10) presented mild to moderate signs of respiratory disease. Secondary bacterial infections, Pasteurella multocida and Mycoplasma dispar as major species, were detected in tracheobronchial lavage samples. Concentrations of SAA and LBP increased at week 1 had the highest values at week 3 and decreased at week 4 of outbreak. Some calves had high Hp concentrations at week 3, but AGP concentrations did not rise during respiratory disease. Higher SAA, LBP and Hp concentrations at a later stage of BRD (week 3) were associated with the low BRSV-specific IgG(1) production, suggesting that these calves had enhanced inflammatory response to the secondary bacterial infection. In conclusion, APPs (especially SAA and LBP) are sensitive markers of respiratory infection, and they may be useful to explore host response to the respiratory infections in clinical research.
- SourceAvailable from: Pedro Jose Sanchez-Cordon[Show abstract] [Hide abstract]
ABSTRACT: Acute infections with bovine viral diarrhoea virus (BVDV), a major pathogen of cattle, are often asymptomatic or produce only mild clinical symptoms. However, they may play an important role in the bovine respiratory disease complex by exerting a marked immunosuppressive effect, as a result of the death of the immunocompetent cell populations involved in controlling innate and adaptive immune responses, together with a marked reduction of both cytokine expression and co-stimulatory molecule synthesis. Although experimental research and field studies have shown that acute BVDV infection enhances susceptibility to secondary infection, the precise mechanism involved in BVDV-induced immunosuppression remains unclear. The present study is aimed at measuring a range of blood parameters in a single group of fourteen calves infected with non-cytopathic BVDV-1. Focus has been put on those related to the cell-mediated immune response just as leucocyte populations and lymphocyte subpopulations, serum concentrations of cytokines (IL-1β, TNF-α, IFN-γ, IL-12, IL-4 and IL-10) and acute phase proteins [haptoglobin, serum amyloid A (SAA), fibrinogen and albumin], as well as BVDV-specific antibodies and viremia. After non-cytopathic BVDV-1 infection, clinical signs intensity was never more than moderate coinciding with the presence of viremia and leucocyte and lymphocyte depletion. An early increase in TNF-α, IFN-γ and IL-12 levels in contrast to IL-1β was observed in line with a raise in haptoglobin and SAA levels on the latest days of the study. As regards IL-4 levels, no evidence was found of any changes. However, a slight increase in IL-10 was observed, matching up the TNF-α decline during the acute phase response. These findings would help to increase our knowledge of the immune mechanisms involved in acute infection with non-cytopathic BVDV-1 strains, suggesting the existence of a clear tendency towards a type 1 immune response, thereby enhancing resistance against viral infections.Transboundary and Emerging Diseases 09/2012; · 2.10 Impact Factor
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ABSTRACT: Objective-To determine the association of CBC variables and castration status at the time of arrival at a research facility with the risk of development of bovine respiratory disease (BRD). Design-Retrospective cohort study. Animals-1,179 crossbred beef bull (n = 588) and steer (591) calves included in 4 experiments at 2 University of Arkansas research facilities. Procedures-Calves underwent processing and treatments in accordance with the experiment in which they were enrolled. Castration status and values of CBC variables were determined at the time of arrival at the facilities. Calves were monitored to detect signs of BRD during a 42-day period. Results-The areas under the receiving operator characteristic curves for CBC variables with significant contrast test results ranged from 0.51 (neutrophil count) to 0.67 (eosinophil count), indicating they were limited predictors of BRD in calves. The only CBC variables that had significant associations with BRD in calves as determined via multivariable logistic regression analysis were eosinophil and RBC counts. The odds of BRD for bulls were 3.32 times the odds of BRD for steers. Conclusions and Clinical Relevance-Results of this study indicated that low eosinophil and high RBC counts in blood samples may be useful for identification of calves with a high risk for development of BRD. Further research may be warranted to validate these variables for prediction of BRD in calves. Calves that were bulls at the time of arrival had a higher risk of BRD, versus calves that were steers at that time.Journal of the American Veterinary Medical Association 10/2013; 243(7):1035-41. · 1.72 Impact Factor
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ABSTRACT: Chlamydia (C.) psittaci is the causative agent of psittacosis, a zoonotic disease in birds and man. In addition, C. psittaci has been repeatedly found in domestic animals and is, at least in calves, also able to induce respiratory disease. Knowledge about transmission routes in cattle herds is still deficient, and nothing is known about differences in host response after either experimental or natural exposure to C. psittaci. Therefore, our recently developed respiratory infection model was exploited to evaluate (i) the presence of the pathogen in blood, excretions and air, (ii) the possibility of transmission and (iii) clinical symptoms, acute phase and immune response until 5 weeks after exposure. In this prospective study, intrabronchial inoculation of 10(8) inclusion-forming units of C. psittaci (n = 21 calves) led to reproducible acute respiratory illness (of approximately one week), accompanied by a systemic inflammatory reaction with an innate immune response dominated by neutrophils. Excretion and/or exhalation of the pathogen was sufficient to transmit the infection to naïve sentinel calves (n = 3) co-housed with the infected animals. Sentinel calves developed mild to subclinical infections only. Notably, excretion of the pathogen, predominantly via feces, occurred more frequently in animals naturally exposed to C. psittaci (i.e. sentinels) as compared to experimentally-inoculated calves. The humoral immune response was generally weak, and did not emerge regularly following experimental infection; however, it was largely absent after naturally acquired infection.PLoS ONE 01/2013; 8(5):e64066. · 3.73 Impact Factor