Abstract
BackgroundSwine influenza (SI) is a contagious, important respiratory disease. Diagnosis of SI is based on the clinical signs, confirmed by the detection of viral RNA or specific antibodies. However, the infection is much more frequent than the disease.ObjectivesThe aim of study was to investigate the kinetics of acute-phase protein (APP) response during subclinical and clinical influenza in pigs. The utility of APP measurements in identification of infected animals was also evaluated.MethodsTwenty-eight piglets were used. C-reactive protein (CRP), haptoglobin (Hp), serum amyloid A (SAA) and pig major acute-phase protein (Pig-MAP) concentrations in serum were measured using commercial ELISAs.Results and ConclusionsNo relevant clinical signs were observed in intranasally infected pigs. In contrast, coughing, nasal discharge, and fever were observed in pigs infected intratracheally. All infected pigs exhibited specific antibodies in the serum at 10 dpi, and viral shedding was confirmed. The concentrations of CRP, Hp and SAA were significantly increased after infection. The level of Pig-MAP remained constant during subclinical and clinical infection. The concentrations of CRP, Hp and SAA were higher in pigs with clinical disease. Although not specific, strategic APP measurements may reveal ongoing clinical and subclinical infection. A close relationship between the magnitude of serum APP response with the severity of disease, providing an objective tool for validation the severity of infection. The maximum concentration of SAA in serum was closely correlated with lung score and makes this APP potential indicator for disease progress or estimation of treatment strategy.
Highlights
The acute-phase response is an innate, non-specific immune response which occurs after many different stimuli such as infections, tissue damage, neoplastic growth, or immunological disorders.[1,2,3,4] The innate immune response induced by viral infection in the upper respiratory tract is characterized by activation of peripheral primary effector cells that function to initiate a local inflammatory response and recruiting activators of the cellular immune response.[5]
Swine influenza (SI) is a highly contagious, important respiratory disease, and the main causative viruses are H1N1, H3N2, and H1N2.9–12 Typical SI outbreaks are characterized by a rapid onset of high fever, loss of appetite, labored abdominal breathing, and coughing.[9,10]
Coughing, sneezing, nasal discharge, and fever were observed in all ITinfected piglets
Summary
The acute-phase response is an innate, non-specific immune response which occurs after many different stimuli such as infections, tissue damage, neoplastic growth, or immunological disorders.[1,2,3,4] The innate immune response induced by viral infection in the upper respiratory tract is characterized by activation of peripheral primary effector cells that function to initiate a local inflammatory response and recruiting activators of the cellular immune response.[5]. Swine influenza (SI) is a highly contagious, important respiratory disease, and the main causative viruses are H1N1, H3N2, and H1N2.9–12 Typical SI outbreaks are characterized by a rapid onset of high fever, loss of appetite, labored abdominal breathing, and coughing.[9,10] Diagnosis of SI infection is currently based on the observation of clinical signs, confirmed by the identification of the infectious agent (PCR, isolation). Infection with swine influenza virus (SIV) is frequently subclinical, and typical signs are often demonstrated in only 25–30% of a herd.[13,14] Whereas the APP response has been documented for a range of clinical infections, the potential uses of APP for recognition of subclinical infection still remain to be established. Swine influenza (SI) is a contagious, important respiratory disease.
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