Objective—To determine serum concentrations of the selected acute-phase proteins (APPs) haptoglobin, serum amyloid A (SAA), and C-reactive protein (CRP) in pigs experimentally inoculated with classical swine fever (CSF) and African swine fever (ASF) viruses.
Animals—8 crossbred (Large White × Landrace) 10-week-old pigs.
Procedures—Pigs were allocated to 2 groups (4 pigs/group). One group was inoculated with the CSF virus Alfort 187 strain, whereas the other groupwas inoculated with the ASF virus Spain 70 isolate. Blood samples were collected at various time points. At the end of the study, pigs were euthanized and a complete necropsy was performed, including histologic and immunohistochemical analyses.
Results—Serum concentrations of APPs increased in pigs inoculated with CSF and ASF viruses, which suggested an acute-phase response in the course of both diseases. The most noticeable increase in concentration was recorded for SAA in both groups (up to a 300-fold increase for CSF virus and an approx 40-fold increase for ASF virus), followed by CRP and then haptoglobin, which each had only 3- to 4-fold increases.
Conclusions and Clinical Relevance—Serum concentrations of APPs increased significantly in pigs inoculated with CSF and ASF viruses. However, differences were evident in serum concentrations of the proteins evaluated in this study.
Objective—To compare pathological changes and viral antigen distribution in tissues of calves with and without preexisting subclinical bovine viral diarrhea virus (BVDV) infection following challenge with bovine herpesvirus-1 (BHV-1).
Animals—24 Friesian calves.
Procedures—12 calves were inoculated intranasally with noncytopathic BVDV-1a; 12 days later, 10 of these calves were challenged intranasally with BHV-1 subtype 1. Two calves were euthanized before and 1, 2, 4, 7, or 14 days after BHV-1 inoculation. Another 10 calves were inoculated intranasally with BHV-1 only and euthanized 1, 2, 4, 7, or 14 days later. Two calves were inoculated intranasally with virus-free tissue culture fluid and euthanized as negative controls. Pathological changes and viral antigen distribution in various tissue samples from calves with and without BVDV infection (all of which had been experimentally inoculated with BHV-1) were compared.
Results—Following BHV-1 challenge, calves with preexisting subclinical BVDV infection had earlier development of more severe inflammatory processes and, consequently, more severe tissue lesions (limited to lymphoid tissues and respiratory and digestive tracts) and greater dissemination of BHV-1, compared with calves without preexisting BVDV infection. Moreover, coinfected calves had an intense lymphoid depletion in the Peyer patches of the ileum as well as the persistence of BVDV in target organs and the reappearance of digestive tract changes during disease progression.
Conclusions and Clinical Relevance—In calves, preexisting infection with BVDV facilitated the establishment of BHV-1 infection, just as the presence of BHV-1 favors BVDV persistence, thereby synergistically potentiating effects of both viruses and increasing the severity of the resultant clinical signs.