Localization of Classical Swine Fever Virus from Chronically Infected Pigs by In Situ Hybridization and Immunohistochemistry

Abstract

Abstract. Classical swine fever (CSF) virus (CSFV) nucleic acid and antigen were detected in 15 pigs with naturally occurring chronic CSF by in situ hybridization and immunohistochemistry. The most consistent and prominent microscopic lesions were perivascular mononuclear cell infiltration and gliosis in the central nervous system of pigs with chronic CSF. Positive cells typically exhibited a dark brown (in situ hybridization) or red (immunohistochemistry) reaction product in the cytoplasm without background staining. A positive signal for both in situ hybridization and immunohistochemistry was detected in mononuclear cells and lymphocytes of lymphoid tissues. Viral nucleic acid was detected in some tissue sections in the absence of viral antigen. The in situ hybridization technique developed in this study was useful for the detection of CSFV RNA in tissues taken from chronically infected pigs and may be a valuable technique for studying the pathogenesis of chronic CSFV infection.

Npro of classical swine fever virus contributes to pathogenicity in pigs by preventing type I interferon induction at local replication sites

“…Moreover, pigs inoculated with the virus carrying functional N pro in the triple mutant virus (vGPE - /N136D; T830A; V2475A; A2563V) showed a longer course of viremia than pigs infected with the parental END - triple mutant virus. Several reports suggested a role for the IRF3-degrading function of N pro in persistent infection in vascular endothelial cells [26], and in mononuclear cells and lymphocytes of lymph node cells, splenocytes and gut-associated lymphoid tissue cells [27,28]. Meyers et al suggested that N pro and E rns of bovine viral diarrhea virus are involved in establishing persistence after trans-placental infection in vivo [29].…”

Necrotising lymphadenitis associated with porcine circovirus type 2 in pigs

“…Immunohistochemistry for PCV-2, classical swine fever virus (CSFV) and porcine reproductive and respiratory virus (PRRSV) was carried out using monoclonal mouse anti-CSFV antibody (WH303), monoclonal mouse anti-PCV-2 antibody and monoclonal mouse anti-PRRSV antibody (SDOW17) as described by Cheon and Chae (1999) and Choi and Chae (2003). In situ terminal deoxynucleotidyl transferase-mediated dUTP-biotin nicked end labelling (TUNEL) was also carried out to detect apoptotic markers as described by Choi and Chae (2002).…”

Classical Swine Fever Virus Detection in Fetal Swine Tissues by Immunohistochemistry

“…Th e availability of reliable diagnostic tests is crucial for eff ective CSF control, and diff erent diagnostic laboratory test procedures for confi rmation of the viral antigen presence are available. Among them, immunohistochemistry proved to be a very reliable and suitable method for viral antigen detection in tissue samples, as well as for studying the pathogenesis of both natural and experimental CSFV infections (Belák et al, 2008;Polaček et al, 2007;2016;Sánchez-Cordon et al, 2003;Choi and Chae, 2003a;De las Mulas et al, 1997). Besides that, the importance of diagnostic IHC is further emphasized by the observation of Belák et al, (2008) where this test gave positive results long (even seven days) before the appearance of the fi rst clinical symptoms.…”

“…CSF viral distribution in diff erent tissues depends on strains of the virus (highly, moderately or low virulent strain), age of pigs, duration of infection, and susceptibility of the breed (Choi and Chae, 2003a). Th e immunohistochemical detection of CSFV antigen in tissues of both naturally and experimentally infected pigs over time is well , 1997).…”