Porcine circovirus type 2 (PCV2) and influenza A virus (IAV) are important pathogens in the swine industry, with economic significance to pork producers worldwide. The pathogenesis of PCV2/IAV co-infection and any synergistic effects between these two viruses is unknown. The objectives of this research were to determine 1) if IAV (H1N1) infection could initiate clinically significant porcine circovirus associated respiratory disease (PCVAD-respiratory) in pigs subclinical infected with PCV2b; and 2) if pre-existing, subclinical PCV2b infection affected the duration and severity of a subsequent IAV (H1N1) infection. When compared to pigs infected with IAV or PCV2b alone, dual-infected pigs (PCV2b+IAV (H1N1) had more severe clinical respiratory signs (increased respiratory effort, cough) which persisted longer; had an increased number of IAV genomic copies shed in nasal secretions and the duration of shedding was prolonged and had increased levels of PCV2b in serum for approximately 10 days following IAV inoculation. Two (of 10) dual-infected pigs developed clinical signs and lesions of severe PCVAD, including wasting, marked pulmonary disease with pleural and peritoneal effusion and diffuse lymphadenopathy. PCV2b only-infected pigs had reduced body weight and decreased average daily gain. Based on these results, we conclude that, under the conditions of this study, IAV infection in pigs subclinically infected with PCV2b, results in increased shedding (both amount and duration) of IAV; a transient increase in circulating PCV2; and induction of severe, clinical signs and lesions of PCVAD in 20% of PCV2b-infected pigs. Influenza virus should be considered as another contributing factor for PCVAD when the IAV infection occurs in pigs subclinically infected with PCV2b.
Vladimir K Sologub has completed his PhD at AllUnion Institute of Expemental Veterinary in 1979. He is the Head of the Laboratory of Hybridoma Technology of Russian Research Center of Molecular Diagnostic, a premier research organization. He has published more than 55 papers in reputed journals.
Traditional classic diagnostics of Rabies Virus infection is based on immunological detection of the virus antigens by Immunofluorescence (IF) with FITC-conjugate of anti-RNP polyclonal Ab’s or Mab’s-“gold standard”. Some more attractive methods like ELISA and Immunochromatography (IC) are now under investigation for practical diagnostics and research applications. The Mab’s for the new methods are probably not the same as for old IF. In our panels of anti-Rabies virus Mab’s there are several candidates for ELISA sandwich test-systems and other methods. Their anti-RNP and anti-G specificity was determined by virus neutralisation test and competition ELISA with standard probes. Two ovine Mab’s from mouse x sheep xeno-hybridomas (1E8ov and 2E12ov) and one mouse Mab (1E9) were active in immuno diffusion (ID) with mouse brain or cell culture virus antigen. One Mab (5B12) was negative in ID but perfect in cell based ELISA and IF for the virus plaque detection in BHK-21 cells. And one Mab (4G4) was negative in ID and IF but produced a very sensitive sandwich ELISA for the soluble antigen as capture Mab and Mab-HRP-conjugate. Neutralizing activity was detected for 4 mouse (4F1,7E3, 5B7 and 9A10) and 4 ovine (4B11ov,3F4ov, 1A4ov, 13-3ov) Mab’s. Combinations of mouse Mab’s with ovine Mab’s and anti-ovine IgG mouse Mab’s allows to create sensitive systems for the detection of different forms of Rabies Virus RNP. and G antigens.