Roman Pogranichniy
Purdue University, USA
Title: Concurrent swine influenza A virus type H1N1 and porcine circovirus type 2b (PCV2b) infection in caesarean-derived and colostrum-deprived (CD/CD) pigs
Biography
Biography: Roman Pogranichniy
Abstract
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.