COUNTERMEASURES TO PREVENT THE PORCINE RESPIRATORY DISEASE COMPLEX (PRDC)
Location: Virus and Prion Research Unit
Title: Coinfection of Pigs with Swine Influenza Virus and Bordetella bronchiseptica
Submitted to: United States Japan Natural Resources Animal and Avian Health Panel
Publication Type: Abstract Only
Publication Acceptance Date: November 15, 2007
Publication Date: December 5, 2007
Citation: Brockmeier, S., Vincent, A.L., Nicholson, T.L., Sacco, R.E., Palmer, M.V. 2007. Coinfection of Pigs with Swine Influenza Virus and Bordetella bronchiseptica [abstract]. In: United States Japan Natural Resources Animal and Avian Health Panel, December 5, 2007, Tsukuba, Japan. p. 25.
Coinfection with two or more pathogens is a common occurrence in respiratory diseases of most species. The manner in which these pathogens interact is not always straightforward, however. Bordetella bronchiseptica and swine influenza virus (SIV) are respiratory pathogens of pigs whose relatives, B. pertussis and human influenza viruses, cause respiratory disease in humans. The effect of coinfection of SIV and B. bronchiseptica was examined in thirty-six, 4-week-old pigs (12 pigs per group) that were infected with SIV, B. bronchiseptica, or SIV and B. bronchiseptica. An additional 12 pigs served as sham infected controls. Four pigs from each group were euthanized at 1, 5 and 10 days post infection. There was no difference in the frequency or amount of SIV isolated from the nasal cavity, trachea, or lung of pigs infected with SIV alone or coinfected with SIV and B. bronchiseptica. However, there was a significantly greater amount of B. bronchiseptica isolated from coinfected pigs compared to pigs challenged with B. bronchiseptica alone from the nasal cavity late in the experiment (day 8 to 10 after challenge), and from both the trachea and lung at day 1 and day 10 after challenge. Lung lesions in the coinfected pigs were more severe on day 1 and 10 after challenge, as compared to pigs infected with SIV or B. bronchiseptica alone, as well. The differences in colonization and lung lesions were not seen on day 5 after challenge. An increase in type I interferon and proinflammatory cytokine transcription was detected by real-time, RT-PCR in the lung of coinfected pigs compared to any of the other groups on day 1 after infection. Thus, there appears to be a synergistic effect between SIV and B. bronchiseptica both in the prodromal and convalescent phases of infection, which may indicate an alteration of the innate and adaptive immune response to these pathogens.