INFLUENZA VIRUS INFECTION IN PIGS

Influenza A virus is a zoonotic agent of great relevance to human and animal health. Swine is an important host to the dynamics and epidemiology of the infection due to its susceptibility to viruses of both the avian and mammalian virus lineages. The great genetic variability of influenza viruses is caused by two main genetic mechanisms: point mutations and gene reassortment. The latter, by letting the exchange of gene segments between two different influenza viruses infecting the same cell, allows a rapid evolution of influenza viruses and the emergence of reassortant viruses against which there is no immunity in the host (human or animal). Influenza is endemic in pigs in many countries and the emergence of new viruses has been challenging its control and diagnostics. Although infections with influenza A virus (IAV) are endemic in most of the pork producing countries throughout the world, in Brazil this pathogen has not received much attention. Since the emergence of the 2009 pandemic H1N1 influenza virus in pigs (H1N1pdm09), many outbreaks of respiratory disease were observed in Brazilian swine populations. Currently, in Brazil, H1N1, H3N2 and 2009 pandemic H1N1 (A(H1N1)pdm09) influenza A viruses (IAVs) circulate in domestic swine herds. DOI:  http://dx.doi.org/10.17525/vrrjournal.v18i1-2.91