The Origin Of Swine Influenza Viruses Isolated From Mainland China Between1979-1992

Swine influenza viruses (SIVs) belong to the family of Orthomyxoviridae influenza viruses, causing acute, febrile and respiratory diseases which are contagious via intimate contact in pigs and bring serious losses to the pig industry. Since pig can be a common intermediate host for both of the human and avian influenza viruses, the swine influenza surveillance is significant in public health. China always has high incidence of influenza. SIVs surveillance was conducted in southern China since1998. However, sequences of SIVs which isolated from mianland China before1998were absent at GenBank. And also their evolution information is insufficient. Therefore, fill this blank has a great significant on exploring evolution pattern of SIVs.The purpose of the projectBy studying the evolutionary history of SIVs, a more in-depth understanding of the evolutionary behavior might be provided as a reference for the prevention and control of influenza pandemic.The main contents of the projectChina National Influenza Centre has been insisting on swine influenza surveillance and isolated19H1N1subtype and11H3N2subtype of SIVs from mainland China between1979-1992. Though whole-genome sequencing and antigenic characteristics analysis of these strains, we presumed the evolution pattern of SIVs in China and analyzed the molecular characteristics and antigenic drift degree of these viruses.The main results of the subject1. We speculated that the first classical SIVs reported in Mainland China might have been introduced by imported pigs from North America.2. All these11H3N2subtype SIVs isolates presumably be introduced into pigs by interspecies transmission from human.