Feral swine could serve as a reservoir of influenza A virus or potentially represent a spatially dynamic "mixing vessel" given their free-ranging habits.Here we studied the dynamics of virus shedding and antibody responses of influenza infections in feral swine.A total of 12 influenza negative feral pigs were separated into INFECTION (8 pigs) and SENTINEL (4 pigs) groups.Each INFECTION pig was infected with 10^6 TCID50 of A/swine/Texas/A011040013/2012 (H3N2) ; the SENTINEL pigs were housed in three pens with at least 5 feet away from the INFECTION pigs in the same room.The INFECTION pigs shed viruses until 6 Days Post Infection (DPI) ,and the viral titers peaked at 4 DPI; in the SENTINEL group,one pig shed virus from 1 to 10 DPI whereas the other three shed viruses on 7 or 8 DPI and lasted from 1 to 4 days.The INFECTION pigs were seroconverted at 8 DPI and the SENTINEL pigs 11 DPI.Their antibody titers peaked 14 DPI (from 1∶1280 to 1∶2560) ,began to drop at 28 DPI,reached the lowest level (from 1∶80 to 1∶320) at 56 DPI,and remained similar.On 104 DPI the pigs were re-infected with the same virus.After reinfection,about half of the pigs were influenza positive.The swine nasal wash samples were sequenced,and the genome wide mutations will be discussed in the context of innate and humoral immunity,respectively.In conclusion,H3N2 influenza A virus can infect and be easily transmitted in feral swine,and the antibody level in feral swine can last at least three months,presenting the challenges in influenza diagnosis and driving forces for viral evolution.