Influenza is a largely species-specific infection, but the threat of zoonotic potential is real. Virulence varies between strains, but all are spread by aerosol routes. They are typified by rhinitis, pyrexia, and anemia. Flu presents a particular challenge to vaccination as antigenic drift within the virus means that strains can vary from one year to the next. As such, vaccine produced from this year's virus may not give protection against next year's virus. | Influenza is a largely species-specific infection, but the threat of zoonotic potential is real. Virulence varies between strains, but all are spread by aerosol routes. They are typified by rhinitis, pyrexia, and anemia. Flu presents a particular challenge to vaccination as antigenic drift within the virus means that strains can vary from one year to the next. As such, vaccine produced from this year's virus may not give protection against next year's virus. |