it turns out that this 2009 h1n1 began
circulating in pigs in 1918 at the same
time the 1918 influenza virus outbreak
was occurring in humans but because
these two viruses were in different
hosts they evolved differently so they
both have a common ancestor going back
to 1918 but because the swine h1n1 was
in pigs it evolved differently from
human h1n1 and now that swine h1n1 is
basically a new virus to humans and
pre-existing immunity we have two
seasonal h1n1 doesn't really protect the
significant from it whales and seals
both carry particular strains of
influenza horses carry influenza virus
strains and recently dogs have become a
significant source of influenza virus
infection the new flu is a virus
particle is roughly round in shape it
has a couple of protrusions coming off
of it in two different shapes one that's
more of a spike in one of more of a
propeller shape eh spike is used to
enter a cell and the other the end spike
that we always refer to is used to
actually get away from a cell anywhere
from nine to twelve hours later the
surface of that cell starts to form
little bubbles in those bubbles our new
virus particles coming off for about
three to four hours that cell will be
able to make infectious virus particles
and it can make anywhere from ten
thousand to nearly a million virus
particles depending on the cell type
so if you're immune to infection with
influenza that means that you had
antibodies that will bind to the virus
particle and keep that virus particle
from interacting with the cell