00:01
Okay, let's go in order.
00:04
Hepatitis A is a single
stranded RNA hepatovirus.
00:08
The transmission
route is fecal-oral,
doesn't sound very pleasant,
but that's what it is,
contaminated food or water
that has come from feces.
00:19
Typically, in every case,
it is a self limited to disease.
00:24
In most cases,
it comes and goes
in about two months,
and it has a very low
morbidity mortality,
much less than 1%.
00:33
And when it does have
mortality or morbidity,
it's in the adult population.
00:39
There is no carrier state
for all intensive purposes,
almost everybody,
virtually everyone who gets
infected with hepatitis A
will develop a good immune
response to it and clear it.
00:51
New infections are
characterized by having IgM
against the hepatitis
A virus or HIV.
00:58
If you've had a prior infection,
a long time ago, or
a couple months ago,
then you will have IgG.
01:04
So that's one way that we can
tell whether you have a brand new
hepatitis A infection,
or you've had one in the past.
01:11
Vaccines are available
because it has such a low risk
of causing mortality
or morbidity.
01:18
And patients do
really well with this.
01:21
Vaccines are not
typically administered.
01:25
This schematic we're gonna see
in some form over
and over again,
for all five of the
different hepatitis viruses.
01:32
And this is just showing you
from the point of infection,
which is always going
to be times zero,
through the subsequent course,
when the various
manifestations occur.
01:44
So for example,
in Hepatitis A infection,
we can detect
relatively early on RNA,
either in the feces
or in the serum
indicating that we have
an active infection.
01:56
That amount of virus
actually precedes
any injury to the hepatocytes.
02:01
That's when we see
a relative spike
in ALT and AST and other enzymes
that the hepatocytes
normally make.
02:10
That will be transient
over the course
of maybe a month or more.
02:15
That goes up and comes down
as the body makes a
specific immune response.
02:19
And it begins with
a T-cell response,
but then it's also
coordinated with
development of IgM antibodies,
and eventually a
maturation of the response
to give you a
chronic IgG serology.
02:32
So that you will have now
chronic protection
forever and ever and ever,
to any subsequent
exposure in Hepatitis A.