Okay, moving on to our fourth herpes
virus, Epstein-Barr virus,
This is transmitted in multiple ways.
Through direct contact with saliva,
through aerosolization of
close contact with anything.
Also via transfusions, if a
blood donor was
actively infected with Epstein-Barr virus,
certainly the same thing with
a solid organ transplant.
There can be congenital transmission,
and pretty much any body fluid.
Because Epstein-Barr virus targets
B lymphocytes, which you see
on the image in front of you.
All those are lymphocytes,
not necessarily actively infected
with Epstein-Barr virus,
but they at least are the proper target.
You may hear infectious mononucleosis
caused by EBV, named
the "kissing disease." It kind of says it all.
Epstein-Barr virus targets its B lymphocyte
starting in the oropharynx, again, because
many of these exposures will occur
through the oral mucosa mechanism.
And from the oropharynx, then you get
progression to and through saliva
into lymphoid tissue,
typically starting in the tonsils,
in the pharynx.
And that's important because, as we'll see,
one of the clinical symptoms with
is a pharyngitis, a sore throat.
Then we have production --
the Epstein-Barr virus is achieving
latency in those lymphocytes,
we have production of immunoglobulin M
eterophile, meaning multiple forms,
is because the lymphocytes are confused.
B lymphocytes produce immunoglobulin M
and progressing to immunoglobulin G.
The immunoglobulin M is supposed
to be specific
to the infecting organism,
but because these cells are being
disrupted by EBV pathology,
they're producing immunoglobulin
M antibodies which may target
anything and everything.
But they can be detected by a test,
as we'll see very shortly.
As the Epstein-Barr virus achieves its
latency, its quietness in the B lymphocytes,
it persists there for life,
which unfortunately means that those
B cells can undergo increased
turn over, increase mitoses
And any proliferation, especially of
a red blood cell or, in this case, a
white blood cell can cause a
So Epstein-Barr virus,
infectious mononucleosis, also highly
associated with malignancies.
So, let's look at our 2 most common
diseases side by side.
Mononucleosis compared to
hairy oral leukoplakia.
Patients at risk for mononucleosis,
classically, are teenagers,
and also young adults, but anybody and
everybody can be infected with
Epstein-Barr virus at any age.
by young adulthood, most say,
25, 26 years of age,
60% of us have been infected
with Epstein-Barr virus,
but we may not know it because it can cause
a completely asymptomatic diseases.
So, teens and young adults, though,
are the classic targets for
The incubation period is up to 2 months.
This is again, it's a very slow
process, which is
great for the incubation to take that long,
but not so great because the disease
lasts similarly, very long.
Hairy oral leukoplakia is a
problem for those patients who
and classically those patients with HIV/AIDS
because they've lost their suppressor
function with the
T lymphocyte, the CD4 T lymphocyte,
and thus, those proliferating B lymphocytes
can get out of control
and cause many things, including
Clinical manifestations for infectious
lassically, we have the exudative
pharyngitis. It looks,
smells, and feels, for all of the world,
like streptococcal pharyngitis,
but the testing for group A
strep is negative.
The other parts of the infectious
are pronounced cervical or, in fact,
posterior cervical lymphadenopathy,
so toward the back of the neck.
These patients come in with what's
called a bowl neck,
a thick neck which looks like
the neck of a bowl.
And that, along with sore throat
or pharyngitis and
palpable splenomegaly, is screaming the
diagnosis infectious mononucleosis.
It makes sense because Epstein-Barr virus
targets B lymphocytes, and
where do they live?
The lymph nodes, the spleen,
nd they came in through the tonsils
in the back of the throat.
Patients with this triad
all have extreme fatigue.
And anybody who has suffered from this,
you have my deepest sympathies.
It may take days to weeks to months
to get out of bed.
We're talking completely flattened.
Along with that fever, headache,
if the patients receive ampicillin
classically, they'll develop discrete
erythematous papular rash.
In fact, that used to be the way that
we diagnose Epstein-Barr virus
prior to having our serologic testing.
We just gave them some amoxicillin
and see if a rash developed.
There was an 80% attack rate with
giving ampicillin or amoxicillin
to a patient with Epstein-Barr
virus to elicit that rash.
As I mentioned before,
asymptomatic infections are very common.
In fact, and luckily, about
80% of Epstein-Barr virus infections
are completely asymptomatic.
Looking now at the clinical parts
for the hairy oral leukoplakia,
these are lesions most often seen
on the tongue, sometimes
toward the back of the tongue,
which are white.
They start off looking like thrush,
the lesions caused by Candida albicans,
a yeast in the mouth.
But, they rapidly go from white to sort
of grayish, just sometimes even black,
and they're fixed.
They don't scrape off.
So, clearly, seeing that kind of
a lesion in the mouth of
a patient who is immunocompromised,
for whatever reason, should raise suspicions,
both of an opportunistic yeast infection,
but also of an Epstein-Barr
So the diagnosis of Epstein-Barr virus
infection, regardless of what it is causing,
can be accomplished in
several different ways.
The first is by blood smear with
an astute hematopathologist.
The lymphocytes, the B lymphocytes of
a patient with Epstein-Barr virus infection
can look very atypical or reactive.
And so the hematopathologist or
the lab may call you and say,
"I'm seeing a whole bunch of reactive
lymphocytes on the blood smear."
These reactive lymphocytes are
also called Downey cells,
and you can see an image of one
of those on the lower right.
The next test is the monospot test
and this detects those
heterophile, immunoglobulin M antibodies
that we were talking about
from early stages of Epstein-Barr
virus infection, those
disordered B lymphocytes producing
anything they can.
And then, we have specific
immunoglobulin M and G
tests for Epstein-Barr virus
antigens, and these can be
from the cell wall,
from the nuclear antigen, or early
And based on the serologic pattern,
one can tell at what stage
the patient is infected: early,
middle, or latent.