The adenoviruses are nonenveloped viruses
which have an icosahedral capsid.
Important to remember about
is that they are a group
which contain double-stranded DNA
in a linear or a straight genome.
The adenoviruses are transmitted
pretty much any way you can imagine.
Through respiratory aerosols,
through fecal-oral contact,
through fomites, i.e.,
little toys that we love to play
with with our children,
close contact, far contact, you name it,
and as a very special gift,
in inadequately chlorinated
As anybody has been to a
municipal pool knows,
you can sometimes get pink eye, one of
our diseases from adenovirus.
How does adenovirus cause its pathogenesis?
It has fibers from its surrounding capsid
that bind to specific cell receptors
and insert the adenovirus into the cell
to begin its growth process.
In addition, it contains growth-
but it a way to inhibit those,
so that its host cell not
only lives until it's
done being used by the adenovirus, but if
and grows even better, which is another
way of sort of progressing
the adenovirus' impact on that local area.
Once adenovirus is ready to leave, it's
already replicated itself,
it's created multiple additional variants,
then it lyses the host cell
And it's only when that lysis occurs, that
rupture of the host cell,
that inflammation from the human immune
system can begin.
Where it begins depends on where the
adenovirus is bound.
And you'll note that I did not name
a specific target cell.
That's because there are many different
types of adenovirus,
each of which have different tropism,
on the part of the body which they
So, one might have a respiratory-based
adenovirus, in which case,
lysis at the cell creates respiratory
Similarly, something in the
the conjunctiva, the cornea -- you get
Some adenovirus, however, are able to
create a persistent or a latent infection,
meaning that they can chronically infect
their host cells,
specifically in the lymphoid tissues
ysing the host cell, without creating
that immune reaction.
That means, though, that they can react --
interact and reactivate
at any point that they're sort of
triggered to do so.
And then, they might develop viremia,
entering the virus into the bloodstream
within like a systemic adenovirus
So let's now look, in comparison, at some
of the infections
caused by adenovirus.
And we'll start with febrile pharyngitis,
really occurs up to a week or so after
after the initial inoculation with
and then we have onset of acute disease.
This occurs also for acute respiratory
disease and conjunctivitis,
and in fact, you'll see this as a pretty
for the incubation period of all of the
Who is at most risk for febrile
Very young children, < 3 years of age.
And that's important because children
older than 2 or 3 years of age
are the ones who most often get
which looks and feels a heck of a lot like
febrile pharyngitis with adenovirus.
So the age here is very important.
Very young children with a strep
more likely than not, have adenovirus.
Acute respiratory disease, and this is
typically an atypical pneumonia,
most often occurs in young adults,
especially those in close quarters, like
or inmates in a prison.
And then conjunctivitis, the so-called
Anybody can get that.
We list older children and adults, but
even younger children in daycare or in
preschool, at a playgroup,
are going to that municipal swimming
anybody can get the conjunctivitis.
We show here, then, some lovely pictures,
and as you see at the bottom on the left
side of the slide,
you see a very erythematous throat.
You can see some slightly enlarged tonsils
That appearance looks very much
like streptococcal pharyngitis would look.
However, it's indeed is caused by adenovirus.
Patients with adenoviral pharyngitis
will have the same manifestations as you
would expect for strep throat,
i.e., fever, a very painful throat,
they might have a dry cough because they
can't handle those secretions.
Coryza -- coryza is nasal secretions,
they cannot swallow very comfortably.
The whole appearance is very much like
a strep throat.
For the acute respiratory disease in our
rapid onset of fever, that dry non-
sore throat is from all the coughing,
and also, post nasal drip with
And they may have swollen lymph nodes in
the neck, cervical adenitis.
And then conjunctivitis, the pink eye.
Well, the picture gives 1000 words.
And I think we've all seen pink eye.
We have probably all experienced
So, the entire conjunctiva is inflamed, as
you can see in the picture.
It's sort of itchy, there's excess tearing,
sometimes it's a mucus discharge.
We wake up in the morning with crusted
sometimes, we actually have to use a
washcloth to open up the eye.
So, we can see that this is a
appearance for pink eye or adenoviral
In adults, unfortunately, this disease
potentially could progress to cause
a full keratitis,
which then might require treatment
by an ophthalmologist.
The next category of infections caused
by adenovirus include are
gastroenteritis, and appendicitis,
and these are,
thankfully, a little bit less common
than the 3 that we just talked about.
For atypical pneumonia,
here, it's a slightly longer incubation
period, up to 2 weeks,
versus gastroenteritis, which is anywhere
from 3-10 days, the typical
incubation we just talked about.
And similarly, with appendicitis,
perhaps a week or so after inoculation
The population at risk for atypical
everybody: children, adults, you name it.
For gastroenteritis, it's far more often
seen in younger children,
the ones who are at risk for other types
of viral gastroenteritis.
And then in appendicitis, similarly,
The reason is that
the targeting tissue for
the gastrointestinally-focused or
also can enter the lymphoid tissue to
create that latent
period, that sort of hiding, within
And it is exactly that lymphoid swelling
which might actually block off the
and create the appendicitis.
So, similar populations for both
gastroenteritis and appendicitis.
The clinical manifestations for atypical
exactly what you would expect
nonproductive, dry, sharp cough,
which persists sometimes for
If one obtains a chest radiograph,
or chest X-ray,
you'll see bilateral, diffused, patchy
It is an interstitial pneumonia, not
an LV or a pneumonia.
In direct distinction to the classic
bacterial lobar pneumonia,
this atypical pneumonia without
at least 1 and more often than not,
several lobes of lung.
Far more likely, you'll see it pretty much
diffusely throughout the entire
In the gastroenteritis, there
serotypes, as we mentioned before,
which have tropism for gut
tissue and the gut lymphoid tissue.
As we can see in the slide, serotypes
40, 41, and 42
are very much associated with
watery diarrhea and some emesis.
The serotypes 25, 26, 27 and 28
will cause focused diarrhea, but those
are far more often
acquired in hospital.
It's a limited population.
Any of these, however, because
of their growth
in the gut associated lymph nodes
can cause intussusception,
because those swollen lymph nodes
serve as a lead point
for the intussusception to occur.
And then finally, as we've been talking
about with appendicitis,
the same lymphoid hyperplasia
compromises blood supply
to the appendix and we can get
Diagnosis of the adenovirus.
Well, it can -- it does cause dense,
basophilic intranuclear inclusion bodies,
which you can see identified with the
arrows on the slide.
Identified because everything looks
rather dense and basophilic,
but these are even darker purple, and
you can see them as little
the cytoplasm of their target cells.
Far more often, since adenovirus
can be a pathologic diagnosis by
but far more often in clinical practice,
we will use serotype specific assays.
Because adenovirus occurs in so many
it's far easier to use immunoassays,
a DNA probe,
or a PCR -- polymerase chain reaction --
which can target uniform sites
for all adenovirus
rather than doing antibody-specific
testing with a serology panel.
So, molecular diagnostics are probably the
way to go without adenoviral detection,
and they pick up the disease far
Prevention and treatment.
Well, this is difficult because
adenovirus is a survivor.
It lives everywhere.
It's resistant to detergent
and acid and drying, and it's resistant
to the acid environment in the
This is unfortunate because if you think
about your typical
kindergarten or preschool,
where children's leavings, their mucus,
gets smeared all over everything,
well, those are a highly adenovirus-rich
and it's very hard to clean that stuff.
So, that simply means the best way to
prevent adenovirus is
wash your hands.
Not that difficult.
For those individuals who are at high risk
for getting, sort of, an epidemic
outbreak of adenovirus and this, again,
would be our military recruits,
there is a oral vaccine
which has decent efficacy,
but it is not in common use in the
There are no antivirals yet discovered
which have any known efficacy
so this is truly a supportive care.
"Tincture of time," is what we say, trying
to make the patient comfortable.
So, adenovirus is ubiquitous.
It's all around. It can cause multiple
different types of diseases,
depending on the tropism of the
But most commonly, it is an unfortunate
cause of pink eye,
which you can get anywhere