The papillomaviridae viruses.
Papilloma viruses are small
with an icosahedral capsid
with -- and this is important to remember --
circular, double-stranded DNA genome.
They are transmitted through direct
or sexual contact with
actively expressed legions, which
mostly are warts.
And the incubation period
is quite prolonged
from 4-21 weeks.
Initial infection occurs at the cutaneous
and mucosal epithelial surfaces,
typically of genital tissue.
And then viral proteins E6 and E7
are expressed, and these inactivate the
growth suppressors in the target tissues,
meaning that those same epithelial tissues
hen develop hyperplasia at the basal layer.
And anytime one has hyperplasia of lesions,
then one is at risk for developing
To make a diagnosis of any
primary lesion with a human
is primarily a clinical diagnosis.
One can look at the lesions
are typically flat,
somewhat hypopigmented compared
to underlying skin,
and they occur in many different places.
You can see an image of several
warts or several lesions
in the top on this slide,
with arrows identifying specific
almost pale-looking HPV warts or lesions.
In addition, there are characteristic
appearances on pathology,
and one further can make diagnoses
through serology and PCR.
Pap smears, especially, will
which are dysplastic squamous
cervical cells with a
It almost sounds like a chocolate
bar and it's not.
Raisinoid nuclei with hyperchromasia.
And on the side slide's picture
to the lower right,
you can see with the red arrow
identify 1 such site
with prominent nuclei.
So, let's look specifically at the diseases
caused by the human papillomaviruses
and the types of diseases depend on
what serotype we're talking about.
This will be important when
we eventually get to
prevention and the vaccines which cover
some, but not all of these.
Starting then with serotypes 1-4,
these human papillomaviruses
all cause skin warts, such as
you see in the picture
of the plantar aspect of a foot.
These are benign, as are
most of the initial warts.
Tan colored to again, hypopigmented.
They feel soft, but they look like
a flattened cauliflower.
So, a description would be a plantar
skin-colored or soft tan colored lesion,
usually on the plantar aspects
of the hands and feet.
These represent epidermal hyperplasia
Human papillomaviruses types 6 and 11
will cause warts as well, but localized to
the anogenital side, and this is known as
And these, again, are benign
warts with extraneous
growth of squamous epithelium occurring
typically in the perianal region.
And again, a picture's worth 1000 words
on the lower part of the slide.
Type 6 and 11 also can cause
and although these are benign
and growing in laryngeal tissue,
they can grow to quite extensive sizes
and extensive numbers,
and actually can cause airway obstruction.
Sometimes, this has additional effects
on swallowing dysfunction
if there is a significant amount
of tissue growth.
So, this ends up
being quite an issue for management for
even otherwise healthy individuals.
Human papillomaviruses 16 and 18
are specifically able to cause cervical
These are the bad ones that we start
to worry about and try to prevent
with vaccines because
they can progress to underlying carcinomas.
You can see a picture on the
lower part of the slide
showing early such lesions, and
this is mucosal dysplasia,
looking both inflamed and also,
again, that sort of paler appearing,
Because all of these potentially can
progress and certainly, are quite ubiquitous
for the cutaneous lesions.
The vaccines available are able to
demonstrate or create seroprotection
to specific types, and you
see them listed there.
1 vaccine product will cover
types 18, 16, 6, and 11.
Another prevents just 16 and 18.
The major goal for these vaccines
is to prevent cervical carcinoma.
So, therefore, the people to vaccinate
are those -- and it says young women,
but also a target is to young men
prior to reaching sexual maturity or
prior to reaching sexual activity.
The goal is to give these young
adults, or children,
protection against the cancer-causing
before they're exposed to them through
age of sexual maturity.
So, human papillomaviruses, then,
when they develop can be treated, but it's
not always a successful process.
Warts, cutaneous warts, even perianal warts
can be removed, they can be scraped,
they can be surgically cauterized.
And then, the injection of interferon alpha
an also reduce the activity of the
to prevent a recurrence.
The laryngeal papillomas, as I noted before,
are quite a significant problem
if they grow to the size to cause
obstruction of the larynx.
And in those cases, surgical
removal is necessary.
However, it only removes the tissue.
It does not treat the underlying virus.
And so, the use of additional
therapies, imiquimod and
cidofovir with antiviral activity,
have been tried, although their
efficacy is not 100%.
So, human papillomaviruses are ubiquitous,
they're sexually transmitted.
In the early ages of life, they
are not an issue,
but as one gets older and older, they
become increasingly of a problem.
Vaccines, again, is to prevent specifically
the serotypes associated with
and the progression to malignancy.