II. Infectious Diseases
After completing this tutorial the student
will be able to:
- list the infectious diseases involving
- specify the etiologic agents and mode of
- describe/recognize clinical lesions
- describe/identify characteristic histologic
- state clinical behavior/complications
- Condyloma acuminatum (Genital or Venereal warts)
acuminata are sexually transmitted warty lesions caused by the
human papilloma virus (HPV), mainly types 6 and 11 but may be
caused by type 16/18. Areas involved include the vulva, vagina,
cervix, urethra, anal canal, perineum and perianal skin. The lesions
may be flat but are usually exophytic, solitary but more frequently
multiple and focal or extensive.
Note the raised, fleshy excrescences that fill and obscure
the vulva and extend to involve the perianal skin (exophytic and
Question: Flat condylomas are more frequent than exophytic
condylomas in which of the areas listed above?
Question: What is the likely implication of finding vulvar
condyloma acuminatum in a child?
The virus invades the basal cells of the stratified squamous
epithelium and establishes a virus-driven stimulation of cell
replication. There is thus thickening of the stratified squamous
epithelium (acanthosis) with widening and elongation of the rete
ridges (papillomatosis). There may be a thickened keratin layer
(hyperkeratosis) which may contain pyknotic nuclei (parakeratosis).
The virus-infected keratinocytes have a distinct morphology referred
to as koilocytosis. The koilocyte (infected cell) is a vacuolated
keratinocyte containing a pyknotic nucleus surrounded by a halo.
These cells serve as markers of HPV infection and are produced
by viral cytopathic effect.
Flat condyloma. Note the circled koilocytes, one of which is being
The disease runs a long, protracted course. The outcome may be
influenced by immunologic factors. In the immunosuppressed, the
lesion can progress to dysplasia, and possibly invasive squamous
Question. How is condyloma acuminata treated?
- Herpes genitalis
This is a sexually transmitted disease caused by Herpes simplex
virus (HSV) types II in 90% and I in 10% of cases.
The lesions appear as multiple, small, painful vesicles that
rapidly erode into shallow, painful ulcers. Similar lesions may
occur in the vagina, cervix, urethra, bladder and anus.
Herpetic vesicles on vulva and perineum.
There is necrosis of infected cells with formation of intraepithelial
vesicles and skin ulceration.
Suprabasal intraepidermal vessicle filled with serum and degenerated
Cells at the margins of vesicles show characteristic viral cytopathic
effect including nuclear homogenization, large eosinophilic intranuclear
inclusions, and formation of multinucleated giant cells.
Multinucleated giant and single cell containing large intranuclear
In the immunocompetent host, the lesions heal in about 2 weeks.
The virus establishes latent infection in sensory ganglia and
reactivation results in recurrent episodes of disease activity.
Question: What is the likely clinical course of the disease
in an individual with AIDS?
Question: What conditions may cause reactivation of a
Question: What complications may arise during pregnancy?
Syphilis is a venereal disease caused by the spirochete Treponema
pallidum.The disease is acquired through sexual contact with an
The organism produces a primary lesion called the chancre at
the portal of entry. The chancre is a painless, indurated, shallow
ulcer accompanied by lymphadenopathy. The ulcer heals spontaneously
within 6 weeks and typically does not leave a scar.
The secondary lesion, which is highly infectious, appears as
papules called "condyloma lata" on the vulva associated
with rash on the palms and soles.
The tertiary lesion, referred to as the gumma, rarely involve
The primary chancre is characterized by ulceration of the epidermis
accompanied by chronic inflammation with large numbers of plasma
cells. Arteritis with severe perivascular inflammatory response
is present. The condyloma lata show similar histological features
but there is marked epithelial thickening and hyperkeratosis with
This requires a high level of clinical suspicion. The histological
are non-specific and organisms can be hard to detect in histological
sections. Serum expressed from the primary chancre or condyloma
lata can be examined for the presence of spirochetes. Serologic
studies of antibody to treponemal antigen are commonly used for
About a third of patients with primary syphilis will develop
spontaneous remission of the disease. The remainder of untreated
cases will progress to the tertiary stage.
Cardiac and central nervous system involvement occurs in tertiary