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Human Papillomavirus and Genital Warts
Human papillomavirus
(HPV) is one of the most common causes of sexually transmitted
disease (STD) in the world. Experts estimate that as many as
24 million Americans are infected with HPV, and the frequency
of infection and disease appears to be increasing. More than
60 types of HPV have been identified by scientists. Some types
of the virus cause common skin warts. About one-third of the
HPV types are spread through sexual contact and live only in
genital tissue. Low-risk types of HPV cause genital warts, the
most recognizable sign of genital HPV infection. Other high-risk
types of HPV cause cervical cancer and other genital cancers.
Like many
sexually transmitted organisms, HPV usually causes a silent
infection, that is one that does not have visible symptoms.
One study sponsored by the National Institute of Allergy and
Infectious Diseases (NIAID) reported that almost half of the
women infected with HPV had no obvious symptoms. Because the
viral infection persists, individuals may not be aware of their
infection or the potential risk of transmission to others and
of developing complications.
Genital
Warts
Genital
warts (condylomata acuminata or venereal warts) are caused
by only a few of the many types of HPV. Other common types
of HPV infections, such as those that cause warts on the hands
and soles of the feet, do not cause genital warts. Genital
warts are spread by sexual contact with an infected partner
and are very contagious. Approximately two-thirds of people
who have sexual contact with a partner with genital warts
will develop warts, usually within three months of contact.
Scientists estimate that as many as 1 million new cases of
genital warts are diagnosed in the United States each year.
In women,
the warts occur on the outside and inside of the vagina, on
the cervix (the opening to the uterus), or around the anus.
In men, genital warts are less common. If present, they are
seen on the tip of the penis; however, they also may be found
on the shaft of the penis, on the scrotum, or around the anus.
Rarely, genital warts also can develop in the mouth or throat
of a person who has had oral sexual contact with an infected
person. Genital warts often occur in clusters and can be very
tiny or can spread into large masses on genital tissues. Left
untreated, genital warts often disappear. In other cases,
they eventually may develop a fleshy, small raised growth
with a cauliflower-like appearance. Because there is no way
to predict whether the warts will grow or disappear, however,
people who suspect that they have genital warts should be
examined and treated, if necessary.
Diagnosis
A doctor
usually can diagnose genital warts by direct visual examination.
Women with genital warts also should be examined for possible
HPV infection of the cervix. The doctor may be able to identify
some otherwise invisible changes in the tissue by applying
vinegar (acetic acid) to areas of suspected infection. This
solution causes infected areas to whiten, which makes them
more visible, particularly if a procedure called colposcopy
is performed. During colposcopy, a magnifying instrument is
used to view the vagina and uterine cervix. In some cases,
it is necessary to do a biopsy of cervical tissue. This involves
taking a small sample of tissue from the cervix and examining
it under the microscope.
A Pap
smear test also may indicate the possible presence of cervical
HPV infection. A Pap smear is a microscopic examination of
cells scraped from the uterine cervix in order to detect cervical
cancer. Abnormal Pap smear results are associated with HPV
infection. Women with abnormal Pap smears should be examined
further to detect and treat cervical problems.
Treatment
Depending
on factors such as their size and location, genital warts
are treated in several ways. Although treatments can eliminate
the warts, none eradicate the virus and warts often reappear
after treatment. Patients should consult their doctors to
determine the best treatment for them.
The U.S.
Food and Drug Administration (FDA) has approved imiquimod
cream, which the patient can apply to the affected area, to
treat genital warts. Other treatments include a 20 percent
podophyllin solution, which the patient can apply to the affected
area and later wash off, and a 0.5 percent podofilox solution,
which also is applied to the affected area, but is not washed
off. Pregnant women should not use podophyllin or podofilox
because they are absorbed by the skin and may cause birth
defects in babies. The doctor may also prescribe 5 percent
5-fluorouracil cream, which also should not be used during
pregnancy, or trichloroacetic acid (TCA).
Small
warts can be removed by cryosurgery (freezing), electrocautery
(burning), or laser treatment. Occasionally, surgery is needed
to remove large warts that have not responded to other treatment.
Some doctors
use the antiviral drug alpha interferon, which they inject
directly into the warts, to treat warts that have recurred
after removal by traditional means. The drug is expensive,
however, and does not reduce the rate of recurrence.
Complications
Low-risk
papilloma viruses cause warts but not cervical cancer. High-risk
viruses, however, cause cervical cancer and also are associated
with vulvar cancer, anal cancer, and cancer of the penis (a
rare cancer). Although most HPV infections do not progress
to cancer, it is particularly important for women who have
cervical dysplasia to have regular Pap smears. Potentially
pre-cancerous cervical disease is readily treatable.
Genital
warts may cause a number of problems during pregnancy. Sometimes
they enlarge during pregnancy, making urination difficult.
If the warts are on the vaginal wall, they can make the vagina
less elastic and cause obstruction during delivery.
Rarely,
infants born to women with genital warts develop laryngeal
papillomatosis (warts in the throat). Although uncommon, it
is a potentially life-threatening condition for the child,
requiring frequent laser surgery to prevent obstruction of
the airways. Research on the use of interferon therapy in
combination with laser surgery indicates that this drug may
show promise in slowing the course of the disease.
Prevention
The only
way to prevent HPV infection is to avoid direct contact with
the virus, which is transmitted by skin-to-skin contact. If
warts are visible in the genital area, sexual contact should
be avoided until the warts are treated. Using a latex condom
during sexual intercourse may provide some protection.
Researchers
are working to develop two types of HPV vaccines. One type
would be used to prevent infection or disease (warts or pre-cancerous
tissue changes); another type would be used to treat cervical
cancers. Clinical trials are in progress for both types of
vaccines.
For
More Information
American Social
Health Association:
ASHA/HPV
P.O. Box 13827
Research Triangle Park, NC 27709
National STD
Hotline
1-800-227-8922
Health
Advice Company
2515 East Highway 54
2200 Century Plaza
Durham, NC 27713
1-888-ADVICE-8 (1-888-238-4238)
http://www.advicecenter.com
National Cancer
Institute:
Cancer Information
Service
1-800-4 CANCER
http://www.nci.nih.gov
National Institutes of Health
July 1998
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