GENITAL HERPES
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Genital herpes (herpes genitalis, herpes
progenitalis) is characterized by the formation of fluid-filled
blisters on the genital organs of men and women. The word "herpes"
comes from the Greek adjective herpestes, meaning creeping, which
refers to the serpent-like pattern that the blisters may form.
Genital herpes is a sexually transmitted disease which means that it
is spread from person-to-person only by sexual contact. Herpes may
be spread by vaginal, anal, and oral sexual activity. It is not
spread by objects (such as a toilet seat or doorknob), swimming
pools, hot tubs, or through the air.
Genital herpes is a disease resulting from an infection by a herpes
simplex virus. There are eight different kinds of human herpes
viruses. Only two of these, herpes simplex types 1 and 2, can cause
genital herpes. It has been commonly believed that herpes simplex
virus type 1 infects above the waist (causing cold sores) and herpes
simplex virus type 2 infects below the waist (causing genital
sores). This is not completely true. Both herpes virus type 1 and
type 2 can cause herpes lesions on the lips or genitals, but
recurrent cold sores are almost always type 1. The two viruses seem
to have evolved to infect better at one site or the other,
especially with regard to recurrent disease.
To determine the occurrence of herpes type 2 infection in the United
States, the Centers for Disease Control and Prevention (CDC) used
information from a survey called the National Health and Nutrition
Examination Survey III (1988–1994). This survey of 40,000
noninstitutionalized people found that 21.9% of persons age 12 or
older had antibodies to herpes type 2. This means that 45 million
Americans have been exposed at some point in their lives to herpes
simplex virus type 2. More women (25.6%) than men (17.8%) had
antibodies. The racial differences for herpes type 2 antibodies were
whites, 17.6%; blacks, 45.9%; and Mexican Americans, 22.3%.
Interestingly, only 2.6% of adults reported that they have had
genital herpes. Over half (50% to 60%) of the white adults in the
United States have antibodies to herpes simplex virus type 1. The
occurrence of antibodies to herpes type 1 is higher in blacks.
Viruses are different from bacteria. While bacteria are independent
and can reproduce on their own, viruses cannot reproduce without the
help of a cell. Viruses enter human cells and force them to make
more virus. A human cell infected with herpes virus releases
thousands of new viruses before it is killed. The cell death and
resulting tissue damage causes the actual sores. The highest risk
for spreading the virus is the time period beginning with the
appearance of blisters and ending with scab formation.
Herpes virus can also infect a cell and instead of making the cell
produce new viruses, it hides inside the cell and waits. Herpes
virus hides in cells of the nervous system called "neurons." This is
called "latency." A latent virus can wait inside neurons for days,
months, or even years. At some future time, the virus "awakens" and
causes the cell to produce thousands of new viruses which causes an
active infection. Sometimes an active infection occurs without
visible sores. Therefore, an infected person can spread herpes virus
to other people even in the absence of sores.
This process of latency and active infection is best understood by
considering the genital sore cycle. An active infection is obvious
because sores are present. The first infection is called the
"primary" infection. This active infection is then controlled by the
body's immune system and the sores heal. In between active
infections, the virus is latent. At some point in the future latent
viruses become activated and once again cause sores. These are
called "recurrent infections" or "outbreaks." Genital sores caused
by herpes type 1 recur much less frequently than sores caused by
herpes type 2.
Although it is unknown what triggers latent viruses to activate,
several conditions seem to bring on infections. These include
illness, tiredness, exposure to sunlight, menstruation, skin damage,
food allergy and hot or cold temperatures. Although many people
believe that stress can bring on their genital herpes outbreaks,
there is no scientific evidence that there is a link between stress
and recurrences. However, at least one clinical study has shown a
connection between how well people cope with stress and their belief
that stress and recurrent infections are linked.
Newborn babies who are infected with herpes virus experience a very
severe, and possibly fatal disease. This is called "neonatal herpes
infection." In the United States, one in 3,000–5,000 babies born
will be infected with herpes virus. Babies can become infected
during passage through the birth canal, but can become infected
during the pregnancy if the membranes rupture early. Doctors will
perform a Cesarean section on women who go into labor with active
genital herpes. |
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