Syphilis
Article courtesy of the NIAID:
Syphilis, once a cause of devastating epidemics, can be
effectively diagnosed and treated with antibiotic therapy. In
1996, 11,387 cases of primary and secondary syphilis in the
United States were reported to the U.S. Centers for Disease
Control and Prevention. Although treatment is available, the
early symptoms of syphilis can be very mild, and many people do
not seek treatment when they first become infected. Of increasing
concern is the fact that syphilis increases the risk of
transmitting and acquiring the human immunodeficiency virus (HIV)
that causes AIDS.
Syphilis is a sexually transmitted disease
(STD) caused by a bacterium called Treponema pallidum. The
initial infection causes an ulcer at the site of infection;
however, the bacteria move throughout the body, damaging many
organs over time. Medical experts describe the course of the
disease by dividing it into four stages – primary,
secondary, latent, and tertiary (late). An infected person who
has not been treated may infect others during the first two
stages, which usually last one to two years. In its late stages,
untreated syphilis, although not contagious, can cause serious
heart abnormalities, mental disorders, blindness, other
neurologic problems, and death.
The bacterium spreads from the initial
ulcer of an infected person to the skin or mucous membranes of
the genital area, the mouth, or the anus of a sexual partner. It
also can pass through broken skin on other parts of the body. The
syphilis bacterium is very fragile, and the infection is almost
always spread by sexual contact. In addition, a pregnant woman
with syphilis can pass the bacterium to her unborn child, who may
be born with serious mental and physical problems as a result of
this infection. But the most common way to get syphilis is to
have sex with someone who has an active infection.
Symptoms
The first symptom of primary syphilis
is an ulcer called a chancre ("shan-ker"). The chancre
can appear within 10 days to three months after exposure, but it
generally appears within two to six weeks. Because the chancre
may be painless and may occur inside the body, it may go
unnoticed. It usually is found on the part of the body exposed to
the partner’s ulcer, such as the penis, the vulva, or the
vagina. A chancre also can develop on the cervix, tongue, lips,
or other parts of the body. The chancre disappears within a few
weeks whether or not a person is treated. If not treated during
the primary stage, about one-third of people will progress to
chronic stages.
Secondary syphilis is often marked
by a skin rash that is characterized by brown sores about the
size of a penny. The rash appears anywhere from three to six
weeks after the chancre appears. While the rash may cover the
whole body or appear only in a few areas, the palms of the hands
and soles of the feet are almost always involved. Because active
bacteria are present in these sores, any physical contact –
sexual or nonsexual – with the broken skin of an infected
person may spread the infection at this stage. The rash usually
heals within several weeks or months. Other symptoms also may
occur, such as mild fever, fatigue, headache, sore throat, as
well as patchy hair loss, and swollen lymph glands throughout the
body. These symptoms may be very mild and, like the chancre of
primary syphilis, will disappear without treatment. The signs of
secondary syphilis may come and go over the next one to two
years.
If untreated, syphilis may lapse into a latent
stage during which the disease is no longer contagious and no
symptoms are present. Many people who are not treated will suffer
no further consequences of the disease. Approximately one-third
of those who have secondary syphilis, however, go on to develop
the complications of late, or tertiary, syphilis, in which
the bacteria damage the heart, eyes, brain, nervous system,
bones, joints, or almost any other part of the body. This stage
can last for years, or even for decades. Late syphilis, the final
stage, can result in mental illness, blindness, other neurologic
problems, heart disease, and death.
Neurosyphilis: Syphilis bacteria
frequently invade the nervous system during the early stages of
infection, and approximately 3 to 7 percent of persons with
untreated syphilis develop neurosyphilis. Some persons with
neurosyphilis never develop any symptoms. Others may have
headache, stiff neck, and fever that result from an inflammation
of the lining of the brain. Some patients develop seizures.
Patients whose blood vessels are affected may develop symptoms of
stroke with resulting numbness, weakness, or visual complaints.
In some instances, the time from infection to developing
neurosyphilis may be up to 20 years. Neurosyphilis may be more
difficult to treat and its course may be different in people with
HIV infection.
Diagnosis
Syphilis has sometimes been called
"the great imitator" because its early symptoms are
similar to those of many other diseases. Sexually active people
should consult a doctor about any suspicious rash or sore in the
genital area. Those who have been treated for another STD, such
as gonorrhea, should be tested to be sure they have not also
acquired syphilis.
There are three ways to diagnose syphilis:
a doctor's recognition of its signs and symptoms; microscopic
identification of syphilis bacteria; and blood tests. The doctor
usually uses these approaches together to detect syphilis and
decide upon the stage of infection.
To diagnose syphilis by identifying the
bacteria, the doctor takes a scraping from the surface of the
ulcer or chancre, and examines it under a special
"darkfield" microscope to detect the organism itself.
Blood tests also provide evidence of infection, although they may
give false- negative results (not show signs of infection despite
its presence) for up to three months after infection.
False-positive tests also can occur; therefore, two blood tests
are usually used. Interpretation of blood tests for syphilis can
be difficult, and repeated tests are sometimes necessary to
confirm the diagnosis.
The blood-screening tests most often used
to detect evidence of syphilis are the VDRL (Venereal Disease
Research Laboratory) test and the RPR (rapid plasma reagin) test.
The false-positive results (showing signs of infection when it is
not present) occur in people with autoimmune disorders, certain
viral infections, and other conditions.
Therefore, a doctor will administer a
confirmatory blood test when the initial test is positive. These
tests include the fluorescent treponemal antibody-absorption
(FTA-ABS) test that can accurately detect 70 to 90 percent of
cases. Another specific test is the T. pallidum hemagglutination
assay (TPHA). These tests detect syphilis antibodies (proteins
made by a person's immune system to fight infection). They are
not useful for diagnosing a new case of syphilis in patients who
have had the disease previously because once antibodies are
formed, they remain in the body for many years. These antibodies,
however, do not protect against a new syphilis infection. In some
patients with syphilis (especially in the latent or late stages),
a lumbar puncture (spinal tap) must be done to check for
infection of the nervous system.
Treatment
Syphilis usually is treated with
penicillin, administered by injection. Other antibiotics can be
used for patients allergic to penicillin. A person usually can no
longer transmit syphilis 24 hours after beginning therapy. Some
people, however, do not respond to the usual doses of penicillin.
Therefore, it is important that people being treated for syphilis
have periodic blood tests to check that the infectious agent has
been completely destroyed. Persons with neurosyphilis may need to
be retested for up to two years after treatment. In all stages of
syphilis, proper treatment will cure the disease, but in late
syphilis, damage already done to body organs cannot be reversed.
Effects of Syphilis in Pregnant Women
It is likely that an untreated pregnant
woman with active syphilis will pass the infection to her unborn
child. About 25 percent of these pregnancies result in stillbirth
or neonatal death. Between 40 to 70 percent of such pregnancies
will yield a syphilis-infected infant.
Some infants with congenital syphilis may
have symptoms at birth, but most develop symptoms between two
weeks and three months later. These symptoms may include skin
sores, rashes, fever, weakened or hoarse crying sounds, swollen
liver and spleen, yellowish skin (jaundice), anemia, and various
deformities. Care must be taken in handling an infant with
congenital syphilis because the moist sores are infectious.
Rarely, the symptoms of syphilis go
undetected in infants. As infected infants become older children
and teenagers, they may develop the symptoms of late-stage
syphilis including damage to their bones, teeth, eyes, ears, and
brain.
Prevention
The open sores of syphilis may be visible
and infectious during the active stages of infection. Any contact
with these infectious sores and other infected tissues and body
fluids must be avoided to prevent spread of the disease. As with
many other STDs, methods of prevention include using condoms
during sexual intercourse. Screening and treatment of infected
individuals, or secondary prevention, is one of the few options
for preventing the advance stages of the disease. Testing and
treatment early in pregnancy is the best way to prevent syphilis
in infants and should be a routine part of prenatal care.
Research
Developing better ways to diagnose and
treat syphilis is an important research goal of scientists
supported by the National Institute of Allergy and Infectious
Diseases (NIAID). New tests are being developed that may provide
better ways to diagnose syphilis and define the stage of
infection.
In an effort to stem the spread of
syphilis, scientists are conducting research on a vaccine.
Molecular biologists are learning more about the various surface
components of the syphilis bacterium that stimulate the immune
system to respond to the invading organism. This knowledge will
pave the way for development of an effective vaccine that can
ultimately prevent this STD.
A high priority for researchers is
development of a diagnostic test that does not require a blood
sample. Saliva and urine are being evaluated to see whether they
would work as well as blood. Researchers also are trying to
develop other diagnostic tests for detecting infection in babies.
Another high research priority is the
development of a safe, effective, single-dose oral antibiotic
therapy for syphilis. Many patients do not like getting an
injection for treatment, and about 10 percent of the general
population is allergic to penicillin.
Recently, the genome of this organism has
been sequenced. The sequence represents an encyclopedia of
information about the organism. Clues as to how to diagnose,
treat, and vaccinate against syphilis have been identified
already and are fueling intensive research efforts in this
ancient but intractable disease.
