KidsHealth.org
Thu Jan 12, 7:00 PM ET




ADVERTISEMENT

Chlamydia is a unique type of bacteria that can live and reproduce
inside human cells. There are 4 known species of these bacteria, 3
of which can cause disease in humans:

Chlamydia trachomatis,
Chlamydia pneumonia, and
Chlamydia psittaci.

The infections caused by these organisms can affect many different
organs, including the eyes, lungs, or urinary-genital area,
depending on the species involved, the age of the person infected,
and how the infection is transmitted.


The name "chlamydia" is derived from the Greek word "chlamys", which
was a kind of cloak worn by men in ancient Greece. This describes
how this type of bacteria drapes itself around the nucleus of a
human cell that it has infected. When inside the cell, Chlamydia
uses energy produced by the cell in order to multiply. It can then
exit the cell, while leaving the cell intact, to move on and infect
other cells. This ability to reproduce inside a cell without
actually damaging it can lead to prolonged infections with minimal
or no symptoms, which is one of the major characteristics of this
type of bacteria.


Chlamydia Trachomatis
Chlamydia trachomatis (C. trachomatis) is associated with a spectrum
of diseases. The most well-known is the sexually transmitted disease
(STD) commonly referred to as "chlamydia", which is the most
frequently reported bacterial STD in the United States today. It is
estimated that between 3 and 4 million new infections occur each
year, primarily among adolescents and young adults. When transmitted
sexually during oral, vaginal, or anal sex, C. trachomatis can
infect pelvic organs in both men and women. If the bacterium comes
into contact with the eyes, it can also cause conjunctivitis.
Besides being transmitted sexually, C. trachomatis can also be
passed from an infected woman to her baby during childbirth. In the
newborn, this can cause conjunctivitis as well as pneumonia.


Diseases causes by C. trachomatis that are rarely seen in the United
States but are common in many developing countries include:
trachoma, a severe chronic inflammatory disease of the eye which is
a leading cause of preventable blindness worldwide; and
lymphogranuloma venereum, a sexually transmitted disease affecting
the lymph nodes as well as the genitals.


Signs and Symptoms
Chlamydia is known as a "silent" disease because about three
quarters of infected women and about half of infected men have no
symptoms. Even if symptoms are present, they may be mild and last
only a few days, and may not be noticed or considered significant by
the person who is infected. Furthermore, an asymptomatic infection
can flare up after weeks or months and suddenly start to cause
symptoms.


Women who have symptoms may experience vaginal irritation with
discharge. Men may have discharge from the urethra (the opening
where urine comes out) and burning upon urination.


Left untreated, C. trachomatis infections in women may spread and
cause pelvic inflammatory disease (PID). This is an infection that
ascends from the vagina and cervix to involve the uterus, fallopian
tubes, and ovaries. Although PID can sometimes be asymptomatic, it
can also cause symptoms that include: abdominal or lower back pain,
a burning sensation while urinating, pain during intercourse,
bleeding between menstrual periods, nausea, vomiting, fatigue, or
fever. Scarring of the fallopian tubes after chlamydial infection
may cause permanent damage to the reproductive system, resulting in
infertility. Other long-term consequences of PID include chronic
pelvic pain and a higher risk of ectopic pregnancy. Untreated
chlamydial infections in men can lead to epididymitis, an
inflammation of the coiled tubes in the back of the testicles. This
can result in testicular swelling and pain, and ultimately even
infertility.


Newborns with chlamydial conjunctivitis are usually alert and have
no fever. Their symptoms can range from mild to severe, and may
include redness of the eyes, swollen eyelids, and discharge from the
eyes which can be thin and watery or thick and yellow.


Chlamydial pneumonia in infants often develops gradually. They are
sometimes brought to the doctor after several weeks of mild
respiratory symptoms. This illness is characterized by a dry
irritating cough with nasal congestion and abnormally rapid
breathing, without fever or wheezing. About half of all newborns
with chlamydial pneumonia have also had chlamydial conjunctivitis.


Contagiousness
C. trachomatis infections are contagious. The bacterium can be
transmitted through semen and vaginal secretions, so all sexual
partners of someone with a genital chlamydial infection need to be
notified and treated with antibiotics, even if they don't have
evident symptoms. This is because an infected person may spread the
infection to other sexual partners even if he or she has no symptoms.


It does not spread through casual contact such as shaking hands or
using the same toilet as someone who is infected.If a pregnant woman
has a genital chlamydial infection, her newborn child can be
infected during delivery. Of all children born to mothers with
genital chlamydial infections, almost 50% develop chlamydial
conjunctivitis and close to 20% develop pneumonia.