Two main species of chlamydiae cause
disease in humans. They can be treated
The first species, C
is responsible for some sexually trans-
mitted infections, including about half
of all cases of
pelvic inflammatory disease
women. It can also cause the tropical
A second species, C
This is a rare
form of pneumonia that is transmitted
to humans from birds.
Chlamydia is also responsible for a type
of pneumonia (see
An infectious organism that can cause a
m ild form of
w hich occurs
particularly in young adults.
An organism that mainly affects birds
but can occasionally spread to people
who are in contact with pigeons, par-
rots, parakeets, or poultry. It causes a
type of pneumonia called
An organism that belongs to the chla-
mydiae group and has several strains. In
men, it is a major cause of the sexually
w hich may cause a discharge
from the penis. In women, the infec-
tion usually causes no symptoms, but
can lead to
pelvic inflammatory disease
of the fallopian tubes). A baby born to
a woman w ith chlamydial infection
In some parts of Africa and Asia, cer-
a serious eye disease
that is the most
common cause of
A skin condition, also called melasma,
in which blotches of pale brown pig-
mentation appear on the face, notably
on the forehead, nose, and cheeks. The
condition is aggravated by sunlight.
Chloasma sometimes develops during
pregnancy. More rarely, it is associated
with the menopause or the use of
The areas of abnormal
pigmentation usually fade in time, but
the condition may recur.
A type of
that is used in the
treatment of some types of cancer, such
commonly used as
drops to treat superficial eye infections.
Chloramphenicol is also used to treat
life-threatening infections of unknown
cause. Rarely, tablets or injections are
associated with aplastic
The toxic effects of chemicals called
chlorates, which are present in some
Symptoms of chlorate poisoning in -
pain, and diarrhoea. Chlorates can also
cause kidney and liver damage, corro-
sion of the intestines, and
(a harmful chemical change
in the blood
Even small doses can be fatal; medical
help is needed immediately if chlorate
poisoning is suspected.
mainly used in
the treatment of
A type of disinfectant mainly used to
before taking a blood sample.
A poisonous, yellowish-green gas with
properties. If inhaled in even very small
amounts, chlorine gas is highly irritat-
ing to the lungs; inhalation of large
amounts is rapidly fatal.
Aerosol propellants, commonly known
as CFCs, that contain compounds of
gases such as carbon, chlorine, fluorine,
and hydrogen. CFCs have contributed
to the damage to the ozone layer.
A colourless liquid producing a vapour
that was formerly used as a general
However, chloroform is associated with
liver damage and heart problems and
safer drugs are now used instead.
A brand name for the antibiotic drug
w hich is often used in
eye and ear preparations.
A drug used mainly in the prevention
and treatment of
It is also used
Possible side effects of chloroquine
include nausea, headache, diarrhoea,
rashes, and abdominal pain. Long-term
use may damage the retina of the eye.
that is used to
treat a number of allergic conditions
such as allergic
gic facial swelling) and
rash). Chlorphenamine is also a com-
ponent of some
An alternative name for
A widely prescribed
used to relieve symptoms of major psy-
chotic illnesses such as
The drug reduces delusional
and hallucinatory experiences and may
have an effect on irritability and overac-
tivity. It is also used as an
to treat nausea and vomiting, especially
when these problems are the result of
treatment with other drugs, radiother-
apy, or anaesthesia.
Chlorpromazine may cause
(increased sensitivity of the skin
to sunlight) and, in some cases,
(a movement disorder), slow
reactions, and blurred vision.
A drug that is used to treat
abnormality of the
which one or both of the nasal cavities
are not fully developed.
A brown swelling in an
cysts may develop in
condition in which endometrial tissue
(w hich forms the lining of the uterus)
is found in sites outside the uterus. The
colour is the result of clotted blood
within the cysts.