Dengue Fever
What is it?
Dengue fever is a type of arbovirus, which is
short for arthropod-borne virus. The virus that
causes dengue fever is carried by Aedes egypti
mosquitoes, and is transmitted to humans through
their bite. An organism that carries a disease,
without actually developing the disease, is called
a vector.
Who gets it?
The risk for being bitten by a mosquito that is
carrying dengue fever is higher in Africa,
Southeast Asia and China, the Indian subcontinent,
the Middle East, South and Central America, the
Caribbean Islands, Australia, and the South and
Central Pacific. Dengue fever is considered
"endemic" to certain regions, which means it is
native to, or naturally occurring, in these areas.
Dengue fever is more likely to occur during or
shortly after the rainy season, when the mosquito
population is larger. It also most commonly
affects children under the age of 10. Dengue fever
is rarely seen in the United States.
What causes it?
When a mosquito that is carrying dengue fever
bites a person, the virus travels through the
body's glands. Once in the glands, it multiplies
and can enter the bloodstream. Dengue fever is not
contagious, which means one person cannot pass it
directly to another.
What are the symptoms?
It takes around five to eight days after being
bitten by an infected mosquito for the virus to
multiply. Then, symptoms including high fever,
headache, chills, swollen lymph nodes, red eyes
and eye pain, severe joint and muscle pain,
flushed face, lower back pain, and general
weakness appear suddenly. These symptoms last for
two to three days. Afterward, the fever drops and
the patient experiences heavy sweats, but feels
better for around one day. This is followed by an
increase in temperature, a rash, and a headache.
The rash consists of small red bumps that begin on
the arms and legs, but then spread to the back,
abdomen, and chest. The soles of the feet and
palms of the hands also turn red and swell.
Symptoms usually last for up to 10 days, but the
patient is weak and extremely tired for up to a
month afterward. In more severe cases, patients
have fever and headache, then develop a cough.
The dengue virus causes the blood vessels to
swell and leak, creating small purple colored
spots on the skin, called petechiae. The skin may
appear bruised in areas where the bleeding is
worse. Bleeding into the stomach causes severe
abdominal pains and vomiting of a black, grainy
substance that looks like coffee grounds. This
severe bleeding, called hemorrhaging, occurs when
the blood runs out of clotting factors. The
damaged blood vessels eventually become so large
that they are unable to supply the needed blood
flow and the oxygen it carries to the body's
tissues. This causes the body to go into shock,
and can damage major organs such as the heart and
kidneys.
Severe cases of dengue fever are called dengue
hemorrhagic fever (DHF) or dengue shock syndrome (DSS).
The body produces antibodies, which are
disease-fighting cells, that protect the patient
who has had dengue fever from being reinfected for
around one year. However, more severe cases of
dengue fever often occur in patients who have
already had the virus, then are reinfected at a
later time. Because the immune system recognizes
the virus, it overreacts, causing more severe
symptoms. Most people who have had dengue fever
are more likely to have recurring similar viral
infections over the years.
How is it diagnosed?
The arbovirus that causes dengue fever can be
diagnosed by a blood test.
What is the treatment?
Dengue fever, like other arbovirus infections,
must run its course. Treatment is focused on
medications to lower fever and reduce pain, fluids
to prevent dehydration, and bed rest. Blood
transfusions are given in cases of severe blood
loss, and oxygen must be given to patients with
dengue shock syndrome (DSS). Almost all patients
with dengue fever have a complete recovery. Those
with DSS have a good prognosis if they receive
immediate medical treatment.
Self-care tips
There are ways to protect yourself if you are
traveling to a country that is known to have a
high population of dengue fever-carrying
mosquitoes. You can avoid mosquito bites by using
a mosquito repellent spray or lotion on your body
and clothes and staying in well-screened areas.
Your sleeping area should have mosquito netting
over the bed. Avoid leaving any containers of
standing water outside where mosquitoes can breed.
See a healthcare professional immediately if you
have been in an area endemic to dengue fever and
you have any illness with fever that lasts for
more than two days.
This information has been designed as a comprehensive and quick reference
guide written by our health care reviewers. The health information written
by our authors is intended to be a supplement to the care provided by your
physician. It is not intended nor implied to be a substitute for
professional medical advice.
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