What is dengue fever?Dengue fever is a disease caused by a family of viruses that are
transmitted by mosquitoes. It is an acute illness of sudden onset that
usually follows a benign course with
headache,
fever, exhaustion, severe joint and
muscle pain, swollen glands (
lymphadenopathy), and
rash. The presence (the "dengue triad") of fever, rash, and headache (and other pains) is particularly characteristic of dengue.
Dengue (pronounced DENG-gay) strikes people with low levels of
immunity. Because it is caused by one of four serotypes of virus, it is
possible to get dengue fever multiple times. However, an attack of
dengue produces immunity for a lifetime to that particular serotype to
which the patient was exposed.
Dengue goes by other names, including "breakbone" or "dandy fever."
Victims of dengue often have contortions due to the intense joint and
muscle pain, hence the name breakbone fever. Slaves in the West Indies
who contracted dengue were said to have dandy fever because of their
postures and gait.
Dengue hemorrhagic fever is a more severe form of the viral illness.
Manifestations include headache, fever, rash, and evidence of
hemorrhage in the body.
Petechiae(small red or purple blisters under the skin), bleeding in the nose or
gums, black stools, or easy bruising are all possible signs of
hemorrhage. This form of dengue fever can be life-threatening or even
fatal.
What areas are at high risk for contracting dengue fever? Dengue is prevalent throughout the tropics and subtropics. Outbreaks
have occurred in the Caribbean, including Puerto Rico, the U.S. Virgin
Islands, Cuba, and Central America. Cases have also been imported via
tourists returning from areas with widespread dengue, including Tahiti,
the South Pacific, Southeast Asia, the West Indies, India, and the
Middle East.
Dengue fever is common and may be increasing in Southeast Asia.
Thailand, Vietnam, Singapore, and Malaysia have all reported an
increase in cases. According to the World Health Organization, there
were 188,684 cases of dengue reported in 2006, with Indonesia having
57% of the reported cases.
How is dengue contracted?The virus is contracted from the bite of a striped Aedes aegypti
mosquito that has previously bitten an infected person. The mosquito
flourishes during rainy seasons but can breed in water-filled flower
pots, plastic bags, and cans year-round. One mosquito bite can inflict
the disease.
The virus is not contagious and cannot be spread directly from person
to person. There must be a person-to-mosquito-to-another-person
pathway.
What are the signs and symptoms of dengue?After being bitten by a mosquito carrying the virus, the incubation
period ranges from three to 15 (usually five to eight) days before the
signs and symptoms of dengue appear. Dengue starts with chills,
headache, pain upon moving the eyes, and low backache. Painful aching
in the legs and joints occurs during the first hours of illness. The
temperature rises quickly as high as 104° F (40° C), with relative low
heart rate (
bradycardia) and
low
blood pressure (hypotension). The eyes become reddened. A flushing or
pale pink rash comes over the face and then disappears. The glands
(lymph nodes) in the neck and groin are often swollen.
Fever and other signs of dengue last for two to four days, followed by
rapid drop in temperature (defervescence) with profuse sweating. This
precedes a period with normal temperature and a sense of well-being
that lasts about a day. A second rapid rise in temperature follows. A
characteristic rash appears along with the fever and
spreads from the extremities to cover the entire body except the
face. The palms and soles may be bright red and swollen.
How is dengue fever treated?Because dengue is caused by a virus, there is no specific medicine or
antibiotic to treat it. For typical dengue, the treatment is purely
concerned with relief of the symptoms (symptomatic). Rest and fluid
intake for adequate hydration is important. Aspirin and
nonsteroidal anti-inflammatory drugs should be avoided.
Acetaminophen (Tylenol) and
codeine may be given for severe headache and for the joint and muscle pain (
myalgia).
How can dengue fever be prevented?The transmission of the virus to mosquitoes must be interrupted to
prevent the illness. To this end, patients are kept under mosquito
netting until the second bout of fever is over and they are no longer
contagious.
The prevention of dengue requires control or eradication of the
mosquitoes carrying the virus that causes dengue. In nations plagued
by dengue fever, people are urged to empty stagnant water from old
tires, trash cans, and flower pots. Governmental initiatives to decrease mosquitoes also help to keep the disease in check.
Wear long pants and long sleeves. For personal protection, use mosquito
repellant sprays that contain DEET when visiting places where dengue is
endemic. Limiting exposure to mosquitoes by avoiding standing water and
staying indoors two hours before sunrise and sunset will help.
There is currently no vaccine available for dengue fever. There is
a vaccine undergoing clinical trials, but it is too early to tell if it
will be safe or effective.