Dengue fever is a quite
dangerous febrile disease that can even cause death. Nowadays, this disease can
be found in the tropics and Africa. Do not think that it is only thick forests
where dengue fever can be found. The urban areas of many developed countries
like Brazil, Singapore, Taiwan, Indonesia, and India are also liable to this
disease. Dengue fever is transmitted by Aedes aegypti mosquito, which also
transmits such diseases as Chikungunya and yellow fever.
n a molecular level, dengue
fever is classified as a flavivirus and appears as a spherical particle, about
40 to 50 nanometers in diameter . There is a lipid envelope enclosing a
nucleocapsid core. The dengue virus genome is a single-strand positive sense
RNA of approximately 11 kilobases . The mature virions contain three structural
proteins: C (capsid), prM (membrane) and E (envelope) and 7 nonstructural
proteins.
Once a person is infected
by dengue fever, symptoms will start to appear anywhere from four to six days
after the pathogen has been transmitted from the infected mosquito to the
person. The virus can not be spread from an infected person to another person.
However, if another mosquito bites the infected person, the virus can be
transmitted to another person through that newly infected mosquito. The
infected person remains a viral source for other mosquitoes for about 6 days.
The signs and symptoms of
dengue fever resemble symptoms of the common flu at first. An infected person
will first experience a sudden high fever, followed by a severe headache, loss
of appetite, a rash, and deep excruciating muscle and joint pains. The disease
is often given the name 'breakbone fever' for the last two symptoms. The rash
commonly shows up first on the torso, and spreads to the face, arms and legs.
The rash usually appears three to four days after the start of the fever
(Spira, 1998). The illness can last for up to ten days, but in some cases, recovery
can take up to one month (Spira, 1998).
Most dengue infections are
mild cases. However, if a person is re-infected with a different serotype of
the dengue virus, there is an increased risk of a more serious disease
resulting in dengue hemorrhagic fever (DHF). DHF causes the blood vessels to
leak and causes bleeding from the nose, mouth, gums, and intestinal tract. In
moderate cases of DHF all signs and symptoms subside after the fever drops. In
severe cases the patient's condition may suddenly worsen. The patient's
temperature may drop abruptly without warning. A rapid drop in blood pressure
and signs of circulatory failure commonly follow this decline in body
temperature. The blood vessels will soon start to collapse and the patient will
enter into a state of shock, which can be fatal. The patient can die within a
few hours or can quickly recover with immediate administration of intravenous
fluids to expand the collapsing veins. With intensive supportive therapy,
mortality may be reduced to less than 1 percent (Rashid, 2000).
Shock is a very serious
condition and one problem that often arises is that DHF often goes
mis-diagnosed by doctors.
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