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Dengue fever is a flu-like viral disease common throughout the tropical and sub-tropical regions around the world, mainly in urban and peri-urban areas. Today, it afflicts an estimated 50 million to 100 million in the tropics (Epstein, 2000). The virus has four antigenically related serotypes, which are named DEN-1, DEN-2, DEN-3, and DEN-4. Each dengue serotype is a variation of the flavivrus genus. Dengue is spread by the aedes aegypti, a domestic, day-biting mosquito that prefers to bite humans. Currently, there is no vaccine available to prevent dengue.

Each type of the dengue virus is re-emerging worldwide, especially in the Western Hemisphere. Research has shown that several factors are contributing to the resurgence of dengue fever such as uncontrolled urbanization, increased international travel, substandard socio-economical conditions, and finally global warming. Global warming has shown to be a major contributor to the spread of dengue fever.

On a molecular level, dengue fever is classified as a flavivirus and appears as a spherical particle, about 40 to 50 nanometers in diameter (www.malarde.pf...). There is a lipid envelope enclosing a nucleocapsid core (www.malarde.pf/...). The dengue virus genome is a single-strand positive sense RNA of approximately 11 kilobases (www.malarde.pf/...). The mature virions contain three structural proteins: C (capsid), prM (membrane) and E (envelope) and 7 nonstructural proteins (www.malarde.pf/...).

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 (http://astdhpphe.org...). 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 (http:///astdhpphe.org...).

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. In other