Dengue Fever 1

"I travel in tropical areas where many tourists come to enjoy their illustrious summer vacations, but they end up leaving feeling hotter than originally anticipated."

                                   

DESCRIPTION

The Dengue fever virus belongs to the viral family of Flaviviridae. This family is enveloped, has quite a small virion particle (40-50 nm), and has a positive-sense single-stranded RNA genome.

Epidemics of this virus were commonly seen in the Caribbean, Australia, Asia, and North America in the 18th and 19t centuries. The virus was isolated by Sabin and Schlesinger in mice in 1944. This virus remains a worldwide problem and it typically recurs in tropical areas. The most severe manifestation of this disease was seen for the first time in 1954, which is the Dengue hemorrhagic fever. It has then emerged as the most important arthropod-borne viral disease that afflicts humans. There are four serotypes of the dengue virus and this particular serotype of the Dengue virus is denoted by monoclonal and polyclonal antibodies.

The incidence of this virus has increased quite a bit since World War II, as populations have grown and expanded thus allowing for a larger population of mosquitoes as well. Furthermore, the rise in numbers of individuals traveling has also led to this increased incidence.

POWER

This serotype of the virus is non-lethal.

OFFENSES

ATTACKS

Transmission is by an arthropod vector, namely an urban mosquito, Aedes aegypti. Proliferation of the dengue virus is found to be in the brain, the midgut epithelium, salivary glands, and fat body of the mosquitoes.

After performing studies on the skin lesions of infected persons, swelling has been observed in endothelial cells of small vessels and infiltration of mononuclear cells.

OUTCOME

The disease begins suddenly with a high fever, facial flushing, pain in the eyes, lumbosacral aching pain, conjunctival congestion, and headache. The fever may last for up to a week. These initial symptoms are followed by bone pain, loss in appetite, nausea, and general weakness. Coughing, sore throat, and rhinitis are also common symptoms. A rash may also appear and it first appears in the abdomen area, thereafter reaching the face and limbs.

The symptoms of a hemorrhagic phenomena include intestinal bleeding, menorrhagia, myocarditis and various neurologic disorders. These neurologic disorders are usually specific to the Dengue hemorrhagic fever and do not pertain to the classic dengue infection.

SPEED

The typical incubation period for Dengue is 2 to 7 days.

The female mosquito is able to transmit the dengue virus, from feeding on an infected human, after an incubation period of 8 to 10 days. In this time, virus replication and dissemination are induced and result in the infection of the salivary glands which causes the mosquito to be infective for life.

Some determinants of the rate of transmission for the dengue virus are the density of vectors and factors which determine exposure to infected female mosquito vectors.

DEFENSES

VACCINES

No vaccine has been successfully developed or licensed. Although several trials of live, attenuated vaccines have been conducted, these vaccines have not proven effective in that some are neurovirulent. Because of this lack of an effective live, attenuated vaccine, there have been strategies implemented to develop a genetically engineered vaccine.

BEHAVIORAL

It has been proven that protection against homoptypic reinfection is complete and is likely lifelong. The cross-protection that exists between the various serotypes remains for less than 3 months.

Because mosquitoes breed in stagnant, still water it is important to avoid these bodies of water, especially at dusk and dawn when mosquitoes are most active, and if you must be in these areas it is important to apply insect repellant.

When there is an epidemic, the emergency measure usually taken is to interrupt the route of transmission. This is done by killing infected adult female mosquitoes. Also, this may be done by restricting the availability of potential breeding habitats.

TREATMENT

Recommended treatment for this virus consists of bed rest and analgesics. Also, if the infected individual is dehydrated, electrolyte and fluid replacement is also used.

Currently, there are no specific anti-viral treatments available.

It is noted that even without treatment, if infected with Dengue Fever 1 the person will recover and the result of death from this type is extremely rare.

GAME ACTION

You are on a lush vacation to Australia. While partaking in a nice walking tour, you happen to pass a stagnant body of water and upon your return to the hotel room, you realize you have several bites. After several days, you display some of the typical signs and symptoms of Dengue fever 1. The doctor makes a call to your hotel room and diagnoses you with Dengue fever. You are due to return home in 2 days and realize that this could be dangerous, in terms of you being able to infect others around you. What is your plan of attack, will you postpone your return home, or will that urgent deadline pressure you to put others in danger?

 

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