Deadly Dengue, A Tropical Disease

Recent news reports show that there has been an increase in the number of dengue victims compared to 2005. The province of Rizal in the Philippines was declared as having an outbreak and already has 6 fatalities because of this disease. Although this disease has become popular in the last 3 years, people still lack the knowledge of what dengue fever really is. We are not really familiar with how dengue is transmitted, the signs and symptoms, and prevention. We also need to know the difference between classic dengue, dengue hemorrhagic fever and dengue shock syndrome, which common people think are the same.

HISTORY
The term "dengue" comes from the Swahili phrase "ki denga pepo" or "cramp-like seizure caused by an evil spirit." Dengue fever used to be called "break- bone fever," a term coined by Benjamin Rush, because of the severe joint and muscle pain that comes with the illness. The first case of dengue was noted in 1789 and the first outbreak was in the Carribean in 1827-1828. The most number of dengue cases occurs after the rainy season in tropical areas like: Africa, Southeast Asia, China, India and the Middle East. There have also been numerous cases in Central and South America, Australia, the South and Central Pacific.

TRANSMISSION
Dengue fever can be transmitted through the bite of an infected Aedes mosquito.

There are two species of this mosquito that are responsible for this disease; the Aedes aegypti and Aedes albopictus. The Aedes aegypti is the most common transmitter of the disease than the Aedes albopictus. These mosquitoes become a carrier once they bite a person with dengue and become infected. Thus, the next victim the mosquito bites will be infected with the disease it is carrying. With this nature of transmission, dengue has become the second most important mosquito- borne disease by the 1990s.

SIGNS AND SYMPTOMS
The first symptom of classic dengue is usually the sudden onset of fever after 5-6 days from the time the person was bitten. This fever is high reaching up to 105 degrees Fahrenheit or 40 degrees Celsius. The person will also experience severe headache, severe joint and muscle pain, pain behind the eyes, nausea, vomiting, gastritis or diarrhea. Rashes will also appear 3 to 4 days from the onset of fever first on the lower limbs and the chest, or in some cases, even all over the body.

Dengue hemorrhagic fever has the same symptoms but with bleeding from the nose, gums or purplish bruising. This form of dengue can be fatal. The criteria set by the WHO used to determine dengue hemorrhagic fevers are as follows:

1.Fever

2.Haemorrhagic tendency (positive tourniquet test, spontaneous bruising, bleeding from mucosa, gingiva, injection sites, etc.; vomiting blood, or bloody diarrhea)

3. Thrombocytopaenia (<100 platelets per mm3 or estimated as less than 3 platelets per high power field)

4. Evidence of plasma leakage (haematocrit more than 20% higher than expected, or drop in haematocrit of 20% o more from baseline following IV fluid, pleural effusion, ascites, hypoproteinaemia)
Dengue shock syndrome is the most severe type of dengue. All symptoms of classic dengue and DHF are present plus fluids would already be leaking outside the victim's blood vessels. There is also massive bleeding, shock caused by very low blood pressure, weak and rapid pulse, clammy skin and restlesness. This form of dengue usually occurs in children or your adults on their second dengue infection and can sometimes be fatal. The best way to prevent fatality is if the signs and symptoms of dengue are already present, going to the doctor should be a must. Most people who succumb to dengue disregarded the symptoms and went to the doctor too late.

DIAGNOSIS
The diagnosis of dengue is clinical or through blood test which will show whether the blood is infected with the dengue virus. This is usually done once the patient complains of high fever for several days but no possible source of infection can be physically determined. The drop in the normal platelet count of the patient could be a possible indication of dengue but they would need to perform the tests several times to establish whether the disease can be considered as dengue hemorrhagic fever.

TREATMENT
There is only supportive treatment for dengue, thus, people afflicted with the disease need to get plenty of rest and increase of oral fluids and water intake. Taking paracetamol to control fever is also advised except for medicines that may contain aspirin since it is found to aggravate the person's illness. For dengue shock syndrome, intensive supplementation of intravenous fluids is administered to prevent dehydration. Platelet and blood transfusion may also be done as per discretion of the doctor.

PREVENTION
The best way to combat and prevent dengue is by avoiding contact with mosquitoes. People are advised to use mosquito repellant and mosquito nets with DEET, wearing protective clothing like long sleeved shirts, pants, socks and shoes. Regular fumigation and public spraying is also required to eliminate mosquitoes especially in areas that attract them. Since the aedes mosquito usually bites during the early morning hours and late afternoon before dark (4-6pm), it is best to apply liberal amounts of mosquito repellants before these hours. Also, we should not stock clean water since the mosquitoes thrive here or if it is necessary. Keep the basins well covered.

There have been studies by a Swiss company, Novartis in 2002 together with the Singapore Economic development to produce an anti-viral drug to prevent dengue but is still in the process of research. The National Institute of Allergy and Infectious Diseases (NIAID) is also trying to develop vaccines to prevent dengue. It is said that immunization for this disease will take a long time to be approved by the Bureau of Food & Drug. The fact is, at present there is still no known way to treat patients with dengue. Scientists are still on the process of discovering how the virus affects the cells of humans or how it affects our immune system. The deadly dengue fever that has been with us for 2 centuries and has killed millions is still in our midst and the possibility to be infected will be forever hanging over our heads until a breakthrough in medicine that would finally put a stop to this disease is discovered. Until then, it will be up to us to take care of our health and make sure that we do everything in our power to prevent it from happening to our children, our fellow men and us.