AsiaLIFE

A mosquito-borne viral disease, Dengue Fever is widespread across tropical areas of the world, especially Southeast Asia. Most common in urban environments, around 2.5 billion people worldwide are at risk. There are about 50 million cases a year. In Cambodia most cases occur in the rainy season between about June and November although there is some transmission all year.

 

 

Dengue is one of the leading causes of child mortality in Cambodia. In 2007, there were almost 40,000 cases with 400 deaths. Last year was much quieter with 10,000 cases and 65 deaths, mostly in children. The relatively low incidence of infection in 2008 means there is now a pool of non-immune children who are susceptible to the infection. This raises the chances of another epidemic this year. Already the number of infections has increased compared to last year, so it is important to be vigilant.

 

The disease is spread by the bite of an infected Aedes aegypti mosquito. Also known as ‘tiger’ mosquito (‘mu klaa’ in Khmer) due to its largish size and stripy legs, Aedes are day biting and have their peak activity after sunrise and for a few hours before sunset. They need small pools of fresh water to breed and can fly up to 200 metres. You cannot get Dengue Fever from direct contact with an infected person!

How Do I Know If I Have Dengue?
The standard version of Dengue is characterised by sudden onset of high fever with intense headache (often right behind the eyes), muscle and joint pains, and intense exhaustion or malaise. The fever usually lasts for five to seven days, sometimes with a rash occurring around day six. This reflects the development of the body’s immunity to the virus. It usually consists of small red spots all over the torso and/or limbs. The palms of the hands may feel very hot, itchy and uncomfortable.

 

It is typical to feel nauseous, to have trouble drinking and to be unable to eat for several days. This often leads to dehydration and a need for intravenous fluids. If you are sick enough to need to see a doctor, blood tests will show a lowered white blood cell count and decreased platelets from about day three of the illness. It is advisable not to travel by motorbike or bicycle if you have low platelets because of the risk of serious bleeding should you have a crash. The low white cell count makes you more susceptible to infection and so you should avoid anyone else who is sick.

 

If you become very dehydrated, show signs of bleeding, have very low platelets, are pregnant, are on blood thinning treatment, or have a stomach ulcer you should be admitted to hospital. Although the disease is usually relatively mild and self-limiting, it may present in a severe form known as Dengue Haemorrhagic Fever or Dengue Shock Syndrome. This is more common in those under 15 years of age having their second infection, but may occur at all ages and with a first infection. For Cambodians, Dengue Fever is largely a disease of childhood. Most adult Cambodians who grew up in Cambodia will have already been exposed to the virus multiple times and likely developed immunity through infection.

How Long Does It Last?
The disease is at its worst in the first week of fever. The second week, after the fever breaks, you should feel better and be able to eat and drink more normally, although you may have a rash and sore/hot hands and feet. It is normal to still feel utterly exhausted during this week. After this, recovery is quite varied. Some adults seem to bounce back quickly while others have a type of post-viral fatigue that may last several months. This can take the form of tiredness, lethargy and even depression. It is also common to experience hair loss around three months. Do not panic if this happens, it will grow back. There are four serotypes of the Dengue Fever virus. Once you have had an infection you have life-long immunity to that strain.

Preventing Dengue
There is currently no vaccine or drug prophyalxis for preventing the disease. Vigilance to prevent mosquito bites during daytime hours is the best means of prevention. Screening of houses and using knock-down sprays every couple of days helps. Making sure your own yard or apartment building does not have breeding sites for mosquitoes is imperative. Get rid of old plant pots, old tyres, any piles of junk lying around. Ornamental ponds should have larvae-eating fish living in them. Use an effective insect repellent daily, especially on the lower legs. The repellent should contain DEET or citridiol – this comes from lemon eucalyptus and is not the same as citronella, which smells lovely but is ineffective. If you eat in an outdoor setting, especially in the hour before dusk or early morning, burn a mosquito coil under the table.