Everything you need to know about Dengue Fever in children and adults

What is Dengue Fever and how does it spread?

Dengue is a type of virus, and it has 4 different strains.
This virus spreads from mosquitoes to people through mosquito bites (by a particular mosquito called Aedes), that can be found in lots of different places in the world.

Where does Dengue commonly occur in the world?

Dengue Fever occurs in over 100 different countries in the world (40% of the world’s population live in areas that are exposed to Dengue), mostly in Asia, Africa, Central and South America, the Caribbeans, the Pacific Ocean and the tropical and sub-tropical regions. Dengue is now spreading to new areas as a result of the change in climate, environmental population and processes of urbanization.
In certain parts of the world, Dengue is considered the most common traveller’s febrile illness.
On the website for Centers for Disease Control and Prevention, there is a map of the world showing countries with recent Dengue outbreaks and you can access it here.

What are the signs and symptoms of Dengue Fever?

Anything is possible with Dengue Fever. Anything from being asymptomatic (no symptoms whatsoever) to a mild disease or a severe disease with fever.
But, and this is a huge but here, over 5% of the people who get the virus for the second or third time (which is obviously more common in locals to endemic areas as opposed to travellers), a severe disease develops, including severe bleedings and shock.

What are the typical clinical symptoms in travellers?

If this is the traveller’s first time to get infected, the symptoms will usually start abruptly and include 2-7 days of fever, muscle pain, join pain and bone pain. In addition, some people complain of headaches, vomiting, pain in the orbital area (around the eyes) and a rash.

Who is at risk of developing severe Dengue Fever?

As I already mentioned above, people who have already had the infection once (or twice) are at higher risk of developing severe disease when contracting it for the second time. However, severe disease has also been reported in babies, pregnant woman, and people with underlying chronic conditions getting infected for the first time.

How long is the incubation period for Dengue Fever and why is it important?

Knowing the incubation period is important for infectious diseases as it gives you an idea of the duration of time between exposure to a virus (in this case exposure would be the mosquito bite) and the onset of symptoms.
Dengue Fever has an incubation period that averages around 2-5 days, but it could be as long as 14 days.
Why is this important for us?
If someone was visiting Thailand, for example, and develops fever 20 days after returning home, then it is unlikely that their fever is due to Dengue and as doctors we must think of other possible reasons.

How can we prove that a person has Dengue Fever?

In addition to the clinical suspicion that arises when a patient presents with fever, the typical signs and rash, often if blood tests are performed, they reveal findings such as a lower white blood cell count (read more here) and platelet count which can be suggestive of Dengue Fever.
Furthermore, viral serology testing (antibody levels) can be performed. The IgM type of antibody will detect a current infection, started the 3rd to 5th day of fever.
Also, PCR blood tests can detect the infection starting the first day of fever and up until 7-10 days after.

How can Dengue Fever be treated?

The only available treatment for Dengue Fever is symptomatic treatment. That means reducing fever, helping with pain alleviation and hydration (providing fluids) for those who are dehydrated.
There is currently no available anti-viral medication specifically for Dengue Fever.
Note that if Dengue is suspected (such as with a returning traveller presenting with fever) we prefer reducing the fever with the help of paracetamol and not with aspirin or any other medication from the NSAIDs family such as ibuprofen (Advil, Nurofen, etc.).

Can you become immune to Dengue after getting the infection once?

Once a person has contracted one of the four strains of Dengue Fever, they become immune to that specific strain for the rest of their life. However, they remain immune to the other 3 strains for 1-3 years only. After those 3 years, they may contract Dengue through one of the remaining 3 strains and then they are at a 5% risk of developing severe disease, as I mentioned above.

So, theoretically speaking, how many times can a person get infected with Dengue?

A person can get Dengue fever up to 4 times in their lifetime.

Is the possibility of exposure to Dengue a reason to avoid travelling to areas at risk?

I personally don’t think so. Anywhere you go to in the world you are at risk of contracting one infectious disease or another. Nonetheless, there are ways through which you can minimize this risk, as you will see below.

What about a person who has already been infected with Dengue? Is that a reason to avoid travelling to areas where the virus can be found?

This is not something that has been recommended in the medical literature and it is obviously a person’s own decision. Keep in mind that there are certain areas that carry a greater risk while others carry a lower risk.
Either way, if someone is travelling to an area at risk for the second time, they should take precautions as listed below.

Is there a vaccine for Dengue?

Yes, a live-attenuated vaccine that is administered in 3 doses is available in several countries around the world. Newer vaccines are under development.

How can we prevent Dengue Fever?

Easy. Avoid mosquito bites by:
a. Ensuring you wear clothes that cover the body and minimize exposure to mosquito bites (long-sleeved shirt and long pants)
b. Apply a good amount of mosquito repellants on areas that are exposed to bites. What kind of mosquito repellants are preferable, you ask? A post dedicated to answering that question will be coming up soon. Keep in mind that areas that are at higher risk of infection tend to carry highly concentrated mosquito repellants. Just make sure that they are suitable for the age of the person you are applying it on.
c. Try to sleep in a room that is closed and air-conditioned, preferably with screened windows and doors. Be aware of these conditions for younger babies and children who sleep during the daytime as well.

In summary, this is an interesting topic. I know quite a few travellers who got infected with Dengue and they all complained of an unpleasant disease. And if you want to read more of travelling abroad with children, use this link (coming soon).
If you live in a part of the world that doesn’t get Dengue, then you’re lucky!

And if you happen to be travelling soon, don’t forget to read my post about travelling abroad with children, here.

Be safe my friends!