Thai Travel Clinic Blog

“What is the chance to get dengue infection while traveling in Southeast Asia?” is a very good question. But it is difficult to answer. Since at least we have to know two numbers; the first one is the total number of travelers in Southeast Asia and secondly we have to know how many of them actually got dengue infection during their trip.

To get these two numbers precisely is not easy since there are many limitations as you might imagine. However, base on previous researches, the risk to develop dengue infection (symptomatic) among travelers is considered to be around 1% per month [1].  The majority of cases (more than 90%) will be mild, only small percentage of cases will develop severe disease [2,3,4].  Fatal dengue cases among travelers are rare.

At this point, several questions may arise such as;

1. So how could we prevent dengue?

Unfortunately, right now, neither vaccine nor medication is available for prevention of dengue. The best way is to prevent yourself against mosquito bite. Please use insect repellent, especially DEET containing repellent. Since it is the most reliable and effective compound. And please keep in mind that mosquito that transmitted dengue exists everywhere in Southeast Asia including in major cities.

2. What happen if I am bitten by a mosquito?

Firstly, don’t panic. Not all mosquito carry dengue virus. And even you expose to dengue virus, you might have no symptom or develop only mild disease.  However, if you do develop high fever during your trip in Southeast Asia, you should go to see a doctor.

3. Which hospital in Thailand that could take care dengue cases?

Dengue is a very common disease in Thailand. Doctors in Thailand and also in Southeast Asia are quite familiar with dengue infection. So virtually all hospital in Thailand is able to manage dengue case. However, in some severe or complicated cases, referral to secondary or tertiary care center may be necessary.

4. “The risk to get dengue seems  to be very high for me,  should I travel in in Southeast Asia?”

First thing to say is, we could not totally eliminate the risk. Risks are everywhere. Such as, if you decide to travel, you have to accept many risks, starting from the risk of transportation accidents, risk of being robbed, risk to get some diseases from the destination, etc. We should try our best to reduce the risk. Risk is not to afraid or panic. Risk is just to understood and managed.

References:

1. Steffen R, Amitirigala I, Mutsch M. Health risks among travelers–need for regular updates. J Trav Med 2008; 15(3):145-6.
2. Jelinek T, Muhlberger N, Harms G, et al. Epidemiology and clinical features of imported dengue fever in Europe: Sentinel Surveillance data from TropNetEurop. Clin Infect Dis 2002;35:1047-52.
3. Laferl H, Szell M, Bischof E, Weinisch C. Imported dengue fever in Austria 1990-2005. Trav Med Infect Dis 2006;4:319-23.
4. Wichmann O, Muhlberger N, Jelinek T. Dengue-the underestimated risk in travellers. Dengue Bull 2003;27:126-37.

Generally, in our travel clinic, when we give some advices about malaria; we will try to add something about dengue also. Since, in fact, the risk for travelers to get dengue while traveling in Southeast Asia is far greater than malaria. However, not surprisingly, dengue infection is less known to travelers when compared to malaria.

Let’s start with some basic, yet important, information about dengue.

1.  Dengue is a mosquito borne disease. It exists in many countries in tropical/subtropical area including in Asia, Africa, Central and South America. See the map from World Health Organization (WHO) below. Among these areas, Southeast Asia is considered to be the most important risky area for travelers.

2.Main mosquito species that transmits dengue is called Aedes aegypti. They exist in both rural and urban area throughout Southeast Asia including major cities such as Bangkok, Singapore.

3. You may get dengue infection if you are bitten by an infected mosquito with dengue virus. The usual incubation period (time between bitten until symptoms develop) is around 3-7 days.

4. Dengue infection has a wide of clinical spectrum, ranging from asymptomatic infection, to fatal disease. Fortunately, most dengue infections are mild or even asymptomatic infection. Small percentage of patients may be severe such as develop bleeding, hence named dengue hemorrhagic fever, and may leading to shock and death.

5. So that’s mean, even you are bitten by an infected mosquito that carries dengue virus, you have a high chance to be fine or develop such a mild fever, especially if that is your first exposure to dengue virus (primary dengue infection). It is unlikely that you will be critically ill.

6. Most common symptoms of dengue infection are fever, headache, muscle pain, bone pain, rash, nausea and vomiting. Fever in dengue infection is usually high and persistent, lasting for 2-7 days. Severe manifestation such as bleeding and shock may occur in some cases especially when fever start to decline.

7. Dengue is a self-limited disease. Most patients with dengue will recover spontaneously. Only few percent of patients will require hospitalization. However, we have to consider dengue infection as a serious disease. Whenever you develop symptoms that resemble to dengue infection as describe above, you should seek for medical care.

Those are some important basic information about dengue, we’ll discuss further on the risk and how to prevent dengue in travelers in the next article.