“To everything, turn…turn…turn
To every season, turn…turn…turn …”
Well it seems to be the season for dengue fever. If you Google dengue fever (conflict of interest … my son Benjamin now works for Google) you will find many useful medical sites, as well as the musical site for the band Dengue Fever. My son Michael’s band is called The Midway State, but how I wish they would have adopted a “tropical name” such as Tickbite Fever, Delhi Belly, Aleppo Boil, Creeping Eruption or Ciguatera Poisoning!
Anyways, back to dengue fever. I have seen and heard of a few patients with this viral illness in the past week. Dengue is transmitted by the Aedes mosquito, which likes to bite during daytime hours, and often in urban areas where there are small collections of water to breed in such as empty tires, planters, construction sites, etc. Dengue has a short incubation period (3-7 days), which means it is going to make you sick fairly soon after your exposure, rather than weeks or months later which might be the case with malaria, typhoid or hepatitis. This infection is on the increase worldwide, as opposed to malaria which is experiencing a decline. Perhaps this is due to factors such as global warming, urban migration and lack of mosquito control programs.
The classical symptoms of dengue are:
- a high fever
- a severe headache, usually behind the eyes
- miserable aches and pains in the bones, hence its nickname “breakbone fever” (another good name for a band)
- a rash towards the end of the illness
Of course, these may overlap with the symptoms of several other tropical and non-tropical infections, such as malaria, typhoid fever, hepatitis, pneumonia, infectious mononucleosis, kidney infections … and much more. The laboratory can be quite helpful in the diagnosis of dengue – the white blood cell count (WBC) may be a bit low, the platelet count (the little cells that help you form a blood clot) are usually low, and the liver function tests may be elevated. Again, many of these lab abnormalities might be present with the other possible diagnoses. Tests which detect antibodies to the dengue virus are the most important way to diagnose dengue, though by the time you receive the results of these tests, the patient / you may be all better, and hopefully hasn’t succumbed to something else.
Perhaps the most important point for you, the traveller with a fever, is to make sure that you are seeing a doctor with experience in tropical, and non-tropical medicine. They should know where there is dengue, where there is malaria … and where there isn’t, what else should be considered, what tests to do, and how to treat whatever it is that you may have.
As with malaria, there are four strains of dengue fever. They may not all be circulating in the same place at the same time. The concern is that if you, or anyone else (such as a local 7 year old boy) is exposed to a second strain of dengue after a previous infection, a more serious illness called dengue hemorrhagic fever may develop. This can cause severe bleeding problems and may prove fatal without adequate supportive care.
As with most, though not all, viral infections, there is no specific treatment for dengue fever. Symptoms such as fever and pain can be treated with acetaminophen (not aspirin due to the tendency to bleed). Dengue usually resolves after about a week, though fatigue and depression may persist for some time. Dengue hemorrhagic fever may require more sophisticated treatment involving the replacement of clotting factors.
So, if you are travelling to the tropics, consider putting on some insect repellent during the day. If you are a doctor or nurse seeing patients returning from the tropics, don’t forget about dengue, or malaria for that matter.