The Dengue Fever... what is it ?
It is not a question of scaring people who want to come to Phuket for a few days of holidays, but there is no harm in warning by reminding them that they should be wary of mosquitoes during the day.
There is no prevention of this disease, no vaccine.
A sharp increase in Dengue fever is reported by Thai authorities, particularly in Phuket: The number of reported cases of Dengue fever is increasing:
Since January 1, 2010, 213 cases have been reported, and places Phuket among the most affected on the entire Andaman coast.
Nearly 14,000 cases of dengue fever infections have been reported in Thailand since the beginning of the year, including more than 7,700 cases of haemorrhagic dengue fever and 17 deaths. The number is expected to increase further.
Dengue fever is an acute infectious disease caused by a virus - a flavivirus. It is an arbovirus, i.e. a disease transmitted by an arthropod (here an aedes mosquito). There are currently more than 400 arboviruses listed, the best known of which are the Yellow Fever and Dengue Fever viruses. This disease is extremely widespread in intertropical areas. It is usually benign but its bleeding forms can be frightening. There are 4 variants of the virus (serotype 1 to 4) which unfortunately do not cause cross immunity: it is therefore possible to make a dengue 1 and a few months after a dengue 2 for example. The sick man represents the reservoir of disease.
Unlike the anopheles, a vector of malaria, which bites at night, the aedes eagypti is a day mosquito, whose activity begins in the early morning and ends at sunset. It lives more in urban and peri-urban areas.
There are about 50 million cases of dengue fever per year among an exposed population of 3 billion people in about 100 countries.
The incubation period of the disease is about one week. The clinical picture is reminiscent of influenza: the onset of symptoms is sudden with high fever, chills, headaches with fairly characteristic retro-orbital pain (behind the eyes), myalgia (muscle pain) and arthralgia (joint pain), sometimes with digestive signs and a skin rash. In malaria-endemic areas, this clinical picture should also evoke malaria. After a few days, the clinical picture fades, sometimes with a small symptomatic rebound around day 6 or 7. Then, a few days later, healing begins but the patient will remain asthenic for several weeks.
There are attenuated forms of the disease, with only fever, forms with fairly severe liver damage (very significant increase in liver enzymes: transaminases) and serious forms, fortunately relatively rare: dengue haemorrhagic fever. After a classic onset, the patient worsens abruptly around day 3 or 4, with the appearance of purpura (purple spots on the skin) and digestive or nasal bleeding. At this stage, the patient may either progress to rapid healing or to aggravation and shock by a decrease in blood mass (bleeding losses can be significant). Death occurs in 5 to 10% of cases. Severe forms mainly affect children under 15 years of age and immonodeficient people. WHO estimates that there are 500,000 cases of dengue haemorrhagic fever annually.
The clinical diagnosis of the disease is difficult, especially when compared to the classic flu-like form. It is almost impossible to differentiate clinically between dengue fever and other arboviruses, but also other tropical fevers such as malaria or even genuine influenza, which do not spare hot intertropical areas as some may think.
Dengue hemorrhagic fever may be confused with a meningococcal disease.
The positive para-clinical diagnosis is based on serology by testing for antibodies in the blood. It should not be undertaken too early or it may be negative. It takes about a week for the antibodies to appear in the patient's blood. In any case, it is of epidemiological interest only.
It is also possible to diagnose by virus isolation. This is interesting at the beginning of the disease, when the serology is still negative.
It is only symptomatic: only the symptoms of the disease (fever, pain...) are treated. There is currently no cure for this disease, nor is there any vaccination available. Hence the importance of mosquito control (vector control): prevention during the day against dengue fever, and in the evening and at night against malaria.
The treatment of the classic uncomplicated form is therefore based on paracetamol-based antipyretics and analgesics. The severe haemorrhagic form will be treated in hospital most often.
NB: Due to the risk of bleeding, aspirin derivatives are contraindicated in the treatment of dengue fever. Thus, in the event of any viral disease in endemic areas, the use of aspirin should be avoided in favour of paracetamol-based medications. For the same reasons, NSAIDs (non-steroidal anti-inflammatory drugs) should be avoided.
Vaccines are under study but will certainly not be available for several years.
Reached in turn...
My Personal Experience
Infected by dengue fever in Phuket, in 2009, I found myself in a hospital room for a week. Fortunately, it was dengue type 1, the least serious, but the fever knocked me out for 6 days.
Treatment was limited to the absorption of paracetamol to reduce fever or treat some temporary headaches.
There is, in fact, no other special treatment.
A blood test every morning (very pleasant to wake up) to monitor the level of blood platelets... which decrease during a dengue infection, this level being normally around 150 to 400,000 per mm3.
During this infection, this rate had decreased to between 30 and 40,000 platelets per mm3. At that time, it was advisable to be suspicious when brushing my teeth or shaving: avoid any bleeding that would be difficult to stop because of the low level of these platelets.
At the end of the 6th day of fever, the platelets started to rise, it was a sign of improvement, and healing.
8th day, return home, with about fifteen days to three weeks of physical recovery. A week's fever makes a body tired...
A few days later, it was my daughter who caught dengue fever in turn. Same symptoms, same treatment, same reaction, but she recovered more easily...
Children have died in Thailand: often children whose parents cannot afford to pay for the hospital (Burmese workers for example), or who thought it was just a simple fever.
Dengue fever 1 is not too serious, but it is advisable to monitor closely by consulting a doctor, especially for children.
At the "Bangkok-Hospital" in Phuket, I was told (only yesterday) that after being sick, immunity was only one year, for both adults and children.
So beware of mosquitoes....
That being said... every mosquito you see prowling around at one time or another, does not necessarily carry dengue fever....
But don't let this stop you from coming without fear and having a good holiday in Thailand.