Issue 18: September 2011 – Dr. Ahmed Jamsheed Mohamed (COO)
Dengue Fever (DF) is the fastest emerging arboviral infection, spread by Aedes mosquitoes and a major public health problem in most of the tropical and sub-tropical countries. A disease outbreak compatible with dengue had been reported in China as early as 992 AD. The first recorded epidemic of dengue was in 1635 in the French West Indies. The first confirmed epidemic of Dengue Haemorrhagic Fever (DHF) was recorded in the Philippines in 1953–1954.
First recorded dengue outbreak in the Maldives was in 1978 with 9 deaths. Relatively few cases were seen since then. However, in the past 5-6 years it has become endemic with the disease incidence increasing significantly, with frequent epidemics. The outbreaks in 2011 are found to be worse than the major outbreak of 2006. Recorded death toll due to dengue in 2011 is 11 so far, but it is very likely that this is lower than the actual figure!
Though in most Central and South American countries, effective disease prevention was achieved by
eliminating the mosquito vector, Aedes aegypti, during the 1950s and 1960s, it has never been achieved in Asia and the disease continues to be a major public health issue. An estimated 50 million dengue infections occur worldwide annually with an estimated 500,000 people with DHF requiring hospitalization while about 2.5% of those affected with DHF die!
There are four sub-types of dengue virus designated as DENV-1, DENV-2, DENV-3 and DENV-4. There is evidence of ongoing microevolution of the virus with considerable genetic variations within each serotype. Three sub-types of DENV-1, six subtypes of DENV-2, four subtypes of DENV-3 and four subtypes of DENV-4, have now being identified.
An individual may get dengue infection on four different occasions with any of the four serotypes. Infection with one serotype confers lifelong immunity to that serotype alone. Subsequent infection with other serotypes increases severity of the disease. Some studies have show that infection with DENV-2
serotype in people who were previously infected with DENV-1 serotype was associated with a 500-fold risk of DHF compared with the first infection.
Dengue infection has a wide range of outcomes; from asymptomatic infection to undifferentiated viral fever, DF and DHF. DHF may also result in Dengue Shock Syndrome (DSS). Contrary to the common belief, DHF is not a continuum of DF. Though there are certain high-risk people, you never know who would develop DHF or DSS among those infected with dengue virus.
There is no specific treatment for DF and medical management is largely symptomatic. Two most important things patients and their caretakers can do at home is to control fever with paracetamol/panadol and to take enough fluids. Taking analgesics (for fever or pain) contribute to more severe disease and its complications hence, are strongly discouraged. Considering the endemicity of dengue in the Maldives and possible complications related to these drugs, patients with any fever should avoid aspirin and painkillers until dengue is ruled out.
With neither a cure nor a specific treatment, prevention becomes the only strategy we have. It is important that we take measures against bite prevention and mosquito breeding. Bite prevention in those with fever is equally important to prevent mosquitoes acquiring the virus and to break the chain of transmission. Remember that Aedes bite can kill you or your loved one!
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