Dengue fever is a viral disease that mostly occurs in tropical regions.
The agent responsible for dengue fever is the dengue virus which belongs to the Flaviviridaefamily and Flavivirusgenus, and is therefore a cousin of the yellow fever and West Nile viruses. The four serotypes of the dengue virus (DENV-1, DENV-2, DENV-3, and DENV-4) are similar although infection with one of them does not confer immunological protection against the other three.
Transmission of dengue fever
Dengue fever is transmitted by the bites of infected mosquitoes. The disease developed in 2009 in the French West Indies as an uncontrolled epidemic. Mainland France has not been spared, with the first indigenous cases being reported in 2010.
Symptoms of dengue fever
There are two forms of dengue fever, both of which can be caused by any of the virus serotypes:
- the classical form is incapacitating but not serious. After an incubation period of two to seven days, a sudden-onset high fever develops, often accompanied by other symptoms (headache, nausea, vomiting, joint and muscle pains, skin rash). The symptoms worsen after three to four days (bleeding, ecchymoses) and then resolve rapidly after a week. Complete recovery takes around fifteen days.
- The haemorrhagic form is far more severe but less common (approximately 1% of cases). The fever persists and multiple haemorrhages (gastro-intestinal, skin and cerebral) may develop. In contrast to young children, recovery in adults can be fast, complete, and without complications. Circulatory failure may occur leading to death if the patient is not treated.
Treatment of dengue fever
At present there is no treatment or vaccine for dengue fever. Only the symptoms are treated. A vaccine is, however, being developed and may be marketed in the next few years.
The aedes albopictus, or Asian tiger mosquito, is responsible for the spread of dengue fever virus. © James Gathany,Centers for Disease Control and Prevention(public domain)