What is dengue fever?
Dengue fever is a mosquito-borne viral infection transmitted by the Aedes mosquitoes, which normally bites during the day time. In Africa, dengue fever outbreaks in 2013 have been reported in Angola, Kenya and Tanzania. Globally, outbreaks have also been reported in several Asian (including Thailand, Vietnam, Cambodia, Hong Kong), South American countries (including Brazil, Mexico, Venezuela) and India. Nevertheless, the dengue virus is endemic to more than 100 countries worldwide and more than a million cases are reported to the World Health Organization annually. There is no dengue fever transmission in South Africa and currently should be suspected in patients presenting with the sign and symptoms of dengue fever and a travel history to affected countries.
What are the features of dengue fever?
Dengue fever symptoms can take up to two weeks to develop from being bitten and the symptoms include: sudden onset of fever, headache, pain behind the eyes, joint and muscle pain, rash, nausea and vomiting. Severe or complicated dengue fever is uncommon but can occur in the form of dengue haemorrhagic fever and dengue shock syndrome. This is more common in the young and elderly.
How is dengue fever diagnosed?
Dengue fever is diagnosed clinically in patients that present with the signs and symptoms and have a compatible and recent travel history. Dengue fever may however be confirmed only with specialized testing offered at the National Institute of Communicable Diseases. Laboratory investigation includes RT-PCR and virus isolation in acute patients (patients that have been ill for less than one week) and serology. Serology is most informative when repeat specimens (i.e. acute and convalescent) are submitted for investigation.
Exclusion of malaria would be important due to the similarities in mode of transmission and clinical features of both diseases.
How is dengue fever treated?
There is no specific treatment for dengue fever. Treatment will be recommended by a medical practitioner to manage symptoms of the patient. Severe cases will require more intensive treatment and most likely hospital- based fluid replacement therapy.
How do you prevent dengue fever?
Currently there is no vaccination available against dengue fever. Travellers to affected areas are advised to use measures to deter mosquito bites. This may include wearing long-sleeved pants and shirts indoors as wells as outdoors. Additional measures include staying in well ventilated (fan/air-conditioned) rooms where possible and use of mosquito repellents containing DEET. Screened doors and windows and use of mosquito nets present practical and effective measures for preventing mosquito exposures.