Description
Dengue virus is a flavivirus found largely in areas of the tropics and sub-tropics. Over half the world's population lives in regions at risk of potential dengue transmission, making dengue the most important arboviral disease in humans, in terms of morbidity and mortality. There are four distinct but antigenically related serotypes of dengue viruses, and transmission is by mosquito, principally Aedes aegypti, Aedes polynesienses and Aedes albopictus.
The clinical manifestations ofranging from sub-clinical through to fatal. The disease is graded dengue virus infection are varied, according to severity as follows: non-specific febrile illness, classic dengue fever, dengue haemorrhagic fever (DHF) (grades I and II), and dengue shock syndrome (DSS) (grades III and IV). Classic dengue fever is characterised by the sudden onset of fever with two or more symptoms of: headache, retro-orbital pain, myalgia, arthralgia, rash, haemorrhagic manifestations or leukopenia. A diphasic febrile course is common as is insomnia and anorexia with loss of taste or bitter taste. DHF and DSS are severe, potentially fatal complications often associated with infection by a second serotype.
Detection of dengue NS1 antigen by ELISA is a valuable procedure, as it allows detection of infection prior to seroconversion. NS1 antigen can be detected in serum from day 1 after onset of fever and up to day 9. This compares to IgM antibodies that are not detectable until days 3-5. Earlier diagnosis of dengue allows earlier implementation of supportive therapy and monitoring. This reduces risk of complications such as dengue haemorrhagic fever or dengue shock syndrome, especially in countries where dengue is endemic