عــدد

Dengue is a flavivirus mainly found in areas of the tropic and subtropics. There are four distinct but antigenically related serotypes of dengue viruses, and transmission is by the mosquito, principally Aedes aegypti and Aedes albopictus. The mosquito-born dengue viruses (serotypes1-4)cause dengue fever, a severe flu-like illness. The disease is prevalent in third-world tropical regions. It spreads to sub-tropical developed countries-including occurs worldwide each year, including a potentially deadly form of the disease called Dengue, a haemorrhagic fever(DHF)and dengue shock syndrome (DSS). Primary infection with dengue virus results in a self-limiting disorder characterized by mild to high fever lasting for 3 to 7 days, severe headache with pain behind the eyes, muscle and joint pain, rash and vomiting. Secondary infection is the more common form of the disease in many parts of Southeast Asia and South America. IgM antibodies are not detectable until 5-10 days in case of primary dengue infection and until 4-5 days in secondary infection after the onset of illness. IgG appears after 14 days and persists for life in case of primary infection and rises within 1-2 days after the start of symptoms in secondary infection. This disease is more severe and results in DHF and DSS. The significant clinical signs can include high fever, haemorrhagic events, and circulatory failure, and the fatality rate can be increased by 40%. Early diagnosis of DSS is critical, as patients may die within 12 to 24 hours if appropriate treatment is not administered. Primary dengue virus infection is characterized by an elevation in specific NS1 antigen levels 0 to 9 days after the onset of symptoms; this generally persists for up to 15 days. Earlier diagnosis of Dengue reduces the risk of complications such as Dengue haemorrhagic fever (DHF) and dengue shock syndrome(DSS), especially in countries where Dengue is endemic.