Facts about dengue.

Above about dengue.

Pathogenic agent
Dengue is caused by four closely related viruses (Den-1 to Den-4) within the genus flavivirus. These are single-stranded RNA viruses with a size of approximately 40 to 50 nm. The RNA genome is associated with the "C"-protein to form a nucleocapsid. In the surrounding lipid membrane, two proteins named "M" and "E" are embedded. The four serotypes differ in the amino acid composition of their "E"-proteins.
Transmission/pathogenesis
The dengue viruses are spread by the bites of infected female Aedes mosquitoes. The most important vector species is Aedes aegypti. In recent years, however, a secondary dengue vector in Asia, Aedes albopictus, has spread into the Americas, parts of Europe and Africa, causing several dengue outbreaks.
Only female mosquitoes transmit the virus. When an infected female feeds on human blood, the virus is transmitted. While the virus circulates in the human blood (for 2 to 7 days), the infected individual experiences fever – the most prominent dengue symptom. During this time, other female Aedes mosquitoes biting the infected human can take up the virus and – after an incubation time of about 10 days – spread it on to other human hosts during subsequent blood meals. The viruses are also transferred vertically, i.e. from a female mosquito to her offspring via the eggs. Human to human transmission does not occur, but the virus can be transmitted by infected blood or blood products (platelets, plasma).