There are four Dengue viruses (DENV) that cause Dengue fever, all of which are spread by a species of mosquito known as the Aedes aegypti mosquito, and more rarely by the Aedes albopictus mosquito. Aedes aegypti originated in Africa, but nowadays is found in all the tropical areas around the world and prospers in and close to areas of human population.
The high risk regions for catching dengue fever are Central America, South America, the Caribbean and tropical Asia; more specifically - northern Argentina, northern Australia, the entirety of Bangladesh, Barbados, Bolivia, Brazil, Cambodia, Costa Rica, Dominican Republic, Guatemala, Guyana, Honduras, India, Indonesia, Jamaica, Laos, Malaysia, Mexico, Micronesia, Pakistan, Panama, Paraguay, Philippines, Puerto Rico, Samoa, Singapore, Sri Lanka, Suriname, Taiwan, Thailand, Trinidad, Venezuela and Vietnam, and increasingly in southern China.
The virus is transmitted from an infected mosquito to human. The process begins when a person who is infected with the Dengue virus is bitten by a mosquito, the virus is then passed on when someone else is then bitten by the infected mosquito.
If you have suffered from dengue fever previously it is still possible to contract it again, because of the number of different types of viruses that cause the fever. If you were infected again and became ill, there is a greater risk of developing a harsher form of the disease, such as dengue hemorrhagic fever (particularly in children). This is unusual because, normally, previous exposure to a virus causes the body to carry antibodies that allow the body to fight off the virus more easily the second time.
article source: http://www.medicalnewstoday.com/articles/179471.php
