Dengue fever is caused by a virus transmitted by mosquitoes. It has an incubation period of 3-14 days and symptoms include high fever, headaches, muscle and joint pains. There are four types of dengue virus. Recovery takes 1-2 weeks but there is a risk of severe dengue during recovery. The only vaccine available is for children who had a previous infection, as it can worsen the disease if given to those without prior exposure.