Dengue fever, a virus that causes flu-like symptoms, is transmitted by the bite of an infected mosquito. The incubation period is generally 5 to 10 days. Dengue fever occurs in tropical regions, with approximately 100 million cases reported annually. Increased travel to endemic areas, along with overpopulation and inadequate public health systems, may be responsible for the increased spread of the virus. Dengue fever is considered the most important mosquito-borne virus affecting humans.
The Pan American Health Organization has developed a task force dedicated to the prevention and control of dengue fever. Its goal is to promote behavioral and environmental changes and achieve effective communication between government, community, and health agencies regarding recognition, treatment, and prevention of the illness.
Dengue fever is caused by one of four types of virus (DENV-1, DENV-2, DENV-3, and DENV-4) of the genus Flavivirus. It is transmitted by Aedes aegypti and Aedes albopictus mosquitoes. Infection with one type of dengue virus provides lifelong immunity against that particular strain but may not provide protection from the other three virus strains.
Several dengue fever vaccines are being investigated, two of which have advanced to human testing. Developing an effective vaccine presents a challenge, however, because the vaccine must be effective against all four types of dengue virus.
Dengue hemorrhagic fever (DHF) is a more severe form of dengue fever in which fevers may reach 106° F (41° C) and cause seizures. This complication occurs when a patient infected with one dengue virus serotype becomes infected with a second type of dengue virus. Thrombocytopenia and hemoconcentration occur, causing leakage of intravascular volume from capillaries. This may lead to the development of dengue shock syndrome (DSS), which may be fatal.