Dengue virus is a flavivirus transmitted to humans by Aedes mosquitoes. An estimated 50-100 million infections occur annually throughout the world. Dengue virus primarily affects persons living in or traveling to tropical areas. Nearly all dengue cases reported in the 48 continental states were acquired elsewhere by travelers or immigrants, with sporadic cases reported along the southern U.S. border (eg, in Arizona, Texas, Florida) and in Hawaii.
Symptoms of dengue infection can range from mild febrile illness to bleeding (dengue hemorrhagic fever) or hypotension (dengue shock syndrome) with potentially high mortality. It is important to diagnose dengue promptly, since other tropical infections can produce similar patterns of illness and may require different treatment.