Dengue virus, a member of the genus Flavivirus, is transmitted via a mosquito vector to human beings. It is a 50-nm virus with an approximately 10.7 kb, positive-sense, single-stranded, RNA genome that encodes a single large polyprotein that is subsequently cleaved into several structural and non-structural mature peptides. Research on dengue virus is important because an estimated 2.5 billion people live in areas at risk for epidemic transmission. Globally, there are an estimated 50 to 100 million cases of dengue fever (DF) and several hundred thousand cases of dengue hemorrhagic fever (DHF) per year. The average case-fatality rate of DHF ranges from 1% to 5%. The NIH/NIAID has classified dengue as a Category A priority pathogen that is regarded as a re-emerging infectious disease and a potential bioterrorist threat.

Dengue virus is made up of four similar serotypes that can cause any of four outcomes: (1) no clinical symptoms, (2) dengue fever, (3) dengue shock syndrome, and (4) dengue hemorrhagic fever. It has been observed that subsequent infection with a different serotype of the disease can result in a greater likelihood of developing dengue hemorrhagic fever due to antibody-enhanced response.

The life cycle of dengue involves endocytosis via a cell surface receptor. The virus uncoats intracellularly, where its RNA genome is translated by the host cell's ribosomes. The resulting polyprotein is subsequently cleaved by cellular and viral proteases at specific recognition sites. The viral nonstructural proteins use a negative-sense intermediate to replicate the positive-sense RNA genome, which then associates with capsid protein and is packaged into individual virions. These virions bud through the host cell membrane to obtain their lipid bilayer envelope. At this point the cycle repeats itself.

Additional research is needed, as there are a number of drug and vaccine trials in progress, but as yet, no therapeutic or preventive agent is available to the public, and the underlying mechanism of pathogenesis has not been elucidated.