Dengue

Abstract

Dengue is a mosquito-borne flavivirus infection, found in tropical and sub-tropical climates worldwide, mostly in urban and semi-urban areas. There are four distinct dengue virus (DENV) serotypes, meaning that it is possible to be infected four times. While 75% of DENV infections are asymptomatic, 20% of result in mild to moderate disease (Dengue fever [DF]), and 5% can cause severe disease with activation of the coagulation system (Dengue hemorrhagic fever [DHF]), which is usually seen with subsequent DENV infections. Antibody-mediated disease enhancement (ADE) is a phenomenon that has been observed in various in vitro assays: low concentrations of cross-reacting antibodies from a previous DENV infection in a subsequent infection with another serotype do not neutralize DENV. Instead, they bind to the virus and attach to host cells; thus, enabling viral replication. ADE is one hypothesis proposed, among many, to explain sensitization to severe disease. There is no specific treatment for DENV. Early detection of disease progression and access to proper medical care lower fatality rates of DHF from about 2.5% to <1%. Severe dengue is a leading cause of serious illness and death in some Asian and Latin American countries. The global incidence of dengue has grown dramatically in recent decades. About half of the world's population is now at risk. There are an estimated 100–400 million infections each year. Dengue prevention and control relies on effective vector control measures. Sustained community involvement can improve vector control efforts substantially. There is one licensed dengue vaccine, CYD live attenuated tetravalent dengue vaccine (Dengvaxia®) developed by Sanofi Pasteur, which is approved for use in several dengue endemic countries for persons 9–45 years of age living in endemic areas who have had a previously documented dengue virus infection. Several other vaccines are in clinical development.