Global Epidemiology of Dengue Hemorrhagic Fever: An Update

Although dengue was once a periodic disease that caused long-interval epidemics, today it is considered the most important mosquito-borne viral disease in the world [1]. Per year, approximately fifty to one hundred million cases of dengue fever are recorded worldwide [2]. Half a million of these cases result in the most severe form of dengue fever (DF) known as dengue hemorrhagic fever (DHF) [2]. DHF is a disease that predominantly affects children under 15 years of age and is characterized by the sudden onset of fever, thrombocytopenia, and vascular leak syndrome [3]. DHF occurs due to an infection by the dengue virus, which is part of the Flaviviridae family [4]. The virus is icosahedral, enveloped, single-stranded, positive-sense RNA [5]. The icosahedral core is forty to fifty nanometers in diameter and contains the C protein that encapsulates the viral genome [5]. Two viral proteins, M and E, which compose the lipid envelope, surround the core [5]. The infection is caused by one of the four serotypes of the dengue virus (DENV): DENV-1, DENV-2, DENV3, and DENV-4 [4]. Infection by one of the serotypes does not provide immunity against infection with the other serotypes [4].