Peptides as Therapeutic Agents for Dengue Virus

Chew, Miaw-Fang; Poh, Keat-Seong; Poh, Chit-Laa

Dengue is a mosquito-borne disease caused by the infection of dengue virus (DENV). It has been estimated that 390 million dengue infections occur annually, of which 96 million manifest clinically [1] . Before 1970, only nine countries experienced dengue epidemics. Currently, dengue is endemic in more than 100 countries, primarily in tropical and sub-tropical countries [2] . There are four dengue virus serotypes, DENV-1-4, which are genetically and antigenically distinct, although each serotype elicits a similar range of disease manifestations during infection [3] . In humans, dengue infection causes a spectrum of illnesses ranging from asymptomatic, fever, rash, joint pain and other mild symptoms to life-threatening dengue haemorrhagic fever (DHF) and dengue shock syndrome (DSS) [4] . Infection with one DENV serotype induces lifelong immunity against the homologous serotype but not against the other three heterologous serotypes. In fact, studies have shown that secondary infection with a different DENV serotype is an important risk factor in causing more severe complications, such as DHF and DSS, due to a phenomenon designated as antibody dependent enhancement (ADE) or the original antigenic sin [5] [6] [7] .