Dengue: epidemiology, prevention and pressing need for vaccine development

Dengue fever is a mosquito born viral infection, and the complicated form of dengue is dengue hemorrhagic fever (DHF). In the recent decades incidence and distribution of dengue has increased dramatically. Dengue viruses belong to family flaviviridae with four serotypes and are transmitted mainly by mosquito Aedes aegypti. Today almost two fifth of world's population (2.5 million) is at risk of dengue and no specific antiviral drug or vaccine is available against it. Uncontrolled population growth in Africa and South East Asia has increased number of susceptible hosts in urban and semi urban areas. About 40% of world population resides in the high risk area for dengue transmission. According to latest estimates by WHO, yearly 50 to 100 million infections occur globally, this includes around 500 000 DHF and 22 000 deaths, mostly among children. Only symptomatic treatment in the form of analgesic, antipyretics and body fluid management is provided to the patient. Prevention strategies mainly focus on two approaches, firstly on activities to control vector and secondly on activities to protect human from mosquito bite but there is always concerns regarding their sustainably and effectiveness. Theoretically development of an effective dengue vaccine is feasible and production of an effective and affordable vaccine could be a viable option to save humans from this dreadful disease. Conceptually vaccine production is possible, but it has to be tetravalent, providing immunity against all serotypes. Few candidate vaccines are in advance stage of their development; however international cooperation is needed to make these vaccines available on cheaper rates to the poor and vulnerable countries. Objective of this review is to discuss various aspects related to dengue, its epidemiology, available preventive methods, need for vaccine and challenges in its development.