Dengue: A water-related mosquito-borne disease

Abstract

Dengue is a common vector-borne disease of tropical and subtropical areas, affecting about 50 million people each year and exposing more than 2.5 billion people at risk. Dengue virus (DENV), responsible for the disease, belongs to family Flaviviridae, genus Flavivirus and has four distinguished serotypes (DENV 1, DENV 2, DENV 3, and DENV 4). The main vector of the virus is Aedes aegypti mosquito. Water logging increases mosquito density and an increase in vector-borne diseases (such as dengue, malaria, West Nile fever) through the expansion in the number and range of vector habitats. Infection with any of the DENV serotypes may be asymptomatic in the majority of cases or may result in a wide spectrum of clinical symptoms, ranging from a mild flu-like syndrome (known as dengue fever [DF]) to the most severe forms of the disease; Dengue Hemorrhagic Fever/ Dengue Shock Syndrome (DHF/DSS). Recently in 2008, WHO has revised its classification and divides the clinical illness to non-severe dengue, dengue ± warning signs, and severe dengue. Pathogenesis of severe dengue disease is very complex and not properly elucidated. Timely diagnosis of the disease is the key to control it. Routine diagnosis largely depends upon NS1 antigen, IgM, and genome detection by different methods. Confirmatory diagnosis is by cell culture method, the most important of which is C6/36 mosquito cell line or intrathoracic inoculation of mosquito. Till date, no effective vaccine is available in the market. Different approaches are being used to develop various formulations of vaccine, but are of not much use. Alternative vaccine strategies in the form of small interfering RNA (siRNA) and micro RNA (miRNA) seem to be quite promising in present era. Though these technologies are in very primitive phase, various studies are going on all over the world to bring them to reality.