Likewise, dengue ranks among the most important mosquitoborne viral diseases in the world. In the last 50 years, the incidence has increased 30-fold. An estimated 2.5 billion people live in over 100 endemic countries and areas where dengue viruses can be transmitted. Up to 50 million infections occur annually with 500,000 cases of dengue haemorrhagic fever and 22,000 deaths,mainly among children(WHO,2012a).