Explained: what is dengue, and why is there a surge in cases in Asia this year?

Dubbed “breakbone fever”, dengue is one of the world’s leading mosquito-borne illnesses and infects as many as 100 million people annually.About half the planet’s population live in at-risk areas, mainly in Asia, Latin America and Africa.Explosive outbreaks have ravaged Southeast Asia this year, with around 670,000 infected and more than 1,800 people dead in the region, according national and World Health Organisation data.At least 622 have died in the Philippines so far this year, cases in…