Aarti Dhar NEW DELHI: With 75 per cent of the population or 2 billion people in the Asia-Pacific region at risk, the World Health Organisation (WHO) has asked the member states to take concrete measures urgently in order to control the spread of dengue. The severity of the public health threat from dengue also led to the inclusion of dengue control in one of the resolutions adopted at the just-concluded 61st Session of the Regional Committee meeting of the WHO South-Asia Region. Pandemic A dengue pandemic swept across the region between 1991 and 2004, peaking with 3,50,000 cases in 1998. Of the 2.5 billion people at risk globally, 1.8 billion live in the Western Pacific. The WHO has said in discussion papers at the ongoing regional committee meeting in Manila that dengue has greatly expanded over the last three decades owing to changes in weather patterns that expanded the habitat of the Aedes aegypti mosquito which carries the virus. Man-made problem Dengue is a man-made problem which is linked to globalisation, rapid, unplanned and unregulated urban development, improper water storage and unsatisfactory sanitary conditions which provide breeding grounds for the mosquito. Movement of people to and from urban areas is another major factor.