Aamir Hussain surveys the fetid floodwaters hemming his family's makeshift rooftop home in southern Pakistan.<br />Four months after the start of record monsoon rains linked to climate change, the standing water has curdled into a pestilent soup breeding malaria, cholera and dengue.<br />The UN has warned of a "second wave" of catastrophe, with the risk that deaths from water-borne disease and malnutrition will outstrip the 1,700 drowned and electrocuted in the initial cascade.
