The World Health Organisation (WHO) estimates that there may be as many as 50 million cases of dengue fever each year and some 20,000 deaths, in what some countries are calling ???explosive??? outbreaks.It is also, as Hadyn Parry is quick to point out, mainly rich countries, particularly the US and the UK, which do not suffer from insect-borne diseases such as malaria and dengue fever, where you f