heating of the planet can cause the dreaded dengue fever to rise to epidemic proportions. Simon Hales and colleagues at the Wellington School of Medicine in New Zealand believe that the occurrence of dengue fever in South Pacific islands could have been the result of regional climate changes, which depend on a weather system known as the El Nino Southern Oscillation (enso). enso is a cyclical weather system which alternates between two extremes of drought and excessive rainfall over periods of two to seven years. While temperature and rainfall are below average in West Pacific and above average in the East and Central Pacific, in South Pacific, the weather scenario is entirely different. Said Hales, "This provides an opportunity to study a strong climate signal on infectious diseases in vulnerable parts of the globe.'

While several factors like poverty, population density, urbanisation and public health infrastructure also lead to an increase in dengue appearance in the Pacific, these factors have been more or less static since the '70s. Climate change therefore, has been narrowed down as the factor responsible for the incidence of dengue.