The World Health Organization has estimated there are about 50 million to 100 million cases of dengue every year. But new research puts the number at around 390 million - though about two-thirds of those people have only mild illness and don't need medical attention. The study was published online in the journal Nature.
The data won't change how patients are handled but could prompt a speedier search for a vaccine for the mosquito-borne disease.
The study was funded by the Wellcome Trust, the US Department of Homeland Security and others.
WHO said it wasn't surprised by the higher estimates. 'We fully agree the spectrum of dengue is very wide and there was every chance we were missing cases,' said Raman Velayudhan, the agency's global dengue co-ordinator. WHO was not involved in the new research.
'The new numbers are not out of the realm of what was expected,' said Jeremy Farrar, director of the Oxford University Clinical Research Unit in Vietnam, one of the study authors. He said the figures came from analysing more evidence than was used in the past and included other factors that influence dengue.
Dengue causes symptoms including fever and severe joint pains. The disease mostly affects people in Asia, Africa and Latin America though it has also recently popped up in parts of Western Europe and the US.
There are four kinds of dengue and catching it once doesn't ensure immunity; subsequent infections raise the risk of severe dengue and may include haemorrhaging. The death rate is usually below one per cent if patients get treated quickly, but can rise to 10 per cent if not.
source: skynews.com.au
