Westerners tend to be unaware of the threat posed by malaria, but researchers in the UK have reported some troubling statistics about the disease. In a report published in Nature, a team of scientists from the University of Oxford are claiming that the number of cases worldwide may in fact be double the number originally estimated by the World Health Organization. They believe that in 2002, there were over a half billion cases.

Even more disturbing, 66 percent of cases occurred in Africa in children under the age of five. Further, it is possible that 2.2 billion people worldwide are at risk for the disease.

The most recent studies were conducted at the Kenyan Medical Research Institute/Wellcome Trust Laboratories. They looked at demographic models, parasitic profile and overall vulnerability to the disease. Other resources included satellites and Geographic Information Systems.

Obviously, one concern is how the original numbers could have been so far off the mark. One reason may be that centers may be under-reporting cases, or not identifying the disease.

Despite the fact that the numbers have doubled, the lead researcher for the study, Professor Bob Snow warned, 'We have taken a conservative approach to estimating how many attacks occur globally each year but even so the problem is far bigger than we previously thought.'

Other areas at risk are South East Asia and the Western Pacific where it is estimated that 25 percent of the cases will occur.

Previously, the WHO intended to reduce malaria deaths in half by 2010, but these estimates are being negatively affected by a problem that is developing with resistance to current drugs.