A team of researchers from Kenya, England, and Thailand have developed
a map of the global incidence of malaria showing that the disease may be far
more common than previous estimates indicated (Snow et al. Nature. 2005;434:214-217).
The group reported that at least 500 million cases of malaria due to Plasmodium falciparum infection occur worldwide each year,
an estimate that is 50% higher than the number of cases reported by the World
Health Organization (WHO). They also found that nearly one third of cases—150
million—occur outside Africa, an estimate that is about 200% higher
than WHO’s figures. The scope of the problem outside Africa has been
underestimated, they said, because of WHO’s heavy reliance on passive
reporting of disease cases and mortality.
Stephenson J. Mapping Malaria. JAMA. 2005;293(15):1848. doi:10.1001/jama.293.15.1848-a