WHO warns that 40 percent of the world is at risk for dengue fever

The World Health Organization released a warning in a statement on Tuesday about the spread of dengue fever, revealing that more than 40 percent of the world's population is at risk for infection.

Reports show that in Southeast Asia, the western Pacific and the Americas, the number of dengue cases exceeded 2.2 million in 2010 after just 1.2 million cases in 2008. The global total of dengue cases was estimated at 50 to 100 million with most going unreported, while an estimated 500,000 people worldwide are hospitalized with severe dengue annually, CIDRAP News reports.

"Today, severe dengue affects most Asian and Latin American countries and has become a leading cause of hospitalization and death among children in these regions," the WHO said, according to CIDRAP News. "(Dengue is) a major international health concern."

Dengue is caused by a mosquito-borne virus and is now endemic in more than 100 countries in Africa, the eastern Mediterranean, Southeast Asia, the Americas and the western Pacific. Prior to 1970, only nine countries had experienced severe epidemics.

"Not only is the number of cases increasing as the disease spreads to new areas, but explosive outbreaks are occurring," the WHO said, according to CIDRAP News.

There is no specific dengue treatment, though the WHO said that experienced nurse and physician care by those familiar with the progression of the disease can reduce the mortality rate from 20 percent to less than one percent. While there is no approved vaccine for dengue, several vaccine candidates are in clinical trials.