for National Geographic News
An outbreak of dengue fever in India has infected more than 5,700 people and killed 103 in the past seven weeks.
The deadly outbreak represents only a small fraction of the estimated 100 million infections that now occur every year worldwide.
Formerly under control in some parts of the world, the mosquito-borne disease has made a rapid resurgence in recent decades, leading scientists to put dengue on par with better-known killers like malaria and the Ebola virus as a global health threat.
"As a public health problem, dengue ranks right up there," said Duane Gubler, director of the Asia-Pacific Institute for Tropical Medicine and Infectious Diseases at the University of Hawaii in Honolulu.
"If you look at vector-borne diseases [those passed by ticks or mosquitoes], it is number two after malaria."
The disease itself is rarely fatal, but a more serious complication, dengue hemorrhagic fever (DHF), is far more dangerous.
DHF can cause liver enlargement and circulatory failure.
Without treatment, DHF can kill 20 percent of its victims. With medical treatment, the fatality rate can drop below one percent.
But as the current crush of patients at hospitals in northern India attests, an outbreak in a region with limited access to health care can take a drastic toll on a community.
"If you just look at the case fatality rate, then it's not so dangerous," Gubler said.
"But if you compare [dengue's overall impact] to [that of] Ebola and Marburgthese highly fatal hemorrhagic fever diseases that get a lot of pressthey aren't even in the same league. I consider them relatively unimportant compared to dengue."
Old Enemy With New Strength
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