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Member Research & Reports

Member Research & Reports

Burden of Dengue, Chikungunya in India Far Worse Than Understood, Johns Hopkins Research Finds

New Johns Hopkins Bloomberg School of Public Health research finds new evidence that an extremely high number of people in southern India are exposed to two mosquito-borne viruses — dengue and chikungunya.

These findings, the researchers say, reinforce the need for officials to be on the lookout for these diseases and to find ways to control its spread not only in India but also around the world.

The researchers, reporting July 16 in PLOS Neglected Tropical Diseases, tested blood samples from 1,010 people across 50 locations in Chennai, a city with over six million people in South India, and found that nearly all of them had been exposed to dengue and 44 percent had been exposed to chikungunya. Surprisingly, almost none of the people who had been exposed to dengue reported having been infected by it, either because they were not properly diagnosed with the disease or because they did not show symptoms.

Even though dengue has been known to be present in India since the 1940s, it is only in the past few years that there is growing recognition of the magnitude of the problem. “Our results show that the extent of the problem has been vastly underestimated,” says the study’s leader Dr. Isabel Rodriguez-Barraquer, a research associate in the Department of Epidemiology at the Bloomberg School.

“People are just not aware of the disease. We asked participants if they had ever been ill with dengue and only one percent of them said yes, when in fact 93 percent had been infected by it.”

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