Dengue infections triple that of WHO estimates
The number of global dengue infections is more than triple the current estimates from the WHO, according to a study published in Nature.
The multinational study revealed that dengue is ubiquitous throughout the tropics, with local spatial variations in risk influenced strongly by rainfall, temperature and urbanization.
"Our aim was to take all of the evidence that is currently available on the distribution of dengue worldwide and combine it with the latest in mapping and mathematical modeling to produce the most refined risk maps and burden estimates," study researcher Samir Bhatt, MD, of the University of Oxford, said in a press release. "We then hope to use this knowledge to help predict the future burden of the disease."
There are no licensed vaccines or specific treatments for dengue, and efforts to control mosquitoes that carry the disease have not stopped its rapid emergence and global spread.
Researchers estimate that there are 390 million (95% CI, 284-528) dengue infections across the globe each year, and 96 million of those infections reach any level of clinical or subclinical severity — more than triple the WHO's most recent estimates of 50 million to 100 million per year.
"This is the first systematic robust estimate of the extent of dengue," study researcher Jeremy Farrar, BSc, MBBS, FRCP, DPhil, of Oxford University, said in the press release. "The evidence that we've gathered here will help to maximize the value and cost-effectiveness of public health and clinical efforts by indicating where limited resources can be targeted for maximum possible impact."
Researchers found that of the 96 million apparent infections, 70% were in Asia and India. They also found that Africa is burdened with 16 million infections, almost equivalent to that of all the Americas and is larger than previously assumed. Bhatt and colleagues believe that the hidden African dengue burden could be a result of the disease being masked by illnesses with similar symptoms, under-reporting and highly inconsistent treatment-seeking behavior.
"Over time, this comprehensive map of global disease burden will also help to demonstrate which control measures are making the biggest difference in reducing the number of people suffering from dengue infection,” Jimmy Whitworth, MD, head of international activities at the Wellcome Trust, said. "Without a vaccine or specific treatment options, it's crucial that we understand where best to direct the limited resources available for preventing this resurgent disease."
Disclosure: The researchers report no relevant financial disclosures.