A new study published in Nature online last week estimates that there are more than three times as many dengue infections as in the official World Health Organization (WHO) figure.  The WHO estimates 50-100 million dengue infections a year, while “The global distribution and burden of dengue” report argues that there are 390 million dengue infections per year.
According to the authors, there were an estimated 96 million apparent dengue infections, and 294 million inapparent infections, in 2010, the year on which the study was based. Apparent infections is a purposefully broad definition designed to be an inclusive measurement of the impact of symptomatic dengue on daily life, while inapparent infections represent asymptotic infections that nonetheless contribute to the spread of dengue and need to be counted due to their effect on the economic and population dynamics of dengue.
The group, based out of Oxford University and the Wellcome Trust, used an improved evidence base and modeling approaches, as well as a continuous global risk map, to calculate their estimates.  They also found that Asia accounts for 70% of the burden of apparent infections, while arguing that Africa’s burden is largely hidden.  They found that urban and peri-urban areas were also linked to greater risk.
“These new risk maps and infection estimates provide novel insights into the global, regional and national public health burden imposed by dengue,” the authors write.  “We anticipate that they will provide a starting point for a wider discussion about the global impact of this disease and will help to guide improvements in disease control strategies using vaccine, drug and vector control methods, and in their economic evaluation.”
You can find the study preview here, as well as read some of the extensive media coverage, including on the Wellcome Trust site, and in National Public Radio, the LA Times and the Washington Post.

Visit the Dengue Vaccine Initiative to learn more.

Photo: Public health officers release Poecilia reticulata (guppy) fry into an artificial lake in Brasília, Brazil, as part of dengue vector control activities. Photo by Fábio Rodrigues Pozzebom/AB.