Global burden of dengue underestimated
medwireNews: Findings from a study published in Nature suggest that the annual number of dengue virus infections worldwide is approximately 390 million, a figure over three times greater than that provided by the World Health Organization (WHO) for the disease.
Simon Hay (University of Oxford, UK) and co-authors explain that the new figure includes an estimate of around 300 million mild or asymptomatic infections not normally picked up by public health surveillance programs, as well as approximately 90 million cases that reach levels of clinical or subclinical severity.
The researchers combined an exhaustive collection of 8309 dengue virus records for 2010 from around the world with mapping and mathematical modeling techniques to produce risk and burden estimates for the disease for different countries and areas.
"We found that climate and population spread were important factors for predicting the current risk of dengue around the world," said Hay in a press statement.
"With globalisation and the constant march of urbanisation, we anticipate that there could be dramatic shifts in the distribution of the disease in the future: the virus may be introduced to areas that previously were not at risk, and those that are currently affected may experience increases in the number of infections."
Hay and colleagues found that 70% of the worldwide disease burden for dengue in 2010 was borne by Asia, with India accounting for 34% of all infections. The Americas accounted for 14% of all infections, although this was largely due to cases from Brazil and Mexico.
The dengue burden in Africa was reported to be similar to that of the Americas, a much larger proportion than previously projected. The researchers suggest this difference is likely to be due to under reporting, great variability in treatment-seeking behavior, and misdiagnosis due to the presence of several diseases with similar symptoms in Africa.
Co-author and investigator Jeremy Farrar, also from the University of Oxford, told the press: "This is the first systematic robust estimate of the extent of dengue. The evidence that we've gathered here will help to maximise the value and cost-effectiveness of public health and clinical efforts, by indicating where limited resources can be targeted for maximum possible impact."
medwireNews (www.medwirenews.com) is an independent clinical news service provided by Springer Healthcare Limited. © Springer Healthcare Ltd; 2013
By Helen Albert, Senior medwireNews Reporter