Google Searches Can Track Dengue Fever Outbreaks

An analytical tool that combines Google (Mountain View, CA, USA) search data with government-provided clinical data can quickly and accurately track dengue fever in less-developed countries, according to a new study.

Researchers at Harvard University (Cambridge, MA, USA) and Boston Children’s Hospital (BCH; MA, USA) modified a mathematical modeling tool known as AutoRegression with GOogle search queries (ARGO) to explore its potential to track dengue activity in Mexico, Brazil, Thailand, Singapore, and Taiwan. The researchers used Google Trends to track the top ten dengue-related search queries made by users in each country during the study period; they also gathered historical dengue data from government health agencies and input both datasets into ARGO.

Using the assumption that more dengue-related searches occur when more people are infected, the researchers used ARGO to calculate near real-time estimates of dengue prevalence for each country. When ARGO's estimates were compared with those of five other methods, it returned more accurate estimates than did any other method for Mexico, Brazil, Thailand, and Singapore. Estimates for Taiwan were less accurate, possibly because the country experienced less-consistent seasonal disease patterns from year to year. The study was published on July 20, 2017, in PLOS Computational Biology.

“The wide availability of internet throughout the globe provides the potential for an alternative way to reliably track infectious diseases, such as dengue, faster than traditional clinical-based systems,” said senior author Mauricio Santillana, PhD, of BCH and HMS. “This alternative way of tracking disease could be used to alert governments and hospitals when elevated dengue incidence is anticipated, and provide safety information for travelers.”

Dengue transmission is subject to complex environmental factors influencing the Aedes aegypti and Aedes albopictus mosquitoes, which spread the disease. A mosquito is able to transmit dengue within a few weeks of contracting the virus, and a person bitten by such a mosquito will usually fall ill within a week, with symptoms lasting for up to 10 days afterward. There is thus a 5-day window when another mosquito can pick up the virus from an infected person. The time scale of these transmission dynamics lends itself to tracking patterns of infection at a weekly or monthly level.

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Harvard University
Boston Children’s Hospital