Using Web Search Query Data to Monitor Dengue Epidemics: A New Model for Neglected Tropical Disease Surveillance

Children's Hospital Informatics Program, Harvard-Massachusetts Institute of Technology Division of Health Sciences and Technology, Boston, Massachusetts,USA.
PLoS Neglected Tropical Diseases (Impact Factor: 4.45). 05/2011; 5(5):e1206. DOI: 10.1371/journal.pntd.0001206
Source: PubMed


A variety of obstacles including bureaucracy and lack of resources have interfered with timely detection and reporting of dengue cases in many endemic countries. Surveillance efforts have turned to modern data sources, such as Internet search queries, which have been shown to be effective for monitoring influenza-like illnesses. However, few have evaluated the utility of web search query data for other diseases, especially those of high morbidity and mortality or where a vaccine may not exist. In this study, we aimed to assess whether web search queries are a viable data source for the early detection and monitoring of dengue epidemics.
Bolivia, Brazil, India, Indonesia and Singapore were chosen for analysis based on available data and adequate search volume. For each country, a univariate linear model was then built by fitting a time series of the fraction of Google search query volume for specific dengue-related queries from that country against a time series of official dengue case counts for a time-frame within 2003-2010. The specific combination of queries used was chosen to maximize model fit. Spurious spikes in the data were also removed prior to model fitting. The final models, fit using a training subset of the data, were cross-validated against both the overall dataset and a holdout subset of the data. All models were found to fit the data quite well, with validation correlations ranging from 0.82 to 0.99.
Web search query data were found to be capable of tracking dengue activity in Bolivia, Brazil, India, Indonesia and Singapore. Whereas traditional dengue data from official sources are often not available until after some substantial delay, web search query data are available in near real-time. These data represent valuable complement to assist with traditional dengue surveillance.

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    • "In 2007, Venezuela, alone, reported more than 80,000 cases, including more than 6,000 cases of DHF. Google dengue trends provides the daily updates of current dengue fever activity for 10 countries, which enables earlier detection of outbreaks and epidemics and public health officials to mobilize outbreak containment measures in a timely manner (Chan et al., 2011). Recent outbreaks of dengue fever have been reported from many countries in Central and South America and Mexico, as well as various regions in Southeast Asia; dengue is endemic in these areas and should always be considered in the differential diagnosis of acute febrile illness, especially in travelers returning from that area (Communicable Diseases Communiqué, 2012). "
    Chapter: Dengue
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    ABSTRACT: Dengue is caused by the dengue virus (DENV), a member of the Flavivirus genus of the Flaviviridae family. This family consists of enveloped, positive-stranded RNA viruses. The dengue viruses are comprised of four distinct serotypes, DENV1 through DENV4, which are mainly transmitted to humans through the bites of two mosquito species, Aedes aegypti and Aedes albopictus. The female Aedes (Stegomyia) mosquito transmits the dengue virus from person to person in the domestic environment. It can also be transmitted via infected blood products and through organ donation (Stramer et al., 2009; Wilder-Smith et al., 2009). Mother-to-child transmission (vertical transmission) during pregnancy or at birth has also been reported by Wiwanitkit (2010). Some other person-to-person modes of transmission have also been reported, but these are very unusual (Chen and Wilson, 2010). The origin of the dengue infection is still unclear. An epidemic of “knee fever” was described in Cairo, Egypt, in 1779 (Thongcharoen and Jatanasen, 1993). The name dengue is actually derived from the Swahili word Ki denga pepo, meaning a sudden seizure by a demon. The term break bone fever was coined during an epidemic in Philadelphia in the United States in 1780 (Ananthanarayan and Paniker, 2000). Outbreaks have occurred in the continental United States in 1780, in Hawaii in 1903, and in Greece during 1927 and1928. The clinical presentation of dengue fever resembles illness caused by chikungunya and O’nyong-nyong viruses (Ananthanarayan and Paniker, 2000). Over the years, the disease has been given several names: break bone fever, dandy fever, Korean hemorrhagic fever, Thai hemorrhagic fever, Philippine hemorrhagic fever, knee fever, 7-day fever, and Dhaka fever (Thongcharoen and Jatanasen, 1993).
    Emerging Epidemics : Management and Control, 06/2013: chapter Dengue: pages 220-259; Wiley Blackwell., ISBN: 9781118393239
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    • "Numerous studies have examined how Internet searches can "predict the present", meaning that search volume correlates with contemporaneous events [18-20]. Specifically in the case of influenza, search volume was shown to estimate flu activity, which was not officially reported until two weeks later, and despite unknown flu status of the searchers. "
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    Malaria Journal 02/2012; 11(1):43. DOI:10.1186/1475-2875-11-43 · 3.11 Impact Factor
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    PLoS Neglected Tropical Diseases 05/2011; 5(5):e1215. DOI:10.1371/journal.pntd.0001215 · 4.45 Impact Factor
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