Can search engines predict dengue outbreaks?

World Health Matters – China – by Gary Finnegan: An increase in the number of people searching Google for information about the flu has been used to identify outbreaks even before they should up in official figures. The number of hits on Wikipedia for ‘flu’ or ‘influenza’ can also help to pick up local epidemics.

Now scientists are using the same approach to detecting outbreaks of dengue fever. The advantage of knowing where a virus is spreading is clear: official statistics tend to lag reality by two weeks, meaning that an epidemic has plenty of time to grow. Real-time signals showing the early stages of an outbreak offer an opportunity for swift intervention.

However, much of the work in this area has been done in English-speaking countries, with some research also carried out in the major European languages. In the US and Europe, Google and Wikipedia are hugely popular and offer valuable insights into what’s on the public’s mind.

These websites are much less popular in China but other frequently-used search engines hold similar potential. New research shows that combining information from internet search engine Baidu (China’s equivalent of Google) with a web-based infectious disease alert system from reported cases and environmental factors hold the key to improving dengue fever early warning systems in China.

Dr Wenbiao Hu from Queensland University of Technology (QUT) Institute of Health and Biomedical Innovation teamed up with the Chinese Centre for Disease Control and Prevention, to test a system which combines internet-based surveillance, an automated dengue fever alert system and monitoring of environmental factors such as temperature, humidity and rainfall.

“What we have found is that internet-based surveillance such as monitoring search engines like Baidu, could accurately predict outbreaks of infectious disease such as dengue fever up to a few weeks faster than traditional surveillance methods,” says Hu.

“This is because traditional surveillance relies on the patient recognising the symptoms and seeking treatment before diagnosis, along with the time it takes for a doctor or health professional to alert authorities through their health networks.”

In China dengue fever has been a major public health concern since it re-emerged in Guangdong province in 1978 and there have been more than 650,000 cases reported since then. Guangdong has seen a significant surge in dengue fever cases this year with already 42,856 reported.

“What we have found through our research is that affected areas appear to have been expanding in Guangdong over recent years, which indicates potentially increasing risk for unaffected areas in other parts of Guangdong province,” said Hu.

“The solution is early detection of dengue fever in China to enable prevention and control the disease and reduce sickness and death.”