Mapping Health Threats

From an outbreak of West Nile virus in the Connecticut suburbs to an Ebola epidemic in rural Africa, the ever–evolving world of infectious diseases is now at the fingertips of medical professionals and laypeople alike with an online surveillance system that provides viewers with an up–to–the–minute snapshot of global epidemiological events.

The HealthMap surveillance system is a multistream, real–time platform that uses a series of algorithms to mine 14 sources (representing some 20,000 Internet sites that include media outlets, government Web sites and discussion forums) for breaking news about infectious diseases.

The result are filtered and checked for duplication, accuracy and relevance and then posted on a global map. Users can click the color–coded icons to get further details about a salmonella incident culled from a Google news story or an anthrax alert acquired from ProMED, a public–health listserv, or the World Health Organization.

There is a “massive” amount of information available on the Internet pertaining to public health, but there was no effective way to sort or display it, said John S Brownstein, a Yale School of Public Health alumnus, Ph.D.’04, who co–created HealthMap with Clark C. Freifeld, a 2000 graduate in computer science and math. HealthMap seeks to synthesize all of this information in an easy–to–use format that is freely available to anyone interested in developing health threats.

“It’s an idea that we had been exploring for some time,” said Brownstein, who studied disease mapping at Yale with Professor Durland Fish. “We’re trying to integrate all of this information to map and predict disease risk.”

The site receives as many as 10,000 hits daily and users range from international tourists checking conditions at their vacation destinations to the ministers of health from some countries seeking timely information on emerging threats. The site is updated continuously, sometimes displaying news of a nascent outbreak before it is tracked by government agencies.

The site made its debut in late 2006, and has since been expanded and enhanced. A new round of improvements is in the works, with an expansion of the languages monitored to get a fuller picture of international outbreaks. The service plans to introduce Hindi, Arabic, Portuguese and certain African languages to the five languages already used (English, Chinese, Spanish, Russian and French).

Brownstein, who is now an assistant professor at Harvard Medical School in Boston, acknowledged that international news media can have potential biases in what they report (and what they do not) that warrant consideration. Media reports also can be incomplete or inaccurate. An evaluation of the data amassed by HealthMap found a wide variety, with 141 infectious diseases reported from Google News alone. The evaluation also found that the majority of reports come from countries with more media outlets and with better developed electronic infrastructures. Relatively little news is generated, for instance, from large parts of Africa, the very area where the risks posed by infectious diseases are most pronounced.

Brownstein said they are considering other data sources, such text messaging from cell phones, which have far greater adoption rates than the Internet and will allow important geographic gaps to be filled in.