HealthMap’s use of so-called informal sources builds on a growing trend. “News reports, blog reports, and various other sources have become more important sources of information for public health,” says Madoff. For example, early indications of the SARS outbreak in China were evident in local discussions on ProMED, an email-based reporting system, long before the outbreak made global headlines. HealthMap uses ProMED, which was developed more than a decade ago and was the first to leverage the Internet to track infectious disease, as one of its data sources.
But along with the widening net of information used by resources like HealthMap comes concern over the accuracy of its data. “Since the information is based on reports combed from the Internet, there may be something lost in translation,” says Arnold Monto, an epidemiologist at the University of Michigan School of Public Health, in Ann Arbor. That will become an even bigger concern as HealthMap researchers begin to explore an even broader array of sources. “This is a major consideration as we move into blogs and chat rooms,” says Brownstein. “We’re spending a lot of time thinking about how valid and reliable sources are.”
HealthMap is also collaborating with ProMED, which is refereed by experts; a team of specialists monitor world news and reports from users and send them out to the listserv. Researchers aim to capture the best of both worlds, using HealthMap’s automated technology to quickly collect data and ProMED’s human experts to curate that information.
Some see HealthMap’s wide net as an advantage. “I think this is the future direction of infectious-disease epidemiology,” says Durland Fish, an epidemiologist at Yale School of Public Health, in New Haven, CT, who has previously worked with Brownstein. “This goes beyond traditional human case reporting, which we’ve done in the past,” he says. For example, the software may pick up reports from scientists working outside the public-health arena, perhaps identifying a new animal virus with the potential to jump to humans. That could conceivably give public-health officials the power to intervene before an outbreak. “We would be able to identify where this virus is likely to emerge in humans,” says Fish. “Once we get the first human case, we would know the virus has made the jump. That’s presumably what happened with SARS.”