New mapping tools bring public health surveillance to the masses

by Kim Krisberg

Many of us probably look into cyberspace and are overwhelmed with its unwieldy amounts of never-ending information. John Brownstein, on the other hand, sees points on a map.

Brownstein is the co-founder of HealthMap, a team of researchers, epidemiologists and software developers at Children's Hospital Boston who use online sources to track disease outbreaks and deliver real-time surveillance on emerging public health threats. But instead of depending wholly on traditional methods of public health data collection and official reports to create maps, HealthMap enlists helps from, well, just about everybody.

"We recognized that collecting data in more traditional ways can sometimes be difficult and the flow of information can take a while," said Brownstein, also an assistant professor of pediatrics at Harvard Medical School. "So, the question was how to collect data outside the health care structure to serve public health and the general public."

HealthMap, which debuted in 2006, scours the Internet for relevant information, aggregating data from online news services, eyewitness reports, professional discussion rooms and official sources. The result? The possibility to map disease trends in places where no public health or health care infrastructures even exist, Brownstein told me. And because HealthMap works non-stop, continually monitoring, sorting and visualizing online information, the system can also serve as an early warning system for disease outbreaks.

Next, Brownstein wants to see what happens if everyone gets involved. To do it, HealthMap teamed up with the American Public Health Association (APHA) and in late October launched a giant public health experiment called Flu Near You, a new online mapping tool that lets people report their flu symptoms and then creates a living map of the results. The tool, data from which is accessible to anyone, generates real-time maps of reported flu activity by ZIP code. To drive participation in the endeavor, APHA is encouraging its members as well as public health practitioners nationwide to join APHA's Flu Near You Challenge and help recruit as many people as possible to take part in the massive surveillance and prevention effort.

"We're trying to raise awareness, to encourage good practices," Brownstein said. "And people can relate to maps -- it resonates with people, that ability to see data spatially."

Mapping for prevention and intervention
Of course, public health is no stranger to the art of mapmaking.

In 1850s England, John Snow, often referred to as the father of modern epidemiology, famously mapped the source of a cholera outbreak to a local drinking water source and talked local officials into removing the well's pump handle (a seminal event in public health history that, as you've probably guessed, inspired this blog's name). A century and a few decades later, all 50 state health departments, most local departments and the country's top public health agencies use advanced geographic information systems, or GIS, to create maps of data from nearly every discipline of public health.

Like Snow, today's public health practitioners use maps to guide interventions. When a disease outbreak occurs today, the solution is often more complicated than shutting off a single contaminated water pump, but maps can still help health professionals raise public awareness about prevention and target interventions in ways that make the most of limited resources.

Susan Polan, associate executive director for public affairs and advocacy at APHA, hopes Flu Near You will do just that. By mapping real-time self-reported data, the tool has the potential to not only help public health practitioners detect geographic disease trends in their earliest stages, but to be an intervention in itself. For example, in addition to creating a map of reported flu symptoms based on a user's location, Flu Near You automatically generates a list of local flu shot providers and provides links to local public health sources. Such interactive and dynamic mapping technologies can provide valuable feedback in understanding what works to engage the public in community health and prevention, said Polan, who reported that Flu Near You is already receiving survey results from every state.

"It's a great opportunity to really bring the public into public health and have them be active participants in creating healthier communities," Polan said.

Mapping is more than just tracking diseases. The technology is also being used to inform decision-making and shape policy -- key components of effective public health work.

"When it's on the map, very often that's all the analyses you need," said Dmitry Sharkov, program manager at Public Health Seattle & King County and the department's representative to King County's GIS Technical Committee.

Sharkov works in the department's emergency medical services division, which uses GIS technology to determine where mobile medic units will be most effective. To do it, Sharkov and colleagues overlay data on where most emergency calls are coming from with data on average emergency response times. The resulting visual illustration lets users quickly see pockets of need and determine how to best utilize limited public resources -- "that's what GIS helps us do -- to first make the analysis and then show elected officials where the hotspots are," Sharkov said.

"You can see the results or you can see the absence of results," he said. "You can not just see the problem, you can go back to see if the solution was right."

In addition to emergency health services, Sharkov said King County public health workers are using GIS to track West Nile virus, map the relationships between hazardous environmental exposures and vulnerable populations, monitor sewage systems to prevent contamination, and examine the spread of heavy metals and toxic chemicals from old smelters.

"GIS doesn't exist for its own purpose," said Greg Babinski, finance and marketing manager at the King County GIS Center. "It has to have some sort of business and what better business than making public health and environmental public health more effective and leveraging limited funds."

Babinski noted that GIS technology helps agencies respond to questions about cost-savings and offers an accessible way to communicate with both policy-makers and the public. For example, if you have to eliminate a clinic, which one do you choose, he asked. With GIS, workers can easily see where current clients are located, what are the smallest increases in travel time and what will have the least impact on residents. In other words, GIS lets agencies "leverage technology and data that you probably already have in ways you may not even comprehend," he said.

"The geography is not just where's the streets and the parks, but what's the underlying characteristics of a community," Babinski said. "The great benefit of GIS is that it takes these data and analyses and puts it in the hands of decision-makers and the people."

After all, GIS isn't just a tool for government agencies and academics -- people are using publicly available data to do their own mapping work too, Babinski reminded me.

"I think in the future, people will go to their local agencies and say 'here's an analysis I've done and I'm concerned about it,'" he said.

For more about GIS and public health, visit To learn more about Flu Near You as well as APHA's Flu Near You Challenge, visit

Kim Krisberg is a freelance public health writer living in Austin, Texas, and has been writing about public health for almost a decade.


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For those with occupational health interests, this can be a very useful technology. One example comes from CAREX Canada, which maps occupational and environmental carcinogens (hazard surveillance, not just health surveillance) and links them to usage statistics, hazard information, etc. They use all kinds of sources, not just the "usual" ones. (See

How could this kind of mapping be done in the US? How could it go beyond the TRI data that sometimes is used? How could occupational health researchers and activists take the HealthMap idea to go beyond data sources?

As a pioneer of workplace mapping that is based on GIS, I'd love to chat with folks about this.

By Dorothy Wigmore (not verified) on 05 Jan 2012 #permalink

Google Flu Trends at is more reliable than Flu Near You, and Google Flu Trends actually works. Flu Near You even pulls data from Google Flu Trends.

Another symptoms-based approach is It analyzes a broad array of symptoms & sicknesses and has some pretty cool features including email alerts, health history and location mapping through social media.