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'Disease detectives' use high-tech sleuthing to protect us from pandemics

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As the 'front-line troops' in the global battle against epidemics, officers in the Centers for Disease Control and Prevention's Epidemic Intelligence Service chase germs and viruses across state and country borders using technology to monitor disease spread, staying on alert for the next great global health threat.

In April 2009, hundreds of epidemiologists gathered in Atlanta for an annual conference at the Centers for Disease Control and Prevention headquarters. The attendees were current and future members of the CDC's Epidemic Intelligence Service (EIS), a two-year post-graduate training program that grooms "disease detectives" to investigate epidemics all over the world.

The week-long conference -- part scientific convention, part job fair -- brings together about 1,800 people each spring. While current EIS officers present their research from the field, new recruits who will begin training in July use the time to choose their ideal EIS assignment. "This is kind of like [fraternity] rush week on steroids," said Douglas Hamilton, EIS director.

But in 2009, amid the usual commotion of the conference, urgent whispers started midweek. Sara Lowther, an EIS officer stationed in Minnesota, was at the conference presenting research when she heard "rumors of this new flu." On the Wednesday of conference week, Hamilton ran into a colleague who told him about two San Diego children stricken with what seemed to be the same flu strain that killed millions worldwide in 1918. "The picture on the ground was not clear," Hamilton said. "We didn't realize what was happening."

That virus would later become known as H1N1, the flu that killed several thousand people and sent scores of others to hospitals worldwide, setting off a frightening global pandemic.

After days of listening to colleagues discuss their work fighting smaller epidemics across the country, EIS officers left Atlanta and fanned out to face arguably the biggest fight of their tenure. On Lowther's first day back at the Minnesota Department of Health, she joined planning meetings and helped with surveillance of local hospitals and schools. Back in Atlanta, CDC staff members, including dozens of EIS officers, formed teams to head out to San Diego and other cities. "Immediately after the conference," Hamilton said, "we had to start lining up officers to go into the field."

Founded in 1951 to protect against mounting concerns of bio-terrorism, the EIS went on to investigate outbreaks from polio and Legionnaires' Disease to E. coli and Severe Acute Respiratory Syndrome (SARS). As the "front-line troops" in the global battle against epidemics, EIS officers chase germs and viruses across state and country borders using technology to monitor disease spread, staying on alert for the next great pandemic.

Aptly portrayed in the 2011 film Contagion (although, as one former member said, "There is no EIS officer who looks like Kate Winslet,") members of the EIS team up with public health agencies to study and squash disease outbreaks -- with the high-stress goal of keeping citizens safe. It boils down to this, Hamilton said: "People are sick. You need to find out why and you need to stop it."

Matching the puzzle pieces

When Sara Cody was an EIS officer from 1996 to 1998, she was among about a third of her class assigned to state and local health departments, while the others worked at CDC programs in Atlanta. Posted in the infectious diseases branch of what is now the California Department of Public Health, Cody began getting reports from the state about an uptick in salmonella diagnoses. Every time a physician diagnoses salmonella, the patient's laboratory results are sent to the state health department, Cody said. The health department further tests the lab results to see if there are commonalities between cases.

Nearly every EIS investigation begins with an invitation from a state, Hamilton said. "In the United States, health is under the jurisdiction of the state government," he said. "It's their investigation. We're providing assistance."

Cody began searching for clues that would answer the most important questions in the salmonella outbreak: Who is involved? Where are they? What is happening to them? In a race to stop the outbreak from spreading, Cody interviewed patients as well as a control group that wasn't sickened. She asked where they shopped for groceries and which restaurants they visited.

As she put the pieces together, Cody found that most of the diagnosed were Spanish speakers living in San Jose. "There were hints that this was a community of people that had something in common," she said. Finding the common thread in a food-borne illness outbreak can lead right to the cause of exposure. In this case, the salmonella infection came from raw milk cheese.

Now, Cody is communicable disease controller and deputy health officer at the Santa Clara County Public Health Department. Her time in the EIS was "a blast," she said. "What I enjoyed the most was outbreak investigation," Cody said. "It's problem solving and detective work. It also tests your ability to get disparate information from many different people."

High-tech sleuthing

While the meat and potatoes of EIS work -- on-the-ground interviews to collect information -- hasn't changed much over the decades, technology has changed other ways the EIS gathers and uses data, said Jonathan Zenilman, an EIS officer from 1985 to 1987 who is now a professor at Johns Hopkins University. Surveillance software and data mining improves detection of epidemics by bringing under-the-radar patterns to the surface. Diagnostic tests that previously took years to develop, Zenilman said, were created in about a month for the SARS and H1N1 outbreaks.

In the event of food-borne outbreaks, state and local health departments share information with federal health agencies on the CDC database PulseNet. If the data shows an uptick in a particular type of salmonella, Cody said, the disparate departments will use the same laboratory procedure to seek out the source of the problem and any connections. (The 2009 salmonella outbreak stemming from peanut butter was detected by the CDC using PulseNet.)

Mapping technology also aids EIS outbreak investigations. Officers use handheld devices with GPS capabilities to administer questionnaires -- a technique particularly useful in rural villages where addresses are ambiguous -- and use the data to map epidemics, Hamilton said. When investigating an "astronomical death rate" among Nigerian children, Hamilton said, EIS officers used mapping to determine that the deaths were related to lead poisoning brought on by gold mining.

Though technology can be tremendously helpful to outbreak investigations, Hamilton said, the CDC and EIS aren't exactly early adopters. "We're probably not as sophisticated as you think," he said. EIS officers frequently use personal communication devices, Hamilton said, but they leave them home when traveling to certain parts of the world, such as China. "They're not allowed to take their Blackberries," he said, "because they can be cloned in a matter of seconds."

And while CDC servers are accessible from anywhere in the world, Hamilton said, privacy concerns keep the agency from making greater use of the cloud. Even thumb drives are fingerprint encrypted, he said. "The challenge there is we are incredibly careful about data security," Hamilton said. "As stewards of the public's data, we have to be super careful."

Chasing germs

From the ease of air travel to the centralization of food processing, borders between states, countries and continents are thinner than ever. For EIS officers, that means battling faster-spreading disease outbreaks. EIS officers face a range of public health problems and are tasked with defining the disease characteristics, who is affected and when. "Our guys are learning to do what we call applied epidemiology," Hamilton said. EIS officers develop "the exact same skills you need to respond to an H1N1 epidemic."

Just as epidemics can move faster than ever, so can the EIS and the CDC. The agency's complex Emergency Operations Center monitors data from sources including airline quarantine stations and health departments. Lab results and DNA patterns submitted to the CDC database are scanned for anomalies. "We are constantly learning about disease outbreaks that five years ago we wouldn't have picked up," Hamilton said.

Each day of work at the EIS is another step in preparing for a global health threat. If that occurs, EIS officers will be on call to achieve their singular goal: protect the public and break disease transmission.

"The possibility of a worldwide pandemic that is passed rapidly around the world is very plausible," Hamilton said. "The concern is that someday something will happen that is both highly transmissible and deadly."

Photo: Sari Dennise/Flickr

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Christina Hernandez Sherwood

Contributing Writer

Contributing Writer Christina Hernandez Sherwood has written for the Los Angeles Times, Newsday, the Philadelphia Inquirer, Diverse: Issues in Higher Education and Columbia Journalism Review. She holds degrees from the University of Delaware and Columbia University's Graduate School of Journalism. She is based in New Jersey. Follow her on Twitter. Disclosure