UMD: Anthrax Investigation

For university researchers' role in solving a national crime, it was a matter of being in the right place at the right time.

In September 2001, computer science professors Steven Salzberg and Mihai Pop had nearly finished sequencing the genome of a lab strain of anthrax at the Institute for Genomic Research — now called the J. Craig Venter Institute — in Rockville when letters filled with the deadly disease started showing up at the offices of news media figures and U.S. senators. The attacks killed five people and infected 17 others.

The National Science Foundation contacted Salzberg and Pop, and before long, the researchers — who were not working at the university at the time — were in confidential meetings with the FBI.

Between 2002 and 2004, Pop said the FBI sent about 20 anonymous test tubes of different strains of anthrax — an infectious disease caused by a bacterium — to their lab, giving no clue about where they came from. The researchers had only one mission: Find any clues in the anthrax genomes that could be traced to a specific lab.

Because the task was sensitive, it wasn't until last year that the FBI gave the researchers permission to discuss their involvement in the anthrax investigation. And until this month, when Pop and Salzberg released a paper detailing their findings and the steps they took to trace the anthrax genomes, no one in the university community had any idea what they had done.

"The reason we started sequencing [the anthrax] was, at the time, research methods couldn't distinguish between strains," Pop said. "We thought sequencing would allow us to get high-resolution pictures of DNA to determine where it came from."

Salzberg and Pop didn't find out what impact their research had on the investigation until they read a newspaper article about it in 2009: Those special genetic markers they identified had pointed to a single test tube in Fort Detrick.

Salzberg said all the anthrax samples the FBI sent came from a strain accessible to multiple labs across the country, so the FBI wanted the researchers to take the seemingly identical samples and find something unique about them.

"The goal of our project was to take the samples with anonymous labels and see if there were any distinguishable features," Salzberg said.

Salzberg said because strains of anthrax tend to be similar, many people were convinced the sequencing wouldn't work. One unaffiliated researcher even told news outlets it was a waste of time.

But they did it.

After close examination, when many researchers might have given up, Salzberg said he and Pop identified extra copies of a gene in a few of the samples and quickly reported their findings to the FBI.

Salzberg said they were confident they had found something meaningful, but the FBI kept them guessing.

"They wouldn't give us any details at all," Salzberg said. "They'd say, ‘Great, that's interesting,' and we'd say, ‘Why is that interesting?,' and they wouldn't tell."

Salzberg said the research played a key role in helping the FBI pinpoint Fort Detrick scientist Bruce Ivins as the key suspect in the 2001 anthrax attacks. Ivins committed suicide in 2008 before being formally charged.

"We didn't know that the mutation was one of the ones used in the [anthrax] letters," Salzberg said.

"When I first read the report and they detailed the techniques used, I was shocked," Pop added.

Salzberg said that at the time of the attacks, sequencing bacteria genomes was extremely expensive and difficult to do. Now, the type of genome sequencing Salzberg and Pop were using 10 years ago is relatively common and employed any time there's a bacterial outbreak in food.

Salzberg said unwittingly playing a key role in a national investigation and becoming pioneers in bacteria sequencing was simply serendipity.

"Had we not been there, a few years later someone else would have started doing it," Salzberg said.

But regardless of the fortuitous timing, Salzberg said the story has a positive message for science students.

"This is why I tell students you should do science," he said. "So you can have an influence on the world."

saravia at umdbk dot com