Genetic fingerprinting fails to identify anthrax source

WASHINGTON -- Sophisticated genetic fingerprinting that investigators hoped would help crack the anthrax case has yet to yield results. With the most promising avenue gone, the FBI is expanding its scientific inquiry, law enforcement officials said Wednesday.

Eight months after the attacks by mail killed five people, standard investigative techniques have yet to produce a breakthrough.

The hope was that genetic matching could help determine which of about a dozen laboratories that have the Ames strain of anthrax -- the type used in the attacks -- was the source of the deadly microbes.

Scientists say it's still possible that genetic analysis will help, but they are increasingly pessimistic.

"I did think this would be a fairly straightforward case when this first came out," said Mark Whellis, a microbiologist at the University of California-Davis who serves on the Federation of American Scientists' Working Group on Biological Weapons. "Now, seven or eight months out from attacks, with no apparent forward movement in the case, it is quite distressing. It makes me pessimistic about ever resolving it."

Conventional genetic fingerprinting, tried early on, didn't work because the genetic makeup of anthrax changes very little from generation to generation, so various samples of the Ames anthrax are virtually identical.

But in January, researchers made an important breakthrough: They found small differences between the anthrax mailed to Florida, where the attacks surfaced, and anthrax from a lab in England, a standard source of the microbe.

These researchers turned their work over to scientists in Arizona who are working for the FBI and have on hand samples of anthrax from every lab known to house the bacteria, and compared them to the attack samples. If anthrax at a particular lab was more similar than others to the attack anthrax, that would suggest that this lab might be the source.

But that genetic fingerprinting failed to narrow the field because they were unable to find the same differences among samples, FBI spokesman Bill Carter said.

The problem could be that the anthrax used in the attacks evolved genetically after it was taken from the lab, explaining why it doesn't match the lab samples, said Philip Hanna, a researcher at the University of Michigan Medical School. Or it could have come from a lab that has not provided a sample to the government.

As a result, researchers working for the FBI are taking a step back, genetically speaking.

They are unraveling the genetic code of the first anthrax sample that was used in laboratory work, which produced all the other samples now scattered around the country, so they can look for other tiny differences that may exist as anthrax changes over time, a senior law enforcement official told the Associated Press.

SMALLPOX SHOTS: The government panel that sets U.S. vaccine policy began two days of meetings Wednesday to decide whether smallpox shots should be offered to the public because of the risk of a bioterrorist attack.

The vaccine is currently offered only to lab workers who handle the deadly virus. But health officials are considering whether more people should get vaccinated as a precaution.

The Advisory Committee on Immunization Practices is meeting in Atlanta to weigh the risks of a bioterrorist attack against the dangerous side effects of the vaccine, which can include brain damage and even death.

The panel is expected to make its recommendation today. A decision would rest with the Centers for Disease Control and Prevention and Health and Human Services Secretary Tommy Thompson.

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