Scientists on the Anthrax Trail

Investigators say the spores of anthrax found in Florida were man-made. However, this does not confirm that a terrorist act has occurred. It only confirms that the source of the bacteria is not naturally occurring.

In order to determine where the bacteria came from scientists have to analyze the DNA of the bacteria found in Florida. Like all organisms, these bacteria will contain variations in its DNA that make them unique — a DNA fingerprint similar how humans are identified.

Once the DNA sequence is determined it can be compared to a library of sequenced anthrax strains found in places such as Northern Arizona University in Flagstaff, Ariz., and Los Alamos National Laboratory in New Mexico.

Genetic Manipulation

The same technology that allows the identification of strains of bacteria also can be used to alter them. The most obvious alteration would be one that renders the bacteria resistant to antibiotics.

Most experts agree this is not difficult to do — through a low-tech way, or more complex process. The low-tech method involves growing the bacteria in the presence of the antibiotic, and selecting the bacteria that survive. The more complicated method involves inserting genes that confer resistance to specific antibiotics. The end result of both is a strain of bacteria, with altered DNA, that is resistant to antibiotics.

However, some experts question whether this is even necessary.

"It is known which [strains] are nasty and which aren't. It isn't necessary to [engineer] anthrax," said Dr. Richard Moyer, a microbiologist at the University of Florida.

In fact, the strain found in Florida was confirmed by the Centers of Disease Control and Prevention (CDC) to be sensitive to antibiotics, suggesting it had not been altered genetically.

Anthrax as a Weapon

Experts differ on whether anthrax is an effective biological weapon.

"I do not consider anthrax a good biological weapon. It is difficult to mass produce, hard to distribute in an effective fashion, [and] is not self-propogating," said Ketan Desai, author of Germs of War.

Other experts note that in theory anthrax, which occurs naturally in dead animals and can be found in certain soil samples, can be a very effective means of killing people.

"Like many biological agents, anthrax has the potential to be an effective biological agent," said Dr. John Clements, chairman of the department of microbiology and immunology at the Tulane University School of Medicine. "The spores are resistant to drying, the organism is relatively easy to grow, the symptoms of the disease are subtle and easily missed early in the infection, untreated cases have a high fatality rate."

But, he said, "The theory falls down in practice."

Historically, there have been no successful uses of anthrax as a biological weapon. The Japanese cult, Aum Shinrikyo, tried unsuccessfully to release anthrax three times in the Japanese subway system. Even with members that had doctorates in molecular biology, the attempts still failed.

The most recent incident in Florida also indicates the difficulty involved. Although tragic, only one man was infected by the bacteria.

Should You Worry?

Rumors of additional cases in places like Virginia and Los Angeles turned out to be false alarms. Hospitals are merely taking the necessary precautions when faced with a patient exposed to the contaminated building in Florida.

Dr. Stephen Johnston, professor of internal medicine and biochemistry and director of the Center for Biomedical Inventions of the University of Texas Southwestern Medical Center, believes there are three positive things that will not allow this to turn into a serious problem:

There was only one confirmed case of an anthrax infection. Public health officials are aware of the problem, and hospitals are looking for the signs and symptoms. The strain is sensitive to antibiotics, and therefore is extremely unlikely to harm more people.

Experts also stress that anthrax can't be contracted from exposure to an infected person. The only way to become infected is to be exposed directly to the bacteria, which is usually in its spore form — the form taken to protect itself from the environment.

Normally, the bacteria are found in soil or on animals in spore form. In some countries it is common for people to be exposed to these spores while handling animal hides. The inhalation form of the disease is rare in these areas as well, and not fatal if people receive treatment early.