- The Washington Times - Wednesday, October 24, 2001

The U.S. Postal Service is exploring a number of technologies that could help sterilize the mail, including some that have been used effectively to sanitize food.
But it is not clear how and when such systems could be installed at post offices, and medical experts caution that more testing is needed.
Irradiation exposing the bacteria to radiation is one process that should work in killing anthrax spores that have appeared in numerous pieces of mail, experts on infectious diseases said yesterday.
The postal agency is exploring a number of other treatments, like disinfectants, microwaves, radio frequencies, and even a stream of subatomic electrons that would blast anthrax spores to shreds. But none of these techniques have been used on the bacteria before, and it remains to be seen which would work most effectively, experts say.
"I don't know about microwave," said Dr. Michael Donnenberg, head of the division of infectious diseases at the University of Maryland Medical School. "The spores are heat resistant."
But irradiation has worked on food, he said.
"Food irradiation is highly effective at killing bacteria that contaminates food," Dr. Donnenberg added. "The way it works is that most of the bacteria's DNA is damaged to the point where the organism can no longer grow. And the spores, even though dormant, still are full of DNA inside so the same technology that kills bacteria should kill spores as well."
Public-health officials say using radiation on mail would not harm the public. But they can't guarantee the content of mail would be unharmed: Food could go bad, and bottles of liquid could burst when heated.
Each possible solution has potential drawbacks.
For instance, ultraviolet rays are a potent disinfectant, but can't pierce envelopes or reach shadowy areas. So while the outside of the mail would be sanitized, the spores inside would remain alive. And heat waves could fry bacteria, killing it, but with a thick package they might not reach all the way inside.
Irradiation, however, could work on anthrax, according to a statement posted on the Infectious Diseases Society Web site. But the medical society says numerous technical questions need to be addressed before this type of technology can be used.
The major questions relate to the dimension, density and amount of mail processed. The Postal Service said earlier this week that it handles 200 billion items a year, traffic volume that would make it difficult to test and process all mail in a timely manner.
Questions also arise about the cost of these technologies and the time that would be needed to get them in place.
"I find it hard to believe with the huge, massive mail service that they'd be able to do that," said Dr. Chris Holstege, director of the division of medical toxicology at the University of Virginia. "But it's an interesting theory."
Dr. Holstege questioned whether such treatments would work on anthrax spores as they do on other bacteria.
"Anthrax can go into hibernation for years before it comes in contract with a person or animal," he said. "It's hard to get live bacteria to spread because it dies. But anthrax is very hardy, so once the spores form they are able to stay around for a very long time."



Click to Read More

Click to Hide