'Cross-Contamination' Enters the Anthrax Lexicon
July 7, 2008
Editor's note: The New York woman suffering from a pulmonary anthrax infection died Wednesday morning, after this story was posted.
(CNSNews.com) - Health officials are scrambling to explain how two women - one in particular -- contracted anthrax infections, even though they had no direct connection with the U.S. postal system.
The experts also are rethinking how many anthrax spores it takes to cause the most dangerous form of the disease. And they're using the word "cross-contamination" more frequently in connection with the anthrax outbreak.
Inhaled - from where?
A New York woman was in critical condition Wednesday morning, unable to speak to investigators. The infected employee, who worked in the hospital stock room near the hospital's mailroom, has the inhaled type of anthrax infection.
Making the case more perplexing, tests conducted at the hospital where she worked turned up no anthrax contamination in the building. But that has not calmed the fears of patients and employees of the Manhattan Eye, Ear and Throat Hospital.
Health officials say it's possible the woman picked up the infection somewhere else, but no one knows where. They say it's particularly troubling that she developed inhalation anthrax, which supposedly results from exposure to a large number of spores.
"All bets are off," said Dr. Anthony Fauci of the National Institutes of Health. He said health officials and investigators need to do "a real full-court press on trying to track this down. This is critical," he said in an interview on NBC's Today show on Wednesday.
In the New Jersey case, health officials said it's possible that the woman who contracted a skin anthrax infection could have received a letter that brushed against anthrax spores somewhere in the postal chain. The experts call it "cross-contamination."
The woman, who is recovering, works as a bookkeeper for an accounting firm, which is a five-minute drive from the Hamilton Township mail-processing center. That's where three anthrax-laden letters, including the one to Sen. Tom Daschle, were postmarked.
Dr. Fauci said although cross-contamination could explain the New Jersey woman's infection, that is no reason to panic.
"There have been over 20 billion pieces of mail that have gone out since the recognition of this crisis that we're in, and we have what looks like a single example of possibly getting contamination from a letter that came to you."
He said the odds of that happening are "very, very slight," and he said that's the reason federal health officials have so far refused to widely disseminate antibiotics to anyone who receives or handles mail.
Recent press reports, quoting scientists, suggest it may take far fewer spores than experts first thought to cause inhalation anthrax infections.
Dr. Fauci said he's "uncomfortable" with empirical evidence suggesting that it takes 8,000-10,000 spores to cause pulmonary (inhaled) anthrax infections.
Studies done on animals suggest that 8,000-10,000 is the critical number, he said. "I actually think that in all of biology, it's a bell-shaped curve, and maybe that's the standard mean amount."
Fauci said it's important to keep an open mind about the minimum number of spores needed to cause pulmonary anthrax infection. He said there's a "gray zone that has people scratching their heads."
Fauci agreed on the need for heightened vigilance on the part of the public, given the fact that "the right dispersal system" could cause a lot of damage. "You don't want to frighten people but you can't disregard that as a possibility," he said.