Cross-Contamination Gains Credence in Anthrax Probe

But officials say mystery deaths of two women still far from solved

MONDAY, Dec. 3, 2001 (HealthDayNews) -- Federal health officials investigating the anthrax attacks on America said today that cross-contamination of mail could explain how two women in New York and Connecticut contracted the fatal infection.

Health and Human Services Secretary Tommy Thompson said the recent finding of a single anthrax spore on a letter in Seymour, Conn., along with traces of the germ at a postal distribution center in the central part of the state make it "clear that cross-contamination of the mail has occurred" there.

But Thompson and other officials stopped short of saying at a teleconference today that they knew the exact source of the germs that killed Otillie Lundgren, 94, who lived near Seymour and died Nov. 21 of inhalation anthrax.

Investigators have also identified a letter bound for the same Bronx, N.Y., neighborhood which was home to Kathy Nguyen, the New York City hospital worker who died Oct. 31 and was the only other victim not connected to the main avenues of the anthrax-by-mail attacks. The letter passed through the Trenton, N.J., mail center that processed the anthrax-laced letters destined for Sens. Tom Daschle and Patrick Leahy. The letter to New York, which has not been found, reportedly was processed within seconds of the one addressed to Leahy.

The prospect that cross-contamination occurred, and that tiny amounts of anthrax may have killed Lundgren and Nguyen, suggests that "tens of thousands" or even more people may have received mail with traces of the bacteria in the bioterror attack, said Dr. Jeffrey Koplan, director of the Centers for Disease Control and Prevention.

People "have a right to be uncomfortable about this," Koplan added, although, he said, there's no evidence yet that such glancing contact is harmful.

However, Koplan said, cross-contamination of mail has been definitively linked to skin anthrax, so there is something of a precedent for infection. "We know there's cross-contamination, and we know that some people can get sick from this cross-contamination," Koplan said.

Lundgren's advanced age has led investigators to speculate that a relatively small amount of the germ might have been sufficient to overwhelm her weakened immune system. Nguyen, on the other hand, was 61 and had no record of lung disease or other problems that might predispose her to serious infection.

Monkey studies have shown that 50 percent of animals exposed to 8,000 to 10,000 anthrax spores will die, experts say. Whether the same holds for humans isn't clear.

Dr. D.A. Henderson, director of the office of Public Health Preparedness at the U.S. Department of Health and Human Services, said at the teleconference that the history of anthrax in people indicated that "it's just not that easy to infect someone with spores of anthrax and cause inhalation anthrax."

After all, Henderson added, there were only 20 reported cases of the disease in the United States in the entire 20th century.

"It's for this reason that we're reluctant to say that now we've got [the source]" of the bacteria that killed Lundgren and Nguyen, he said. "All the evidence indicates that this is not that sort of a risk," he said.

Koplan agreed that for such a low level of exposure to cause lung anthrax "would be extraordinary given past scientific evidence.

But," he added, "we've learned new things on a regular basis" during the investigation of the bioterror attack that has so far claimed five lives and sickened as many as 17 others.

Meanwile, Tom Ridge, the homeland security chief, put the nation on high alert today for a possible terrorist attack. Thompson said his agency was trying to stay prepared, but he didn't have any specific information about a bioterrorism attack.

What To Do

What should you do if you're elderly or have a weakened immune system? Officials downplay the risk of anthrax from cross-contamination of mail. However, Koplan says that people worried about the disease should wash their hands after handling their mail, and try not to open envelopes too close to their face.

For more on anthrax, try the Centers for Disease Control and Prevention, which also has the latest information on the bioterror investigation.

To learn more about the microbe, try the University of Wisconsin.

SOURCES: Teleconference with Tommy Thompson, Health and Human Services Secretary, Jeffrey Koplan, M.D., director, Centers for Disease Control and Prevention, and D.A. Henderson, M.D., M.P.H., director, HHS Office of Public Health Preparedness, Dec. 3, 2001
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