GWEN IFILL: Joining me now is the director of the Centers for Disease Control, Dr. Jeffrey Koplan.
Dr. Koplan, the mystery seems to deepen. What should we make of this latest Connecticut case? What do you make of it?
DR. JEFFREY KOPLAN: We don't know yet. We're looking to see what the possible source of exposure was, working with the Connecticut state health department, and at the moment we're not taking for granted any conclusion on that.
GWEN IFILL: Is it reasonable to assume that mail could be the source, since this is a woman who apparently didn't leave her house very often, didn't travel to any of the circle we've seen this kind of infection turn up in before?
DR. JEFFREY KOPLAN: Well, as we've seen earlier in this bio-terrorism event that we've been having for several weeks, mail has been a vehicle for infection and exposure, and that is high on our list of concerns in this particular case.
GWEN IFILL: So this woman was 94 years old. When she first was admitted to the hospital they thought she had pneumonia. Is her age a factor in either the diagnosis of what she was suffering from or the fact that she succumbed?
DR. JEFFREY KOPLAN: I think the age is certainly a factor in her clinical course and the fact that she's passed away. Certainly her immunologic defenses, her resistance to infection is diminished at this age.
GWEN IFILL: Does that also mean that it would not take as much anthrax, for instance, to kill someone who had a weakened immune system like an older person might?
DR. JEFFREY KOPLAN: We don't know that. I mean, it's a reasonable hypothesis, but it's not something that we have data on.
GWEN IFILL: What do we know now after all these cases that we didn't know say two months ago when we first started hearing about anthrax or a month ago?
DR. JEFFREY KOPLAN: Well, many things. We know that recent cases of anthrax that we've been looking at have been criminally caused, purposeful by a terrorist threat.
We know that there's been a mixture of both cutaneous and inhalation cases, and that the inhalation cases can present in ways that weren't typical, that weren't typical for the scientific literature that we had looked at earlier.
We know that the organisms that are being used, the spores that are being used are such that they can pose a threat even when they're sealed in an envelope.
We found that certain occupations are particularly at risk and in this case it's been directed almost occupationally by people in the media, at people in government, and possibly unintentional victims have been postal workers.
GWEN IFILL: And perhaps this woman in Connecticut and another mystery case, the woman in New York, could have been unintentional victims as well. What do we know with the woman in New York, the other mystery case?
DR. JEFFREY KOPLAN: We have yet to be able to identify a source of exposure for the woman in New York, despite very intensive study by a number of investigators and repeated looking.
We're not done with that investigation; the New York City Health Department as well as our CDC staff are still working hard at trying to identify a possible cause, a place and time and basis for exposure for that woman, but we don't have the information yet.
GWEN IFILL: When you say very intensive searching looking for the source of this, how do scientists begin to sort out this kind of a puzzle?
DR. JEFFREY KOPLAN: Well, for one, accept all the possible causes. We don't assume that because something happens one way last time that it's the same this time. We bring in a range of different scientists, people with expertise in infectious diseases, laboratory work, epidemiology, environmental issues.
And we methodically go through how a person has spent their days in the period of time before they began to develop symptoms.
So, for example, in the woman in Connecticut, our teams, the public health teams in general will be looking at a day by day recall of what went on, where she was, what she did, what came into the house, and what might have been a source of exposure to anthrax spores.
GWEN IFILL: Now here in Washington on Friday they discovered what they had long suspected, which was a second anthrax laced letter, addressed to a Senator on Capitol Hill, in a bag full of other letters that had been quarantined I guess since the first one was discovered.
Does the discovery of that second letter to Senator Leahy help the investigation of the source of the other, the Daschle letter, the Brokaw letter, the other letters we know about?
DR. JEFFREY KOPLAN: Well, I think it will provide both law enforcement in particular with potentially useful information. From our end and the public health investigation, it may have some benefits, but it is probably less useful than to the criminal investigation.
GWEN IFILL: Apparently there was quite a great quantity of an spores in this letter and surrounding area. Does that affect the health investigation at all? Does that help it?
DR. JEFFREY KOPLAN: Only in the sense that it's good to have confirmation that it is biologically the same material that we've seen in these other parts of this criminal investigation.
GWEN IFILL: As you continue your investigation about the source of this for health purposes, does it help you at all to be able to determine whether this is a domestic investigation, a domestic source that you're looking for or a foreign source?
DR. JEFFREY KOPLAN: It doesn't really help that much in the public health investigation part of it. Whatever the source is or whatever the type of bacteria is, it is a lethal bacteria. We know that from the first case, this is a serious organism. It's killed people. It continues to kill people, as we saw today. And its mechanism of causing disease and its epidemiology, which we're studying, probably don't make much difference as to where its origin is. That's, of course, crucial to the criminal investigation. But in terms of our ability to investigate these cases from a public health end, its origin is less important.
GWEN IFILL: Today seeing a woman who died, who lived in a home by herself, was fairly elderly, who was not in any of the at risk professions that you identified earlier, does that mean we should be expanding our definition of who is at risk?
DR. JEFFREY KOPLAN: Well, we don't know yet, because, for one, we've got some intensive study to do as to what was the exposure here, and it may turn out that the nature of the exposure is similar to ones we've seen before, it may be different, this may give us a real clue as to, in some way, as to how these crimes have been committed.
By the same token, we may end up as we did in New York with very little information to go on. So there's a potential here for some more information, but there's also the potential for a dead end and more frustration in knowing how this woman was specifically exposed.
GWEN IFILL: Does the CDC -- after all of these cases now entered into the annals one after the other -- does it feel more confident now that it has a handle on what would happen with new outbreaks than it did last time?
DR. JEFFREY KOPLAN: Well, we learn a little bit with each one of these, there's no question about it. And our folks become more experienced and we can become more efficient and more adept -- laboratory work, the epidemiology, et cetera.
But, nevertheless, ultimately, the person has got to be apprehended who's doing this. We can get more efficient and more adept, but we're still reacting to a purposeful criminal act.
GWEN IFILL: Dr. Jeffrey Koplan, thank you for joining us.
DR. JEFFREY KOPLAN: Thank you.