Press Briefing Transcript

MMWR Update on Anthrax Investigations
with Dr. Julie Gerberding

November 1, 2001

CDC MODERATOR: Thank you. Good afternoon and welcome to today's telebriefing. Please make a note of the following. These telebriefings will be conducted every day from noon to 12:45 for the entire month of November except Thanksgiving. The call-in number for these briefings will remain the same as today. That number is [866] 254-5942, and our speaker for today is Dr. Julie Gerberding, acting deputy director of CDC's National Center for Infectious Diseases. Dr. Gerberding will discuss the information updated in this week's MMWR.

Dr. Gerberding.

DR. GERBERDING: Good morning, and thank you. I'm going to focus my opening comments on highlighting some of the issues in the MMWR that came out this morning, and then, you know, take whatever questions you might have in that context. Basically, this MMWR updates the investigations that have been ongoing and presents information about some of the additional cases in New York, New Jersey, and Washington, D.C.

In addition, some algorithms to help guide clinicians to make the diagnosis of anthrax. Both inhalation and cutaneous are provided. The same issue also contains some additional information on preventing anthrax in pregnant women who are exposed, as well as reference to the new guidelines for protecting people who handle the mail. Those actual guidelines are on the Internet.

So let me just give you a brief capsule of the overall epidemic investigation. At this point in time we have 16 confirmed cases of anthrax and five suspect cases in the United States.

These cases are located in the D.C., Florida, New Jersey and New York City areas as before. All of the persons involved in these cases work in those three areas, although some of them live in surrounding states.

We recognize that ten of these cases are inhalational and the others represent cutaneous anthrax, and obviously the investigations of all of them are going.

I should make a couple of comments about the two cases that involve individuals who are not directly associated with the mail delivery system.

First of all, the investigation of the woman who was a hospital employee in Manhattan, who died yesterday morning of inhalation anthrax, is ongoing at a serious pace. We have yet to detect the clues that would lead us to identify the source of her infection. CDC is obviously interested in this from a public health perspective.

We are reviewing the routes that mail might have traveled to reach her in her home or in her mail room, but so far we have found no clues to suggest that the mail or mail handling per se was the source of her exposure.

The other individual, the bookkeeper in New Jersey has similarly engaged the attention of both the FBI and the CDC, to try to understand how her cutaneous infection occurred. We cannot rule out cross-contamination of a letter, or mail item as the source, but we have no evidence to confirm that either.

So these are very, very active areas of work and we'll do everything we can to update you as we're able to confirm new information.

Moving sort of into the arena of what lessons have we learned from the clinical evaluation of patients with anthrax, I can tell you that our clinicians around the country, who have been involved in these investigations, have just done an outstanding job of recognizing and treating the patients.

We have learned that one of the most critical pieces of information when someone presents with febrile illness, with fairly nonspecific symptoms, is to take a careful history of the occupation or environment in which that individual works.

Obviously, if someone is a mail handler and presents with the febrile illness, the index of suspicion, at least on the East Coast is high, that that individual would be infected with bacillus anthraces, and additional evaluation is indicated.

We know from the cases that have been reviewed so far, that most of the patients with inhalation anthrax had high white blood cell counts, or indications of acute inflammation on their white cell count, and perhaps more importantly, none of the patients had a low white cell count, or an increase in the number of lymphocytes.

A low white cell count and lymphocyte increase are more consistent with viral infections such as influenza, so if this holds true prospectively, this might be one of the clues that will help us distinguish between influenza and anthrax as we approach the flu season.

We also recognize that the chest x-ray is a critical diagnostic tool in evaluating these patients. All of the patients had some abnormality on their chest x-ray, although in a few cases it was subtle. If the chest x-ray was abnormal and a CT scan was performed, abnormalities were detected on all of these studies, and so a combination of chest x-ray, and if it's nondiagnostic, a CT scan would lead one to make the diagnosis of anthrax in all of these individuals.

The appropriate treatment for inhalation anthrax was discussed in last week's MMWR, and I'll take any questions you have about that but I'm not going to comment on that at this particular point in time.

Lastly, I would, from the clinical perspective, just like to mention a few of the lessons learned about cutaneous anthrax. We know that people can acquire this skin condition in any exposed area of skin. We've seen it on the extremities as well as the face and neck, and the presentation does seem to follow a fairly typical development.

The characteristic description is often spider bite-like lesion that progresses to a pustule or a vesicle with an ulcer, and then, ultimately, with the black scab on the top. The diagnosis of the cutaneous lesions has been complicated by the fact that many of the patients took antimicrobial therapy before the appropriate bacteriologic studies were performed. That's because it's common in clinical practice for skin infections to be treated with oral antibiotics, since they generally respond, and a specific microbial diagnosis often is unnecessary.

Nevertheless, if a person has been on antibiotics for more than 24 hours, it is unlikely that the cultures of these cutaneous anthrax lesions will demonstrate the organism by growth, and so additional studies are needed. CDC has been extremely successful in obtaining evidence of anthracis--b anthracis infection on biopsy specimen if the patient is on antimicrobial therapy. So what happens is a biopsy of the lesion is performed, the tissue is sent to CDC, and then special stains, either using PCR or antibodies to the b anthracis are performed that can, in the clinical context, make the diagnosis.

All of the patients with cutaneous anthrax have done very well. They are all recovered or recovering. One patient had a more complicated infection with positive blood cultures, and we do suggest to clinicians that if the patient is febrile or has evidence of a systemic infection that blood cultures be obtained, and that patient be treated using the recommendation for inhalation anthrax, as opposed to the less-complicated regimens recommended for treatment of cutaneous disease.

Let me just say a few words about how to put this in the broad picture of what is really going on. I think we are on a steep learning curve, and we have learned an awful lot in an awfully short period of time, and I suspect we will have more to learn as this progresses, but our focus at CDC remains on the public health implications of this bioterrorist attack.

In particular, we are focused on protecting the safety of persons who handle the mail or who are otherwise victims of this dreadful situation. We have great concerns for mail handlers who have been the highest--the most frequent target of these attacks and have been very pleased with the opportunities to collaborate with the Postal Service in developing what we feel are prudent measures to really emphasize the safety of social workers or mail handlers in a variety of settings.

Those guidelines, what you will see, are people wearing gloves and masks in various Postal situations, but what you may not see is the additional recommendations that are going on behind the scene. In particular, the entire Postal Service is on the alert for suspicious letters or envelopes and will do everything possible to get them out of the mail distribution system.

In addition, steps are being taken to improve the air quality in Postal handling facilities and to change the work processes there so that some of the procedures or activities that generate aerosols are reduced or eliminated. In environments like the high-speed electronic mail sorters that are associated with some of the cases of inhalation anthrax, the workers are being advised to wear masks and other personal protections to ensure that they don't inhale anthrax spores.

And then, finally, the gloving that has become widespread in many mail-handling situations will certainly provide an additional margin of safety for cutaneous anthrax, but as we always say at CDC, hand washing is the important last step in the whole chain of safety.

We know that these steps are not going to completely eliminate the risk entirely, but they certainly will help reduce the risk and ensure the safest possible mail service that we can hope for.

As I mentioned before, these investigations are all ongoing. They are at various states of progress as we move up and down the East Coast, and different strategies are in place in these various environments. One of the points of confusion that I would like to specifically address is that of the use of nasal swabs for managing exposures. I hope you can help me out here because we really want to get this message straight on the nasal swabs.

Nasal swabs are useful in this specific situation. If there has been a powder or a source of anthrax known to be released in an environment, a nasal swab is useful in determining what is the zone of contamination and helps determine what people need to be included in the treatment groups for prevention of inhalation anthrax.

We know from the experience in the Hart Building in Washington, D.C., that even among the people who initially had positive nasal swabs, within just a few days their nasal swab follow-up was negative. This means that if you get a spore of anthrax in your nose, it doesn't stay there very long, and there is no point at all in doing a nasal swab if you are several days out from the exposure because it is simply not going to be positive in anybody, and it doesn't help determine who has been in the zone of exposure or not.

So we do not recommend nasal swabs for people who are involved in exposure when it was more than a few days in the recent past. We do not recommend swabs to diagnose exposure in any individual person. We do not recommend nasal swabs for determining specifically who does or does not need prophylaxis. We certainly do not recommend nasal swabs as a nonspecific probe to determine whether anthrax has ever been present in an environment.

I think the early experience in Florida, when we did swab the individuals at the AMI building, helps us understand why the perception was created that everyone needed a nasal swab, but I can tell you that if we had to do that investigation over today, we certainly would not have recommended the widespread nasal swabbing that we did there, mainly because we were too far out from when the suspected day of exposure occurred and would have expected to see exactly what we did see, which was a thousand people with negative nasal swabs. So help us out here, and reassure people that if we're not doing a nasal swab, it's not because we don't care about them, or we're not concerned about their health and safety. It's because it is not a useful test, and we need to base our recommendations for taking care of them on something besides that particular piece of information.

What we do focus on is understanding the overall air flow and air environment as well as the ventilation system of the particular location where these things occur, and, specifically, we hone in on any kinds of activities, or machinery or equipment in an environment that can generate an aerosol and create a temporary hazard of aerosolized inhalation of spores that might be present.

So I think at this point I'll stop and take whatever questions you might have.

AT&T MODERATOR: Ladies and gentlemen, if you have a question to ask or a comment to make, please depress the one on your touchtone phone. If you're using a speaker phone, please pick up your handset before depressing the one. One moment, please, for your first question.

Your first question is from Andrew Rifkin [ph] of New York Times. Please go ahead.

MR. RIFKIN: Hello. Yes; a couple things. Do you--I wanted to get an update on the traces of anthrax that were supposedly found on the clothing of the New York City victim, the woman. Do you have a sense of where, on her clothing, for example?

DR. GERBERDING: We do not have that sample here at CDC. What I've been told is that there was a bag of clothing in the hospital and the bag was sampled, and it is currently not possible to determine what specific clothing items were contaminated, at this point . Since they were all jumbled up together in a bag, I'm not sure we will be able to say for sure what was and was not tially contaminated. But I know they are reculturing individual items in the bag to see if they can get any clues.


MR. RIFKIN: And one totally unrelated, quick question, if you don't mind. Will CDC play a role, at all, in determining sort of an "all clear" on the various buildings that are going to be decontaminated, both postal and government, other government buildings?

DR. GERBERDING: Actually, the Environmental Protection Agency has the lead for the decontamination process and its their call as to whether or not buildings are safe. Having said that, I think what we're beginning to appreciate is that there's a vast difference between finding a spore or two in a specific work environment that's been carried there on a letter or some other cross-contaminated item versus a situation where there's been a release or an aerosol of anthrax as a contaminated letter moved through a sorter.

So what we're working on now is how to sort of draw the line between the safe levels of spores in an environment in those situations where there's a health risk.

MR. RIFKIN: Right. And a quick last thing on that is are you going to be releasing any of the data that shows this vast difference that you describe here? In other words, can you tell the media the kind of findings you're getting around these sorting machines and how that compares to the just general findings you've gotten in mail sorting facilities and other facilities?

DR. GERBERDING: We're obviously working in partnership with a lot of different agencies who are involved in the sampling, and as the data are matched up and aligned, we can make some estimates about the quantitative relationship between sampling and risk, but we are not at a point where we can make any precise statements at this point.

MR. RIFKIN: Okay; thanks.

AT&T MODERATOR: Your next question is from Charles Ornstein of the Los Angeles Times. Please go ahead.

MR. ORNSTEIN: Hi there. I had a couple questions as well. The first is have you done analysis of the strain of anthrax found in Ms. Nguyen, and specifically, if it was consistent with the strains that you found in patients elsewhere in New York, New Jersey, and Florida, or if this was some sort of a different strain?

And then the second question is, I'm wondering if you are at all considering revising your guidelines based on the age of the patients of inhalation anthrax, which seem the average age, or the median age to be 56 years, and if you were going to suggest different steps for people who may be older as opposed to people with less compromised resistance perhaps?

DR. GERBERDING: With respect to the strain of the isolate implicated in this recent case in New York, CDC has not done all of the steps necessary to characterize that strain. Some of those are being done elsewhere. What we have accomplished so far allows us to say that we haven't identified anything about this strain that's different from the strains in the other areas, and, in particular, the antimicrobial susceptibility profile is basically identical.

So we have no reason to suspect it's different but additional work is necessary before we can state that across the board.

MR. ORNSTEIN: And then the second question dealt with age.

DR. GERBERDING: So with respect to the age of the patients, you know, keep in mind that we're really including a small number of patients in this sample and it can be a very skewed sample, depending on who we include or exclude in estimates of the mean, and we are not making any special recommendations based on age, although there tends to be older age in the inhalation case, I think is not at an age level where we would be concerned about immune compromised being the explanation for the presentation.

One of the patients at least had other chronic medical conditions, and that may have accounted for the severity of the inhalation disease, but it's premature to speculate about any specific relationship. So one size fits all for now.

MR. ORNSTEIN: Let me ask you one additional question. That deals with the co-worker that you're monitoring at the hospital in Manhattan.

Is there any developments on that?

DR. GERBERDING: I don't have anything to report on that today.

MR. ORNSTEIN: Thanks.

AT&T MODERATOR: Your next question is from Diana Gonzalez of WTVJ. Please go ahead.

MS. GONZALEZ: Hi. It's something, actually, that you just addressed very briefly, but earlier this week Dr. Koplan had mentioned that there was some concern that in the New York case there might be some antibiotic resistance, because the trio of antibiotics used in this case, and had worked successfully in other states, obviously did not work in Ms. Nguyen. Do you have an update on that as far as resistance to antibiotics?

DR. GERBERDING: Let me say, again, that we have, at CDC, evaluated the susceptibility of this bacteria to the same panel of antibiotics that we've looked with the other strains and they are completely identical. So we cannot account for the patient's death on the basis of antibiotic resistance.

MS. GONZALEZ: Okay.

DR. GERBERDING: I think she arrived in the hospital late in the course of her illness and that a more likely explanation is that she did not receive early treatment for the infection, and it's probably the early treatment that accounts for the better outcome in patients.

MS. GONZALEZ: Thank you.

AT&T MODERATOR: Your next question is from Helen Chickering [ph] of NBC News Channel. Please go ahead.

MS. CHICKERING: Thank you. Playing off on the nasal spore, or the nasal swabbing, which I know NBC underwent massive nasal swabbing, is there any test at all, or is there any work for a test, a quicker test to screen for the bacterium before it progresses to an infection at all?

I mean, I know, obviously, nasal swabbing and blood tests have not even been that successful. So are there any efforts that you know of to find a way?

DR. GERBERDING: The biology of the infection makes that very difficult. What happens is when a spore is inhaled into the lungs, it's picked up by macrophages and other specific and nonspecific cells of the immune system where it sits for a while before it activates and can cause disease, and while it's sitting in that form it's not very immunogenic. You can't find it because there's actually not a lot of it around and its intracellular. So if we had very sensitive tests for antibody development, they may become positive, and we're looking at to see if there's any evidence of that in people who have not yet developed disease, but that's too late to make decisions about treatment because most of the disease occurs early after exposure, long before we would expect the antibody test to become positive and tell us anything.

So right now, there is no test for exposure and there is no test to tell us who might develop anthrax in the near future.

MS. GONZALEZ: Thanks.

AT&T MODERATOR: You have a question from Susan Dentzer of NewsHour with Jim Lehrer. Please go ahead.

MS. DENTZER: Yes. Hi, Dr. Gerberding. Following up on this whole issue of spores, the other day Dr. Koplan said, and others have said that there is no clear awareness, now, about the threshold at which a certain number of spores becomes highly, highly infected. That one is at the low end, 10,000 is obviously high end, high risk, but knowing where is uncertain.

In spite of that, though, some of the people involved with the former Soviet Union's bio weapons program have said that they were able to establish cutaneous infections on the basis of as few as a dozen spores and that they are highly suspicious of the fact that it didn't take perhaps that many more spores to create inhalation anthrax infection.

What are you all now thinking about that and what light does that shed on your suspicions now about cross-contamination of mail as having been the primary agent in some of these apparently harder-to-explain cases?

DR. GERBERDING: Well, first of all, we are not privy to the specific data that the persons you referenced have at their disposal to comment on their conclusions about the number of spores necessary to cause cutaneous disease, but we've known from animal studies that there's clearly less, that the amount of bacteria necessary to cause cutaneous disease is lower than the amount necessary to cause inhalation disease.

And we are getting the impression, although we can't be sure, from the cases that we've evaluated so far, that you don't always have to have a break in the skin or if you need a portal of entry for the bacteria, it doesn't necessarily need to be conspicuous. But in terms of defining any specific numbers, I'd have to just concur with what Dr. Koplan said earlier, and that is that we don't know the cutoff. We suspect that it's not as much as the inhalation case, and we look forward to doing the animal studies to follow up and try to get a more deftive answer.

From an epidemiologic perspective, it is certainly plausible that contaminated mail, if it is handled by someone downstream from a contaminated letter, may be a source of cutaneous anthrax. That fits with an epidemiologic hypothesis, but we actually don't have data to prove that at this point.

MS. : Okay. I just want to follow up and clarify. So you are saying that one thing you are getting the impression of is that you don't need to have a break in the skin to get cutaneous anthrax?

DR. GERBERDING: I'm saying that we don't need to have a conspicuous break in the skin to have cutaneous anthrax. You know, for example, it's not just people who have psoriasis or who had a recent, you know, wound in their skin and that's the portal of entry. It may be that less-conspicuous routes of access are sufficient to cause the tial infection.

MS. : Does that mean a nick from having shaved; are you saying that degree of conspicuousness?

DR. GERBERDING: I'm saying I don't know.

MS. : Okay. And then just back to the inhalation one, the place you are still on that is that you really don't know at all what the threshold is at this point?

DR. GERBERDING: But what we do know is the people who have acquired inhalation disease have been either in situations where they've likely handled contaminated envelopes and had a very high degree of exposure or worked in environments where there was a potential for a very high degree of aerosolization.

We're not seeing cases downwind from where the primary source was likely to be, and that suggests that as the product is diluted in the air, the inhalation risk drops off as the distance from the source increases, and therefore there is a threshold at which there is no risk.

MS. : Okay. Thank you.

AT&T MODERATOR: Your next question is from Seth Ornstein of Knight-Ridder Newspapers. Please go ahead.

MR. ORNSTEIN: Yes, Dr. Gerberding. I will have a follow-up after this.

Going into what the MMMWR [ph] talks about and what would be helpful with diagnosis, I was wondering if you could characterize the confidence in using white blood, you know, WBC, in terms of determining the difference here in influenza and anthrax.

Obviously, you've got a very small sample size, like you're talking about with other things, is this ready or how close is this ready to be used by clinicians to say, yes, you more likely have anthrax or you more likely have flu, and how important is that coming into flu season?

DR. GERBERDING: Well, it's obviously an important issue because we are beginning flu season. We don't have enough experience yet to be able to provide firm clinical guidance, but I think the strategy is to rely on the same tools we always use when we're trying to make a differential diagnosis. It's very rare that we can rely on a single piece of information.

So, as I said, it is important to take a careful history from the person when they present. And if that individual is a mail handler in a professional environment, where they're dealing with large amounts of mail that is not their own, then the index of suspicion should be raised and more testing should be done to be sure there aren't additional clues to suggest that it is not a common viral infection.

One of the other clues that we are noticing is that the patients with inhalation anthrax actually do not have nasal congestion or a runny nose. They don't have the symptoms of an upper-respiratory tract infection, they have a more systemic chest presentation, and that may be another distinguishing characteristic. Although, as you said, we haven't seen a lot of patients, so we don't want to hang our hat on any specific symptom, sign or test at this point.

More likely, we are going to get a constellation of pieces of information that, together, will lead us either into the flu category or toward the anthrax category, but I can't emphasize enough the importance of the clinical history of the occupation and the environment in which the person right because right now that is a major risk factor and should help gear the clcian to doing the additional appropriate test to either rule in or rule out the diagnosis.

MR. ORNSTEIN: To follow up on that, I guess how much effort is the CDC putting in right now to help develop that better constellation to go along with you have the emphasis on environment that the person works, so that by maybe next--I mean, you've only been doing this for about a month now, and you've already started to see the signs of a constellation to be able to use.

And as we hit the flu season, is it fair to say that in the next 2 to 3 weeks the amount of work that is being put in should be able to give even more clear guidance on so people could tell--so clinicians will have a better view of who is flu and who is not?

DR. GERBERDING: I, with all my heart, hope that we don't have enough information to deftively answer this question. I hope we have no more cases of inhalation anthrax. Because in order to really answer your question, we have to have a large clinical experience. If we do our job, we will not face that large clinical experience and will not really need to know the answer to your question.

But with that preface, I can say that we expect to put out everything we can to help clinicians sort this out. We are going to provide some updated information for clinicians about the rapid diagnostic tests for flu so that they will understand some of the things that they might be able to do to firm up that diagnosis and not have to go down the path of the additional, more complicated and expensive tests that would be necessary to diagnose anthrax.

MR. ORNSTEIN: Just one last follow up on that.

So, in other words, are you saying that these rapid diagnostic tests for flu which have come out are good enough and sensitive enough to tell the difference between flu and inhalation anthrax, that they should be used more often, if used properly, and the key question there is are they good enough to tell the difference between inhalation anthrax and influenza?

DR. GERBERDING: Once again, it is not appropriate and good medicine to rely on a single test. The combination of the history, the clinical presentation, and diagnostic laboratory tests in the right context of a person where you have a clinical suspicion of flu, and you do the tests properly, you can come away from that experience with confidence that you've made the diagnosis.

If you are noticing the treatment algorithm, we also have some caveats there that if you think it's flu and you respond accordingly, it doesn't mean that the patient doesn't deserve a follow-up evaluation or to be alerted to the need to keep in close contact with the medical provider if the situation changes.

So it is a constellation of history, clinical findings, and laboratory tests. Hopefully, when we get these all together, we'll be able to at least reduce the anxiety among some people and help clinicians diagnose those patients that really do require the antibiotic treatment.

What we don't want to have happen is for everybody coming in with the flu to get an antibiotic because that undermines a whole other set of public health issues relating to antimicrobial resistance and proper management of influenza.

MR. ORNSTEIN: Plus, it doesn't help the flu.

DR. GERBERDING: Absolutely. Thank you.

AT&T MODERATOR: Your next question is from Kim Dixon of Bloomberg News. Please go ahead.

MS. DIXON: Hi. Thanks. I have two questions. The first is what are the chances that these new cases of non-Postal workers getting anthrax, that they got it in a public place, and what sort of things are you doing to look at? And the second question is are you, is the CDC involved in testing some of the mail that was sent from the Brentwood facility, that was sent to Lima, Ohio, and now it's coming back, and I guess officials are going through it and doing some tests on it. Once it's irradiated, can traces of anthrax be found?

DR. GERBERDING: With respect to the first question about the source of infection in the hospital employee in New York City, we do not know how this employee acquired her infection. What we do know is that the New York City Health Department has an extremely effective and aggressive system for detecting cases of disease that might be anthrax. They have more than 22 hospitals around the metropolitan area, that are doing very active surveillance for fever and pulmonary symptoms, and those hospitals are designed to detect additional cases.

If a individual was exposed in a public setting, one might expect additional cases of disease. The fact that those have not been seen is somewhat, at least in my mind, reassuring that this was not something that posed a broader health risk in a public environment.

Obviously, the vigilance is high and the health department is taking every potential case seriously, so we need to remain alert, that new information could come forth.

With respect to the safety of the mail that's been irradiated, you know, this is new for everyone. We don't have experience or a lot of data about the efficacy of radiating the mail. CDC is not involved with that process and we do not have any information about its benefits, and we look forward to learning from this experience, and the Postal Service, and finding out exactly how successful this really is.

MS. : What about testing some of the mail that was irradiated? Are you involved in that?

DR. GERBERDING: We are not currently involved in testing the mail.

MS. : Okay.

AT&T MODERATOR: You have a question from Meagan Garvey [ph] of Los Angeles Times. Please go ahead.

MS. GARVEY: Hi, Doctor. I wanted to ask you. You said that you could not rule out cross-contamination in the skin, New Jersey case of the New Jersey bookkeeper. Do you think at some point you might be able to rule it in, to determine that that is the source of her infection?

And also I wanted to ask you about how your work with law enforcement has been going. There seemed to be some tension, early on, about how much information was shared about the danger of the Daschle letter.

Are you continuing to work close with them? Have you worked out any problems you may have had?

DR. GERBERDING: With respect to the sources of infection in the bookkeeper in New Jersey, that investigation, as I said earlier, is an ongoing investigation, and, you know, we hope we learn the source of that infection and that will allow us to either conclude or refute the concept that it was related to the mail in any way. If we can ascertain that it was related to the mail, then either it's cross-contamination or we find a letter that is ultimately deemed to be the source.

But I can't help you out there until we have more information.

With respect to our relationship with the FBI and the criminal investigation side, I'm not aware of any problems that you've alluded to, but I can tell you that from day one in Florida our CDC field investigators have been working side by side with the FBI investigators, interviewing patients and exposed people side by side, and exchanging data on a day to day basis.

We are also here in the CDC leadership group on a telephone call, no less than two hours every day, with investigators from the FBI and other federal agencies, sharing information and data.

I don't think we could be more collaborative than we are right now.

AT&T MODERATOR: Your next question is from Cheryl Stalberg [ph], New York Times. Please go ahead.

MS. STALBERG: Hi, Dr. Gerberding. I want to ask you a little more about the fact that anthrax traces were found on this woman's clothes. You said that she arrived at the hospital late in the course of her disease, yet the anthrax was found on her clothes. So what does this clue tell you, if anything?

DR. GERBERDING: Well, it doesn't tell me anything because I can't interpret which clothing items were contaminated or what else was in the bag. For example, if there was some object in the bag that was contaminated with anthrax, the bag would test positive. It doesn't necessarily mean that it's a clothing item per se.

I understand that her shoes were in the bag. So does it--you know, was the bottom of her foot, or shoe contaminated with anthrax? We just can't speculate at this--

MS. STALBERG: So these were clothes that she wore into the hospital, that were then removed from her, presumably she was placed in a hospital gown, the clothes were put in a bag, and then they were subsequently tested?

DR. GERBERDING: That's my understanding.

MS. STALBERG: And do we have any idea how long anthrax spores could hang around on somebody's clothing?

DR. GERBERDING: Well, we don't have an answer to the question, specifically. I mean, these spores are hearty. We know that we can detect them in environments, here and there, long after there's been a source of the exposure. So if someone stepped on an anthrax spore and it stuck to their tennis shoe, it would probably stay there for a long time.

MS. STALBERG: Okay.

DR. GERBERDING: I don't mean, in any way, to imply that that represents a health risk. It's just simply what spores do.

MS. STALBERG: So it's not that great a clue.

DR. GERBERDING: It's not that great a clue.

MS. STALBERG: Okay.

AT&T MODERATOR: Your next question is from Sean Loughlin [ph] of CNN. Please go ahead.

MR. LOUGHLIN: Doctor, I'm just a little confused by your last point. You're saying now these spores are hearty, they can stick around for a while, but how does that jive with your point at the beginning of this about how the nasal swabs aren't reliable because the spores can disappear within a day or two from your nose. I'm a little confused there.

DR. GERBERDING: Because most people blow their nose.

MR. LOUGHLIN: Okay; okay.

DR. GERBERDING: If you have a spore sitting in there, it's really no different than if you have a spore sitting on top of your desk and, you know, you blow it off.

MR. LOUGHLIN: I see.

DR. GERBERDING: If you have a spore in your nose, you know, your nose is not an inanimate object, and what's in there comes and goes.

MR. LOUGHLIN: Okay. And you talked about cross-contamination being, you know, a possibility with the skin anthrax cases. Is it a possibility as well with the inhalation cases, or is that really remote?

DR. GERBERDING: I think it's very unlikely that cross-contamination would be a source of inhalation, and so far the epidemiologic information we have supports that, that cross-contamination would be an unlikely source of inhalation.

MR. LOUGHLIN: Which really points to the puzzle of the New York City victim.

DR. GERBERDING: Exactly.

MR. LOUGHLIN: Okay.

CDC MODERATOR: We have time for just one more question.

AT&T MODERATOR: Your next question is from Paul Reiser [ph] of Associated Press. Please go ahead.

MR. REISER: Yes. This is Paul Reiser. The GSA says that they are coordinating the cleanup with the CDC and using CDC recommendations, which prompts the question, at what--there are some rooms that they already used, they cleaned with foam, and they're considering using gas in a building.

Is the CDC recommending such measures for all buildings that, where there's a proven exposure, including the Postal Service? And I've got a follow-up.

DR. GERBERDING: Let me address your question. The CDC, as I said before, is not the lead for the cleanup procedures. Those cleanup procedures are being coordinated by the Environmental Protection Agency. We're there to provide some technical information about the microbiology of anthrax, but are not making the decisions about what types of decontamination are appropriate.

MR. LOUGHLIN: Okay. But you are making recommendations regarding the microbiology, and so the point is in that light, do you anticipate that cleaning these buildings to a point of, that they reach your public health standards, that it'll require the foam or the gas, or are there other methods that can be used?

DR. GERBERDING: I can't really comment on that at this point in time.

MR. LOUGHLIN: All right. Well, one more question then. Anthrax is a natural bacillus and it's quite common in agricultural areas in parts of the country. What is the natural background of anthrax in these federal buildings and how do you separate the natural background from spores that were added with malicious intent?

DR. GERBERDING: It's an excellent question. We do not know the natural background of anthrax spores. We have assumed that it's very low to nondetectable, and we know that we have several facilities where we have not been able to find any anthrax. So it's not a ubiquitous contaminant of the environment. In the current context, we need to assume that if we find anthrax it's arrived there recently as a consequence of these bioterrorism attacks, but until we get more information about the overall ecology of the organism, we can't be sure.

One way that we can tell the difference is by typing the isolate to see whether they are indistinguishable from the strains we know were part of the bioterrorism attack and obviously those studies are ongoing.

CDC MODERATOR: Thank you, ladies and gentlemen, for joining us for the telebriefing today.

As a reminder, these telebriefings will be hosted every day through the month of November, except Thanksgiving, Monday through Friday, 12:00 noon to 12:45. The number is [866] 254-5942. Thank you.

AT&T MODERATOR: Ladies and gentlemen, that does conclude your conference for today. Thanks very much for using AT&T Executive. You may now disconnect.

[END OF TAPE RECORDING.]

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U.S. DEPARTMENT OF HEALTH AND HUMAN SERVICES