Update on Anthrax Investigations
with Dr. Bradley Perkins

November 5, 2001

CDC MODERATOR: Good morning, everybody. Today's call will be an anthrax update, and our expert today, Dr. Bradley Perkins, is not a smallpox expert, so I want to make that clear.

First of all, let's go over the case count. Currently CDC is confirming 17 cases of anthrax, and there are five suspected cases.

Now I want to open this up now for questions and answers from everybody, and I'm going to turn it over to Dr. Brad Perkins.

DR. PERKINS: I'll take the first question.

AT&T MODERATOR: Ladies and gentlemen, if you do have questions, please press the one on your touchtone phone. You'll hear a tone indicating you've been placed in the cue. You may remove yourself from cue by pressing the pound key, and if you're using a speaker phone, we do ask that you please pick up your handset before pressing the numbers.

Our first question will be from the line of Kim Dixon from Bloomberg News. Go ahead, please.

QUESTION: I was wondering how the recent case in New York, how you're--what your thoughts are on cross-contamination, whether they've changed in the past two weeks. I think members--statements by members of the CDC have sort of evolved. First we didn't think it was possible and now we think it's possible in only skin cases.

Is it possible that in rare cases inhalation anthrax could be caused by cross-contamination, especially in light of the fact that we're not seeing any additional cases in New York after the woman who died last week?

DR. PERKINS: Yeah, that's a good question. We're continuing to evaluate our experience in the course of this investigation to make sure that we make the best public health recommendation to protect the public health.

Basically at this time the epidemiology we're seeing suggests that the level of contamination we would expect from cross-contamination may be sufficient to cause cutaneous disease.

At this point we do not have any evidence that that kind of contamination would be sufficient to result in inhalational anthrax. However, we remain extremely vigilant for evidence that that could occur.

In regard to the New York City case, we do not think that that resulted from a situation of cross-contamination, but at this point we do not have any very good leads as to where or how the exposure occurred in that individual.

QUESTION: I just have one follow-up. In this pause that we have now in lack of cases in the past couple of days, what is the CDC doing specifically to improve responses to a future attack?

DR. PERKINS: Yeah, over the last week or so we've worked very aggressively to codify what we've seen during the progress of this investigation, what lessons we've learned, and to translate that into a set of generic public health guidelines that are currently under development.

CDC MODERATOR: Next question.

AT&T MODERATOR: That will be from the line of Andrew Revkin with New York Times. Go ahead, please.

QUESTION: Thanks again for doing the briefings. With the New York City case again, what kind of picture, albeit incomplete, I guess, has emerged now of her whereabouts in the days leading up to her sickness? And do you still have a sense that she first got ill on the 25th of October, or have you been able to kind of push back any further there in your understanding of when and how she got ill?

DR. PERKINS: In regards to the New York City investigation of the single confirmed inhalational case, I think we do have good information in regard to the development of her illness, certainly after the time that she presented to the hospital, and based on the information that was collected at that time.

Beyond that, however, we are having, you know, difficulty identifying all aspects of where she might have been, how she might have been exposed, in the two weeks prior to development of illness.

We are using every possible clue that we can identify to track down every possible location where she has been, or where she may have been in those two weeks prior to development of her illness. But at this time there are no good clues as to the circumstances of her exposure.

QUESTION: And the quick follow-up is I think the last time we all spoke, the environmental testing was still a little scant or initial on her apartment, her clothing, all that stuff. Have you found anything in her environment at all that had even a trace of spores? Meaning in her closet, her clothes, her shoes, her--you know, is there anything that--at all?

DR. PERKINS: We have not found any evidence of Bacillus anthraces in any of the environments that we think she may have been, or where we know she was in the two weeks prior to her illness. The initial reports of a preliminary positivity on her clothes, or on a sample of paint from her clothes, that sample failed to grow on culture, and which we would consider the gold standard for identification of bacillus anthraces. So at this point, we do not have any confirmed positive B. anthraces in any location associated with this individual.

CDC MODERATOR: Next question.

AT&T MODERATOR: That will be from the line of Robert Bazell with NBC News. Go ahead, please.

DR. BAZELL: Hi. Two questions, please, and I'll give you the first one and then pause.

As you may know, the Mayo Clinic just held a press conference before this in which they were talking about a PCR-based rapid diagnostic test for anthrax, and do you have any information about--and which they're planning to give away to large numbers of labs around the country, at least initially give away, and then sell, starting next year, and they have claims about how good it is, although it's not backed up with a lotta data.

What's the CDC's opinion about this test? Should these labs start using it? Should this become a new clinical standard for anthrax testing?

DR. PERKINS: To my knowledge, CDC, or particularly the scientists working on anthrax here at CDC have not been in contact with the Mayo Clinic researchers in evaluation or interaction regarding this test. I will say that there is room for development of new diagnostics for rapid diagnosis of anthrax. The PCR test that CDC has worked to develop over the last couple of years with a number of partners is performing extremely well in a variety of settings during this investigation, and obviously one thing we would do with any new diagnostic test is want to see it compared to the PCR assay that we're currently using here at CDC and at state health departments.

DR. BAZELL: This is a follow-up, it's not my second question, but they made a "big deal" outta talking about how much they've been in communication with the CDC in developing, in the course of developing this test. So I find that a bit confusing.

DR. PERKINS: That may very well be true but I'm not aware of that communication.

DR. BAZELL: My second question was the--and I've asked you this before on these conferences but things change. Is there anybody with a suspect cutaneous case in any environment where the New York patient with inhalation anthrax lived?

DR. PERKINS: There is not.

CDC MODERATOR: Next question.

AT&T MODERATOR: And that's from Ellen Beck with United Press International. Please go ahead.

MS. BECK: Yes. Following up on the Mayo Clinic announcement today, is there going to be, if Mayo's going to be releasing this test, what kind of regulatory procedures might there be for them to follow before they can release it, or can they just put it out on the market? What, from the CDC's viewpoint, do they have to do yet to get this going?

CDC MODERATOR: We would suggest you follow up with FDA.

DR. PERKINS: And, again, I have not, I did not see the press conference, and I'm not aware of any technical aspects regarding that test.

CDC MODERATOR: Next question, please.

AT&T MODERATOR: And that's from Frank Rolance with Baltimore Sun.

MR. ROLANCE: Yes. Good morning and thanks for this briefing as well. Could you update us on the status of any plans to vaccinate laboratory workers and decontamination workers for anthrax.

DR. PERKINS: Currently, because of the changing risk that we perceive among laboratory scientists working in the laboratory response network for bioterrorism, we are trying to make plans to have those people vaccinated. This is not a precedent-setting move and it's consistent with the Advisory Committee on Immunization Practices guidelines for the use of this vaccine in preexposure settings. The thing that's changed is with the recognition that we now have powders that are indeed contaminated with B. anthraces spores, and these people are receiving large numbers of powders, most of which fortunately are not contaminated, but which they don't know which ones might be and might not be, we think the risk has changed in that population and we're trying to make arrangements to have those people vaccinated.

CDC MODERATOR: Next question.

AT&T MODERATOR: Thank you, and that's from Justin Blum with the Washington Post. Please go ahead.

MR. BLUM: Dr. Perkins, can you tell me when did CDC learn that the spores in the Daschle letter were different from the spores in the Florida case, and who provided that information to the CDC?

DR. PERKINS: I cannot comment on the exact timing of that communication and I'm not--and I don't know who that information was communicated to.

CDC MODERATOR: Next question, please.

AT&T MODERATOR: Thank you. That's from Susan Ferraro with the New York Daily News. Please go ahead.

MS. FERRARO: Good morning, Dr. Perkins. Thank you, once again. I've got two questions. One is we have another inhalation anthrax patient, this one in New Jersey's leaving the hospital today, and we're wondering if you all have learned anything new from her treatment, if it's expanded your knowledge.

And the other question is about the murder investigation, criminal action in the Bronx, or with, concerning the woman who lived in the Bronx. And are you also involving the work of the New York Police Department in tracking down where she might have been in her neighborhood? And I'm talking about the shops, and the subway, and the bus stop.

DR. PERKINS: In regard to your first question, we have worked very aggressively to pull all of the clinical information about the ten confirmed inhalational cases together, collate that information, compare it to the clinical information that we have from the 18 cases that occurred in the last century, look for common features, look for differences that we may have identified with these most recent cases, and we're in the process of getting that information out to clinicians, to help them better recognize and better treat these individuals.

I will say that, you know, based on our experience in this investigation, it looks like the case fatality, the proportion of deaths that occur in confirmed inhalational cases is gonna be much lower than it was among the 18 cases that occurred in the last century.

We think that that probably represents better modalities of treatment, earlier recognition of these cases, and we're pleased to see that decline in case fatality rate.

In regard to working with the New York City Police Department, New York City and CDC team are using all available avenues to help identify locations where this individual may have been. I presume, although I don't know for sure, that the police department is involved in that effort.

CDC MODERATOR: Next question.

AT&T MODERATOR: Thank you. That's from Maggie Fox of Reuters. Please go ahead.

QUESTION: Hi. Afternoon, and thank you again. I want to ask you, and I don't want to write some scary story, but what is the possibility that a lot of people have stacks of unopened mail that may indeed be contaminated with spores? Can you talk about the persistence of the spores in a nice dry environment like a stack of mail? And if CDC is taking that contingency into consideration.

DR. PERKINS: That certainly is a possibility, and we have worked aggressively with the postal authority and law enforcement authorities to reclaim or recollect mail that we think has a high likelihood of being a risk for inhalational anthrax.

In terms of the potential for cross-contamination that we think exists, that's a more difficult problem, and we do not believe that there is anything short of stopping the mail that's going to eliminate the potential for cross-contamination of mail, and that the risk for cutaneous disease, for the most part, is the risk that we're concerned about in that situation.

We want people to be vigilant in handling their mail and take precautions, including washing their hands after they've handled mail, to further decrease their risk for the development of cutaneous disease.

CDC MODERATOR: Next question.

AT&T MODERATOR: Thank you. And that's from Lori Garrett with Newsday.

QUESTION: Yes, good morning. I have a quick question or kind of a couple mooshed together that have to do with how we're assessing what sites are contaminated or not contaminated.

I wonder if you could talk to me about--I assume you're using the smart cards that were DOD-developed, and I wonder if you could talk to me about the specificity of the smart cards, cross readout for all other bacilli [inaudible] and what level of spore saturation they can actually pick up? Are they picking up one spore per square milliliter, a thousand per milliliter, or millimeter, depending on the nature of the surface? What? Talk to me about specificity.

And I assume since you said you had to culture your Bacillus anthraces and that it did not culture in one example, that you're going a step beyond Smart Cards to doing culturing? Are some of the false positives we've heard about because they were just Smart Card positive but didn't culture? So that's my question.

DR. PERKINS: Yeah. Let me be very clear that CDC is not using, nor are we advocating the use of these rapid field deployable techniques for identification of B. anthraces.

All of the sampling that CDC is advocating or participating in is based on culture of environmental samples for detection of Bacillus anthraces. So that's a misperception that CDC is involved in using those technologies to assess environmental samples.

There's two problems, from our perspective. Those technologies are, number one, incompletely validated, at least in the hands of CDC; and number two, the validation that has been done to date suggests that they are not appropriate--do not have appropriate sensitivity for use in environmental sampling, and that the sensitivity is in the range of needing to have 10,000 spores before you get a positive.

Now in some situations that may be fine. For example, the envelope that went to the Hart Building, using one of these rapid field deployable technologies to evaluate that sample that had very high concentrations of spores, may be a good thing to do, and we are actively moving to further evaluate that situation. But to use it in a building to detect whether there's been contamination or not, we do not think that's currently appropriate, nor do we think that's likely to be appropriate in the future.

CDC MODERATOR: Next question.

AT&T MODERATOR: Thank you. And that is from Nell Boyce with U.S. News and World Report. Please go ahead.

QUESTION: Thank you very much for having these conferences. Could you please comment if you're aware of this on how the investigation of anthrax is impacting other epidemiological investigations that the CDC might currently be conducting? I'm thinking specifically with West Nile, for example.

DR. PERKINS: The investigation of the current anthrax-related bioterrorism is an extremely high priority for CDC, and a number of people, a large number of people, have been mobilized to participate in this activity. However, we are currently meeting other critical public health needs regarding West Nile and other infectious diseases, as well as preparing for other possible bioterrorism events involving the use of other infectious pathogens.

CDC MODERATOR: Next question.

AT&T MODERATOR: Thank you, and that is from Sara Luck with The Wall Street Journal. Please go ahead.

QUESTION: Yeah, hi. You said just before that you worked with the law enforcement authorities to reclaim mail that has a high potential for cross-contamination, I believe. Could you give a couple of examples of what mail that is that you have identified specifically, and what's been done with that?

DR. PERKINS: The two specific examples I will give you is that in the context of investigation of the America Media, Incorporated inhalational cases that we worked with the FBI to evaluate mail that arrived after the building was closed for identification of any suspicious envelopes.

We also reclaimed mail that--criminal authorities reclaimed mail from other AMI associated sites where envelopes may have gone.

Also in the case of the Washington, D.C. investigation, as soon as the letter that went to the Hart Building was identified, mail was reclaimed from around Capitol Hill offices and mail rooms for examination.

CDC MODERATOR: Next question.

AT&T MODERATOR: And that is from Emily Harris with National Public Radio. Please go ahead.

QUESTION: Thanks. Thanks for having these. Two questions, one kind of related to that last question. I'm trying to get some more specific information about the environmental test results at Brentwood, where the traces of anthrax bacteria were found specifically in that big back room, and if you could tell me, I'd really appreciate it.

DR. PERKINS: I don't have those data in front of me. There have been a number of confirmed positives, environmental samples obtained from the Brentwood facility. Additional sampling is also anticipated in that facility to try to better understand the circumstances of exposure that occurred there.

QUESTION: Where would I get the better specifics on that, then, if you don't have it? Is there another way to get that information?

DR. PERKINS: Yeah, I would refer you to the D.C. health authorities for the specifics on the proportion of positives and the locations of those positives.

I will tell you that, you know, there are environmental positives associated with the sorting machine that was involved in the sorting of the letter, the implicated letter that went to the Hart Building.

CDC MODERATOR: Question?

QUESTION: Sorry, one other question, if I may. Is that all right? That was in relation to the woman in New York who died of inhalation anthrax, is there anything in the timing of her illness and death that gives any clues as to how early she could have been infected? I mean could she have been infected before the letter was actually to Daschle--or any letters were actually in the mail system? Or does the timing of it give any indication that she would have had to be infected afterwards?

DR. PERKINS: That's a good question. What we have seen is with the other confirmed inhalational cases where we have a good idea of how and when the exposure occurred is that the incubation period, the period between exposure and development of disease, is fairly tightly clustered in the four-to-six-day range.

That makes the occurrence of the last case in New York City, the confirmed case of inhalational disease slightly out of what--the range that would be expected related to any of the known letters in the New York City area.

In addition, you know, she did not have a very firm letter or mail-sorting connection. So she remains very much enigmatic in terms of the circumstances of her exposure.

CDC MODERATOR: Next question.

AT&T MODERATOR: That would be from the line of Charles Seabrook with the Atlanta Journal-Constitution. Please go ahead.

QUESTION: I know you said at the beginning that you're not a bioterrorism--I mean I'm sorry, not a smallpox expert, but would the vaccination for anthrax be done in conjunction with the smallpox vaccination of the workers there at CDC?

DR. PERKINS: No. Not necessarily. And there are efforts to prepare for bioterrorism using both of those--either of those agents are obviously overlapped, but there's no plans to simultaneously vaccinate people for smallpox and anthrax.

CDC MODERATOR: Next question, please.

AT&T MODERATOR: That will be the line of Karen Garlock with the Charlotte Observer. Go ahead, please.

MS. GARLOCK: Thank you, Dr. Perkins, for having these meetings. Last week, a group of people who work at a bank here, and a mail-handling center that receives mail from Brentwood were offered Cipro as a precautionary measure, and I know that's happening in other parts of the country, and I also read that some of the people who were exposed in the American Media building in Florida had stopped taking their antibiotics before the 60 days was up.

I wonder how concerned you are about the development of antibiotic-resistant bacteria, weighing that against the threat of anthrax.

DR. PERKINS: We are concerned about that issue, especially as we reach numbers in the tens of thousands that may be taking particular antibiotics. That issue is particularly concerning with the widespread use of Ciprofloxacin, which is an antibiotic that's frequently used for empiric treatment of other serious infections, and when I say empiric, I mean it's frequently an antibiotic that doctors choose to use before they know what the organism that's causing infection is, or before they have information on its antimicrobial susceptibilities.

MS. GARLOCK: Uh-huh.

DR. PERKINS: That particular issue is less of a problem with Doxycycline, which is know is an appropriate antibiotic for the strains of Bacillus anthraces we've been seeing, and that's why, as we moved up through tens of thousands of people being on antibiotics, we began to more aggressively recommend the widespread, more widespread use of Doxycycline, is because we want to prolong the usefulness of Ciprofloxacin and other drugs in the Fluoroquinalone class of drugs that it belongs to.

MS. GARLOCK: Thank you.

CDC MODERATOR: Next question.

AT&T MODERATOR: That will be from the line of David Carvallo from CBS. Go ahead, please.

MR. CARVALLO: Hi, Doctor. Thanks for helping us out here. As you know things now around the country, what does concern you more? Instances of cross contamination or letters? Which is the less threatening, if you will, scenario?

DR. PERKINS: Certainly, we think the risk of disease is related to the amount of exposure to Bacillus anthraces, and we are particularly concerned and dedicated to the prevention of inhalational anthrax, and for that to occur, you have to have particle size that are in the right range, and you have to have enough of those particles to actually cause infection.

We think that that situation, based on the current epidemiology we've seen, is most likely to occur with letters. We are concerned about disease associated with cross contamination but we think that the risk of inhalational disease in those settings is extremely low, although there may be a risk for cutaneous disease.

The problem is that with the number of spores that were, that are included in the letters that we know about, that there is the potential for widespread low-level contamination in a variety of settings, and we're starting to see that with increased testing of a number of facilities.

But the important thing to recognize there is that environmental positivity does not equal disease risk, and we are quite aware of other environments in the United States where there is environmental positivity and there is no risk of human disease.

Those environments include a large part of the Midwestern and southern part of the United States where animal disease occurs, and we know the spores are in the soil, and we don't see disease in those situations. So we know that some level of contamination is, does not pose a risk for human disease.

CDC MODERATOR: Next question.


AT&T MODERATOR: That will be from Brian Bectel of Infectious Disease News. Go ahead, please.

MR. BECTEL: Yes; thank you. I noticed in the MMWR report last Friday, several patients presented with similar radiographic findings, and this is kind of a follow-up to another question, but are there specific case similarities that doctors can keep an eye out for, or tests that they can run, that would be helpful in diagnosing inhalation or cutaneous cases?

DR. PERKINS: Yeah; that's an excellent question and we're again in the process of aggressively trying to get that information out to clinicians for their use.

One of the findings that I think is important is that it looks like chest x-ray abnormalities have been uniformly seen among all of the confirmed inhalational cases, and those abnormalities have sort of a slightly-different-than expected profile. Many people, as we've talked about this disease in the past, have suggested that mediastinal widening, sort of an enlargement of the lymph nodes in the center of the chest, was the key thing to look for, and we have found that to be present in essentially all of the patients, but sometimes it's required going beyond the chest x-ray and getting a CAT scan or CT scan of the chest.

But even in lieu of that particular findings, we are seeing, consistently, other abnormalities on chest x-ray, either fluid collecting in the bottom of the lungs, or actually evidence consistent with pneumonia in these individuals.

So I think chest x-ray is gonna be an important screening tool for early identification of inhalational anthrax cases.

CDC MODERATOR: Next question.

AT&T MODERATOR: That will be from the line of Nancy Metcalf of Consumer Reports magazine. Go ahead.

MS. METCALF: Well, this is very well-timed because it's kind of a follow-up to that. I noticed also in the case descriptions in the MMWR, that some of the inhalational cases presented with gastrointestinal symptoms, and I couldn't help notice in the descriptions of inhalational anthrax written before this current outbreak, that that didn't, at least the ones that I have seen, never mentioned gastrointestinal symptoms and I wondered if you could comment on that.

DR. PERKINS: Yeah. No, that's an appropriate observation, and there have been several of the confirmed cases that had gastrointestinal complaints. It hasn't been uniformly seen among all cases. What we're looking for are things that we think have a very good sensitivity in picking up early inhalational anthrax, and I think still, at this point, focused principally on the use of chest x-ray and early culture of blood prior to obtaining antibiotics, is likely to be the most useful early test for identification of inhalational anthrax.

CDC MODERATOR: Next question.

AT&T MODERATOR: That will be from the line of Rick Weiss with the Washington Post. Go ahead.

MR. WEISS: Thank you. Two questions. One, can you tell me what you know so far about Ms. Nguyen's, in New York, means of getting to work, whether she walked, bussed, or took the subway?

And secondly, can you tell me whether you know if she was a cigarette smoker and what you can say about the smoking status of the other inhalational victims, or status of any other hosts factor, or behavioral factor that might have affected their ability to fight off this disease.

DR. PERKINS: Yeah. The routes and the means of transportation that were used by the last case of inhalational disease in New York City are being aggressively explored, using information from a variety of sources, and she clearly did use the subway system, and other means of transportation going back and forth to work. However, investigation of those systems, to date, has not revealed any circumstances, you know, consistent with her exposure along those routes.

And your other question? I'm sorry.


MR. WEISS: Whether she was a smoker and whether you have any evidence that there's an unusual proportion of smokers among, or other risk factors like that among those who have been diagnosed with inhalational anthrax.

DR. PERKINS: Yeah, we're aggressively looking for things like that, to try to explain what we think is a slightly older age distribution than we would expect, based on, you know, the occupations that have been targeted, and also the clear difference in the distribution of inhalational, age distribution of inhalational disease compared to cutaneous.

However, at this point--and I was just talking to some other investigators about this--we've only got one--one of the confirmed cases at this point is a current smoker. However, a number of them are former smokers, and we're still in the process of collecting and collating the more specific information. There's at least one of the inhalational cases that has evidence of some other medical conditions, that may suggest an immune system that was not performing as well as it might have been. But we're aggressively looking for clues that can be used by practicing physicians to help identify these cases early.

CDC MODERATOR: Next question.

AT&T MODERATOR: That'll be from the line of Laura Meckler with Associated Press. Go ahead, please.

MS. MECKLER: Thank you. In New York, what's--you said that you're sort of at a standstill. What, specifically, are you doing at this point, from an epidemiological point of view?

I mean, where do you go now?

DR. PERKINS: Yeah. We're absolutely not at a standstill and basically we continue to aggressively broaden the rings of investigation of circumstances that may have led to her exposure.

There are a number of leads that are still in the process of being tracked down, a number of places where she either visited and ate in restaurants, or may have actually been employed, that we're still in the process of tracking down. We're working with law enforcement officials to identify other persons that may have known her or known where she was in the two weeks prior to the development of her illness, but we are clearly not at a standstill, and additional environmental examples are actively being obtained from a variety of locations.

MS. MECKLER: Uh-huh. You said where she may have been employed, a restaurant, she may have also worked at a restaurant?

DR. PERKINS: That's one of the leads that we're actively investigating.

CDC MODERATOR: Next question.

AT&T MODERATOR: Also from the Associated Press. Lauren Nergard, go ahead, please.

MS. NERGARD: Can you tell us a little bit more about what kind of testing you're recommending on the basis of the cross contamination that you've discussed, the fact that there is a fairly wide possibility of cross contamination across a wide amount a mail. Are you recommending testing of all government buildings? You pointed out the flaws of some of the widely used field tests. So what should those people do?

DR. PERKINS: Right. At this point we are working to develop these generic public health guidelines that specifically deal with environmental positivity for anthraces spores in the absence of disease, and most of the positives that are now coming up, and ones that we anticipate will be coming up in the future, these will not be linked to disease, and will result from cross contamination with low levels of Bacillus anthraces spores. Also believe that at this level of contamination represents a very low risk for human disease, and we want to be appropriately aggressive in prevention of that disease enough, and appropriate sampling to identify it. At the same time we do not want to see people put on prolonged courses of antibiotics for prevention of inhalational disease. We don't think that risk exists, so we are trying to find the right balance point, you know, based on those perspectives.

QUESTION: Next, have you actually issued recommendations for what buildings need to have additional environmental sampling, and how?

DR. PERKINS: CDC has been in the process of making recommendations on a case-by-case basis as we have proceeded through this investigation, and the point we are at right now is codifying some more general recommendations that can be applied to future circumstances, based on what we have learned to date.

CDC MODERATOR: Next question.

AT&T MODERATOR: We will go to the line of Anita Manning from USA Today. Go ahead, please.

QUESTION: Yes. Dr. Perkins, in what way--you mentioned that the CDC is preparing for other bioterrorism events, and I wondered if you could go into some detail about how you're preparing and what pathogens are being prepared for.

DR. PERKINS: Yeah, you know, there is an active effort right now that's been in the press to protect the public's health in case of an intentional release of smallpox, and teams of CDC employees have been vaccinated against smallpox and are attending readiness training currently.

However, we have no evidence of a planned attack using the smallpox virus, but we feel like it's quite prudent to be vigilant and prepare for the possibility of such an attack right now.

CDC MODERATOR: Next question.

AT&T MODERATOR: And that will be from the line of Lori Garrett from Newsday. Go ahead, please.

QUESTION: Yes. Thank you. I hadn't finished my question the last time, so I'm glad that you could come back to me. In terms of the case of Cathy Nguyen, I understand that--in fact, I know for a fact that Manhattan Eye, Ear & Throat Hospital issued a memo on November 1st warning faculty that three faculty members there had received letters from Pakistan with no return addresses that were suspicious, and telling everyone on the faculty not to open any mail that appeared to have a postmark from Pakistan.

Can you talk about that and let us know whether there's any potential link?

DR. PERKINS: I don't know anything about that advisory, and that has not been a focus of at least the investigation from the CDC perspective in Atlanta.

CDC MODERATOR: Next question.

AT&T MODERATOR: And that will be from the line of Arthur Allen with Salon dot.com. Go ahead, please.

QUESTION: Yes. I was wondering, I know that you're doing surveillance to look for drug-resistant bacteria, and I was wondering if you actually have numbers on how many people are getting Cipro versus Doxycycline at this time?

DR. PERKINS: Those numbers are being actively assembled by members of the investigation team now, but I don't have those right here in front of me. We think that at this point, for the largest numbers of people in the Washington, D.C. area, for example, most of them have been transitioned to Doxycycline at this point, and I believe those numbers are in the range of, you know, 10 to 15,000 persons.

CDC MODERATOR: This is the last question. Next question, please.

AT&T MODERATOR: And that will be from the line of Robert Schronberg from The New Jersey Star Ledger. Go ahead, please.

QUESTION: Doctor, I'm calling you from New Jersey where we have had a number of cases where we found traces of anthrax contamination in postal facilities, and our governor is asking that we test every post office in the state for anthrax. At some level do we start picking up just background levels of anthrax that was there all along and went completely unnoticed because it never caused any harm to anyone? And how would we know?

DR. PERKINS: In some parts of the United States, there may be a background of anthrax spores. However, along the East Coast of the United States, we would not expect any background contamination, especially in occupational settings. And all the data we have to date regarding the subtyping of isolates from environmental settings suggests that the contaminations, the low levels of contamination, were seen from cross-contamination or from the intentional releases that have occurred over the last month.

So, you know--but to follow on with that, in terms of extensive sampling, what we think we're going to see is that a variety of places are going to be found to have low level contamination, and we believe that contamination should be cleaned up, but that it does not represent a substantial risk to human health, particularly for inhalational disease, but also for cutaneous disease.

CDC MODERATOR: Thank you for being on today's conference call. We will have another telebriefing tomorrow at noon.

AT&T MODERATOR: And, ladies and gentlemen, that does conclude your conference call for today. Thank you for your participation and for using AT&T's Executive Teleconference Service. You may now disconnect.

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U.S. DEPARTMENT OF HEALTH AND HUMAN SERVICES