Webcast Transcript
Anthrax: What Every Clinician Should Know, Part 1
(October 18, 2001)
(View the webcast on the University of North Carolina School of Public Health site.)
Segment 6 of 6
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Dr. Baker (moderator):
Brad, let’s turn back to this case definition if we
could for a minute. This is a real important part of our program today
because obviously our desire is to have clinicians out there report
to their local or state health department if a case occurs. So maybe
we can go over that again.
In the anthrax case definition you mentioned that culture or other
laboratory tests that could be used to confirm an anthrax case. Could
you tell us then some more about how clinicians can get this testing
on a suspect case? How is that available?
Dr. Perkins:
Well, again, I think this is a very important area. The case
definitions I presented earlier are designed to reflect various levels
of diagnostic certainty in patients with clinically consistent illness
either with or without known exposure to Bacillus anthracis.
We would like to see culture isolation from all of these because we
feel that that’s the gold standard for diagnosis, but that is not
possible in all circumstances and we are fortunate to have a variety
of other laboratory tools that will allow us to confirm cases of disease.
In the routine clinical setting it is possible to get a fair ways
down the road in terms of diagnosis of anthrax disease in just the
regular clinical microbiology laboratory. Again, this organism grows
phenomenally well on routine sheep blood agar plates that are used
in essentially all clinical laboratories. It is easy to get the bacillus
level identification, and at that level any bacillus species that
is nonmotile, nonhemolytic that is growing under aerobic conditions
should be quite suspicious in a setting of clinically consistent illness.
And actually even that level of diagnostic confirmation should trigger
a report to the public health system.
What’s difficult is when you get beyond that. It is actually quite
challenging to distinguish many of the other bacillus species from Bacillus anthracis. At that point we have established—CDC
has established a network of laboratories. The Laboratory Response
Network for bioterrorism, which is a public health—part
of the public health infrastructure to move these specimens or strains
related to these high threat agents such as Bacillus anthracis into a setting where further confirmatory testing can be done. And
so if someone has a bacillus species in their clinical laboratory
they need to contact their local and state public health authorities
and work with them to get that isolate into the Laboratory Response
Network for bioterrorism. These laboratories are all connected to
CDC. They are using standard protocols and reagents that have been
provided by CDC and other partners in bioterrorism, and they have
the ability to confirm, in almost all instances, an identification
of Bacillus anthracis.
Now when we don’t have culture, when we don’t have an isolate, there
are some other tests. These tests are less available in clinical laboratories
and actually in some of the Laboratory Response Network as well. They
can be used to confirm cases, but they are generally less available
and some of them you actually have to come into CDC laboratories to
get those tests. That’s the PCR test for detection of Bacillus
anthracis DNA; the immunohistochemistry test, which uses antibodies
that allow us to visualize Bacillus anthracis; and then the
serology test, which is a research test that currently is only available
at CDC.
Dr. Baker (moderator):
What you described sounded to me like sort of a 3 level system.
In local hospitals, in local communities, the capacity is there to
basically identify the organism, and that would lead the clinician
in to make a report to the health department. That’s kind of that
first level—is that right?
Dr. Perkins:
Exactly. After the bacillus species in the setting of clinically
suspicious illness.
Dr. Baker (moderator):
And that would trigger that case report that you talked about
earlier?
Dr. Perkins:
It should trigger that case report and that’s exactly what
happened in the Florida situation.
Dr. Baker (moderator):
And the second level is more the Lab Network, that’s the more
definitive identification. The third level are those very specialized
tests that you mentioned at the end.
Dr. Perkins:
Yes.
Dr. Baker (moderator):
So it’s sort of a 3-tiered system.
Dr. Perkins:
That’s exactly right.
Dr. Baker (moderator):
Let’s go on to some other issues here. The question has come
in regarding anthrax vaccine, whether or not it is available, whether
or not it is the thing that should be done here in this setting. Could
one of you help us with the issue of anthrax vaccine?
Dr. Stephens:
Sure. We both may want to comment. There is an anthrax vaccine; it
was developed through the efforts of the Centers for Disease Control
some years ago in prevention of disease when workers exposed to wool
and goat hair became ill with wool sorter’s disease in the ‘50s and
‘60s when inhalational anthrax was a problem. The vaccine is currently
not recommended except for those individuals who work with Bacillus
anthracis. And, Brad, you may want to comment on that issue.
Dr. Perkins:
Yeah, the people that have generally been vaccinated with the anthrax
vaccine in this country are those people that have an occupational
risk for exposure. At this time, the vaccine is only used in those
individuals as well as the military population, although we are actively
vigilant for situations where it may be beneficial to use the vaccine
in the civilian population.
Dr. Baker (moderator):
So basically what you are saying is, the general population does not
need to even think about anthrax vaccine. That is not an issue. It
is really related to those individuals that have a very clear risk
of anthrax as a result of doing certain occupational things like the
wool sorters and the things that you mentioned before.
Dr. Perkins:
Exactly.
Dr. Baker (moderator):
Now there are other people out there that in their work are concerned
about being exposed to anthrax—for
example, first responders, healthcare providers and those kinds of
individuals, who, again, across the country, would have a very low
likelihood of being in contact with anthrax. But again, people are
starting to wonder, “Is this something I need to be thinking about
in my occupation?” Obviously, not the traditional things that you
talked about. Are we developing guidelines that go beyond those traditional
occupations to think about other groups?
Dr. Perkins:
Well, the Advisory Committee for Immunization Practices, which is
CDC’s recommendation for use of licensed vaccines, entertained this
issue in quite a substantive way over the last couple of years. There
was a statement made by that committee that suggests that there is
no current need for any pre-exposure vaccination of specific populations
in the United States. Populations that were considered included emergency
first responders, law enforcement officials, persons that would receive
suspicious packages in the laboratory. At that time there was a firm
recommendation from the committee that there was no need for pre-exposure
vaccination because there was no ability at that point to calculate
risk versus benefit of that protection. Over the last month we are
seeing the occurrence of cases and the occurrence of risk and I think
that based on that change of risk that we are going to have to re-evaluate
the need for vaccination in selected populations.
Dr. Baker (moderator):
So we are rethinking that question in light of recent events basically?
Dr. Perkins:
We are. We are.
Dr. Baker (moderator):
A different question on nasal swabs. We’ve heard about nasal swabs.
You did a lot of nasal swabs in Florida, and that is happening now
in various places around the country. Maybe, David, you can help us
with this. What can you say about when it is indicated and what do
nasal swabs really mean? What is the significance of that?
Dr. Stephens:
Nasal swabs, as Brad has indicated, were used and are being used in
settings of epidemiological investigations regarding these anthrax
outbreaks. However, they shouldn’t be used in an individual situation
for making decisions. And I think that Brad would agree with that.
The key element is that they serve a purpose in epidemiological investigation
studies, but not for the individual decision-making regarding prophylaxis
or treatment.
Dr. Baker (moderator):
Would you say it is fair to say that a nasal—a positive nasal swab is really more a measure of exposure? It means
that person has been around the bacillus but it doesn’t have direct
clinical implications in terms of triggering, say, drug use. Is that
a correct statement?
Dr. Perkins:
That is exactly correct. Again, the decisions about antibiotic prophylaxis
are driven by the epidemiologic investigation, and the nasal swabs,
the environmental sampling, and the potential serology done are all
adjuncts to the epidemiologic investigation, trying to draw circles
around populations that are at risk. Those tests—none
of those tests should be used to make individual decisions about this
patient or this individual should be treated and this one should not.
Dr. Baker (moderator):
Let’s turn a little bit to sort of the early part of the action. You
talked about this a little bit in your description of Florida. That’s
this issue of a suspicious letter or a package. Many people now want
to know what they should do. How does one identify a suspicious package?
What are we now learning about how to handle these letters or packages
from the ongoing investigations?
Dr. Perkins:
We are learning some interesting things. We are learning some things
about human nature. We have literally—in
the context of the multiple investigations that CDC is currently involved
with—we literally interviewed hundreds of
people that have been involved in handling or exposure to either confirmed
or suspected envelopes or packages containing Bacillus anthracis.
There are a couple of things that have emerged from that experience.
First of all, when someone opens or finds a suspicious envelope or
package that contains powder, we would strongly recommend that they
do not carry the letter around an office environment, for example,
and show it to people. We are finding that that’s quite a frequent
response to finding something unusual or something that people don’t
understand.
Secondly, we are finding that people often, when they get a powder
or a substance and they don’t know what it is, they will do two things:
they will try to smell it to determine what it is or they will try
to look at it very closely. Both of those things are extremely dangerous
practices if the material actually contains Bacillus anthracis spores.
Lastly, some recommendations have suggested that if a suspicious envelope
or package is identified, that a plastic bag or a container should
be identified and that the suspicious letter, or envelope, or package
should be put inside that container. As we start to understand more
about these exposures I would suggest that’s probably not what we
want people to do. I think the most prudent advice at this point is
that if something suspicious is received, that it is carefully laid
down on the nearest flat surface, that it is left there, that the
person and anybody else in that room leave the room and call 911 for
assistance.
Dr. Baker (moderator):
Any further thoughts on that, David?
Dr. Stephens:
I certainly think that suspicion for anthrax and notifying your state
health department and following the instructions that Brad just gave
you is sound advice.
Dr. Baker (moderator):
Great. I want to thank both of you for being with us today and also
for all that you are doing on this extraordinary situation here at
CDC. Thank you for being with us today.
Drs. Perkins and Stephens:
Thank you.
Dr. Baker (moderator):
That brings our program really to a close. I want to say that at the
completion of this broadcast, this program will be available online
at the Web site address that is on your screen: www2.cdc.gov/phtn.
For further information on the Health Alert Network that was mentioned
before, there is a different Web address, and that’s on your screen
as well. We also plan to rebroadcast this program on Monday, October
22, from 5:00 until 6:30 p.m. Eastern Daylight Time. At that point,
please check satellite coordinates; they will be different from those
today. Additionally, you may obtain a VHS tape of this program free
of charge from the Public Health Foundation by calling 1-877-252-1200
between 9:00 and 5:00 Eastern Standard Time. International callers
should call 301-645-7773. Thank you very much for joining us and we
also want to again express our appreciation to our three experts for
providing us with this exceptionally informative program. Thanks very
much to Secretary Thompson and particularly thanks to our partners
at the American Medical Association and the American Hospital Association.
Thank you very much for being with us today.
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