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 4 of 6
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Dr. Baker (moderator):
What we would like to do now is to turn to our second expert, Dr. Brad Perkins. Brad, thank you for being with us today. Brad is with the Meningitis and Special Pathogens Branch here at CDC. He leads CDC’s group of scientists with technical responsibility for anthrax. He is board certified in internal medicine and he is just back from Florida where he led the team that was investigating the outbreak there. Good to have you with us.

Dr. Brad Perkins:
Thanks very much. It is a pleasure to have an opportunity to talk with all of you about medicine and public health and give you an inside glimpse at some of the strategies we are using to investigate these outbreaks and to help us define the cases and the approaches we are going to recommend to identify people that are at risk and get them on appropriate therapy.

On October 4, through the efforts of an astute physician, as Dr. Koplan has already mentioned, we were notified of a suspected case of inhalational anthrax. By the next morning, even before the case was confirmed at CDC and state public health laboratories, we had teams ready and on route to 2 locations that the case patient (or the index patient) had visited within the incubation period for inhalational anthrax, Florida and North Carolina. This slide outlines the investigative strategy. Early in the investigation the 2 primary focus areas were the case investigation (that’s the who, what, when and how did this individual contract inhalational anthrax) and surveillance. Both of those efforts proceeded intensively in parallel in both Florida and North Carolina. As those investigations proceeded, intervention strategies were designed based on the information that was yielded from those efforts. For example, in the case investigation, we rapidly ascertained that there was no clear explanation for natural exposure that could account for the inhalational anthrax case. In addition, through our surveillance efforts we found that there was a second case of inhalational anthrax also employed by the same company as the index patient. Through selected and epidemiologically driven environmental sampling of the index patient’s place of employment we identified contamination with Bacillus anthracis in multiple locations of the building. Those pieces of combined information that were yielded from case investigation and surveillance allowed us to design an intervention strategy that included targeting approximately 1,000 persons that we felt may be at risk for inhalational anthrax. That intervention was delivered, those people are on antibiotics, and we have identified no further cases of inhalational disease. Still, there is an ongoing public health and criminal investigation to try to completely define the circumstances of this exposure.

Let me tell you a little bit about anthrax case definitions. These are epidemiologic case definitions that have some relevance to clinical medicine, but are primarily designed to help us track the occurrence of these cases on local, state, and national levels. We are considering a confirmed case of anthrax to be a person that has a clinically compatible illness with isolation of Bacillus anthracis from affected sites or tissues, or two supporting non-culture laboratory tests. Those nonculture tests may include staining with immunohistochemical staining techniques, PCR studies identifying DNA of Bacillus anthracis in clinical tissues or from clinical sites, or serology that suggests that there has been seroconversion or strong seropositivity to the anthrax organism.

For a suspected case, we are considering that there needs to be a clinically compatible illness, and in this situation we don’t have isolation of Bacillus anthracis, but we have at least one supportive non-culture laboratory test, or we have an epidemiologic link to a confirmed environmental exposure. That is, we know this person was exposed to a letter in which Bacillus anthracis has been identified or to some other source of environmental contamination that has been documented.

I want to go over just briefly what we would suggest is an algorithm for action for clinicians when encountered or when there is a suspected anthrax case. These steps—these three steps—must be entertained simultaneously. First of all, if there is any suspicion of anthrax, the patient has to undergo appropriate clinical testing. Beyond the clinical suspicion, the tests that can serve as early confirmatory evidence of anthrax include Gram stain of affected tissues or sites, culture (we are in very good shape with culture because this organism grows extremely well on traditional culture media that’s available in all clinical laboratories), or biopsy of affected sites, particularly in the case of cutaneous anthrax.

The treatment of the patient when anthrax is suspected should be based on the clinical impressions of the physician. It is unlikely that there will be definitive test results from any of these methods so that treatment—initial treatment, as Dr. Stephens has outlined—should be begun on clinical suspicion. While all of this is going on, just as the physician in Palm Beach County did, you must notify local or state public health authorities. That is going to trigger the larger investigation, the larger public health response that is necessary for rapid identification of persons that may be at risk for developmental, inhalational, or other forms of anthrax.

Right now we are experiencing and actively engaged in a number of investigations that are presenting a variety of challenges to the public health system. In Florida, we were presented with inhalational cases first, with no obvious vehicle. In New York City, we were presented with cutaneous disease with a confirmed vehicle, a letter that was positive for Bacillus anthracis. And lastly, most recently in Washington, D.C., we are presented with a situation where there is no obvious disease, but a very recent exposure with a confirmed vehicle or letter. This set of experiences is serving as a basis for us to develop a public health framework to approach these situations in a systematic and scientifically based manner.

So in closing, I would like to suggest that the clinicians are our first line of defense for bioterrorism in the United States. We want you to be suspicious at this time. We want you to consider testing for Bacillus anthracis, and as those situations arise, report to your local and state public health authorities so we can get into the public health investigation and identify people that may be at risk for development of disease. Thank you.

Dr. Baker (moderator):
Brad, thank you very much.

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