B. Gerstman
May 2003

Background | Descriptive Epi | Agent & Reservoir | Portals & Transmission
Immunity, Treatment, and Host Factors | Preventive Measures


After completing this exercise the student will be able to:

  • Use the Control of Communicable Diseases Manual to learn about infectious agents, reservoirs, portals, host factors, and control measures.
  • Search the CDC website for epidemiologic information about reportable disease and reportable disease occurrence.
  • Integrate knowledge about the infectious disease process into the control of a communicable disease.


Following the terrorist attacks of September 11, 2001, in early October, 2001, a sentinel case of fatal anthrax occurred in an employee of a tabloid newspaper company in southern Florida. Soon thereafter an employee of NBC in New York tested positive for anthrax. On Sunday, October 14, 2001, five more employees at the tabloid newspaper developed signs of anthrax and a second employee at NBC developed anthrax symptoms. This exercise walks you through some of the questions that might arise while investigating these cases. But first it also requires you to conduct background research. Thus, you are to read:

As background for this exercise please read Chin, J. (Ed.). (2000). Anthrax (pp. 20 - 25) in Control of Communicable Disease Manual (17th ed.). Washington, DC: American Public Health Association. the material on anthrax epidemiology in the Control of Communicable Diseases Manual. Available: .


(A) Before the current cases occurred, when was the last case of human anthrax in the United States? Search for this information on limiting your search to 1990 - 2001. Where did this previous case occur? How did it occur? .

(B) Prior to the penultimate case, when did human anthrax last occur?

(C) Are you alarmed by the single case in October 2001? Why or why not?


(D) What agent causes anthrax? (Provide Genus species and morphology characteristics.)

(E) What is the agent's normal reservoir?

(F) What is the agent's reservoir when used as a biological weapon?

(G) Why is the anthrax agent difficult to destroy? What environmental methods can be used to neutralize the agent?


(H) Can anthrax be transmitted from person-to-person?

(I) Describe the clinical forms of anthrax. What are its three distinct forms? Describe the portals for each form. How might this knowledge influence your handling of potentially contaminated materials?

(J) Although the primary mode of transmission for cutaneous anthrax is by direct contact, the Communicable Disease Manual also mentions the possibility of transmission by biting flies. Is the fly a mechanical, developmental, propagative, or cyclopropagative vector for anthrax? Is the fly a common transmitter? Are you concerned about transmission by biting insects in the instance of human-to-human transmission? Animal-to-animal?


(K) What is the typical incubation period for anthrax?

(L) What percentage of cutaneous anthrax cases recover?

(M) What percentage of respiratory anthrax cases recover?

Although an effective vaccine for anthrax is available, it is not in general use. Here's advice from a CDC publication ( ) concerning anthrax prophylaxis:

Although groups initially considered for preexposure vaccination for bioterrorism preparedness included emergency first responders, federal responders, medical practitioners, and private citizens, vaccination of these groups is not recommended. Recommendations regarding preexposure vaccination should be based on a calculable risk assessment. At present, the target population for a bioterrorist release of B. anthracis cannot be predetermined, and the risk of exposure cannot be calculated. In addition, studies suggest an extremely low risk for exposure related to secondary aerosolization of previously settled B. anthracis spores. Because of these factors, preexposure vaccination for the above groups is not recommended. For the military and other select populations or for groups for which a calculable risk can be assessed, preexposure vaccination may be indicated.

Options other than pre-exposure vaccination are available to protect personnel working in an area of a known previous release of B. anthracis. If concern exists that persons entering an area of a previous release might be at risk for exposure from a re-release of a primary aerosol of the organism or exposure from a high concentration of settled spores in a specific area, initiation of prophylaxis should be considered with antibiotics alone or in combination with vaccine as is outlined in the section on post-exposure prophylaxis.

(N) Why do you suppose the anthrax vaccine is NOT used in the general public?


(N) Using what you now know about the natural history and epidemiology of anthrax, list interventions that might be used to thwart anthrax bioterrorism. Consider interventions that can be directed toward (a) the agent, (b) the  reservoir, (c) protection of  portals, (d) its mode of transmission, and (e) host factors.