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:
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
As background for this exercise please read Chin, J. (Ed.). (2000). Anthrax
(pp. 20 - 25) in Control of Communicable Disease Manual (17th ed.).
(A) Before the current cases occurred, when was the last case of
human anthrax in the
(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 ( http://www.cdc.gov/mmwr/preview/mmwrhtml/rr4915a1.htm ) 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.