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Update: Investigation of Bioterrorism-Related Anthrax, 2001

This report updates the investigation of bioterrorism-related anthrax and the provision of antimicrobial prophylaxis to exposed persons and highlights CDC assistance to other countries investigating cases of bioterrorism-related anthrax. Since November 7, 2001, CDC and state and local public health agencies have identified no new cases of bioterrorism-related anthrax. As of November 14, a total of 22 cases of anthrax has met the CDC case definition (1); 10 were confirmed inhalational anthrax, and 12 (seven confirmed and five suspected) were cutaneous anthrax. Investigation of a case of inhalational anthrax in a hospital stock room worker aged 61 years in New York City (NYC) found no evidence of anthrax contamination at the work site or home; the source of exposure is unknown. Environmental clean-up of contaminated facilities continues, and surveillance for new cases of bioterrorism-related anthrax is ongoing in Delaware (DE), District of Columbia (DC), Florida (FL), Maryland (MD), New Jersey (NJ), NYC, Pennsylvania (PA), Virginia (VA), and other states.

Use of Antimicrobial Prophylaxis

A 60-day course of antibiotics to prevent inhalational anthrax has been recommended for persons potentially exposed to Bacillus anthracis aerosols in FL, NJ, NYC, VA, and DC. These recommendations are for persons at risk for inhalational anthrax by 1) the presence of an inhalational case at a facility (e.g., media company in FL), 2) environmental specimens positive for B. anthracis in facilities along the path of a contaminated letter in which aerosolization might have occurred (e.g., postal facilities in NYC), and 3) exposure to an air space known to be contaminated with aerosolized B. anthracis from an opened letter (e.g., Senate office building in DC). These persons should receive a full 60-day course of antimicrobial prophylaxis. Specific recommendations by site include:

  • Boca Raton, FL---prophylaxis is recommended for employees and visitors who spent >1 hour during August 1--October 6 in the American Media, Inc., building.
  • New York City, NY---prophylaxis is recommended for all employees who worked during October 9--26 on the second and third floors of the south section of the Morgan Central Postal Facility in Manhattan.
  • Hamilton Township, NJ---prophylaxis is recommended for all employees and business visitors (i.e., temporary postal workers, vendors, contractors, and anyone in nonpublic work sites) who were in the U.S. Postal Service Route 130 Processing and Distribution Center during September 18--October 18.
  • Washington, DC (Capitol Hill)---prophylaxis is recommended for persons who were on the fifth and sixth floors of the southeast wing of the Senate Hart Building on October 15, from 9 a.m. to 7 p.m.
  • Washington, DC---prophylaxis is recommended for all employees and business visitors to the nonpublic mail room of the U.S. Postal Service Processing and Distribution Center at 900 Brentwood Road during October 12--21.
  • Sterling, VA---prophylaxis is recommended for all mail room employees and business visitors who were at the Department of State Annex 32 mail room facility during October 12--22.

In addition, a 60-day course of antimicrobial prophylaxis is recommended for other workers with specified risks for inhalational anthrax. In some areas, local health authorities facilitated access to a 60-day course of antimicrobial prophylaxis for persons who handled mail in facilities from which B. anthracis was isolated but did not have exposures for which antimicrobial prophylaxis is recommended (2). These persons may choose or may be directed by local health authorities to discontinue antimicrobial prophylaxis before completing a 60-day course.

CDC Assistance to Other Countries

CDC has assisted authorities in other countries investigating cases of bioterrorism-related anthrax. During October 12--November 13, CDC received 111 requests from 66 countries. Of these, 47 (42%) requests were laboratory related; 43 (39%) were general requests for bioterrorism information; 13 (12%) were for environmental or occupational health guidelines; and eight (7%) were about developing bioterrorism preparedness plans. The largest proportion of requests were from Central and South America (26%). Of the 66 countries, 15 (23%) received laboratory assistance, including testing or arrangements for testing of suspected isolates at a CDC-supported laboratory or a reference laboratory in another country. Forty-two (64%) countries received telephone or email consultation regarding specific tests for suspected B. anthracis isolates. CDC has confirmed two isolates from outside the United States as B. anthracis. These isolates were recovered from the outer surface of letters or packages sent in State Department pouches to the U.S. Embassy in Peru. These items were processed at the U.S. State Department mail sorting facility where a case of inhalational anthrax had occurred (1). No cases of bioterrorism-related anthrax have been confirmed in U.S. Embassy employees or in persons from other countries. Requests for information regarding bioterrorism-related issues outside the United States should be directed to the International Team of CDC's Emergency Operations Center (telephone, [770] 488-7100, e-mail,

Reported by: J Malecki, MD, Palm Beach County Health Dept, West Palm Beach; S Wiersma, MD, State Epidemiologist, Florida Dept of Health. New York City Dept of Health. E Bresnitz, MD, State Epidemiologist, G DiFerdinando, MD, New Jersey Dept of Health and Senior Svcs. P Lurie, MD, K Nalluswami, MD, Pennsylvania Dept of Health. L Hathcock, PhD, State Epidemiologist, Delaware Div of Public Health. L Siegel, MD, S Adams, I Walks, MD, J Davies-Coles, PhD, M Richardson, MD, District of Columbia Dept of Health. R Brechner, MD, State Epidemiologist, Maryland Dept of Health and Hygiene. R Stroube, MD, State Epidemiologist, Virginia Dept of Health. J Burans, US Naval Research Center Detachment, Lima, Peru. US Dept of Defense. EIS officers, CDC.

Editorial Note:

Since the previous report, all patients with bioterrorism-related anthrax who were hospitalized have been discharged and continue to recover; no new cases have been reported. The source of these bioterrorist attacks has not been identified, and additional cases might occur. Public health authorities, health-care providers, and laboratorians should remain vigilant for cases of anthrax.

Antimicrobial prophylaxis is indicated to prevent inhalational anthrax after a confirmed or suspected aerosol exposure. Persons recommended to receive prophylaxis should complete the 60-day regimen. Public health programs should work with health-care providers and patients to promote completion of antimicrobial prophylaxis and to monitor the occurrence of adverse events (1).

CDC continues to respond to inquiries about anthrax and bioterrorism. The CDC Public Response Hotline was established to provide the public with information about anthrax and other biologic and chemical agents. During November 1--12, CDC received approximately 4,400 calls through the hotline and to the Emergency Operations Center. The hotline is available in English (888-246-2675) and Spanish (888-246-2857). CDC also receives requests for information by e-mail through the Health Alert Network (<>), MMWR (<http://www.cdc/gov/mmwr/contact.html>), and other public health communications systems.

Additional information about anthrax is available at <>. A compendium of MMWR reports and recommendations related to anthrax and bioterrorism is available at <>.


  1. CDC. Update: Investigation of anthrax associated with intentional exposure and interim public health guidelines, October 2001. MMWR 2001;50:889--93.
  2. CDC. Update: Investigation of bioterrorism-related anthrax and adverse events from antimicrobial prophylaxis. MMWR 2001;50:973--6.

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