Investigation of Bioterrorism-Related Anthrax, United States, 2001: Epidemiologic Findings

Abstract

In October 2001, the first inhalational anthrax case in the United States since 1976 was identified in a media company worker in Florida. A national investigation was initiated to identify additional cases and determine possible exposures to Bacillus anthracis. Surveillance was enhanced through health-care facilities, laboratories, and other means to identify cases, which were defined as clinically compatible illness with laboratory-confirmed B. anthracis infection. From October 4 to November 20, 2001, 22 cases of anthrax (11 inhalational, 11 cutaneous) were identified; 5 of the inhalational cases were fatal. Twenty (91%) case-patients were either mail handlers or were exposed to worksites where contaminated mail was processed or received. B. anthracis isolates from four powder-containing envelopes, 17 specimens from patients, and 106 environmental samples were indistinguishable by molecular subtyping. Illness and death occurred not only at targeted worksites, but also along the path of mail and in other settings. Continued vigilance for cases is needed among health-care providers and members of the public health and law enforcement communities.

The Critical Role of Pathology in the Investigation of Bioterrorism-Related Cutaneous Anthrax

“…There were 3 suspect cases: 1 based only on IHC (number 6); 2 based only on serology (numbers 9 and 10). One suspect case, described in another report, 7 was excluded because no skin biopsy sample was available for histopathological evaluation and IHC testing.…”

“…However, the epidemiology and laboratory diagnosis of cutaneous anthrax changed after October 2001 because of the intentional release of B. anthracis spores through the U.S. postal system and the subsequent identification of anthrax in 22 patients, including 11 with cutaneous disease. 6,7 The index cutaneous anthrax case-patient from the 2001 outbreak, a 38-year-old woman who worked at a major news network, initially developed an ulcerative lesion on the chest and was seen by an infectious disease clinician. She reported handling "threat" letters at work.…”

“…The investigation of both inhalational and cutaneous anthrax cases clearly exemplifies these roles. 6,7,60,61 In addition to B. anthracis, several rapid and sensitive IHC assays have been developed for detecting other bioterrorism-related agents, such as Ebola virus, 62,63 Fransicella tularensis, 64 Yersinia pestis, 65 and smallpox virus. These assays provide a method for rapid diagnosis and have fortified the preparedness of responses to possible bioterrorism events.…”

“…This report underscores the critical role of pathology in investigating potential bioterrorism events and in guiding epidemiological studies, Anthrax captured worldwide attention and aroused serious public health concerns following the intentional release of the etiological agent Bacillus anthracis in the United States postal system during Fall 2001, 1,2 resulting in 11 cases of inhalational anthrax and 11 cases of cutaneous anthrax. [3][4][5][6][7] In its conventional form, cutaneous anthrax accounts for 95% of all naturally occurring B. anthracis infections in the United States. 8 -11 Patients often have a history of occupational contact with animals or animal products contaminated with B. anthracis spores.…”

“…[3][4][5][6][7] In its conventional form, cutaneous anthrax accounts for 95% of all naturally occurring B. anthracis infections in the United States. 8 -11 Patients often have a history of occupational contact with animals or animal products contaminated with B. anthracis spores.…”