Update: Investigation of Bioterrorism-Related Inhalational Anthrax ---Connecticut, 2001

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Since October 3, 2001, CDC and state and local public health authorities have been investigating cases of bioterrorism-related anthrax (1--5). As of November 28, a total of 23 cases have been identified; 11 were confirmed as inhalational anthrax, and 12 (seven confirmed and five suspected) were cutaneous. Epidemiologic investigations to identify the source of exposure to Bacillus anthracis continue for a case of inhalational anthrax in a hospital stockroom worker in New York City (NYC) and, most recently, a case of inhalational anthrax in an elderly woman in Connecticut (CT). Antimicrobial prophylaxis is continuing in persons exposed to B. anthracis, and surveillance to detect new cases of bioterrorism-related anthrax is ongoing. This report summarizes the findings of the case investigation in CT.

On November 16, a 94-yearold woman who resided in Oxford, CT (2000 population: 9821), presented to a local hospital with fever, cough, weakness, and muscle aches of approximately 3 days' duration. She had no history of chills, headache, rhinorrhea, vomiting, diarrhea, or abdominal or chest pain. She had a medical history of chronic obstructive pulmonary disease, hypertension, and renal insufficiency. On admission, the patient had a temperature of 102.3 F (39.1 C) with an elevated heart rate and room air oxygen saturation of 93%. Physical examination was otherwise unremarkable. Initial chest radiograph had no evidence of pulmonary infiltrate, pleural effusion, or widened mediastinum. Her white blood cell count was 8,100 cells/mm³ (78% neutrophils, 15% lymphocytes). Hematocrit, platelet count, and electrolytes were normal. Blood and urine cultures were obtained and the patient was admitted for dehydration and possible urinary tract infection.

On November 17, gram positive rods were noted on microscopic evaluation of the blood culture and gram negative rods were isolated from the urine. Antibiotic therapy was initiated for possible sepsis with vancomycin and ceftazidime, and changed to ampicillin/sulbactam and oral ciprofloxacin later that day. On November 18, the patient had progressive respiratory distress and confusion. Repeat chest radiograph revealed a left-sided pleural effusion and possible infiltrate but no mediastinal widening. A chest CT was not performed. Thoracentesis performed the following day obtained 800 ml of serosanguinous fluid with 4,224 red blood cells and 1,463 white blood cells. On November 19, the patient was transferred to the intensive care unit and required mechanical ventilation and vasopressor support. Clindamycin was added to her antibiotic regimen, and ciprofloxacin was changed to intravenous administration. The patient's condition deteriorated, and she died on November 21.

On November 19, the Connecticut Department of Public Health (CDPH) was notified by the hospital of the positive blood culture results. On November 20, the isolate was identified as B. anthracis at the CDPH laboratory with confirmation at CDC the following day. The B. anthracis isolate was indistinguishable by molecular typing and antibiotic susceptibility patterns when compared with the strain from recently identified cases of bioterrorism-related anthrax. An autopsy revealed hemorrhagic mediastinal lymphadenitis with positive immunohistochemical staining for B. anthracis on spleen and mediastinal lymph node tissue.

The patient lived alone in a rural area of CT and was homebound except when provided transportation by friends and family. Interviews with family members and others were conducted to construct a time line of the patient's activities during the 60-day period preceding her illness. The time line was used to guide environmental sample collection. As of November 27, none of the environmental samples from the patient's home, local businesses, and other areas that she frequented has yielded B. anthracis. In addition, nasal swabs from friends and relatives who may have had common exposures with the patient were negative for B. anthracis. These persons were started on ciprofloxacin or doxycycline for postexposure prophylaxis. The decision whether or not a full 60-day course is necessary will be made after further investigation into the potential source of exposure.

On November 20, environmental testing was conducted at the local post office and regional mail distribution facility involved in delivery of the patient's mail. In addition, sampling was performed on mail recovered from the patient's home, area mailboxes, and the mail carrier vehicle. As of November 27, none of the samples have yielded B. anthracis. Nasal swabs also were taken from 460 postal employees in the two facilities; all are negative for B. anthracis. Mail flow investigations have identified several letters that were delivered to the area serviced by the patient's local post office and that had previously passed through the mail facility in Trenton, NJ, shortly after the B. anthracis contaminated letters addressed to two U.S. Senators. However, no such letters are known to have been received by this patient. On November 21, approximately 900 postal employees at two facilities in CT were started on either ciprofloxacin or doxycycline, pending the results of further investigation.

Surveillance for new and possibly undiagnosed anthrax cases is being intensified by contacting hospitals, laboratories, physicians, and by reviewing death certificates. Environmental and case investigations to identify a source of B. anthracis exposure are ongoing.

Reported by: H Quentzel, MD, S Spear, MD, L Barakat, MD, Griffin Hospital; N Lustig, MPH, Pomperaug Health District, Oxford; K Spargo, MPH, Naugatuck Valley Health District, Shelton; M Cartter, MD, J Garcia, MD, DM Barden, MT (HHS), DR Mayo, ScD, KA Kelley, DrPH, J Hadler, MD, State Epidemiologist, Connecticut Dept of Public Health. EIS officers, CDC.

Editorial Note:

The source of exposure to B. anthracis for the 94-year-old CT resident remains unknown. The genetic characteristics of B. anthracis isolated from this patient links this case with the previous bioterrorism-related cases of anthrax. However, this patient differed from most previously identified cases in both epidemiologic characteristics and potential sources of exposure. The patient in CT had limited activity outside her home, had not visited a media company or postal facility, and had an onset of symptoms at least 3 weeks later than previously reported patients. In addition, one notable clinical finding was the absence of a pulmonary infiltrate, pleural effusion, or mediastinal widening on the admission chest radiograph.

Epidemiologic findings indicate that recent cases of inhalational anthrax most likely occurred from aerosols generated from opening a letter containing B. anthracis powder or from aerosols generated in processing a sealed letter containing B. anthracis powder at a postal facility. The most recent case in CT and a case of inhalational anthrax in the 61-year-old hospital stockroom worker in NYC did not have either exposure identified. Possible sources of B. anthracis under investigation include exposures inside and outside the home and mail that passed through contaminated mail facilities. The investigation by public health and law enforcement authorities to find the source of exposure continues and surveillance for new cases of bioterrorism-related anthrax is ongoing.

Clinicians and laboratorians should remain alert for symptoms or findings that might indicate anthrax (6). Information on anthrax is available at <http://www.bt.cdc.gov>.

References

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