Unusual Case of GI Anthrax in New Hampshire Raises Questions
By Amesh A. Adalja, MD, January 8, 2010
Since the anthrax attacks in 2001, public health authorities have been attuned to the detection of this deadly pathogen, the presence of which may be the result of natural infection or may signal a bioterrorism event. Of the 3 types of anthrax infection (cutaneous, inhalational, and gastrointestinal), gastrointestinal (GI) is the most rare, with no cases reported in the United States prior to the one reported in New Hampshire in December.
African Drum Skin Implicated
On December 26, 2009, the New Hampshire Department of Health and Human Services announced that a female member of a drumming group was diagnosed with gastrointestinal anthrax, presumably contracted at an event held on December 4. The woman, a dancer, did not use the African drums that were used by others at the event.
The woman's symptoms began on December 5, she was diagnosed on December 24, and she is being treated in a Boston hospital. However, the details of her case history, including symptoms, diagnostic tests, and clinical course, have not been made public as of this writing. What is known is that 2 drum skins and an electrical outlet from the drumming group’s center have tested positive for the same strain of anthrax found in the patient. The isolate is sensitive to all antibiotics with activity against Bacillus anthracis, and post-exposure prophylaxis with doxycycline and the anthrax vaccine are being given to 94 other people who may have been exposed on December 4. No other cases have been detected to date.
Gastrointestinal Anthrax is Extremely Rare
Prior anthrax infections involving African drums have been of the cutaneous or inhalational variety, with no recorded cases of GI anthrax. GI anthrax from any cause is thought to represent just 1% of all anthrax cases, and it is almost exclusively confined to rural regions of the developing world. With mortality rates that can reach 40%, GI anthrax is acquired by eating meat contaminated with the vegetative form, rather than the spores, of the B. anthracis bacterium. Symptoms typically occur after an incubation period of 1 to 5 days. The table below highlights the clinical features and diagnostic testing for GI anthrax.
|Clinical Presentation||Fever, dysphagia, oral ulcers, nausea, vomiting, abdominal pain, hematemesis, massive ascites, bloody diarrhea, secondary bacteremia, secondary meningitis|
|Diagnostic modalities||Throat culture, rectal culture, stool culture, ascites culture, blood culture|
Several important questions remain unanswered:
- What was the case patient’s presenting symptom?
- What is the presumed mechanism of exposure that allowed GI anthrax—and not inhalational anthrax—to develop?
- How was the diagnosis made?
- What has been the clinical course of the patient?
- Have any other members of the drumming circle had spores isolated from their bodies?
Expeditious publication of the details of this case and the investigation are essential to understanding the epidemiology of this case and the pathophysiology of GI disease, and not inhalational disease, in this patient.
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