CDC says drumming-related anthrax risk is low

Jul 22, 2010 (CIDRAP News) – In describing a case of gastrointestinal anthrax linked to a drumming event in New Hampshire last December, federal health officials said the anthrax risk related to such events is very low and that the patient may have had an unusual susceptibility to the disease.

The report from the Centers for Disease Control and Prevention (CDC) details the case of a 24-year-old New Hampshire woman who got sick after participating in a drum circle at a community center on Dec 4 and was hospitalized for nearly 2 months. The CDC said the case is the first gastrointestinal anthrax illness linked to the use of animal hide drums. A few cases of inhalation and cutaneous anthrax have occurred in US drum makers in recent years.

The article in the Jul 23 Morbidity and Mortality Weekly Report notes that no one else among many people who attended the drum circle got sick, though later testing found anthrax spores on drums and on some other surfaces in the building. That suggests that the woman might have a special susceptibility, the report says.

The woman fell ill with influenza-like symptoms the day after the drum circle. Though her symptoms worsened in ensuing days, she didn't seek medical care until Dec 14. She was admitted to a hospital, where computed tomography revealed large abdominal fluid accumulations and swollen sections of the small intestine.

The woman underwent a small bowel resection surgery, and pathology studies later revealed that she had a nematode infection of the small intestine and appendix. She was released from the hospital after nearly 2 months and was doing well, the report says.

After the patient's surgery, tests of blood samples taken earlier led to the diagnosis of gastrointestinal anthrax on Dec 24, which triggered an epidemiologic investigation by New Hampshire health officials. Two rounds of environmental testing of dozens of samples at the community center led to the finding of nine anthrax-contaminated samples, including samples from two drums and several other surfaces. The patient denied any contact with the two drums.

A genetic analysis by the CDC showed that all the anthrax spores found in the environmental sampling matched the patient's anthrax strain.

Investigators identified 84 people who had potentially been exposed to anthrax at the drumming event, none of whom were sick. As a precaution, they were offered antibiotics and anthrax vaccine adsorbed. One person accepted both, and 36 (43%) accepted antibiotics only.

The findings suggest that the woman was exposed to aerosolized anthrax spores at the drumming event, the report says. She might have become infected through direct aerosol exposure, by consuming food or water contaminated with airborne spores, or by contact with others who had handled contaminated items.

Investigators concluded that anthrax contamination in the community center was not widespread or high level, which suggests that the patient might have had an unusual susceptibility to Bacillus anthracis, the bacterium that causes anthrax, the report says. It is unclear whether underlying immunologic factors or the nematode infection contributed to the woman's illness, it states.

The infection risk from handling animal-hide drums or attending drumming events is hard to estimate, the report says, but adds, "Drumming circles are common practices, and given the extreme rarity of cases like the one reported here, the risk for infection must be considered to be very low."

However, physicians treating patients with symptoms consistent with anthrax, such as unexplained fever, skin lesions, or serious respiratory or gastrointestinal illness, should be aware of the possible connection to hide drums, the CDC says.

CDC. Gastrointestinal anthrax after an animal-hide drumming event—New Hampshire and Massachusetts, 2009. MMWR 2010 Jul 23;59(28):872-7 [Full text]

See also:

Dec 29, 2009, CIDRAP News story "New Hampshire probes GI anthrax case"

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