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Shaving brushes made from animal hair once carried anthrax risk
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A resurgent interest in shaving brushes made from animal hair prompted researchers from the CDC to remind consumers and physicians about an erstwhile danger linked to the old-fashioned grooming product.
The brushes, which are used to apply shaving cream, were once a source of potentially fatal anthrax infections.
Almost all of these cases occurred between 1915 and 1925, after the disruption of global markets during World War I changed the demand for higher quality brushes made from disinfected animal hair, Kate Hendricks, MD, MPH&TM, medical officer in the Bacterial and Special Pathogens Branch at the CDC, told Infectious Disease News.
A century later, strict import regulations ensure there is next to no risk for acquiring anthrax from modern-day shaving brushes, which have grown in popularity over the past couple of decades, Hendricks and colleagues wrote in a report published today in Emerging Infectious Diseases.
“I wouldn’t worry at all if my husband used a brush from 1930 to 2017,” Hendricks said. “It’s hard to prove a negative, but in my opinion, it is about as close to no risk as one can get.”
Likewise, Hendricks said the risk from a brush made before 1930 is almost zero. Just about every case they uncovered as they searched the literature occurred among people using new or almost-new brushes.
“If you’ve been using one or are purchasing a used vintage brush, your brush is past being new,” she said.
Modern mentions of anthrax tend to be related to the threat of bioterrorism, but Hendricks and colleagues said there were at least 400 human anthrax cases in 2015. According to the CDC, people who handle animal products such as wool, hides or hair are among the most at risk for contact with Bacillus anthracis, the bacteria that causes anthrax.
Cutaneous anthrax, which usually occurs when B. anthracis enters the skin through a cut or scrape, is the most common form of the disease and can be deadly in up to 20% of patients who are not treated, according to the CDC. As long as a shaving brush is being used properly, this is the only way it can cause an anthrax infection, Hendricks said.
Before World War I, the bundles of hair that were shipped to the United States from countries like Russia, China and Japan to make shaving brushes were first cleaned and disinfected in France and Germany, according to Hendricks and colleagues. Consumers preferred brushes made from badger hair because they were better at holding water.
But while global commerce was interrupted during the war, bundles arrived directly in the U.S. without being cleaned and disinfected and mostly consisted of horse hair, Hendricks and colleagues said. According to their report, public health officials speculated that manufacturers used the hair believing it had already been disinfected or avoided disinfecting it because the high-temperature treatment made it look less like the preferred badger hair. Some brushes made it to troops on the battlefield, who were issued shaving kits in response to chemical weapons attacks because officials believed that gas masks would fit better on clean-shaven soldiers.
Looking at outbreak summaries from 1915 to 1924, Hendricks and colleagues counted 149 cases of anthrax infection from shaving brushes in members of the American military, 28 in members of the British military, and 67 cases in American and British civilians. Surveillance data from the U.S. showed that contaminated shaving brushes accounted for at least 10% of all anthrax cases between 1919 and 1924, including up to half of the cases in New York City, Hendricks and colleagues reported. A review of other literature found dozens more cases between 1880 and 2013, including one in India in 1989 that is thought to be linked to a head-shaving ritual.
The cases, although numerous, represented a small percentage of the at-risk population — those who regularly shaved.
“Even though it might seem that there were quite a few cases, it should be put in the context of the number of males who would have been shaving,” Hendricks said.
She was not aware of any other premodern grooming habits that carried a similar infectious disease threat, but a statistician from the CDC dug up nine examples of anthrax cases related to brushes not used for shaving: one from a hair brush, one from a cleaning brush, and seven cases of anthrax related to brush making. According to the CDC, drums made from animal hides also have been an infrequent source of anthrax infections over the years.
As renewed interest in using shaving brushes grows, Hendricks and colleagues said their report should help health care providers and public health officials answer any questions about their past link to anthrax.
“It was not meant to be a warning,” Hendricks said. “It was more a fun medical history story we found when we were reviewing the literature. Shaving brushes are very safe.” – by Gerard Gallagher
Reference:
Szablewski CM, et al. Emerg Infec Dis. 2017;doi:10.3201/eid2305.161554.
Disclosure: The researchers report no relevant financial disclosures.