CDC Reports on Historical Link Between Anthrax Cases and Shaving Brushes

During World War I (WWI), the number of anthrax cases markedly increased among individuals in the United States and England. This increase seemed to be linked to use of new shaving brushes made of imported horsehair.

These cases predominantly occurred among men in the military. The rise in the number of cases appears to have been associated with disrupted commerce during WWI that led to a change in the source material and origin of shaving brushes used during the war.

According to the authors, “[c]heap brushes of imported horsehair were being made to look like the preferred badger-hair brushes. Unfortunately, some of these brushes were not effectively disinfected and brought with them a nasty stowaway: Bacillus anthracis.”

Christine M. Szablewski, from the Centers for Disease Control and Prevention (CDC), and colleagues published the results of their study in the May 2017 issue of Emerging Infectious Diseases, CDC’s monthly peer-reviewed public health journal.

Old-fashioned shaving tools, including natural shaving brushes made from animal hair, have regained popularity in recent years. This rise in popularity has simultaneously renewed interest in historical cases of anthrax linked to these brushes.

Anthrax is a potentially fatal disease caused by the spore-forming bacterium Bacillus anthracis which occurs naturally in soil. The disease predominantly affects grazing animals, but is rare in the United States. It can also be transmitted to people through contact with infected animals or their products.

“CDC conducted a systematic review of anthrax cases hospitalized and described in the English-language literature from 1880 to 2013,” said Kate Hendricks, MD, MPH&TM, from CDC’s Division of High Consequence Pathogens and Pathology, in an interview with Contagion^®.

During the review, the term “shaving brush” repeatedly appeared in the “exposure item” variable, said Dr. Hendricks, in particular during the early 1900s. “At that point, we thought it would make an interesting history of medicine-type paper.”

The researchers reviewed 3 sources of published data about anthrax cases—outbreak summaries, surveillance data from the United States, and individual case reports.

Early outbreak summaries from Europe and the United States showed that, from 1915 to 1924, 149 shaving brush—associated anthrax cases occurred in members of the US military; 28 occurred in members of the British military; 17 in American civilians; and 50 in British civilians.

US surveillance data from 1919 to 1924 suggested that contaminated shaving brushes were linked to at least 10% of all anthrax cases nationwide, and up to half of those occurred in New York City.

In addition, according to individual reports of anthrax, 43 cases described from 1917 to 1989 were linked to use of a new shaving brush: 23 were found to be “definitely associated” to the use of the brush, while the other 20 were “possibly associated.”

The authors explain how the change in commerce during WWI led to this mini epidemic. Apparently, before the war, badger hair from Russia was used for the brushes. However, this became difficult to acquire during the war, and horsehair was instead used to make imitation badger brushes.

Before the war, the animal hair was first disinfected in France or Germany before shipping to the United States. However, during the war, the hair was directly shipped to the United States from Russia, China or Japan. Public health officials have speculated that these imitation brushes made from horsehair were not as adequately disinfected as those previously made from badger hair were.

Currently, although anthrax rarely occurs in the United States or the United Kingdom, it remains a reportable medical condition.

Dr. Hendricks noted that she and her colleagues have been asked whether they think shaving brushes are safe. “Our paper was not meant to be a warning,” she stressed. “We think the piece is interesting because of its historical context. The article is also timely as the US entered WWI 100 years ago last month.”

“The bottom line is that shaving brushes are very safe,” she emphasized. “If you are purchasing a new one, there are import regulations in place that protect the consumer.”

She stressed that the anthrax cases were linked to new brushes marketed from 1915 to 1925. And although the case number might appear relatively high, “it was a small percentage of the ‘at risk (ie, regularly shaving)’ population,” she noted.

“Our findings can be used by medical and public health personnel to answer questions on vintage shaving brushes,” said Dr. Hendricks, although she concluded that this would probably be a rare topic.

Dr. Parry graduated from the University of Liverpool, England in 1997 and is a board-certified veterinary pathologist. After 13 years working in academia, she founded Midwest Veterinary Pathology, LLC where she now works as a private consultant. She is passionate about veterinary education and serves on the Indiana Veterinary Medical Association’s Continuing Education Committee. She regularly writes continuing education articles for veterinary organizations and journals, and has also served on the American College of Veterinary Pathologists’ Examination Committee and Education Committee.