TORONTO -- As a growing number of Canadians don masks to prevent the spread of COVID-19, the ubiquitous image of surgical masks in the era of coronavirus has drawn comparisons to the infamous beaks worn by plague doctors in 17th-century Europe.

A search for “plague masks” on social media returns hundreds of results showing users dressed up in costume variations of the beaked masks, mocking their usefulness in light of the novel coronavirus outbreak.

While the costume has been popularized by cosplay, video games and historical depictions of plague times, the reason behind the beaked masks was a misconception about the spread of the historical disease -- one that highlights advancements in the understanding of germs and viruses.

THE PLAGUE COSTUME

During the Middle Ages, an outbreak of the plague devastated Europe, killing around 50 million people.

At the time, those who tended to plague victims covered themselves head to toe in robes, wore long leather gloves, goggles and a mask with a long bird-like beak that had two holes, one on each side near the nostrils.

The look was created by Charles de Lorme, a plague doctor who played a role in treating many European royals during the 17th century. According to National Geographic, de Lorme described the outfit as “a coat covered in scented wax, breeches connected to boots, a tucked-in shirt, and a hat and gloves made of goat leather.”

Plague doctors also carried a rod that allowed them to maintain distance from their victims, or push them away -- the medieval equivalent of physical distancing.

DESIGNED TO COMBAT ‘POISONED AIR’

But the masks were more than just a barrier between doctors and patients.

Before the germ theory of disease, now the accepted scientific theory for many diseases, doctors believed that the plague spread was through poisoned air.

The beaked masks were filled with theriac, a mixture of more than 55 herbs and other compounds including ingredients such as cinnamon, myrrh, and honey. The shape of the beak was supposedly designed to give the air enough time to be cleansed by the herbs before it reached the nose.

According to the U.S. National Library of Medicine, theriac was widely used in Europe and the U.K. during the Black Death.

“The streets were to be kept clean and flushed with water in order to purify the air, fires were to be lit in streets and houses, and the burning of certain aromatic materials such as resin, tar, turpentine, juniper, cedar and brimstone was enjoined,” reads a document about the history of the compound.

“The use of perfumes on the person was recommended.”

Victims of the plague were also treated with variations of these herbal compounds.

The bubonic plague still exists today. In fact, cases were reported in China as recently as November 2019.

The disease is caused by bacteria and transmitted through flea bites and infected animals. Bubonic plague causes swollen lymph nodes, while pneumonic plague infects the lungs.

According to the World Health Organization (WHO), more than 3,248 cases and 584 deaths related to the plague were reported worldwide from 2010 to 2015. The disease is most commonly reported in the Democratic Republic of Congo, Madagascar and Peru.

QUESTIONS REMAIN ABOUT MASKS AND COVID-19

While today’s modern masks are used much differently than those of the 17th century, there has been much confusion about who should wear a mask and when during the coronavirus outbreak.

Earlier this month, the U.S. Centers for Disease Control (CDC) reversed its decision that only the sick should wear face masks and recommended that all Americans start wearing homemade cloth face masks outside due to COVID-19.

Officials in Canada have been wary of recommending masks, instead urging the public to focus on the essential measures of physical distancing and frequent hand washing.

But, on Saturday, chief public health officer Dr. Theresa Tam said that there are scenarios in which she believes a homemade facial covering could be beneficial.

"For example, if you’re in public transit and you cannot easily practice the two metres (of physical distancing), for example, then having that additional covering, like covering up your cough, I think, is a good idea,” she said.

The advice marks a shift in Tam’s advice. Just a week earlier, she said she was concerned that wearing masks might tempt people to touch their faces more often, and potentially increase the risk of infection.

Officials have also stressed that surgical-grade medical masks need to be reserved for health-care workers, especially in light of the country’s low supply of personal protective equipment (PPE).

CDC instructions specify that you should not touch your eyes, nose and mouth when removing a mask, and you should wash your hands immediately.

The agency’s website provides instructions for how to wear a cloth face mask safely, how to wash one (a washing machine will do), and how to remove one safely.