'Black fungus' Myths and facts

 Black Fungus

The infection is every bit as dangerous as the media have portrayed it, but several myths are circulating on social media about potential sources of the infection and its treatment

Myths about transmission

Several theories about the source of mucormycosis infections are circulating on social media, many of them unfounded.

Person-to-person transmission

Crucially, mucormycosis cannot be transmitted from person to person, so there is no need for people to isolate — unless, of course, they have an ongoing SARS-CoV-2 infection.

Rather, the source of infection is environmental, from airborne spores produced by the fungi.

Fungi growing in water, oxygen cylinders, humidifiers

Some media pundits have concluded that the fungi must be growing in dirty water in hospital oxygen cylinders or humidifiers. However, there is no evidence that this can occur, and mycologists have pointed out that fungi cannot produce spores in fluid.

What is more, the pure oxygen stored in cylinders is likely to be detrimental to the growth of microorganisms of all kinds.

Face masks harbor black fungus

This is a myth. There is no evidence that face masks can harbor the fungi.

Onions are to blame

Another popular theory is that the black mold sometimes seen on onions in refrigerators is Mucorales fungus and, therefore, a potential source of infection.

As we have seen, the species in question are not black. In fact, the black mold found on onions and garlic is usually the fungus Aspergillus niger.

In a 2019 paper, Prof. Richardson and his co-author explain that Mucorales fungi grow on moldy bread, decaying fruit and vegetables, crop debris, soil, compost, and animal excreta.

He points out that they have a high moisture requirement and are unlikely to survive on common building materials, such as wood, painted surfaces, and ceramic tiles. He concludes:

“All of these observations suggest that house residents are not generally exposed to zygomycetes in their home environment, apart from mould-contaminated food items, such as bread and fruit.”