Surgeons at the Seven Star hospital in Nagpur, India, operating on a patient with mucormycosis ‘black fungus’ Credit: Simon Townsley
Sophie O’Sullivan | 07 April 2025 6:00am BST
Blood congealed “like black sausage”, sexually-transmitted athlete’s foot, and bloodstream-born pathogens untreatable with existing drugs. These are the kinds of fungal infections Professor Darius Armstrong-James, Infectious Diseases and Medical Mycology at Imperial College London, is used to treating.
“Probably about a third of the world is infected by some kind of fungus,” says Prof Armstrong-James, “mostly skin, mucocutaneous, vaginal candidiasis, athlete’s foot. Those kinds of fungi that aren’t deadly but they are increasing in resistance”.
More lethal fungal varieties are spreading too: invasive fungal infections are killing an estimated 2.5 million people each year – twice the global fatalities of tuberculosis.
The world remains critically underprepared for fungal infections, the World Health Organization (WHO) warned this week, with a lack of diagnostic tests, effective treatments, and surveillance creating an urgent need for research.
But how serious is the problem?
The WHO’s fungal priority pathogens list, compiled in response to this rising public health threat, is an itch-inducing read.
‘Critical priority’ fungi with mortality rates of up to 88 per cent take the top spots.
“Black fungus” or Mucormycosis, which turns tissue into black lesions, made headlines during the Covid-19 pandemic when 51,000 cases were reported in India.
“It invades very often through the nose, and then it can get into the eyes […] down the optic nerve into the brainstem and kills you,” Prof Armstrong-James told the Telegraph.
“We have to give [patients] all the strongest drugs we can find…cut out all of the infected tissue which often means major surgery to the face and half their brain”.
For some patients, the amount of blackened tissue that needs removing is so extreme it’s impossible and they die within days.
Yet Mucorales, the fungal family which causes Mucormycosis, is not one considered ‘critical’ by WHO ranking.
There are four invasive fungal pathogens deemed ‘critical’ on the list, and their insidious spores can even be found in the UK.
One of them, “Candida albicans”, can be found “in about half the population inside our guts,” says Dr Rebecca Drummond, Associate Professor in antifungal immunity, University of Birmingham.
Aspergillus, another critical priority pathogen, is in fact so widespread that most people inhale between 100 to 1000 spores every day from the air we breathe.
Even the mould on bread can contain Mucor, a fungus that causes Mucormycosis.