Fungal attack: Everything you need to know about India’s ‘black fungus’ and similar pathogens

·6-min read
A nurse rests in a makeshift ward at an emergency Covid-19 care center  -  T. Narayan/Bloomberg
A nurse rests in a makeshift ward at an emergency Covid-19 care center - T. Narayan/Bloomberg

There are concerning reports emerging from India that an aggressive flesh-eating “black fungal” infection is maiming Covid-19 patients and survivors, attacking their noses, eyes and sometimes brains.

Doctors have warned that the rare condition, called mucormycosis, has been detected far more frequently than usual in hospitals across the country, with some fears that it is linked to Covid-19 treatments. So what’s going on?

Is the infection really a face eating fungus?

Yes. Mucormycosis, colloquially known as the “black fungus”, is a fast-moving infection that attacks a person’s sinuses, lungs and brain.

While there are antifungal treatments that can be used to treat the condition, they often don’t work, and poor diagnosis means it is often detected after the fungus has spread. In many cases, patients need surgery to cut out the affected tissue before it spreads to the brain - leading to the loss of their upper jaw and sometimes even an eye.

“The fungus grows incredibly fast,” says David Denning, a professor of infectious diseases at the University of Manchester and chief executive of the Global Action Fund for Fungal Infections (Gaffi). “Once it gets in, it just marches through the tissue and doesn’t respect tissue planes, so it can go straight from ordinary tissue through into bone, into nerves.”

He adds that the mortality rate is, typically, around 50 per cent - but it can be as high as 80 per cent if diagnosed late.

So it’s not a bacteria or a virus?

No. Mucormycosis is a third class of pathogen, a fungal infection. It’s caused by exposure to the mucor mould, which is commonly found in soil and decaying organic matter, including plants, compost and fruit.

A person can get sick if they breathe in these fungal spores, but it’s thought it isn’t possible to catch mucormycosis from another infected person.

Symptoms include a bleeding nose, swelling and pain in the eye, drooping eyelids and blurred or lost vision. Black patches of skin can also emerge around the nose.

“All fungi affect different parts of the body and can be slow or fast growing, can be relatively easy to treat, or can be very resistant,” says Dr Elizabeth Ballou, lecturer in Cellular Microbiology at the University of Birmingham. “Mucormycosis is one of the most feared because it grows very quickly and is very difficult to treat.”

So how serious is the threat of mucormycosis?

The condition is very rare and tends to affect those who have diabetes or are severely immunocompromised – such as cancer patients or people living with HIV/Aids. Usually the condition does not pose a major threat to healthy individuals.

Even before the pandemic, India had a far higher baseline of infections than other regions. Experts estimate that the vast country reported roughly 17 cases per million people each year, compared to between two and 10 cases in Britain or France.

This is largely because India has a large population living with diabetes, almost 80 million people, who are at risk of severe mucormycosis. Exposure to the mucor mould is also relatively high, says Prof Denning, as it's a dusty environment with a lot of material spreading in the air.

But why has India seen a surge in cases?

The current increase is thought to be linked to the country’s devastating coronavirus surge, as the steroids used to treat severe Covid-19 – including dexamethasone – dampen the immune response, which can go into overdrive and attack itself in response to the viral infection.

Some experts also say that, as hospitals are overwhelmed, many families are self-medicating and may be overusing steroids. And a large proportion of those sick with the “black fungus” have diabetes, as mucormycosis “attacks people with uncontrolled sugar”, says Dr VK Paul, a member of NITI Aayog, an Indian Government think tank.

Diabetes is harder to control when a patient is unwell, regardless of the disease. But the steroids used to tackle Covid also push up blood sugar levels.

“I think you’ve got a triple effect,” says Prof Denning. “Essentially there’s already lots of exposure, plus [high rates of] poorly controlled or out of control diabetes, and then add steroids to treat severe Covid-19 into the mix.”

So how many cases have been reported in India?

It’s not entirely clear, as reports are trickling out from individual hospitals. Dr Paul has said that “there is not a big outbreak of it”, but the picture emerging is clear: cases are far higher than usual.

For instance in Mumbai, the Sion Hospital has reported 24 cases of the fungal infection in the past two months, up from six cases a year, according to Dr Renuka Bradoo, head of the hospital's ear, nose and throat wing. She told the BBC that 11 patients had to lose an eye, while six died.

Are there cases in the UK?

Yes. Limited numbers of cases have been reported in countries including the UK, France, Austria, US, Iran, Mexico and Brazil, Prof Denning says.

What about other fungal infections? Are they a risk here?

Yes. There is a huge range of fungal infections, including many that aren’t life threatening – including thrush, athletes foot and dandruff. But, worldwide, roughly two million people are estimated to die from serious fungal infections every year.

Though many have underlying health conditions which weaken their immune response – including leukemia or HIV/Aids – experts say a large proportion of these deaths are avoidable.

“We think two thirds of those are preventable if we just had all the diagnostics, and all the medicines that are listed by the WHO is essential,” says Prof Denning. “If they were available to everybody, combined with good clinical education, we think 1.6 million lives could be saved every year.”

Some of the nastiest fungal infections include aspergillosis, which affects the lungs and causes breathing difficulties – impacting more than 4,000 people in the UK every year – and cryptococcal meningitis, a serious infection of the brain and spinal column that affects those living with HIV/Aids, leading to roughly 200,000 fatalities a year.

But what’s really worrying experts is the growing threat of multi-drug resistant fungal infections, such as Candida auris, an emerging threat which caused an outbreak at the Royal Brompton Hospital in London in 2015 and has now been detected across the globe.

The fungi causes a yeast infection, but can also trigger bloodstream infections that are lethal 45 per cent of the time, and most existing antifungal drugs are ineffective treatments.

Is it possible that a fungi could trigger a new pandemic?

Fungal infections have proved devastating for frogs and plants in the past. For instance chytrid fungus, which eats away at the skin of amphibians, has been linked to the decline of 500 species in the past 50 years – including 90 extinctions.

Meanwhile fungi like ash dieback, chestnut blight and Japanese larch disease, have wiped out thousands of trees.

But experts say they are less likely to trigger a pandemic, as fungi rarely jump from person to person. “Let’s put it like this: I don't think we're going to see the end of the human population because of fungal infections,” says Prof Denning.

Instead, experts warn about a slow moving crisis of increasingly untreatable infections.

“Fungal infections are a growing problem that has definitely been underestimated, but not because they’re going to suddenly spread person to person like Covid-19,” says Dr Ballou, warning that drug resistant infections will instead “creep up on us.”

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