A deadly plant fungus has infected humans and caused flu-like symptoms in a world first, researchers say.
Chondrostereum purpureum causes silver leaf disease in flora, most commonly on rose varieties.
It spreads via airborne spores, hence its name, as it gradually turns leaves silvery—and often fatal.
It’s not known to infect humans, but doctors in India have reported what they believe is the first ever case.
The patient, a 61-year-old man, was treated at the Apollodoth Specialist Hospital in Kolkata and had been suffering from cough, fatigue, dysphagia and hoarseness for three months.
Unlike those considered most at risk for fungal infections, such as those with cancer, HIV, respiratory disease and organ transplants, the man had no medical history.
He was a plant mycologist, which included the study of mushrooms and various plant fungi.
How fungal infections are discovered
Scans taken at the hospital showed the infection had left a paratracheal abscess in the man’s neck, partially blocking his airway.
Medics drained the pus and prescribed the man daily antifungal medication for two months.
Two years later, he is said to be “perfectly cured” with no recurrence of the infection.
But the man’s surprising case “raises serious questions” about the ability of plant pathogens to cause disease in healthy humans and animals, the doctors who treated him wrote in the journal Medical Mycology Case Reports.
“If fungi can escape the phagocytosis pathway and are able to evade the host immune system, they could establish themselves as human pathogens,” they said.
Why can fungi infect humans?
There are estimated to be millions of species of fungi, of which we only know about 150,000.
The few fungi that can infect people do so because they can cope with our body temperature of 37 degrees Celsius — and medical staff in India managed to grow it at the same temperature in the lab.
The fungus also tends to only affect immunocompromised people.
Professor Elaine Bignell from the MRC Center for Medical Mycology told Sky News that the man in the Kolkata case “could have some kind of genetic immunodeficiency that we don’t know about”.
“This patient did not have any obvious risk factors for fungal disease that we would normally expect to find,” she said.
“But there are still questions to be asked about his proclivities, this organism, and how it was able to colonize the airwaves.
“We can never rule out any unknowns – he was clearly studying this fungus in some sort of experimental or botanical situation. He may have somehow been exposed to a surprising number of spores.”
Professor Bignell stressed there was no need to panic, but added: “This is a new kid on the block – we don’t know much about it.”
Should we be worried?
There has been concern that, as the planet warms due to climate change, known and unknown fungi could become potential threats as they learn to survive on a hotter planet.
Professor Bignell said mycologists talk about the “possibility of pathogens” – pathogens that are ubiquitous in the environment and could, under the right conditions, cause disease in humans.
Last year, the World Health Organization (WHO) lists 19 it fears could be a threat to public health.
The World Health Organization also reports ‘Significant’ increase in fungal infections during COVID pandemic.
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Fungi known to infect humans
Earlier this month, U.S. authorities disclosed one such fungus, A type of yeast called Candida auris or Candida aurishas been spreading rapidly through health facilities.
Candida is at the root of diseases such as thrush and rashes, and is one of the leading causes of blood infections in intensive care patients.
Another fungus known to affect humans is Cryptococcus neoformans – it infects the lungs and brain, causing pneumonia and meningitis in immunosuppressed patients.
It kills more than 100,000 people every year in sub-Saharan Africa.
Aspergillus fumigatus, a common mold found widely in homes and outdoor environments, can cause “chronic and acute lung disease” and can be fatal.