'Advanced medicines still can't treat these': Deadly fungal infections a concern post-COVID-19, influenza
While fungi are not about to start turning the human race into zombies, like in the HBO blockbuster series The Last of Us, the World Health Organization (WHO) says invasive fungal infections are an increasing threat to human health.
Aspergillosis is one fungal infection common in our environment but, in some circumstances, it can turn deadly. In an average day, most of us will inhale hundreds to thousands of Aspergillus spores with no adverse effects, but for people with weakened immune systems it can cause deadly infections. That includes people undergoing cancer treatments, or bone marrow transplants, but it is now recognized that some viral infections, like influenza (flu) and SARS-CoV-2 (COVID-19) increase the risk of deadly fungal infection even in otherwise healthy people.
"When these kinds of things happen in the ICU, it can be devastating because even advanced medicines still can't treat these infections," said Dr. Bryan Yipp, an intensive care physician and researcher at the University of Calgary.
"Once many of these infections really get ingrained and take over, clearing them with medications alone, antifungal or anti microbials, can be very difficult."
Dr.Yipp began studying Aspergillus — a type of fungus that is a common mould — and its connection to viral infections in 2019, following three deaths in intensive care units of patients initially admitted for influenza, but who subsequently died of the fungal infection.
"It was very much a surprise when people first started identifying the fungus in the lung. There was a lot of discussion around the table of ICU doctors, infectious disease doctors, asking 'Was Aspergillosis really the cause of death, or was this just a secondary finding?'" said Yipp. "The pathologists who looked at the samples and the autopsies, were convinced that it was Aspergillosis that was the main problem."
UCalgary researchers have determined exposure to Aspergillus, a common fungal mould, can lead to a potentially dangerous Aspergillosis infection in people with weakened immune systems.
Working in Yipp's lab, lead researcher Nicole Sarden, a PhD candidate, isolated the mechanism by which the immune system starts failing to prevent fungal infections.
"In healthy humans. specific immune cells, called B cells, produce molecules (antibodies) that basically tag invaders so that other cells in the immune system, called neutrophils, can recognize them, eat them, and clear the infection," said Sarden
"But when you have infections with viruses, such as influenza, or if you get COVID, these molecules are no longer present, which means that the immune systems that are trying to eat, and clear the fungi cannot do it because they cannot see it."
Working with both mice and human blood and tissue samples, the researchers discovered that following a viral infection, neutrophils could identify a fungal infection and surround it but did nothing to destroy it.
"The virus kills the B cells, no messenger molecules exist, so the neutrophils that would normally attack, the fungus, are blinded. They sit there and don't know what to do," said Sarden.
The research team also discovered that reintroducing Aspergillosis reactive antibodies can protect infected mice, leading to hopes a similar treatment will be available in the near future for humans with Aspergillosis infections.
While Yipp and Sarden focused on Aspergillus, it is not the only fungus that can cause serious, or fatal infections. It is estimated fungal infections kill an estimated 1.5 million people worldwide every year. Most of those are due to four different fungi; Cryptococcus, Candida, Aspergillus, and Pneumocystis. Since the advent of COVID, a previously rare infection of the fungus Mucormycosis has been increasing rapidly in India. It affects the sinuses, brains and lungs of its victims. The rise in Mucormycosis has also been seen in patients who are recovering or have recently recovered from COVID.
Yipp is hopeful the research being conducted at Calgary's Cumming School of Medicine could lead to treatments for these infections as well.
"We have some hunches that that could be a similar mechanism to what we see here with what we have found." said Yipp. "So we think that this could be applied to multiple different types of fungi around the world."
The research team, led by Sarden, published their findings in the journal Science Translational Medicine.
CTVNews.ca Top Stories
Grandparents killed in wrong-way crash on Hwy. 401 identified
The Indian couple killed in a wrong-way police chase crash on Highway 401 earlier this week has been identified by the Consulate General of India in Toronto.
Police arrest 3 Indian nationals in killing of B.C. Sikh activist Hardeep Singh Nijjar
Three people have been arrested and charged in the killing of B.C. Sikh activist Hardeep Singh Nijjar – as authorities continue investigating potential connections to the Indian government.
TD worst-case scenario more likely after drug money laundering allegations: analyst
TD Bank Group could be hit with more severe penalties than previously expected, says a banking analyst after a report that the investigation it faces in the U.S. is tied to laundering illicit fentanyl profits.
Human remains found in rural Sask. possibly a decade old, RCMP say
RCMP say human remains found in a rural area in central Saskatchewan may have been there for a decade or more.
2 charged after police find 'concerning and diverse' explosives at Manitoba home
Winnipeg police say they have arrested two people in their 20s after a large amount of explosives were found in a home outside of Winnipeg, Man.
Canadian doctor concerned new weight-loss drug Wegovy may be used inappropriately
As Wegovy becomes available to Canadians starting Monday, a medical expert is cautioning patients wanting to use the drug to lose weight that no medication is a ''magic bullet,' and the new medication is meant particularly for people who meet certain criteria related to obesity and weight.
Spain abolishes national bullfighting award in cultural shift
Spain scrapped an annual bullfighting award on Friday, prompting a rebuke from conservatives over a backlash against a centuries-old tradition they see as an art form but which has run into growing concern for animal welfare.
Drew Carey is never quitting 'The Price Is Right'
Drew Carey took over as host of 'The Price Is Right' and hopes he’s there for life. 'I'm not going anywhere,' he told 'Entertainment Tonight' of the job he took over from longtime host Bob Barker in 2007.
Police officer hit by driver of fleeing vehicle in Toronto
York Regional Police say they are continuing to search for a suspect in an auto theft investigation who was captured on video running over a police officer in Toronto last month.