'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
Quebec nurse had to clean up after husband's death in Montreal hospital
On a night she should have been mourning, a nurse from Quebec's Laurentians region says she was forced to clean up her husband after he died at a hospital in Montreal.
Northern Ont. lawyer who abandoned clients in child protection cases disbarred
A North Bay, Ont., lawyer who abandoned 15 clients – many of them child protection cases – has lost his licence to practise law.
Bank of Canada officials split on when to start cutting interest rates
Members of the Bank of Canada's governing council were split on how long the central bank should wait before it starts cutting interest rates when they met earlier this month.
Maple Leafs fall to Bruins in Game 3, trail series 2-1
Brad Marchand scored twice, including the winner in the third period, and added an assist as the Boston Bruins downed the Toronto Maple Leafs 4-2 to take a 2-1 lead in their first-round playoff series Wednesday
Cuban government apologizes to Montreal-area family after delivering wrong body
Cuba's foreign affairs minister has apologized to a Montreal-area family after they were sent the wrong body following the death of a loved one.
'It was instant karma': Viral video captures failed theft attempt in Nanaimo, B.C.
Mounties in Nanaimo, B.C., say two late-night revellers are lucky their allegedly drunken antics weren't reported to police after security cameras captured the men trying to steal a heavy sign from a downtown business.
What is changing about Canada's capital gains tax and how does it impact me?
The federal government's proposed change to capital gains taxation is expected to increase taxes on investments and mainly affect wealthy Canadians and businesses. Here's what you need to know about the move.
New Indigenous loan guarantee program a 'really big deal,' Freeland says at Toronto conference
Canada's Deputy Prime Minister Chrystia Freeland was among the 1,700 delegates attending the two-day First Nations Major Projects Coalition (FNMPC) conference that concluded Tuesday in Toronto.
'Life was not fair to him': Daughter of N.B. man exonerated of murder remembers him as a kind soul
The daughter of a New Brunswick man recently exonerated from murder, is remembering her father as somebody who, despite a wrongful conviction, never became bitter or angry.