Mechanism behind spread of deadly fungal infection found

Scientists have discovered a unique mechanism that drives the spread of a rare and deadly fungal infection that affects the lungs and brain.

Cptococcosirys is a fungal infection that usually only occurs in people with impaired immunity, according to researchers at the University of Birmingham in the UK.

However, one strain of the fungus - known as the Pacific Northwest strain of Cryptococcus gattii - has gained the ability to infect otherwise healthy individuals.

The infection affects the lungs first, because it is acquired by inhaling fungal spores.

In the absence of therapy, and sometimes despite it, the infection quickly spreads to the brain and other organs with often fatal consequences.

 

Those infected with the disease have to undergo antifungal drug therapy that can last months - but those drugs often fail to curtail the disease and instead surgery is required to remove the infection from the lungs and central nervous system.

"It is vital that new drugs are developed to combat this disease, and in order to do that we need to find out how the disease spreads," said Ewa Bielska, lead author of the research published in the journal Nature Communications.

Previous research demonstrated that the high virulence of this Cryptococcosis gattii strain results from its remarkable ability to grow rapidly within human white blood cells which relies on a unique 'division of labour' mechanism within the infection.

"To achieve this, individual fungal cells must work together to coordinate their behaviour, but how they do this has, up until now, been unknown," said Bielska.

Now, researchers have discovered that this 'division of labour' can be triggered over large cellular distances and is mediated through the release of microscopic fluid-filled "bags" called extracellular vesicles.

"These vesicles act like 'carrier pigeons', transferring messages between the fungi and helping them to coordinate their attack on the host cell," said Robin May, Director of the University of Birmingham's Institute of Microbiology and Infection.

"This is a previously unknown phenomenon in infectious disease, but also provides us with a potential opportunity to develop new drugs that work by interrupting this communication route during an infection," said May.