Fungal Disease Awareness Week August 14-18 2017
The Fungal Infection Trust is proud to support Think Fungus: Fungal Disease Awareness Week.
During the week the FIT will particularly highlight the health threats to our health caused by the fungus Aspergillus. Over the last few years, we have increased awareness of particular household activities or habits we all might do that raise our risk of coming into contact with Aspergillus.
There is always a low risk of inhaling Aspergillus spores wherever we live in the world, in fact, we all inhale spores most days of the year. Aspergillus spores are the tiny ‘seeds’ that this fungus uses to disperse itself, and these spores are so light they can float easily on the air for long periods of time. If there is sufficient wind they can travel many miles. Aspergillus also grows anywhere and everywhere there is a little dead plant material and some water. That means it grows pretty much anywhere in the world, and this combination of ubiquity and ease of travel means we are probably all breathing in at least one species of Aspergillus every hour of the day.
This is not a problem for most of us as we have very effective ways to stop spores getting into our lungs. Each spore has to run a gauntlet of airways and sinuses that are lined with sticky mucus designed to capture and remove all foreign materials before the spore can get very far.
The above video shows neutrophil (killer) cells (coloured in green) moving through (red) lung tissue and capturing and eating (blue) fungal spores. This is exactly what is happening within our lungs all of the time to prevent infection. NB These amazing images were produced by Bruns et. al. 2010 PLOS Pathogens Apr 29;6(4):e1000873. Read full paper
If spores do manage to avoid all of the traps and get into our lower airways then we have special ‘killer cells’ that wander around our lungs and can find, eat and destroy any fungal material it finds. In people with fully functional immune systems, nothing gets through – and that includes all the bacteria and other particles we inhale. Healthy lungs can clean themselves.
Unfortunately for a few people that don’t have a fully operational immune system a few spores do get through their defences and can grow. Sometimes the fungal growth cannot penetrate the membranes lining our lungs so it remains in the airways themselves, eventually clogging them up and causing chronic inflammation and scarring (Allergic Bronchopulmonary Aspergillosis ABPA). This restricts the ability to breathe efficiently. We have already found that some of these people have genetic differences that slow down mucus removal, leading to lung clogging, scarring, and allergy. To date there is no cure for this infection.
If the spores are able to pass through the thin but tough membrane lining our airways or get deep enough to reach the more delicate areas of our lungs then they can start to grow and will slowly erode lung tissue causing holes and cavities (Chronic Pulmonary Aspergillosis CPA). This damage restricts the ability of the lungs to breathe and can gradually get worse unless they are treated with anti-fungal drugs. There is currently no cure for CPA.
A few thousand people a year have to have transplants to replace solid organs or bone marrow. A common example is someone (adult or child) that has a form of leukemia which needs to be treated by removing all active cells in their bone marrow. Amazingly cancer doctors can replace all of their bone marrow cells with cancer-free cells, curing the cancer. Unfortunately, the marrow replacement takes several days to grow and during that time the patient has a severely reduced ability to fight off infection i.e. they are severely immunocompromised. If they inhale bacteria or virus particles during that time they will get a nasty infection that will require antibiotics to help support their depleted immune system. Likewise, if they inhale fungal spores during that time and they manage to get deep into the lungs of the patient there is an opportunity for the spores to grow unhindered and become an Acute Invasive Aspergillosis IA. There can then be a race between how quickly the fungal spores grow versus how quickly the new bone marrow will grow back to replace the patient’s immune system.
Doctors will be watching for signs of a fungal infection but there are few signs of infection they can look for as the patient has little active immune system function so it is a difficult task. There are some tests that can detect the infection but these are not 100% accurate. Overall only 40% of immunocompromised patients with IA are cured, partly because doctors often cannot detect it quickly enough and start treatment early enough.
During Fungal Disease Awareness Week we will be publishing a page each day on a different aspect of awareness of what life is like for patients living with Aspergillosis and information of some ways we are all exposed to the fungus Aspergillus, often when we are least expecting it.