NOTE: For clarity we will only refer to Invasive Aspergillosis (IA) on this page. For information on Chronic Pulmonary Aspergillosis (CPA) go to this page.
The vast majority of cases of IA are the result of the patient being immunocompromised, that is to say that their immune systems are not working as efficiently as they could. The reasons for this could be one of a few causes, in order of severity of immunocompromisation:
- Chemotherapy & radiotherapy for the treatment of some cancers
- Bone marrow transplant for the treatment of some cancers e.g. leukemia
- Use of immunosuppressive drugs after a transplant
- Genetic defect e.g. Chronic Granulomatous Disorder
- Overuse of some steroids
- Some organs are 'less well' protected by the immune system as they have a less rich blood supply e.g. eyes, joints
Those infections of patients closer to the top of this list are likely to have a more rapidly progressing infection, so for example bone marrow transplant patients are retained within specially protected wards while they are more severely immunocompromised. Further down the list patients can usually be allowed home on antifungal medication.
The next most important factor in contracting an Aspergillus infection is the route of entry of the fungus. Naturally enough for an air-borne fungus those parts of the body that are most vulnerable are the lungs and sinuses - moist and thin skinned.
Most other organ infections come as a secondary infection after the body has been invaded via the lungs.
Finally there is a small group of infections caused by a breaching of the natural barrier to infection - our skin. So surgery and other wounds can rarely become infected, but in some countries eyes (keratitis) are a relatively common target.
There are one or two exceptions to these rules - the external ear canal can be infected (otomycosis), the fungus often feeding on ear wax, and finger or toenails can be attacked (onychomycosis) as they are effectively dead tissue with no immune system and can be moist - especially in poorly ventilated footwear. Skin itself is too dry as a rule, though there have been cases of plaster casts being removed to expose an aspergillus growing on top of the skin!
The Treatment section of the Aspergillus Website has full details of the treatment and prognosis of all the different sites of invasive aspergillosis.
You will need to be a member of the website to read the full articles but it is free of charge and involves filling in a short form here. Access is granted immediately.
Nosocomial infection: Building works in hospitals.
Severely immunocompromised people are isolated from sources of infection as far as is possible to achieve. At the present time it has not been possible to prevent all cases of invasive aspergillosis on these wards and research is ongoing to discover the reasons why.
It is known that the risk of infection increases if there are building works in the immediate vicinity of the hospital. Digging soil releases huge amounts of fungal spores into the air so it is possible that these could be carried onto wards by spores that have settled on visitors clothing for example.
Awareness of this problem is increasing and precautions are now taken but there is no consistent national or international standard practice on how best to prevent infection in this case.
The Aspergillus Trust and Andrew Poplett joined forces to produce a series of well informed suggestions to limit nosocomial infection caused by building works.
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Chronic Granulomatous Disorder (CGD)
If you suffer from this genetic disorder you may also be vulnerable to Aspergillus infections (aspergillosis, aspergilloma). Any advice related to CGD.