Aspergillosis is an infection caused by the Aspergillus fungus or a growth or allergic response to aspergillus.
There are three main forms of aspergillosis:
Pulmonary aspergillosis is an infection of the respiratory system that can spread to other systems. Aspergillosis is largely restricted to people with compromised immune systems, for example, people with cancer or AIDS, and people who have been treated with organ transplantation, cancer chemotherapy or other medications that lower resistance to infection.
Allergic bronchopulmonary aspergillosis (ABPA) is an allergic reaction to aspergillus; it usually develops in people who with lung problems such as asthma or cystic fibrosis.
Aspergilloma is a fungus ball that develops where there has been lung disease or lung damage, for example, following tuberculosis.
Where is aspergillosis usually found?
Aspergillosis is commonly found on dead leaves, stored grain, compost piles, or in other decaying vegetation, and also in damp buildings, building materials and may be found in some food items.
common is aspergillosis?
Incidence has been estimated to be of the order of 2 per 100,000 per year; this general statistic is of little value, however, as local conditions and individual risk factors will determine local incidence.
How is aspergillosis transmitted?
Aspergillus is a common fungal organism that forms spores which are inhaled; in most people, the body's defences would ensure that no infection occurred.
there a genetic / familial / hereditary factor?
Research suggests that there may be increased vulnerablity in some people, and this should be considered before putting patients at risk (eg chemotherapy, lung surgery, transplant). However, the level of increased risk has not been quantified, and more obvious factors (eg age and genral debility) may be of much greater significance.
aspergillosis be spread from person-to-person?
is most at risk from aspergillosis?
People with damaged or weaken immune systems; this includes:
- People with cancer, leukaemia, HIV
- People treated with radiation or cancer chemotherapy
- Older people
People working with aspergillus (eg demolition and construction workers) are probably at slightly greater risk than the general population.
What are the
symptoms of aspergillosis?
As this condition can spread to other systems (eg brain, heart, kidneys, skin), the following list of respiratory-related symptoms cannot be complete:
- Fever and chills
- Cough, often including hemoptysis
- Severe bleeding from your lungs
- Shortness of breath
- Chest or joint pain
- Facial swelling on one side
- Skin lesions
Allergic bronchopulmonary aspergillosis (ABPA)
- A cough that may bring up blood or plugs of mucus
- Worsening of the underlying disease
The fungal mass may develop if there are cavities in the lungs, typically in people with pre-existing conditions, such as emphysema, tuberculosis or advanced sarcoidosis. Aspergilloma is a benign condition that may not produce symptoms at all, but over time it can cause:
- Cough - sometimes with severe haemoptysis (coughing with blood)
- Shortness of breath
- Unintended weight loss
- Secondary infection (often pneumonia)
When is it necessary
to contact a doctor?
When any of the symptoms become distressing or worrying - there is no set pattern. Haemoptysis, unintended weight loss, chest pain, prolonged fever and unexplained shortness of breath or fatigue, should always be investigated.
What are the long term
effects of aspergillosis?
Untreated or delayed treatment can lead to spread to other systems, and can be fatal. In people with astmma, aspergillosis can make the condition worse.
With prompt treatment, there may be no long term effects following an extended recovery period; but the lungs are fragile, and scar tissue, with diminished lung function, is not uncommon.
What is the mortality
rate for aspergillosis?
The most recent available figures (2004) show 700 reported deaths worldwide (USA: 261, UK: 3), but as many people who contact the disease may have other serious conditions (eg AIDS, cancer, organ or bone marrow transplant), and aspergillosis is often misdiagnosed, it is likely that there is some underreporting.
How is aspergillosis diagnosed?
Diagnosis is initially by symptoms, but is confirmed by Chest X-ray and a CT scan are both used to check for the presence of a fungal ball. Sputum and a bronchoscopy sample of lung mucus may also be taken to check for antibodies and fungal spores. Occasionally a lung biopsy may be required at bronchoscopy.
Allergic bronchopulmonary aspergillosis (ABPA)
If ABPA is suspected, an allergic skin test is the key procedure, followed by blood tests to check for antibodies indicating allergy to the aspergillus mould. Computerised tomography (CT scan) may be ordered to check for bronchiectasis (excessive mucus) which is common in ABPA.
Chest X-ray and a CT scan are both used to check for the presence of a fungal ball. Sputum and a bronchoscopy sample of lung mucus may also be taken to check for antibodies and fungal spores.
there a treatment for aspergillosis?
High-dose intravenous amphotericin B has been the traditional antifungal used to eradicate the underlying organism, and it is highly effective, though can be extremely unpleasant. Increasingly, alternative antifungal agents are used, including Voriconazole (usually considered first-line treatment). Other drugs include itraconazole, lipid amphotericin formulations, caspofungin, micafungin, and posaconazole.
Is there a
way to prevent infection?
For most people, the preventative measures would not be justified by the small risk; however, immunocompromoised people should avoid garden work, dusty areas (especially construction sites), and consider a protective mask in risky areas. Preventative antifungals may be prescribed in some circumstances.
Can aspergillosis be controlled
Aspergillus species are ubiquitous molds found in organic matter. Although more than 100 species have been identified, the majority of human illness is caused by Aspergillus fumigatus and Aspergillus niger and, less frequently, by Aspergillus flavus and Aspergillus clavatus. There is no prospect of eradicating them from the environment.
Is there legal protection for
workers and others?
The nature of the disease means there can be no absolute protetcion; however, workers in dusty environments are usually entitled to have access to masks, if dust inhalation is a risk, and construction sites increasingly use water spray to damp down dust - workers denied these basic measures may have a case in law.
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Article written by Andrew Heenan BA (Hons), RGN, RMN