Aspergillus is a species of moulds, some of which cause fungal infections in humans called aspergillosis. The majority of infections are caused by Aspergillus fumigatus and less frequently Aspergillus flavus and Aspergillus clavatus
The Aspergillus species are soil mould but are capable of living anywhere in the environment where there is moisture and basic substrate. Outdoors they are often found in rotting vegetation and agricultural settings. In buildings they are found in damp wallpaper and plaster, fireproofing, pipe lagging and air-conditioning systems.
Infection is usually spread via inhalation, which affects the respiratory tract and can be life threatening. People with compromised immune systems are particularly vulnerable to infection. Four main syndromes have been identified:
Allergic bronchopulmonary aspergillosis
This is an allergic reaction to the spores of the Aspergillus mould. It affects up to 5% of adults with asthma and is also common in patients with cystic fibrosis. The infection causes problems with asthma control and repeated episodes may result in fibrotic lung disease. Treatment includes steroids and antifungal drugs.
Aspergilloma and chronic pulmonary aspergillosis
This occurs when the fungus ball (mycetoma) develops in a pre-existing cavity in the lung, previously damaged during an illness such as tuberculosis. Cavities can also be formed in the lung by Aspergillus. The patient may be asymptomatic or suffer from weight loss, chronic cough, feeling rundown and tired and complain of haemoptysis (blood present in sputum). Antifungal drugs can help to control symptoms. Surgical removal of the mycetoma is possible and antifungal drugs can be injected directly into the affected cavity.
This is a rapidly progressive and often fatal infection and is of particular concern to patients who are immunocompromised, for example, following a bone marrow transplant. The infection can disseminate to other organs. Features of invasive pulmonary aspergillosis include cough, pleuritic chest pain, haemoptysis, and shortness of breath. Early treatment with antifungal drugs improves the chances of survival.
This presents as an allergic sinusitis, a mycetoma in the sinuses or as an invasive aspergillosis infection. Treatment includes antifungal drugs and surgical intervention.