Aspergillosis is the group of diseases caused by the fungus Aspergillus. It is an opportunistic fungus that exists as moulds and is found in organic debris, dust, compost, foods, spices and rotting plants. It is the second most common fungal infection. Aspergillus fumigatus is the most common species followed by flavus and niger.

Symptoms can include fever, cough, chest pain and breathlessness which also occur in many other illnesses which can make diagnosis difficult. Usually only patients with weakened immune systems or pre-existing lung conditions are susceptible.
The major forms of disease are:
* Allergic bronchopulmonary aspergillosis – this affects patients with respiratory disease such as asthma, CF and COPD.
* Acute invasive aspergollosis – a form that grows into surrounding tissue, common with patients that are immuno-compromised such as those with AIDs or receiving chemotherapy.
* Disseminated invasive aspergillosis – an infection that spreads throughout the whole body
* Aspergilloma – a ‘fungus ball’ that can form within cavities, especially within the lungs. The fungus settles in a cavity and is able to grow freely because some elements of the immune system are unable to penetrate into the cavity. As the fungus multiplies, it forms a ball, which incorporates dead tissue from the surrounding lung, mucus, and other debris.
The Aspergillus spores are inhaled and spread by airborne transmission. The spores are in the atmosphere all year round but are at their peak during the late autumn. If inhaled by a healthy individual you are unlikely to present with any symptoms however if you are susceptible then you may present with weight loss, a cough, shortness of breath, coughing up of blood, fever, tiredness and chest pain.
Bed rest, humidified oxygen therapy and cough suppressants are normally enough to treat an infection. However, if the symptoms are graver then postural drainage, anti-fungal drugs or lung surgery may be required. Aspergillosis typically heals with treatment though it may reoccur if you are repeatedly exposed to the fungus. Complications include airway blockage, respiratory failure, kidney damage, and bleeding in the lungs.
Oxygen therapy helps not only to relieve the symptoms caused by the fungus but also because the fungus cannot survive in high oxygen levels If the fungus infection is within the lungs themselves or nose and throat then they will be surrounded instantly and continuously by the higher oxygen levels breathed in by the patient and it will help to disperse the fungal infection.
Those patients who have lung diseases or are otherwise susceptible to infection are advised to check their homes and environments for mould and to check their bedding and not inhale near composts or rotting vegetation. If you get any symptoms then check with your doctor who can test for the presence of a fungal infection and treat accordingly to the type of infection that you have, as different species of the fungus will present with differing symptoms and may need to be treated slightly differently.
References: http://en.wikipedia.org and www.nacpatients.org.uk and www.healthline.com