Aspergillus General Information

Aspergillus was first identified in 1729 Aspergillus was first catalogued by an Italian biologist - P Micheli.

Aspergillus Species Information

It is a genus of around 200 fungi (moulds) found worldwide.Aspergillus is a group of molds, which is found everywhere world-wide, especially in the autumn and winter in the Northern hemisphere. 3000+ Genera

Aspergillus Scientific Information

Aspergillus is a filamentous fungus as opposed to yeast which is single celled. Fungi are identified in the lab by their structure and appearance. They may appear as round single cells like yeast, or made of chains of cells called hyphae.

Aspergillus Growth Characteristics

Fungi reproduce by forming tiny spores which can easily be airborne. Conidial head or fruiting body of Aspergillus - producing spores It grows well under a variety of conditions and many are known to be plant pathogens.

Where is Aspergillus found?

Its natural habitat is in hay and compost. some species withstand heat eg; Aspergillus fumigatus (pathogenic type) these are commonly found in compost. This type of mold can be found everywhere indoors (prefers damp materials) and outdoors. Soil Air; spores may be inhaled Water / storage tanks in hospitals etc Food Compost and decaying vegetation Fire proofing materials Bedding, pillows Ventilation and air conditioning systems Computer fans

Is Aspergillus Allergenic?

It is a potential allergen but has not been studied extensively

Toxins Produced by Aspergillus

Aspergillus can produce mycotoxins – these are often found in contaminated foodstuff and are hazardous to the consumer. Many toxins of this type of mold have been identified and depend greatly on genus and species.

Aspergillus Health Effects

 

we normally breathe in 100-200 spores daily. Certain types of this mold have been reported to cause disease. Molds are also called filamentous fungi. Only a few of these molds can cause illness in humans and animals. Most people are naturally immune and do not develop disease caused by Aspergillus. However, when disease does occur, it takes several forms.

The types of diseases caused by Aspergillus are varied, ranging from an allergy-type illness to life-threatening generalised infections. Diseases caused by Aspergillus are called aspergillosis. The severity of aspergillosis is determined by various factors but one of the most important is the state of the immune system of the person. The first known case of infection was in a jackdaw in 1815 and in a human in 1842.In the 19th century it was an occupational hazard amongst wig combers when it caused allergic disease of the lungs.

Which species of Aspergillus are pathogens?

The most common causing invasive disease are Aspergillus fumigatus and Aspergillus flavus.

The most common causing allergic disease are Aspergillus fumigatus and Aspergillus clavatus.

Aspergillosis

is a group of diseases caused by Aspergillus. The symptoms – fever, a cough, chest pain or breathlessness occur in many other illnesses so diagnosis can be hard. Usually only patients with already weakened immune systems or who suffer other lung conditions are susceptible.

Some Aspergillus species cause serious disease in humans and animals – it is pathogenic.

Allergic aspergillosis (affects asthma, cystic fibrosis and sinusitis patients). Acute invasive aspergillosis (risk increases if patient has weakened immunity such as some cancer patients and those on chemotherapy).

Disseminated invasive aspergillosis (widespread through body).

Allergic bronchopulmonary aspergillosis (ABPA)

This is a condition, which produces an allergy to the spores of the Aspergillus molds. It is quite common in asthmatics; up to 5% of adult asthmatics might get this at some time during their lives. ABPA is also common in cystic fibrosis patients, as they reach adolescence and adulthood. The symptoms are similar to those of asthma: intermittent episodes of feeling unwell, coughing and wheezing. Some patients cough up brown-coloured plugs of mucus. The diagnosis can be made by X-ray or by sputum, skin and blood tests. In the long term ABPA can lead to permanent lung damage (fibrosis) if untreated.

The treatment is with steroids by aerosol or mouth (prednisolone), especially during attacks. Itraconazole (an oral antifungal drug) is useful in reducing the amount of steroids required in those needing medium or high doses. This is beneficial as steroids have side-effects like thinning of the bones (osteoporosis) and skin and weight gain, especially when used for a long time. It is not known whether patients with ABPA not on steroids (or on low doses) benefit in some way.

Aspergilloma and chronic pulmonary aspergillosis

This is a very different disease also caused by the Aspergillus mold. The fungus grows within a cavity of the lung, which was previously damaged during an illness such as tuberculosis or sarcoidosis. Any lung disease which causes cavities can leave a person open to developing an aspergilloma. The spores penetrate the cavity and germinate, forming a fungal ball within the cavity. In some people, cavities in the lung are formed by Aspergillus, and no fungal ball is present. The fungus secretes toxic and allergic products, which may make the person feel ill. The person affected may have no symptoms (especially early on). Weight loss, chronic cough, feeling rundown and tired are common symptoms later. Coughing of blood (haemoptysis) can occur in up to 50-80% of affected people. The diagnosis is made by X-rays, scans of lungs and blood tests.

Treatment depends on many factors including whether the patient is coughing blood and how much lung disease there is. Those with no symptoms may need no treatment. Oral itraconazole (usually 400 mg daily) helps symptoms in many patients but rarely kills the fungus in the cavity. A new alternative is voriconazole, which is at least as effective as itraconazole. Sometimes surgical removal is possible, especially if the patient is coughing blood. Surgery is difficult however, and therefore is best reserved for single lung cavities. Sometimes other antifungal drugs (especially amphotericin B) can be injected directly into the cavity by a tube, which is put into position under local anaesthesia.

Aspergillus sinusitis

Aspergillus disease can happen in the sinuses leading to Aspergillus sinusitis. Just as in the lungs, Aspergillus can cause the three diseases - allergic sinusitis, a fungal ball or invasive aspergillosis. Allergic disease is asssociated with long standing symptoms of a runny blocked up nose, and may lead to nasal polyps. Surgical drainage, including removal of polyps, careful attention to treatment of bacterial infection, local steroids and/or short courses of oral steroids and antifungals applied locally are the approaches to therapy. The fungal ball caused by Aspergillus happens in a similar way to an aspergilloma. In those with normal immune systems, stuffiness of the nose, chronic headache or discomfort in the face is common. Drainage of the sinus, by surgery, usually cures the problem, unless the Aspergillus has entered the sinuses deep inside the skull. Then antifungal drugs and surgery is usually successful.

When patients have damaged immune systems - if, for example they have had leukaemia or have had a bone marrow transplant - Aspergillus sinusitis is more serious. In these cases the sinusitis is a form of invasive aspergillosis. The symptoms include fever, facial pain, nasal discharge and headaches. The diagnosis is made by finding the fungus in fluid or tissue from the sinuses and with scans. Surgery is done in most cases as it is important to find out what is exactly wrong and is often helpful in eradicating the fungus. Treatment with powerful antifungal medicines is essential. Choices of treatment include amphotericin B, caspofungin, voriconazole or itraconazole. Response may be better to amphotericin B than voriconazole or itraconazole; the role of caspofungin is uncertain, as there is little experience.

Invasive aspergillosis

Many people with damaged or impaired immune systems die from invasive aspergillosis. Their chances of living are improved the earlier the diagnosis is made but unfortunately there is no good single diagnostic test. Often treatment has to be started when the condition is only suspected.

This condition is usually clinically diagnosed in a person with low defences such as bone marrow transplant, low white cells after cancer treatment, AIDS or major burns. There is also a rare inherited condition that gives people low immunity (chronic granulomatous disease) which puts affected people at moderate risk.

People with invasive aspergillosis usually have a fever and symptoms from the lungs (cough, chest pain or discomfort or breathlessness) which do not respond to standard antibiotics. X-rays and scans are usually abnormal and help to localise the disease. Bronchoscopy (inspection of the inside of the lung with a small tube inserted via the nose) is often used to help to confirm the diagnosis. Cultures and blood tests are usually necessary to confirm the disease.

In people with particularly poor immune systems, the fungus can transfer from the lung through the blood stream to the brain or to other organs, including the eye, the heart, the kidneys and the skin. Usually this is a bad sign as the condition is more severe and the person sicker with a higher risk of death. However, sometimes infection of the skin enables the diagnosis to be made earlier and treatment to be started sooner. Treatment is with antifungal drugs

 

Aspergillus Uses

Some Aspergillus species produce enzymes which have important industrial applications. Many industrial uses have been identified and depend greatly on genus and species

How to test for / identify the presence of Aspergillus

It can be identified via Air and Direct Sampling. Often identified as “other colorless”

Is Aspergillus a "black mold"