- What Is It?
Facts you should know about Aspergillus infection
- Aspergillus is a genus name that represents over 185 fungal species, some of which cause several types of aspergillosis (fungal allergy or infection) in humans.
- The causes of an Aspergillus infection are fungi (mold). Risk factors include the following:
- Aspergillus infection signs and symptoms vary with the type of aspergillosis but all include airway problems that range from mild to severe.
- Diagnosis is confirmed by identifying the fungal genus and species by tests, biopsy, and microscopic observation.
- Treatment options depend on the disease type and severity and may include antifungal drugs, corticosteroids, and/or surgery.
- Complications include blood clots, multiple organ damage, organ failure, and fatal bleeding.
- The prognosis of allergic types of aspergillosis is good to fair, but invasive types have a poor prognosis.
- It is possible to reduce the risk of aspergillosis by avoiding airborne dust and mold, mold removal, and using antifungal medications appropriately.
What is Aspergillus? What are the types of Aspergillus?
Aspergillus is the genus name for a group (over 185 species) of filamentous fungi or common molds, most of which occur in an asexual state, and reproduce by producing conidia (asexual spores or conidiophores) that can spread into many different environments, germinate, and then grow. About 20 species cause infections in humans. Aspergillus fumigatus is the most common of the group, followed by Aspergillus flavus and Aspergillus brasiliensis (formerly termed niger). Aspergillus penicillium is mainly allergenic. That means this species tends to induce a hypersensitive (allergic) reaction instead of infecting the body. Other types or species such as Aspergillus clavatus, the Aspergillus glaucus group, Aspergillus nidulans, Aspergillus oryzae, Aspergillus terreus, Aspergillus ustus, and Aspergillus versicolor less commonly cause disease (note...species may have different names). Infections that these fungi cause are termed aspergillosis. These fungi may cause lung (Aspergillus pneumonia) and other organ infections and allergic reactions (mold allergy or ABPA [allergic bronchopulmonary aspergillosis], for example). The U.S. Centers for Disease Control and Prevention (CDC) web site lists several types of aspergillosis:
- ABPA (allergic bronchopulmonary aspergillosis) (not infectious)
- Allergic Aspergillus sinusitis (not infectious)
- Azole-resistant (meaning resistant to azole antifungal drugs like miconazole or ketoconazole) Aspergillus fumigatus (infection)
- Aspergilloma -- a ball of fungus that grows in an organ like the lung
- Chronic pulmonary aspergillosis -- cavities or fungal ball formations (for 3 or more months)
- Invasive aspergillosis -- aspergillosis spreads to one area in the lungs and/or to more than more than one organ system
- Cutaneous (skin) aspergillosis -- aspergillosis infection that starts in a skin break (skin infection) or spreads to the skin from another body site
What are the causes and risk factors of an Aspergillus infection?
The cause of an Aspergillus infection is a fungus (mold) that may, if conditions are favorable, spread and damage tissue and human organs. However, most people breathe in Aspergillus spores (conidia) daily with no ill effects. In general, people who develop any type of Aspergillus infection have risk factors that have airway compromise and/or weak immune systems. The following are some examples of risk factors:
What are Aspergillus infection symptoms and signs?
Aspergillus infection signs and symptoms vary with the type of aspergillosis:
- Allergic Aspergillus sinusitis
- Chronic pulmonary aspergillosis
- Invasive aspergillosis
How do doctors diagnose an Aspergillus infection?
Doctors make a diagnosis by evaluating a patient's history, risk factors, symptoms, physical exam, lab tests, and imaging tests like a chest X-ray or CT. They may send respiratory fluid for tests (for example, Aspergillus galactomannan test, a blood test that detects galactomannan, a molecule found in the cell wall of Aspergillus) and microscopic exams (view Aspergillus hyphae and conidia), and they may examine and/or culture biopsy samples.
What are treatment options for an Aspergillus infection?
Treatment options depend on the aspergillosis disease type and severity.
- Allergic types of aspergillosis: the antifungal medication itraconazole, corticosteroid
- Aspergilloma: antifungal medications are the same for invasive aspergillosis listed below and/or surgical removal
- Invasive types and chronic types of aspergillosis (including cutaneous or skin types): antifungal medications such as voriconazole, lipid amphotericin formulations, posaconazole, isavuconazole, itraconazole, caspofungin, and/or micafungin
Although many individuals have died from the invasive disease, there is one report that states voriconazole cured a patient of invasive Aspergillus. Thus, the disease may be curable in some people. Curability should be discussed with the patient's doctor.
What are possible complications of an Aspergillus infection?
A rapidly invasive infection is dangerous because it may cause multiple organ damage, organ failure, and death without treatment. Aspergillomas may cause blood clots and/or fatal bleeding in the lungs.
What is the prognosis of an Aspergillus infection?
The prognosis of allergic types of the disease is good to fair and depends on the patient's response to therapy. Unfortunately, invasive types have a poor prognosis as only about 25%-60% may respond to therapy and many patients relapse. Also, over long-term therapy, the fungi may develop resistance to some antifungals.
Is it possible to prevent an Aspergillus infection?
It is possible to reduce the risk of Aspergillus infections, especially in people with weak immune systems, by avoiding activities that cause dust and mold to become airborne, like mowing grass. Mold removal (in home or workplace) by certified technicians may reduce risk. Isolation precautions for transplant patients and others when white blood cell levels are very low may also reduce risk. Some people with suppressed immune systems may take antifungal medications prophylactically, meaning that they are given to prevent infection.