Clinical Overview of Aspergillosis

Etiology

Aspergillus species, most commonly including Aspergillus fumigatus and A. flavus, is found in the environment, including soil, decomposing plant matter, household dust, building materials, plants, food, and water.

Risk factors

Groups at risk for invasive aspergillosis include people who:

• Have severe/prolonged granulocytopenia.
• Have hematologic malignancies.
• Received a hematopoietic stem cell or solid organ transplant.
• Received high-dose corticosteroids or other immunosuppressive therapies.

Groups at risk for allergic aspergillosis include people with asthma, cystic fibrosis, or other underlying lung diseases.

How it spreads

Transmission occurs through inhaling airborne spores. Healthcare-associated infections are sporadic and associated with dust exposure during building renovation or construction. Occasional outbreaks of cutaneous infection have been linked to contaminated medical devices.

CDC's Healthcare Infection Control Practices Advisory Committee (HICPAC) has developed guidelines for environmental infection control.

Clinical features

In people with weakened immune systems, aspergillosis is an invasive pulmonary infection, usually accompanied by a fever, cough, and chest pain. Infection may spread to other organs, including the brain, skin and bones.

In people with underlying lung disease, allergic bronchopulmonary disease, and allergic sinusitis, aspergillosis is a localized pulmonary infection.

Diagnosis

Several diagnostic tools are used to diagnose aspergillosis:

• Microscopy: Tissues are observed under the microscope for Aspergillus elements. Definitive identification is difficult to make by this method alone.
• Histopathology: Similar to microscopy, sampled tissues are observed under the microscope for Aspergillus. This method is important for documenting the disease.
• Culture: This method can be done on a variety of sterile specimens to observe Aspergillus, which is typically visible 1 to 3 days after incubation. Culture allows for the microscopic identification down to the species level.
• Galactomannan antigen test: This test detects a polysaccharide that makes up part of the cell wall of Aspergillus. The Platelia assay is approved by the US Food and Drug Administration (FDA) for serum and bronchoalveolar lavage fluid.
• Beta-d-glucan assay: This test also detects a component in the cell wall of Aspergillus species. The Fungitell® assay is approved by the FDA for diagnosis of invasive fungal infections.
• Polymerase Chain Reaction (PCR): PCR for detection of Aspergillus species from clinical specimens, including tissue and bronchoalveolar lavage fluid, is offered by some laboratories.

Treatment and recovery

Aspergillosis treatment depends on the type of infection.

• Allergic aspergillosis: Treatment is usually itraconazole but can also be corticosteroids.
• Aspergilloma: Treatment may be a combination of surgery and antifungal medications.
• Invasive and cutaneous aspergillosis: People with severe cases may need surgery. Immunosuppressive medications should be discontinued or decreased, if possible.

For more detailed recommendations, please refer to the Infectious Diseases Society of America's Practice Guidelines for the Diagnosis and Management of Aspergillosis.