Aspergillus fumigatus is a species of fungus. It can be found throughout the environment, including in soil, plant matter, and household dust. The fungus can also produce airborne spores called conidia.

Most people can inhale many of these spores on a daily basis. In a healthy individual, the immune system often clears them from the body without a problem. However, for some people, inhaling A. fumigatus, spores can lead to a potentially severe infection.

You’re at most at risk for becoming ill from A. fumigatus if you:

  • have a weakened immune system, which can include if you’re taking immunosuppressive drugs, have certain blood cancers, or are in the later stages of AIDS
  • have a lung condition, such as asthma or cystic fibrosis
  • have a low white blood cell count, which can occur if you’re undergoing chemotherapy, if you have leukemia, or if you’ve had an organ transplant
  • have been on long-term corticosteroid therapy
  • are recovering from a recent influenza infection

An infection that’s caused by an Aspergillus species of fungus is referred to as aspergillosis.

A. fumigatus is one of the most common causes of aspergillosis. It’s important to note that other Aspergillus species can also infect people. These species can include A. flavus, A. niger, and A. terreus.

There are several different types of aspergillosis, including:

Allergic bronchopulmonary aspergillosis

This condition is an allergic reaction to the Aspergillus spores. This reaction can lead to damage in your airways and lungs. It’s often found in people that have conditions such as asthma and cystic fibrosis.

Symptoms can include:

  • fever
  • weakness
  • general feelings of illness or discomfort
  • coughing up brown plugs of mucus or mucus that contains blood

People with asthma may also notice that their asthma symptoms begin to worsen. This can include an increase in shortness of breath or wheezing.

Chronic pulmonary aspergillosis

Chronic pulmonary aspergillosis develops progressively. It can occur in people with chronic lung conditions that cause air spaces called cavities to form in the lung. Examples of such conditions include tuberculosis and emphysema.

Chronic pulmonary aspergillosis can manifest in several ways, which can include:

  • small spots of Aspergillus infection in the lungs, called nodules
  • tangled balls of fungus within a lung cavity, called aspergillomas (these can sometimes cause complications such as bleeding in the lungs)
  • more widespread infection of multiple lung cavities, which may or may not contain aspergillomas

When left untreated, widespread infection can lead to thickening and scarring of lung tissue, which can lead to loss of lung function.

People with chronic pulmonary aspergillosis may develop the following symptoms:

  • fever
  • cough, which may include coughing up blood
  • shortness of breath
  • feelings of fatigue
  • general feelings of illness or discomfort
  • unexplained weight loss
  • night sweats

Invasive aspergillosis

Invasive aspergillosis is the most severe form of aspergillosis and can be fatal if not treated. It occurs when an aspergillosis infection begins in the lungs and spreads to other parts of your body, such as your skin, brain, or kidneys. Invasive aspergillosis occurs only in people who have a severely weakened immune system.

The symptoms of invasive aspergillosis can include:

  • fever
  • cough, which can include coughing up blood
  • shortness of breath
  • chest pain, which can be worse when you take deep breaths

When the infection spreads outside of the lungs, symptoms can depend on what part of the body is affected, but can include:

  • headache
  • swollen eyes
  • nosebleed
  • joint pain
  • lesions on the skin
  • difficulties with speech
  • confusion
  • seizures

An A. fumigatus infection can be difficult to diagnose because the symptoms often resemble other lung conditions such as tuberculosis.

Additionally, microscopic examination of sputum or tissue samples can be inconclusive because Aspergillus species can appear very similar to other fungal species when viewed under a microscope.

Diagnostic methods for Aspergillus can include:

  • culture of a sputum sample to detect Aspergillus growth
  • a chest X-ray to look for signs of infection, such as aspergillomas
  • a blood test to detect if antibodies to Aspergillus are present in your bloodstream
  • polymerase chain reaction (PCR), which is a molecular method that can be used to detect Aspergillus species from a sputum or tissue sample
  • tests to detect a component of the fungal cell wall of Aspergillus and other fungal species (the galactomannan antigen test and the beta-d-glucan assay)
  • skin or blood tests to confirm an allergy to Aspergillus spores

Allergic bronchopulmonary aspergillosis can be treated with oral corticosteroids. Sometimes you’ll take corticosteroids in combination with antifungal medications such as itraconazole.

Chronic pulmonary aspergillosis that consists of nodules or single aspergillomas may not require treatment. This is particularly true if you don’t have any symptoms. The nodules should be monitored regularly to make sure that they don’t progress.

Antifungal medications are used to treat more serious cases of chronic pulmonary aspergillosis, as well as invasive aspergillosis. Examples of medications that may be effective are voriconazole, itraconazole, and amphotericin B.

Recently, researchers have noticed an increase in the resistance of A. fumigatus to azole antifungal medications. These include drugs like voriconazole and intraconazole. In cases where an infection is resistant to azole antifungals, other antifungals such as amphotericin B will need to be used for treatment.

Embolization or surgical removal is also an option if aspergillomas are causing complications such as bleeding in the lungs.

A. fumigatus and other Aspergillus species are present throughout the environment. For this reason, it can be difficult to prevent exposure. However, if you’re in an at-risk group, there are some steps that you can take to make infection less likely.

Avoid activities that are more likely to bring you into contact with Aspergillus species.

Examples include gardening, yard work, or visiting construction sites. If you must be in these environments, be sure to wear long pants and sleeves. Wear gloves if you’ll be handling soil or manure. An N95 respirator may help if you’re going to be exposed to very dusty areas.

Take prophylactic antifungal medication

If you’ve recently undergone a procedure like an organ transplant, your doctor may prescribe antifungal medications to prevent infection.

Testing for Aspergillus species

If you’re in an at-risk group, periodic testing for Aspergillus may help to detect an infection in its early stages. If an infection is detected, you and your doctor can work together to develop a treatment plan.

Aspergillus fumigatus can cause potentially serious illnesses in people with a weakened immune system or lung conditions. An infection that’s caused by A. fumigatus and other Aspergillus species is called aspergillosis.

The outlook for aspergillosis depends on several factors, including:

  • the type of infection
  • the location of the infection
  • your overall immune state

Prompt detection and treatment of aspergillosis can help to improve the outlook.

If you’re in a group that’s at risk for developing aspergillosis, speak to your doctor. They can tell you ways that you can prevent becoming infected.