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All about Aspergillus

By September 17, 2021December 18th, 2021No Comments
What are Clearance Tests?

I am thrilled to publish another addition to our ongoing compendium on different mold varieties. This time, I will be covering Aspergillus, a wide genus of more than 800 mold species, several of which thrive in human habitats and can present a hazard to one’s health. Most studies related to mold stop just short of making claims about causation. Despite this, they frequently argue a position affirming the dangers of mold exposure to human health. These affirmations are further supported by a large volume of anecdotal evidence.

Our mission at Pure Maintenance of Santa Barbara and San Luis Obispo Counties is to support your improved and ongoing health by restoring the health of your home. These articles are one way we pursue that goal. If you are here looking for answers, I hope this brings you a little bit closer. If you feel worried you may be experiencing some mold-related health problems, I highly recommend that you speak with a trusted medical professional.

Now on with the post!

Table of Contents

  1. What is Aspergillus?
  2. How it grows indoors
  3. Aspergillus and your health
  4. Aspergillosis
  5. Aspergillosis statistics
  6. How to prevent Aspergillus
  7. Aspergillus removal
  8. Conclusion

What is Aspergillus?

Aspergillus refers to a broad genus of opportunistic mold species. It is among the most commonly cited mold varieties in indoor environments, and some of its strains, A. niger, in particular, is frequently mistaken for Stachybotrys (black mold) due to its black coloring. Like Stachybotrys, many species of Aspergillus are marker molds. Marker molds produce mycotoxins, making them even more hazardous to the health of those exposed. Although marker molds may be found outdoors in very low numbers, their detection in any indoor testing is a clear indication of a hazardous indoor mold issue. Aspergillus fumigatus is especially dangerous for immunocompromised individuals, who may be at high risk for death if infected.

How it grows indoors

Mold may enter a home in any number of ways. Mold spores drift in through an open door or window. They can track in on clothes, shoes, or even a pet’s coat. 

Once spores land on surfaces within an indoor space, they settle, as though in waiting, ready to thrive once they encounter water. They may drift under a bathroom sink, where a leak or the frequent humidity of a steamy shower facilitates stable cultivation. They may lie dormant in your crawlspace until a burst pipe floods the space, causing a spike in its growth. The quantitative volume of mold spores in a given indoor environment is what we call its “Total Mold Load”.

Aspergillus behaves much the same. Aspergillus thrives in damp, cellulose-rich spaces. As such, human housing is a uniquely suitable environment for it to grow. It is no wonder Aspergillus is among the most common molds found infesting indoor environments.

Aspergillus and your health

Is Aspergillus dangerous?

Consistent exposure to Aspergillus, A. fumigatus in particular, appears to be hazardous to an exposed person, and immunocompromised people are especially vulnerable. As immunosuppressive therapies reacting to other medical conditions become more common, we see the frequency of infection because of Aspergillus increasing.

Different studies indicate a wide variety of medical symptoms associated with Aspergillus infection. Among them exists a collection of medical conditions colloquially referred to as Aspergillosis that are directly related to Aspergillus infection. 

“Aspergillosis” refers to a disease caused by Aspergillus, of which the CDC lists seven types.

Types of Aspergillosis

From the CDC:

  • Allergic bronchopulmonary aspergillosis (ABPA), which occurs when Aspergillus causes inflammation in the lungs but doesn’t cause an infection. Symptoms may appear similar to allergies and include coughing and wheezing, shortness of breath, and even fever in some rare cases.
  • Allergic Aspergillus sinusitis, which occurs when Aspergillus causes inflammation in the sinuses and symptoms of a sinus infection (drainage, stuffiness, headache) but doesn’t cause an infection. 
  • Azole-Resistant Aspergillus fumigatus, which occurs when A. fumigatus becomes resistant to certain medicines used to treat it. Patients with resistant infections might not get better with treatment.
  • Aspergilloma, which occurs when a ball of Aspergillus grows in the lungs or sinuses, but usually does not spread to other parts of the body. Aspergilloma is sometimes called a “fungus ball.” Symptoms of aspergilloma include frequent coughing, coughing up blood, and shortness of breath.
  • Chronic pulmonary aspergillosis, which occurs when Aspergillus infection causes cavities in the lungs. Chronic pulmonary aspergillosis can be a long-term condition, lasting three months or more. Additionally, one or more fungal balls (see aspergillomas above) may also be present in the lungs. Symptoms of chronic pulmonary aspergillosis include weight loss, coughing and coughing up blood, fatigue, and shortness of breath.
  • Invasive aspergillosis, which occurs when Aspergillus causes a serious infection. Invasive aspergillosis usually affects people who have weakened immune systems, such as people who have had an organ transplant or a stem cell transplant. It most commonly affects the lungs, but it can also spread to other parts of the body. Among symptoms of those who experience invasive aspergillosis in the lungs are fever, chest pain, coughing and coughing up blood, shortness of breath, and more.
  • Cutaneous aspergillosis, which occurs when Aspergillus enters the body through a break in the skin (such as after surgery or a burn wound) and causes infection, usually in people who have weakened immune systems. Cutaneous aspergillosis can also occur if invasive aspergillosis spreads to the skin from somewhere else in the body, such as the lungs.

Aspergillosis statistics

Aspergillosis is generally very treatable for immunotypical individuals but may be very dangerous for the immunocompromised.

According to the CDC,

“a large prospective study found that the one-year survival for people who had invasive aspergillosis was 59% among solid organ transplant recipients and 25% among stem cell transplant recipients. In a systematic review of intensive care unit autopsy studies, aspergillosis was one of the top four most common diagnoses that likely lead to death.”

One study found that

“the disease is very serious, with an overall mortality of >50% and a mortality approaching 100% in allogeneic BMT patients”.

As you can see, the dangers of exposure to Aspergillus are real and severe. If you believe you are exposed, I encourage you to seek appropriate medical help, as well as whatever steps are possible to end your exposure to black mold.

How to prevent infestation

The best way to deal with Aspergillus – or any mold, for that matter – is to prevent it! Mold loves to grow in dark, damp environments. Here are a few tips we recommend for preventing black mold.

Maintain healthy humidity levels in your home. If you live somewhere with high humidity, consider investing in a dehumidifier to keep indoor humidity down. The EPA recommends keeping your indoor relative humidity (RH) below 60%, ideally between 30%-50%.

Use, maintain and update ventilation systems in high-moisture rooms. I frequently see bathrooms and kitchens with obsolete, neglected fans or stove hoods. Ensure you follow the manufacturer’s instructions on routine upkeep, especially as it concerns keeping them clean! Excessive dust and oil will create problems. If you are resolving a mold issue in your home and your ventilation appliances are old, consider investing in new ones.

Have your home – especially your pipes – professionally inspected. A burst pipe will nearly guarantee the activation of a dormant mold colony. Investing in upgrades costs less than dealing with sudden damage.

The same goes for avoiding flooding! If you live in an environment prone to floods, take steps towards solutions that mitigate flooding. These might include installing and maintaining drainage, sealing cracks & gaps in your walls and windows, and keeping sandbags on hand with which to build an emergency barrier.

Aspergillus removal

Let’s say it’s too late – the damage is done, and you worry you already have an Aspergillus infestation. What can you do?

The first step I recommend taking is getting a professional out to perform a test or inspection. We at Pure Maintenance of Santa Barbara use a variety of methods, including tape, spore traps, and ERMI (Environmental Relative Moldiness Index) testing. A reliable inspector will be proficient in these tests.

Next, look at available options for reducing the total mold load throughout your home to zero. Pure Maintenance specializes in unique technologies that accomplish this goal, and I wouldn’t settle for less. 

Many conventional mold remediators address an urgent mold outbreak by sealing off the affected room and removing the visible mold colony. They typically demolish infested walls and structures due to the fact that the building components have been compromised.

A limitation of this process is that when mold becomes agitated, it ejects mold spores in a desperate attempt to continue propagating. These methods achieve very little in the way of reducing the total mold load of your home or building. The next time those spores encounter moisture, then your problem will resurface.

Pure Maintenance reduces the mold load within the treated area to nearly zero! That is often lower in relative quantity than the baseline environment. Not only that, but we also protect your space from mold’s return, guaranteed for up to one year!


As with other marker molds, Aspergillus can be very dangerous. Be proactive in preventing opportunities for mold to anchor and thrive! Reduce the indoor moisture levels of your space and maintain a clean home. If you notice mold growing, take immediate action. I recommend looking up your closest Pure Maintenance licensee. If you are in Santa Barbara or San Luis Obispo counties, you know who to call!