Aspergillis Structure - Daniel Friedman 05-02-00Aspergillosis: basic information
Aspergillus-related disease & health complaints, inspecting buildings for Aspergillus mold contamination

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Aspergillosis illnesses & Aspergillus mold in buildings:

This article provides basic descriptions of Aspergillus-related illnesses and discusses valid versus in-valid inspection and testing techniques used to detect mold contamination in buildings, including Aspergillus sp. molds.

At page top: an Aspergillus sp. conidiophores under the microscope at about 1200x.

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Aspergillus related illnesses & Aspergillus Contamination Testing in Buildings

Aspergillus fumigatus conidiophore in our laboratory (C) Daniel FriedmanWatch out: people who are concerned about possible mold-related illness should consult their primary care physician and with that doctor's advice decide if referral to a pulmonologist with expertise in mold related illness is appropriate. We also issue this trigger warning: reading this material can cause an anxiety-induced asthma attach, though most likely if you read with care you'll see that for most people anxiety is merited.

Greenberger (2002) discusses allergic bronchopulmonary aspergillosis (ABPA) as an illness complicating asthma and cystic fibrosis, noting that The survival factors in Aspergillus fumigatus that support saprophytic growth in bronchial mucus are not understood.

At left: Aspergillus fumigatus conidiophore showing characteristic long spore chains - lab photo, Daniel Friedman.

[Click to enlarge any image]

Beyond asthmatics and people with cystic fibrosis, and focusing on immunie-impaired patients, Cornet (2002) notes that invasive aspergillosis is the most prevalent mould infection, and Soubani (2002) offers this recap of the importance of recognizing and treating pulmonary aspergillosis, particularly for people with a compromised immune system but as well for patients suffering from asthma:

Aspergillus is a ubiquitous fungus that causes a variety of clinical syndromes in the lung, ranging from aspergilloma in patients with lung cavities, to chronic necrotizing aspergillosis in those who are mildly immunocompromised or have chronic lung disease. Invasive pulmonary aspergillosis (IPA) is a severe and commonly fatal disease that is seen in immunocompromised patients, while allergic bronchopulmonary aspergillosis is a hypersensitivity reaction to Aspergillus antigens that mainly affects patients with asthma.

In light of the increasing risk factors leading to IPA, such as organ transplantation and immunosuppressive therapy, and recent advances in the diagnosis and treatment of Aspergillus-related lung diseases, it is essential for clinicians to be familiar with the clinical presentation, diagnostic methods, and approach to management of the spectrum of pulmonary aspergillosis.

Patterson (2000) as well as virtually all authors writing in this field emphasize the importance of early diagnosis and treatment in the successful outcome for people with invasive aspergillosis while also noting that rapid diagnosis of invasive aspergillosis - a more serious illness - is difficult as most facilities lack the tools for definite diagnosis, making clinical detection of central importance.

By 2007 Greene described the use of computed tomography (CT) and the "halo sign" in diagnosing invasive pulmonary aspergillosis (IPA), concluding

Initiation of antifungal treatment on the basis of the identification of a halo sign by chest CT is associated with a significantly better response to treatment and improved survival.

Reader Question: what kind of home tests make sense for someone testing positive for Aspergillus fumigatus?

15 September 2015 Caroline said:
My father tested positive for Aspergillus fumigatus. I called some mold testing people to come out & all of them said they would do an air test in his room ( which is in the basement) and in the basement. I read how you said an air quality test is not always accurate because of the changes in the room, so I was wondering what kind of testing you would recommend. Also, I do have a compost heap outside. So I wondered if I got rid of it, would it take care of the situation?



You can find my email at the page bottom CONTACT link and by email I can offer a number for pro-bono consulting in this matter.

There is a place for air testing and properly done it can be informative. But considering the orders of magnitude variation in measurements of the level of airborne particles just in response to very small changes (waving a notebook in the air for example), a "negative" air test result cannot be trusted, and even a "positive" air test for mold that produces a high mold count cannot for a moment be presumed to actually describe the level of exposure of the building occupants to mold.

Recommended Buiding Inspection & Test Procedures for Mold Contamination

And no “test for mold” alone is going to tell us where the problem is nor what needs to be done about it. It’s instead a profitable “indicator test” that might find evidence of a problem that’s really there - or it might miss a real problem. The physician needs to be included in the process.

An effective mold contamination investigation, to be useful, must be accurate and it must be prescriptive.

  1. Decide if a mold investigation is warranted. 
  2. A thorough client interview, case history, complaints, relationship of complaints to building, other occupants' experiences. If the client or person of concern has not yet done so she or he should see their doctor promptly. If you and your doctor need to look further for a specialist in environmental medicine
  3. A thorough visual inspection of the building by an expert who understands building science, how air moves in building, how and where leaks occur, what building materials are mold friendly, how to decide when invasive inspection is justified (cutting openings to look into a wall where leaks have occurred, for example)
  4. Collection of a few intelligently-selected samples of settled building dust to be screened for unusual levels of harmful molds or even at very low levels, for clues suggesting a nearby Aspergillus contamination source (mold reservoir) such as the observation of Aspergillus spores in spore chains.
    See MOLD TEST KIT INSTRUCTIONS - note: do not send mold samples to InspectApedia; select a qualified mold lab.
  5. Air tests as a screen for mold: Optionally, I don't mind air testing as well, with the caveats I've already given. A negative air test result, taken alone, cannot be trusted.
  6. An action plan: Identification of mold reservoirs in the building and if appropriate, an action plan for removing the mold and correcting its cause.

Watch out: opportunists of all levels of education and training have leapt enthusiastically into the "mold business"; but only a few do the real job. It is far too tempting, too profitable, and easier and faster to just stop by and "collect an air sample. Even if the sample’s lab result says “yes there is a problem here” that alone is not diagnostic nor prescriptive. It doesn't tell us where the problem is (or where they are), what cleanup is needed, what corrections are needed to prevent future problems.

Aspergillus sp. mold spore photographs

The following is excerpted from MOLD by MICROSCOPE

Aspergillis Structure - Daniel Friedman 05-02-00 Aspergillis Structure - Daniel Friedman 05-02-00

Photographs of Aspergillus sp. mold spores under the microscope (above left) and Aspergillus niger culture (above right). Because their airborne spores look similar, also see Penicillium culture [image file], and also see these Penicillium spores [image file].

Aspergillus and Penicillium spores are difficult to differentiate when they are found in air that you may see them reported in test results as "Pen/Asp".

Watch out: Most Pen/Asp spores are round, hyaline (colorless) and small and lack surface features to aid in their precise identification by microscope when the spores are found alone, or in air samples (and if not in spore chains). In that case the spores may not even be identified as (potentially harmful) molds and may just be called amerospores in the lab report. But when these spores appear in spore chains (as that's how they are born) they should not be labeled as amerospores, and at least some of these airborne spores in the Aspergillus/Penicillium group can be identified from the spore alone (such as Aspergillus niger).

Aspergillus niger and Aspergillus fumigatus growing together (C) Daniel Friedman Aspergillus niger and Aspergillus fumigatus growing together (C) Daniel Friedman

Above at left we're examining an Aspergillus fumigatus conidiophore from a top-down view. The Aspergillus fumigatus conidiophore is the spore-producing structure and as you can see spores are produced in dense profusion and in long chains.

Above at right we illustrate a quite dense building-surface growth of Aspergillus niger and Aspergillus fumigatus side by side, in the same surface sample, but not quite intermixed. These spores were collected by a tape lift sample. The colorless spores in the open area may be another species of Aspergillus or of Penicillium.

See MOLD APPEARANCE - WHAT MOLD LOOKS LIKE for images of what mold looks like when growing on building surfaces or materials.

A thumbnail Sketch about Aspergillosis-related Illnesses and Aspergillus fumigatus.

List of Aspergillus-mold-related illnesses

The following is excerpted from MOLD RELATED ILLNESS SYMPTOMS

  1. Allergic Bronchiopulmonary Aspergillosis (ABPA) - worsening of underlying asthma or cystic fibrosis, coughing up blood, weight loss, fever, wheezing, mucous plugs produced by coughing - uncommon, occurs in persons with asthma and those with cystic fibrosis (CF).
  2. Aspergilloma (fungal growth in lung), cough, cough, fever, weight loss. Uncommon. May be asymptomatic but show up in a lung X-ray in some patients who have a pre-existing lung cavity (e.g. due to T.B.), occurs in patients suffering HIV + pneumonia; coughing up blood is a serious and life threatening condition.
  3. Aspergillosis, Chronic necrotizing Aspergillus pneumonia, or Chronic necrotizing pulmonary aspergillosis (CNPA) occurs in patients with an underlying disease such as COPD or alcoholism, symptoms include sub acute pneu7monia, fever, cough, night sweats, weight loss.
  4. Aspergillosis, Invasive, occurs in patients who suffer from immunosuppression or prolonged neutropenia, leukemia, and others; symptoms include fever, cough, chest pain, difficulty breathing (dyspena), rapid breathing (tachypnea).

Everyone breathes in some Aspergillus spores every day, including Aspergillus fumigatus that is itself quite common in the air. In healthy people breathing in mold spores does not cause a health problem as they are breathed out, coughed-out, or handled by the individual's immune system. In people with a suppressed immune system there are however health risks from breathing in such spores.

I don’t know what test your Dad had performed nor whether or not the test that was performed distinguishes between the presence of Aspergillus spores (they can be hard to speciate) and the existence of Aspergillosis disease.

Many people have Aspergillus spores in their lungs. I do. I have exampled coughed up flem for, and found, significant levels of Aspergillus spores.
That alone does not mean that a person has Aspergillosis.

Aspergillosis is detected by a variety of means including a combination of imaging and sometimes biopsy or even surgical procedures. Under the microscope
we’d see not just spores but living, branching fungal hyphae (think “roots” or “branches” that ultimately produce as well conidiophores or spore-producing structures).

Denning (1998) notes that invasive aspergillosis was first identified as an opportunistic infection in 1958 and adds that the diagnosis of Aspergillosis has since then increased significantly. He cites four reasons for an increase in the number of poeple at risk of developing invasive aspergillosis:

  1. The spread of AIDS
  2. Increased use of chemotherapy for treatment of solid tumors, lymphoma, leukemia and myeloma
  3. Increase occurrence of organ transplants
  4. Increased use of immunosuppressive treaments for other illnesses such as lupus and erythematosus.

For those of us including myself who can be frightened by reading about Aspergillosis it is significant to note that while there are fungal diseases that can affect healthy people, those whose immune system is impaired or suppressed are at the greatest risk. Having some Aspergillus spores in your spit doesn't mean you've got Aspergillosis.

Fisher (1981) noted that:

In one year, only 9 percent of the patients with Aspergillus species isolated from the sputum had an invasive infection.

Yu (1986) points out:

One hundred and eight consecutive patients were evaluated in whom Aspergillus species were isolated from respiratory secretions. Invasive aspergillosis was not demonstrated in non-immunosuppressed patients or in patients with solid tumors in the absence of neutropenia. Lung tissue was examined in 17 patients with leukemia and/or neutropenia [few neutrophils in the blood, leading to increased susceptibility to infection. It is an undesirable side effect of some cancer treatments - Ed.]; all had invasive aspergillosis. Tissue examination was not performed in 20 neutropenic patients; of 17 not receiving antifungal therapy, 16 died.

Aspergillosis is usually a quite serious medical problem deserving expert medical care (often treated with anti-fungal medicines, steroids, sometimes surgery). Un-treated it can be fatal.

A common species of Aspergillus found in people suffering from Aspergillosis is Aspergillus fumigatus - shown below in photos from our laboratory.

Aspergillus fumigatus under the microscope (C) Daniel Friedman Aspergillus fumigatus under the microscope (C) Daniel Friedman

Your dad will want to discuss his medical condition with his doctor immediately and if they agree, to be referred to a pulmonologist who is a specialist in the area of fungal diseases.

I add that Aspergillosis usually affects seriously people who suffer from immune system impairment for any of a variety of reasons. In healthy people the Aspergillus spores that we inhale do not cause a medical problem.

Aspergillosis related diseases can occur in anyone (at least some of of the Aspergillus-related diseases) but affect particularly seriously people who suffer from immune system impairment for any of a variety of reasons. In healthy people the Aspergillus spores that we inhale do not normally cause a medical problem.

Why are Aspergillus and Penicillium of Particular Health Concern Inside Buildings?

Well they are and they aren't. Certainly there are other mold genera/species that can be quite harmful, pathogenic, toxic, or allergenic to humans.

But these two mold groups, in my opinion, particularly Aspergillus sp., grow happily on an enormous variety of materials that are found on or in building interiors. So do some other molds such as Stachybotrys chartarum that has taken a beating in the public media and that is often a mycotoxin-rich mold spore. Here's an important difference:

Stachybotrys chartarum is a comparatively huge spore, maybe 10 x 20 microns, and it's sticky. It evolved to be spread by sticking to a cow's foot as the cow rambled around in damp or wet straw. Bit spores are not easily airborne unless you kick them around and they tend not to be airborne in huge numbers unless you're doing a maniacal demolition of moldy drywall without dust control. Big mold spores want to get stuck in the nose of the inhaler.

Aspergillus and Penicillium spores can be as small as 1u, that's 1 micron. These teensy spores pass easily through small openings, remain airborne for a long time, are easily carried on indoor convection currents, and can be inhaled deeply into the lung.

During a building investigation for problematic levels of mold contamination (more than 30 sq. ft. deserves professional remediation) we need to look not just at the external visible surfaces but we need to be alert for the possibility of a large but hidden mold reservoir in a building ceiling or wall cavity or even in building insulation.

How do those Aspergillus spores get out to become inhaled? Building pressure changes can indeed cause air to move in and out of walls or ceilings enough that if there is a significant mold reservoir we may find it in the indoor environment even though it's not visible. And surprisingly (to those of us who are not mycologists), changes in temperature, humidity, and sometimes even barometric pressure can cause a veritable explosion of production of mold spores.

In a college library in New York and inspecting and testing both before and after a building dry-out project began, I could both measure and actually see a tremendous increase in the airborne Aspergillus sp. level in the building after a mold "remediation" company installed fans and dehumidifiers.

The drop in humidity converted a large mold reservoir on some books to a large airborne mold cloud. When the humidity level plummeted I could actually see little clouds of green Aspergillus spores swirl into the air as I walked past moldy books on shelves. The Aspergillus had been there for a while, in a damp environment. Things dried out and the Aspergillus conidiophore mommas said to their spore-babies: Hey you kids, you're outa-here! Everybody into the air, now!

Should We Cut Holes to Inspect for Mold in Ceilings or Walls?

I don't suggest running through the house with an axe, but it is worth a careful inspection for humidity or moisture traps as well as possibly hidden leaks. If I can identify one or more high risk locations in a building I'd make a small test cut to look inside the cavity.

If I cannot find any high risk locations AND if there are not building-related IAQ complaints AND if I do not find abnormal occurrences of problematic mold spores in tape samples of representative settled dust, then I have to conclude there's not sufficient evidence of an indoor resevoir to cut or dig further.

Aspergillosis Research & References


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