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Is Black Mold (Stachybotrys) a New Emerging Opportunistic Human Fungal Pathogen?

The black mold, Stachybotrys, is a well known producer of toxic byproducts (mycotoxins). The species most common in building environment are Stachybotrys chartarum and Stachybotrys chlorohalonata. These species have been linked with health problems associated with poor air quality in mold- contaminated buildings.

Stachybotrys black mold — *Stachybotrys chartarum*

In eastern Europe, in the 1930s, outbreaks of a disease of horses and other animals that was characterized by symptoms such as irritation of the mouth, throat, and nose; shock; dermal necrosis; a decrease in leukocytes; hemorrhage; nervous disorder; and death were associated with Stachybotrys chartarum (then known as S. alternans) present in straw and grain fed to the horses.

Currently, health effects in humans attributed to Stachybotrys chartarum, are controversial. However, it is generally agreed that Stachybotrys chartarum can potentially cause allergic reactions from inhaled spores and also poses the threat of mycotoxin poisoning.

One of the disputed claims is the association of Stachybotrys with the idiopathic pulmonary hemorrhage that resulted in deaths of infants in Cleveland, Ohio, USA, in 1993-1994. After a review of the reports, the US Centers for Disease Control and Prevention (CDC) concluded that a possible association between pulmonary hemorrhage in infants and exposure to molds, specifically Stachybotrys chartarum, was not proven.

Spores of Stachybotrys are believed to contain high concentrations of mycotoxins. Therefore, inhaling large numbers of these spores potentially can cause mycotoxin poisoning. Luckily, spores of Stachybotrys are not readily disseminated in the air, primarily because they usually occur in a cluster covered with wet slime. Therefore, exposure to huge amounts of airborne Stachybotrys spores would only occur when the spores dry out and are disturbed, for example, during renovations.

Black Mold (Stachybotrys) as a New Emerging Opportunistic Human Fungal Pathogen

Recently, Stachybotrys chlorohalonata, was isolated from the sinuses of a patient. This is the first reported case of invasive Stachybotrys chlorohalonata sinusitis. The patient was cured from this infection after sinus surgery and antifungal treatment.

S. chlorohalonata is very closely related to S. chartarum. It differs morphologically from S. chartarum by having smooth spores, and having more restricted growth on lab media.

How and why to keep your carpet mold and bacteria free

Carpets are usually reservoirs of any particulates including dust and microorganisms that settles from the air or brought in from outside via various means. By their nature carpets can hold these tiny particles without being noticed. The problem comes when the carpet becomes wet. Wet carpets made of natural material and the settled dust supports microbial growth. If you have ever entered a building that had a damp or wet carpet for 2 or more days, you must have smelt a strong musty odor. The odor is due to the growth of mold and bacteria in the wet carpet.

Carpets with higher concentrations of dust are more likely to support proliferation of microbial growth than those with lower concentrations. Even if the carpet was made of synthetic material that may not support mold growth, the dust and the moisture could be sufficient to support microbial growth.

How to reduce microbial growth on carpets

The most important cause of microbial growth on any organic material is moisture. Therefore, drying the carpet immediately after it gets wet will prevent mold and bacteria from growing. The drying should be done within 48 hours if mold growth is to be prevented.

The second important thing to do is to frequently vacuum clean the carpet, at least once a week. This removes most of the dust which is food for the microorganisms. Dust also carries spores, and so by removing it, the spores are also removed. Fewer spores on the carpet would also mean less microbial growth if the carpet becomes wet.

Why keep your carpet mold and bacteria free

Disturbing a dusty carpet by normal activities like walking re-suspends the dust into the air. This dust carries mold spores, bacteria and other allergenic material such as animal dander and dust mites.

For people sensitive to mold, inhaling airborne mold spores can cause serious allergic reactions, including sneezing and runny nose. People with serious mold allergies may have more severe reactions, including shortness of breath and even asthmatic attacks.

Scared of buying a moldy house? Here is what you should know

Quite often home buyers are confronted by the fact that the home they wanted to buy was said to have mold. Is it okay to buy a house with mold in it? It depends on the extent of mold growth and how much it would cost to restore the house to it’s original condition prior to mold growth. Air samples report indicating presence of mold shouldn’t stop you from buying a house that you liked. Results of air samples alone are not enough to declare a building as having a serious mold problem.

The reality is that no house is mold spores-free since mold spores exist naturally in the environment. It is also important to know that depending on the time of the year, the majority of mold spores in the houses come from outside. These spores settle on various surfaces indoors and if still viable, they only need the right conditions to germinate and develop into visible mold growth.

fungal growth on wood — Visible mold growth

No one want to buy a house that is known to have mold. Hence the presence of mold has a direct impact on the selling price. If you are a seller, failure to address the mold challenge properly prior to putting your home in the market may lead to your house losing value and incurring unwarranted costs.

As a buyer the presence of mold in a house gives you a better opportunity to negotiate for a lower price. The good news is that majority of indoor molds are not likely to affect the structural integrity of the house and therefore removing the mold would restore the home to it’s original condition. But before committing yourself to buying the moldy house, you may consider paying a qualified professional to assess the extent of mold contamination, identify the causes and estimate how much it would cost to rectify the problem. If the reduction in the buying price is higher than the amount you would spend to remove the mold, then there is no reason why you should not buy the house if you liked it.

Remove the Mold Before Occupying the House

If you decided to buy the home, remove the mold before occupying the house. It is easier to deal with the mold problem before bringing in your own stuff. The mold remediation should be performed by a qualified contractor who is familiar with the current mold remediation guidelines.

Damp and humid conditions provide the perfect environment for mold to proliferate. While majority of the common indoor molds don’t necessarily have an immediate effect on the property, if not removed early enough and the moisture eliminated the mold will continue spreading and damaging the aesthetic appearance of the house. Apart from damaging the house, elevated levels of mold spores indoors are a health hazard.

Below are some mold guidelines that a qualified contractor could follow to restore the house to it’s original condition.

1. Mould Guidelines by the Canadian Construction Association

2. Mould Abatement by the Environmental Abatement Council of Ontario (EACO)

3. Guidelines on Assessment and Remediation of Fungi in Indoor Environments by the New York City Department Of Health.

What You Should Know Before Buying the Moldy House

The cost of fixing the mold problem will primarily be determined by the size of the affected area and the location of the mold. If the mold extends throughout the walls or the HVAC system, then the cost may be far much higher than what you would save from a lower sale price.

How to Prevent Mold Growth on Cannabis (aka Marijuana)

cannabis-infected-with-mold Cannabis (popularly known as marijuana or weed) is now legal in Canada for both medical and recreational use. In the United States, it has been approved for medicinal use in 33 states and in 11 states for recreational use for adults aged 21 and over.

Moldy Cannabis is a serious problem facing both producers and consumers. In 2019 there were many reports of legal Cannabis being recalled both in Canada and the United States due to mold contamination. Mold growth on Cannabis can prevented.

The prevention of mold growth on Cannabis has to be done at the cultivation/production, processing, distribution and consumer level. While contamination can occur at any of these levels, it can mean total loss of the product if it occurs at the production, processing and distribution levels.

As a Cannabis grower recognising the signs of a potential mold infestation, and how to prevent it is very important. The most common molds that attack Cannabis plants during cultivation are Botrytis (bud rot) and powdery mildew. While powdery mildew is not a post-harvest problem Botrytis can be a problem in the field and also on harvested dry leaves.

The powdery mildew was thought to be caused by the fungi Podosphaera macularis or Golovinomyces (Erysiphe) cichoracearum but molecular studies suggest the Cannabis powdery mildew could be caused by a different species.

As the saying goes, prevention is better than cure. By focusing on sound agronomical practices, Cannabis growers can significantly minimize the risk of mold growth on their crops. The potential for Cannabis infection by airborne mold and pathogen spores can be monitored by collecting air samples for analysis.

For Cannabis grown indoors, Botrytis and powdery mildew thrive well under cool temperatures, stagnant air, and wet or humid conditions. Therefore, the best way to prevent both diseases is to ensure proper air circulation and maintaining low humidity.

It’s important that processing is performed in a clean, dry environment. Marijuana for smoking should not be transported or stored in a damp, humid environment. The end consumer should also ensure that they store their weed in a clean and dry environment.

How to test for mold on clothes

One of the most common indicators of possible mold growth on clothes and fabrics is its smell. If you have a mold problem on clothes, they may have strong musty, earthy odour. Visible mold growth on clothes may appear as irregular white, bluish, greenish or greyish to black spots or stains. Depending on the color of the mold and the color of the cloth or fabric, the mold may or may not be easily visible.

Can moldy clothes make you sick?

Little is known about the medical significance of mold on clothes and fabrics. However, prolonged exposure to mold may cause a variety of health effects to people who are sensitive to mold. For sensitive individuals, exposure to molds can lead to symptoms such as stuffy nose, wheezing, and red or itchy eyes, or skin. People with allergies to molds or with asthma, may have more intense reactions. If your home suffers from dampness, it’s important to find ways of improving ventilation and also to regularly inspect clothing and fabrics for stains and remove them when possible. Contaminated clothes should be isolated.

How do clothes become moldy?

Mold spores are almost everywhere in the environment including on the surfaces of the clothes that we’re wearing. Therefore if clothes are stored in a damp, warm environment, these spores will germinate and develop into mold. Clothes or fabrics stored in zipped plastic bags are likely to develop mold due to condensation and high humidity in the bag. If you have to store clothes in plastic bags, the bags should be perforated to let air in and out and avoid condensation and humidity build up. Hanging clothes in a closet before they are fully dry also increases the chances of mold growth.

Should moldy clothes be thrown away?

Appearance of mold on clothes does not necessarily mean that the clothes should be thrown away. The clothes can be cleaned to get rid of mold so they’re safe to wear again. If the mold has just developed, washing the clothes and drying them completely is all you need to do to get rid of mold.

It’s important to know that if mold has been growing on clothes for a long time, it can cause total damage. Such clothes may have to be discarded.

How to test clothes for mold

If you suspect your clothes have developed mold you can easily take samples using clear scotch tape and send them to a lab for testing. Follow the steps below:

Step 1: Look for visible mold growth on the clothes
Mold is a living organism that can attach to most surfaces including fabrics leaving stains and damage. Mold growth is easily visible as spots or stains of various colors and shades. The spots may appear almost “fuzzy” or “powdery”. Even if you can’t see any spots or growth, if an odour is present there is microbial growth and treatment is needed.

Step 2. Tear off a 2- to 3-inch piece of clear scotch tape
Hold the piece of tape at one end, place sticky side down onto the mold-like spots you find and press gently. Then remove tape and stick them in individually labelled ziplock bags (i.e., white shirt, brown trouser or dress, etc). Then enclose your samples in an envelope or bag and deliver or mail them to a lab.

If the clothes have musty smell and no visible mold, you can send the whole piece of cloth to the lab for analysis. Clear scotch tape can be used to take samples from any surface including mold on walls.