What is Mold and Other Mold Facts?
Molds or (molds) are but one type of fungi that exist in nearly every location across the globe. The purpose of fungi is to break down organic materials and recycle them for future use by plants and animals. The family of fungi includes mildews, yeasts, large mushrooms, and mold. Fungi require organic materials in order to form and expand.
When damp conditions are present, mold is able to grow on such diverse materials as wood, carpet, insulation, cloth, and all types of food. Mold thrives in damp, moist, or wet surroundings, frequently in areas where humans exist. Molds typically reproduce through their spores that are released into the air and land on moist, organic materials. The spores then germinate and began expanding out in elaborate networks. The factors that determine the rate of this growth include the amount of moisture, type of food or organic material, temperature, and many others.
Humans often come in contact with molds in moist areas in or around their homes or when mold spores become airborne. These airborne mold spores can come into contact with humans either through the skin or when ingested.
If the mold spores are “toxic”, they can adversely affect the health of humans. The effect on humans will depend on the type of mold involved, the metabolic byproduct of the mold, as well as how much contact there is and the length of exposure, as well as the level of susceptibility of the human victim. This last factor is important for children who can be affected much more easily than adults.
The ill-effects of molds generally break down into 4 categories that include allergies, infections, irritations, and toxicities.
Allergies are probably the most common reaction to contact with molds. Atopic individuals (those who experience allergic reactions that are often hereditary) who are exposed to mold, mold spores, or mold byproducts may manifest allergic reactions once they become vulnerable (sensitized) to the particular mold. The reactions can run the spectrum, from very mild and temporary reactions to acute, chronic illness. Of course, molds are simply one of the causes of indoor allergens. Other common causes include dust mites, cockroaches, effluvia from domestic pets, and other microorganisms (molds are included in this category).
However, according to The Institute of Medicine:
- 1 in 5 Americans suffers from allergic rhinitis, the most common chronic disease in humans.
- 1 in 9 Americans suffers from allergy-related sinusitis.
- 1 in 10 Americans has allergic-related asthma. 1 in 11 Americans experiences allergic dermatitis.
- Less than 1 in 100 Americans suffer from serious chronic allergic diseases.
These statistics indicate that allergic reactions are extremely common in humans. Oftentimes, the specific cause of the allergies is in question. Recently, the existence of mold in homes and workplaces has cropped up as a very real possibility as the cause of some of these allergic reactions.
Many different types of molds can put their spores and byproducts into the air, but only a few purified mold allergens are available for allergy tests. Atopic individuals can become sensitized to certain molds, but this may not always be cited by a health care professional as a mold-related allergy. A positive mold allergy test indicates that an individual is susceptible to a specific allergen, but testing negative doesn’t necessarily rule out mold allergy for atopic individuals.
This type of reaction from indoor mold is fairly rare, occurring primarily in those individuals who are susceptible. Aspergillus types of mold have been known to be pathogenic (a disease-producing microorganism) For instance, Aspergillus fumigatus (A. fumigatus) is a fairly weak pathogen thought to cause infections in vulnerable individuals. A. fumigatus is also fairly commonly implicated in ABPA and allergic fungal sinusitis.
Other fungi that cause infection include Coccidioides, Histoplasma, and Blastomyces. However, these fungi are rarely found indoors, growing instead in soil and dirt. Human contact is usually due to contact with animals.
Fungal exposure can also come from any volatile compounds (VOCs) that a fungi/mold creates through primary or secondary metabolism that then becomes airborne. (Primary metabolic processes are those necessary to sustain the life of an organism.) These volatile compounds may be constantly created as the fungus consumes its food source during the primary metabolic process. VOCs can irritate the mucous membranes of the eyes and respiratory system.
Fungi that consume certain organic sources can release highly toxic gases. For instance, a fungus that grows on wallpaper often releases toxic gas arsine directly from the wallpaper that contains arsenic pigments. Thus, fungi and molds can release dangerous materials when they break down the host material. This can cause mucous membrane irritation in sensitized individuals.
Fungal volatile compounds may impact the “common chemical sense” which senses pungency and responds to it. This sense is primarily associated with the trigeminal nerve. The sensory and motor nerves respond to pungency by trying to hold the breath, discomfort, or through sensations such as itching, burning, and skin crawling. Changes in sensation, swelling of mucous membranes, constriction of respiratory smooth muscle, or dilation of surface blood vessels may be part of fight or flight reactions in response to trigeminal nerve stimulation. Reactions often include a reduced attention level, general disorientation, lowered reflex time, dizziness, etc.
Volatile Compounds found in or around homes can be responsible for mucous membrane irritants. It is thought that fungi can add to the already existing compounds when breaking down certain organic substances. A mold-contaminated building may have a significant contribution from its fungal contaminants that are added to common VOCs—building materials, paints, plastics, and cleaners. VOCs in general can result in symptoms that include lowered attention span, headaches, lack of concentration, and dizziness.
Reaction to Mold Odors
Some individuals have very strong reactions to the smells given off by molds. Among humans, there is a high degree of variation in ability to detect these odors. Certain individuals can detect low levels of VOCs, while others can only detect relatively high levels. Those individuals who are particularly susceptible to mold odors may react with headache, nasal stuffiness, nausea or even vomiting. Asthmatics often exhibit symptoms when exposed to certain odors.
Molds also produce secondary metabolites such as antibiotics and mycotoxins (a poisonous substance produced by a fungus). Sometimes it is possible to isolate antibiotics from the molds themselves in order to utilize some of their properties in fighting infections. Secondary metabolisms are not necessary for maintaining the existence of a mold—either by creating energy or synthesizing structural components, informational molecules, or enzymes. They do, however, function to provide molds with advantages over other mold and bacteria and are toxic to certain plant and human cells.
Toxic conditions exist when a human has exposure to these mycotoxins—either through ingesting mycotoxin-containing mold spores or with skin contact to mold itself. Mycotoxins are nearly all cytotoxic (substances produced by microorganisms that are toxic to individual cells), which disrupt various cellular structures such as membranes, and interrupt important processes, including protein, RNA, and DNA synthesis.
Mycotoxins vary in how dangerous they are for humans. Mycotoxins pose a threat to larger organisms not because they are specifically targeting them, but rather because these large organisms inadvertently come across the byproduct of the competing molds all vying for the same ecological niche. Numerous mold types produce mycotoxins, including some found indoors in contaminated homes and office buildings. Another factor that determines the mycotoxins that are produced by specific molds usually depends on the materials or organisms that they grow on.
It used to be thought that dangerous molds were primarily contaminants in foods. This notion is quickly changing. Recently, researchers have become more concerned with multiple mycotoxins that derive from many types of mold spores growing in moist indoor environments. Health effects from exposures to such mold mixtures can differ from those related to single mycotoxins in controlled laboratory exposures.
Although it is difficult to predict how exposure to multiple toxigenic molds can affect an individual (they can synergize the effects), the following provides possible poor health effects from mycotoxin exposure to multiple molds indoors:
- Problems with the vascular system. Increased vascular fragility, the possibility of hemorrhaging into body tissues. Possible molds include aflatoxin, satratoxin, and origins.
- Problems with the digestive system. Diarrhea, vomiting, intestinal hemorrhage, liver effects (such as necrosis and fibrosis). Aflatoxin results in deleterious effects on mucous membranes.
- Problems with the respiratory system. Including respiratory distress, and bleeding from the lungs.
- Problems with the nervous system. Tremors, lack of coordination, depression, and headaches.
- Problems with the cutaneous system. Symptoms include rash, burning sensation, and sloughing of skin.
- Problems with the urinary system.
- Problems with the reproductive system. Including infertility, changes in reproductive cycles, etc. Many mycotoxins can produce changes or a weakening of the immune system.