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Molds are ubiquitous in nature, and mold spores are a common component of household and workplace dust. However, when mold spores are present in large quantities, they can present a health hazard to humans, potentially causing allergic reactions and respiratory problems. Because of this, mold allergy has become a serious problem for many people. Research in the field of environmental health has yielded tests such as the MELISA assay, which is capable of identifying whether or not a person is allergic to specific molds. If a person is found to be allergic, the remedies listed below are often helpful in reducing allergic reaction.
Some molds also produce mycotoxins that can pose serious health risks to humans and animals. Exposure to high levels of mycotoxins can lead to neurological problems and in some cases death. Prolonged exposure, e.g. daily workplace exposure, can be particularly harmful. The term toxic mold refers to molds that produce mycotoxins, such as Stachybotrys chartarum, and not to all molds in general.
The health hazards produced by mold have been associated with sick building syndrome.
History
Since Biblical times it has been known that indoor mold growth can be a health hazard. In the 1930s, mold was identified as the cause behind the mysterious deaths of farm animals in Russia and other countries. Stachybotrys chartarum was found growing on wet grain used for animal feed.
In the 1970s, building construction techniques changed in response to the energy crisis. As a result, homes and buildings became more airtight. Also, cheaper materials such as drywall came into common use. This combination of increased moisture and suitable substrates contributed to increased mold growth inside buildings.
Today, the agriculture industry keeps a close eye on mold and mycotoxin levels in grains in order to prevent the contamination of animal feed and human food supplies. In 2005 Diamond Pet Foods, a US pet food manufacturer, experienced a significant rise in the number of corn shipments containing elevated levels of aflatoxin. This mold toxin eventually made it into the pet food supply, and dozens of dogs died before the food could be recalled.
Health issues and symptoms
- See also: Category:Fungal diseases
Molds cause three types of illness:
- Allergenic / irritant effects
- Immunotoxic
- Infection
Exposure to bacteria and fungus in indoor air has emerged as a significant health problem in residential environments as well as in occupational settings[citation needed].
Mold spores can be allergenic, causing irritations of eye, nose, throat, and lungs. In response to this, environmental health research has yielded tests such as the MELISA test, which can determine whether or not a person is allergic to a specific mold.
Molds may excrete liquids or gases, not all of which can be detected by smell. Some molds generate toxic liquid or gaseous compounds, called mycotoxins. Molds that produce mycotoxins are sometimes referred to as toxic molds. It is thought[citation needed] that all molds may produce mycotoxins and thus all molds may be potentially toxic. Mycotoxins are not produced all the time, but only under specific growing conditions. Mycotoxins are harmful or lethal to humans and animals when exposure is high enough. Some of the most deadly chemicals on the planet are mycotoxins. Mycotoxins are then carried on the mold spore, mold fragments, and are found on the substrate of the surface they grow on. They can cause human illness through ingestion, but also through dermal exposure and inhalation of mycotoxin-contaminated debris or spores.
Dermatophytes are the parasitic fungi that cause skin infections such as Athlete's foot and Jock Itch. Most dermataphyte fungi take the form of a mold, as opposed to a yeast, with appearance (when cultured) that is similar to other molds.
Opportunistic infection by molds such as Penicillium marneffei and Aspergillus fumigatus is a common cause of illness and death among immunocompromised people, including people with AIDS.
Environmental illnesses can be difficult for healthcare practitioners to diagnose. Those who are living in houses contaminated by the mold may not be able to smell any odor and may be unaware that the problem exists.
Mold spores
- See also: spores, allergy, allergens, bioaerosol, and Allergic bronchopulmonary aspergillosis
Health problems associated with high levels of airborne mold spores include[1] allergic reactions, asthma episodes, irritations of the eye, nose and throat, infections, sinus congestion, and other respiratory problems. When inhaled, mold spores may germinate, attaching to cells along the respiratory tract and causing further problems in those with weak immune systems.
Another serious health threat from mold exposure is systemic fungal infection. Immunocompromised individuals exposed to high levels of mold, or individuals with chronic exposure paired with mycotoxin exposure may become infected. Sinuses and digestive tract infections are most common; lung and skin infections are also possible. Alcohol and mycotoxin production may result from the fungal growth, leading to myriad symptoms. Sudden food allergies and digestive problems can mislead diagnosis. Treatment can be long-term (many years). Systemic infection may be of the environmental mold itself, or by other common food-related molds consumed under a weakened immune system. A weakened immune system may also give rise to opportunistic infections, for example bacterial infection.
The most common form of hypersensitivity is caused by the direct exposure to inhaled mold spores that can be dead or alive or hyphal fragments which can lead to allergic asthma or allergic rhinitis.[2] The most common effects are Rhinorrhea (runny nose), watery eyes, coughing and asthma attacks. Another form of hypersensitivity is hypersensitivity pneumonitis (HP). This is usually the direct result of inhaled spores or fragments in an occupational setting.[2] About 5% of individuals are predicted to have some allergic airway symptoms from molds over their lifetime.[3]
Mold-produced mycotoxins
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Certain molds excrete toxic compounds called mycotoxins, sometimes only under specific growing conditions. Certain mycotoxins can be harmful or lethal to humans and animals when exposure is high enough.[4]. [5] One example of toxic mold is Stachybotrys chartarum which has been associated with sick building syndrome. Some mycotoxins cause immune system responses that vary considerably, depending on the individual. The duration of exposure is a key factor in triggering immune system response. Farm animals often die or suffer from mycotoxin poisoning of their feed. Mycotoxins often resist decomposition from cooking, and some can remain in the food chain.
Originally, Toxic effects from mold were thought to be the result of exposure to the mycotoxins of some mold species, such as Stachybotrys chartarum (S. chartarum). However, studies are suggesting that the so-called toxic effects are actually the result of chronic activation of the immune system, leading to chronic inflammation. Studies indicate that up to 25% of the population have the genetic capability of experiencing chronic inflammation to mold exposure, but only 2% actually experience such symptoms. A 1993-94 case study based on cases of pulmonary hemorrhage in infants in Cleveland, Ohio originally concluded there was no causal relationship between the exposure and the disease. The investigators revisited the cases and established a link to the exposure to S. chartrum and the infants in their homes. This relationship was later disproved by a different panel and re-evaluation.[3]
Causes, growing conditions, and remedies
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Mold growth in buildings can lead to a variety of health issues. Various practices can be followed to mitigate mold issues in buildings, the most important of which is to reduce moisture levels that can facilitate mold growth. Removal of affected materials after the source of moisture has been reduced and/or eliminated may be necessary for remediation.
Notes
- ^ "Mold: A Health Hazard (Release #1605-096)". FEMA (November 8, 2005). Retrieved on 25 September 2007.
- ^ a b Indian Health Service: Bemidji Area Office of Environmental Health and Engineering Environmental Health Services Section “ Guideline on the Assessment and Remediation of Fungi in Indoor Environments”
- ^ a b Hardin, B.D., Kelman B., And Saxon A. “Adverse Human Health Effects Associated with Molds in the Indoor Environment” Evidence-based statements, American College of Occupational and Environmental Medicine, [on-line], Available [2002, October 27.]
- ^ Ryan KJ; Ray CG (editors) (2004). Sherris Medical Microbiology (4th ed. ed.), McGraw Hill. pp.pp. 633–8. ISBN 0838585299.
- ^ Etzel RA, Montaña E, Sorenson WG, Kullman GJ, Allan TM, Dearborn DG, Olson DR, Jarvis BB, Miller JD. (1998) Acute pulmonary hemorrhage in infants associated with exposure to Stachybotrys atra and other fungi. Archives of Pediatrics and Adolescent Medicine. 152(8):757-62.
References
See also
External links
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