Mold health issues

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Light micrograph of the hyphae and spores of the human pathogen Aspergillus fumigatus

Molds (also spelled "moulds") are ubiquitous in nature, and mold spores are a common component of household and workplace dust. However, when mold spores are present in unspecified quantities, they can present a health hazard to humans, potentially causing allergic reactions and when present in large quantities, other types of respiratory problems. Mold allergies have always been 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 epitopes associated with any particular mold. If a person is found to be allergic, the remedies listed below are often helpful in reducing allergic reaction.

Some molds, called "toxigenic molds" also produce byproducts mycotoxins, which in high enough doses, can be beneficial or detrimental to human health. A common mycotoxin known to the general population of most western societies is penicillin. Extreme exposure to very high levels of mycotoxins can lead to neurological problems and in some cases death; fortunately, such exposures, rarely to never occur in normal exposure scenarios, even in residences with serious mold problems. Prolonged exposure, e.g. daily workplace exposure, can be particularly harmful. The term toxic mold is a misnomer and has no scientific basis. The term was a recent creation by news media who possibly confused it with the term "toxigenic."

The health hazards produced by mold have been associated with sick building syndrome, but no validated studies have been able to demonstrate that normal indoor exposures to these common organisms pose a significant threat.

Contents

[edit] History

Since Biblical times it has been known that indoor mold growth can be a health hazard. However, the frequently repeated reference to mold in the Bible is another myth. The biblical reference most commonly cited is Leviticus 14:45; the actual reference is in Leviticus 14:37 which is part of a larger passage that discusses leprosy; and which is actually the embodiment of an even larger teaching on defilement as a punishment for disobedience to God. The apparent growth mentioned in the Bible (“greenish or reddish spots” appearing on stones and mortar) could not be mold, based on those descriptions since mold does not readily grow on stones or mortar. Nowhere does the Bible warn of “toxic molds.”

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. The illnesses and deaths also occurred in humans when starving peasants ate large quantities of rotten food grains and cereals that were heavily overgrown with the Stachybotrys mold.

In the 1970s, building construction techniques changed in response to the changing economic realities including the energy crisis. As a result, homes and buildings became more airtight. Also, cheaper materials such as drywall came into common use. The newer building materials reduced the hygric buffering capacity of the structures making moisture problems more prevalent. This combination of increased moisture and suitable substrates contributed to increased mold growth inside buildings.

Today, the FDA and the agriculture industry keeps a close eye on mold and mycotoxin levels in grains and foodstuffs in order to control the contamination of animal feed and human food supplies to specific levels. 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.

[edit] Health issues and symptoms

See also: Category:Fungal diseases

Some specific molds and/or their mycotoxins can exacerbate or in some cases cause different types of illness including:

  • Allergenic / irritant effects
  • Immunotoxic
  • Infection

Exposure to Bacteria and fungus in indoor air in some occupational settings may present a significant threat to health problem, but this has not been demonstrated with any confidence in residential environments.

Molds 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 low volatile gases, but the concentrations are so low, that frequently the by-product cannot be detected even with sensitive analytical sampling techniques. Sometimes the by-products are detectable by odor, in which case they are referred to as “ergonomic odors” meaning the odors detectable, but do not indicate toxicologically significant exposures.

It is thought[citation needed] that all molds may produce mycotoxins and thus all molds may be potentially toxic if large enough quantities are ingested, or the human becomes exposed to extreme quantities of mold. Mycotoxins are not produced all the time, but only under specific growing conditions. Mycotoxins are harmful or lethal to humans and animals only when exposure is high enough. Some of the most deadly chemicals on the planet (such as benzene, and plutonium) similarly are harmless at the concentrations normally encountered in ambient air.

Mycotoxins can be found on the mold spore, and mold fragments, and, therefore, they can also be found on the substrate upon which the mold grows. Routes of entry for these insults can be through ingestion, dermal exposure and inhalation.

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 usually are aware of the fact due to the dramatic appearance of molds. There are no documented cases where illnesses have been caused by "hidden" molds in houses. Actually, one documented case was recently aired on the Sundance Channel, on the show "Is Your Home Killing You?" An entire family was suffering from respiratory and eye problems, along with a general lack of energy, and a compromised quality of life and overall happiness. When the show's team investigated the home, large amounts of mold were revealed to have spread among the walls and in the infrastructure of the house. When the family returned after the mold was treated by professionals, they each claimed to have recovered from every one of their illnesses.

[edit] 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 by an immunocompromised individual, some mold spores may begin to grow on living tissue, attaching to cells along the respiratory tract and causing further problems in those with weak immune systems. Generally, when this occurs, the illness is an epiphenomenon and not the primary pathology.

A serious health threat from mold exposure for immunocompromised individuals is systemic fungal infection. Immunocompromised individuals exposed to high levels of mold, or individuals with chronic exposure may become infected. Sinuses and digestive tract infections are most common; lung and skin infections are also possible. Mycotoxins may or may not be produced by the invading mold. 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]

[edit] Mold-produced mycotoxins

Main article: mycotoxin

Certain molds excrete toxic compounds called mycotoxins, usually only under specific environmental conditions. Certain mycotoxins can be harmful or lethal to humans and animals when exposure is high enough.[4] [5]

Some mycotoxins cause immune system responses that vary considerably, depending on the individual. The duration of exposure, the frequency of exposure and the concentration of the insult (exposure) are elements in triggering immune system response.

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.[citation needed] 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 causal relationship between the exposure and the disease. The investigators revisited the cases and established that there was no link to the exposure to S. chartrum and the infants in their homes.[citation needed]

[edit] Causes, growing conditions, and remedies

Main articles: Mold growth, assessment, and remediation and Indoor air quality

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.

[edit] Notes

  1. ^ "Mold: A Health Hazard (Release #1605-096)". FEMA. November 8, 2005. http://www.fema.gov/news/newsrelease.fema?id=20379. Retrieved on 25 September 2007. 
  2. ^ 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”
  3. ^ 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.]
  4. ^ Ryan KJ; Ray CG (editors) (2004). Sherris Medical Microbiology (4th ed. ed.). McGraw Hill. pp. 633–8. ISBN 0838585299. 
  5. ^ 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.

[edit] References

[edit] See also

Fungi portal

[edit] External links

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