Mold health issues
Mold health issues are potentially harmful effects of molds.
Molds (also spelled "moulds") are ubiquitous in the biosphere, and mold spores are a common component of household and workplace dust. The United States Centers for Disease Control and Prevention reported in its June 2006 report, 'Mold Prevention Strategies and Possible Health Effects in the Aftermath of Hurricanes and Major Floods,' that "excessive exposure to mold-contaminated materials can cause adverse health effects in susceptible persons regardless of the type of mold or the extent of contamination." When mold spores are present in abnormally high quantities, they can present especially hazardous health risks to humans, including allergic reactions or poisoning by mycotoxins, or causing fungal infection (mycosis).
Molds are ubiquitous in nature, and mold spores are a common component of household and workplace dust. However, when spores are present in large quantities, they are a health hazard to humans, potentially causing allergic reactions and respiratory problems.
Some molds also produce mycotoxins that can pose serious health risks to humans and animals. The term "toxic mold" refers to molds that produce mycotoxins, such as Stachybotrys chartarum, not to all molds. 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.
Symptoms of mold exposure
Symptoms of mold exposure can include:
- Nasal and sinus congestion, runny nose
- Eye irritation, such as itchy, red, watery eyes
- Respiratory problems, such as wheezing and difficulty breathing, chest tightness
- Throat irritation
- Skin irritation, such as a rash
- Sneezing / Sneezing fits
Infants may develop respiratory symptoms as a result of exposure to a specific type of fungal mold, called Penicillium. Signs that an infant may have mold-related respiratory problems include (but are not limited to) a persistent cough and/or wheeze. Increased exposure increases the probability of developing respiratory symptoms during their first year of life. Studies have shown that a correlation exists between the probability of developing asthma and increased exposure Penicillium. The levels are deemed no mold to low level, from low to intermediate, from intermediate to high.
Mold exposures have a variety of health effects depending on the person, some people are more sensitive to mold than others. Exposure to mold can cause a number of health issues such as; throat irritation, nasal stuffiness, eye irritation, cough and wheezing, as well as skin irritation in some cases. Exposure to mold may also cause heightened sensitivity depending on the time and nature of exposure. People at higher risk for mold allergies are people with chronic lung illnesses, which will result in more severe reactions when exposed to mold.
There has been sufficient evidence that damp indoor environments are correlated with upper respiratory tract symptoms such as coughing, and wheezing in people with asthma.
Health problems associated with high levels of airborne mold spores include[unreliable medical source?] allergic reactions, asthma episodes, irritations of the eye, nose and throat, sinus congestion, and other respiratory problems, although it should be noted that mold spores won't actually cause asthma, just irritate existing conditions. For example, residents of homes with mold are at an elevated risk for both respiratory infections and bronchitis. When mold spores are 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. Generally, when this occurs, the illness is an epiphenomenon and not the primary pathology. Also, mold may produce mycotoxins, either before or after exposure to humans, potentially causing toxicity.
A serious health threat from mold exposure for immunocompromised individuals is systemic fungal infection (systemic mycosis). 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.
Dermatophytes are the parasitic fungi that cause skin infections such as athlete's foot and tinea cruris. 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 or asthma.
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. The most common effects are rhinorrhea (runny nose), watery eyes, coughing and asthma attacks. Another form of hypersensitivity is hypersensitivity pneumonitis. Exposure can occur at home, at work or in other settings. It is predicted that about 5% of people have some airway symptoms due to allergic reactions to molds in their lifetimes.
Hypersensitivity may also be a reaction toward an established fungal infection in allergic bronchopulmonary aspergillosis.
Molds excrete toxic compounds called mycotoxins, secondary metabolites produced by fungi under certain environmental conditions. These environmental conditions affect the production of mycotoxins at the transcription level. Temperature, water activity and pH, strongly influence mycotoxin biosynthesis by increasing the level of transcription within the fungal spore. It has also been found that low levels of fungicides can boost mycotoxin synthesis. Certain mycotoxins can be harmful or lethal to humans and animals when exposure is high enough.
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, such as daily workplace exposure, can be particularly harmful.
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.
It is thought 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.
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 include ingestion, dermal exposure and inhalation.
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. 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 it is unknown how many actually experience such symptoms due to frequent misdiagnosis. 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.
Exposure sources and prevention
The main sources of mold exposure are from the indoor air in buildings with substantial mold growth, and from ingestion of food with mold growths.
Prevention of mold exposure and its ensuing health issues begins with prevention of mold growth in the first place by avoiding a mold-supporting environment such as humid air. Extensive flooding and water damage can support extensive mold growth. Following hurricanes, homes with greater flood damage, especially those with more than 3 feet of indoor flooding, demonstrated higher levels of mold growth compared with homes with little or no flooding. The aftermath of a hurricane is the worst case scenario, but the concept of water damage supporting widespread mold growth is more generally applicable.
It is useful to perform an assessment of the location and extent of the mold hazard in a structure. Various practices of remediation can be followed to mitigate mold issues in buildings, the most important of which is to reduce moisture levels. Removal of affected materials after the source of moisture has been reduced and/or eliminated may be necessary. Thus, the concept of mold growth, assessment, and remediation is essential in prevention of mold health issues.
A common issue with mold hazards in the household is the placement of furniture, and the lack of ventilation which this causes to certain parts of the wall. The simplest method of avoiding mold in a home so affected is to move the furniture in question.
Adverse respiratory health effects are associated with occupancy in buildings with moisture and mold damage.
Molds may excrete liquids or low-volatility gases, but the concentrations are so low that frequently they cannot be detected even with sensitive analytical sampling techniques. Sometimes these by-products are detectable by odor, in which case they are referred to as "ergonomic odors" meaning the odors are detectable, but do not indicate toxicologically significant exposures.
Molds that are often found on meat and poultry include members of the genera Alternaria, Aspergillus, Botrytis, Cladosporium, Fusarium, Geotrichum, Mortierella, Mucor, Neurospora,Paecilomyces, Penicillium and Rhizopus. Grain crops in particular incur considerable losses both in field and storage due to pathogens, post-harvest spoilage and insect damage. A number of common microfungi are important agents of post-harvest spoilage, notably members of the genera Aspergillus, Fusarium and Penicillium. A number of these produce mycotoxins (soluble, non-volatile toxins produced by a range of microfungi that demonstrate specific and potent toxic properties on human and animal cells) that can render foods unfit for consumption. When ingested, inhaled, or absorbed through skin, mycotoxins may cause or contribute to a range of effects from reduced appetite and general malaise to acute illness or death in rare cases. Mycotoxins may also contribute to cancer. Dietary exposure to the mycotoxin aflatoxin B1, commonly produced by growth of the fungus Aspergillus flavus on improperly stored ground nuts in many areas of the developing world, is known to independently (and synergistically with Hepatitis B virus) induce liver cancer. Mycotoxin-contaminated grain and other food products have a significantly impact on human and animal health globally. According to the World Health Organization, roughly 25% of the world's food may be contaminated by mycotoxins.
Prevention of mold exposure from food is generally to consume food that has no mold growths on it. Also, mold growth in the first place can be prevented by the same concept of mold growth, assessment, and remediation that prevents air exposure. In addition, it is especially useful to clean the inside of the refrigerator, and to ensure dishcloths, towels, sponges and mops are clean.
Ruminants are considered to have increased resistance to some mycotoxins, presumably due to the superior mycotoxin-degrading capabilities of their gut microbiota. This suggests that since mycotoxins are difficult to digest by human microbes due to better degradation by rumen microbes as compared to mono-gastric animals like humans. The passage of mycotoxins through the food chain may also have important consequences on human health. For example, in China in December 2011, high levels of carcinogen aflatoxin M1 in Mengniu brand milk were found to be associated with the consumption of mold-contaminated feed by dairy cattle.
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. Illness and death 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 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 drying potential 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 US Food and Drug Administration and the agriculture industry closely monitor mold and mycotoxin levels in grains and foodstuffs in order to keep the contamination of animal feed and human food supplies below 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 and cats died before the company was forced to recall affected products.
- Building biology
- Environmental engineering
- Environmental health
- Occupational asthma
- Occupational safety and health
- Ventilation issues in houses[dead link]
- Weinhold B (June 2007). "A spreading concern: inhalational health effects of mold". Environ. Health Perspect. 115 (6): A300–5. PMC 1892134. PMID 17589582.
- Indoor Environmental Quality: Dampness and Mold in Buildings. National Institute for Occupational Safety and Health. August 1, 2008.
- Indoor Environmental Quality Dampness and Mold in Buildings. National Institute for Occupational Safety and Health. August 1, 2008.
- Minnesota Department of Health. "Mold and Moisture in Homes". Minnesota North Star. Retrieved 22 November 2011.
- Gent, Janneane. "Levels of Household Mold Associated with Respiratory Symptoms in the First Year of Life in a Cohort at Risk for Asthma". Department of Epidemiology and Public Health, Yale University. Retrieved 18 November 2011.
- Cohen, Aaron. "WHO Guidelines for Indoor Air Quality: Dampness and Mould". World Health Organization. Retrieved 18 November 2011.
- "Mold: A Health Hazard (Release #1605-096)". FEMA. November 8, 2005. Retrieved 25 September 2007.[unreliable medical source?]
- Fisk WJ, Eliseeva EA, Mendell MJ (2010). "Association of residential dampness and mold with respiratory tract infections and bronchitis: a meta-analysis". Environ Health 9: 72. doi:10.1186/1476-069X-9-72. PMC 3000394. PMID 21078183.
- Müller FM, Seidler M (August 2010). "Characteristics of pathogenic fungi and antifungal therapy in cystic fibrosis". Expert Rev Anti Infect Ther 8 (8): 957–64. doi:10.1586/eri.10.72. PMID 20695750.
- Simicic S, Matos T, “Microbiological diagnosis of invasive aspergillosis.” Zdravnisji vestnik-slovanian medical journal. 2010, Vol. 79, Issue 10, p. 716-725.
- Erol S (April 2010). "Nosocomial aspergillosis: epidemiology and control". Mikrobiyol Bul (in Turkish) 44 (2): 323–38. PMID 20549969.
- Nucci M, Anaissie E (October 2007). "Fusarium infections in immunocompromised patients". Clin. Microbiol. Rev. 20 (4): 695–704. doi:10.1128/CMR.00014-07. PMC 2176050. PMID 17934079.
- Gaviria JM, van Burik JA, Dale DC, Root RK, Liles WC (April 1999). "Comparison of interferon-gamma, granulocyte colony-stimulating factor, and granulocyte-macrophage colony-stimulating factor for priming leukocyte-mediated hyphal damage of opportunistic fungal pathogens". J. Infect. Dis. 179 (4): 1038–41. doi:10.1086/314679. PMID 10068606.
- McCormick A, Loeffler J, Ebel F (November 2010). "Aspergillus fumigatus: contours of an opportunistic human pathogen". Cell. Microbiol. 12 (11): 1535–43. doi:10.1111/j.1462-5822.2010.01517.x. PMID 20716206.
- Ben-Ami R, Lewis RE, Kontoyiannis DP (August 2010). "Enemy of the (immunosuppressed) state: an update on the pathogenesis of Aspergillus fumigatus infection". Br. J. Haematol. 150 (4): 406–17. doi:10.1111/j.1365-2141.2010.08283.x. PMID 20618330.
- Shang ST, Lin JC, Ho SJ, Yang YS, Chang FY, Wang NC (June 2010). "The emerging life-threatening opportunistic fungal pathogen Kodamaea ohmeri: optimal treatment and literature review". J Microbiol Immunol Infect 43 (3): 200–6. doi:10.1016/S1684-1182(10)60032-1. PMID 21291847.
- 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”
- "What Is Hypersensitivity Pneumonitis?". National Heart, Lung, and Blood Institute. October 1, 2010. Retrieved 2014-01-15.
- Hardin, B. D.; Kelman, B. J.; Saxon, A. (2003). "Adverse human health effects associated with molds in the indoor environment". Journal of occupational and environmental medicine / American College of Occupational and Environmental Medicine 45 (5): 470–478. PMID 12762072.
- Reverberi M, Ricelli A, Zjalic S, Fabbri AA, Fanelli C (July 2010). "Natural functions of mycotoxins and control of their biosynthesis in fungi". Appl. Microbiol. Biotechnol. 87 (3): 899–911. doi:10.1007/s00253-010-2657-5. PMID 20495914.
- Bohnert M, Wackler B, Hoffmeister D (June 2010). "Spotlights on advances in mycotoxin research". Appl. Microbiol. Biotechnol. 87 (1): 1–7. doi:10.1007/s00253-010-2565-8. PMID 20376632.
- Ryan KJ; Ray CG, ed. (2004). Sherris Medical Microbiology (4th ed.). McGraw Hill. pp. 633–8. ISBN 0-8385-8529-9.
- Etzel RA, Montaña E, Sorenson WG, et al. (August 1998). "Acute pulmonary hemorrhage in infants associated with exposure to Stachybotrys atra and other fungi". Arch Pediatr Adolesc Med 152 (8): 757–62. PMID 9701134.
- United States Food Safety and Inspection Service > Molds On Food: Are They Dangerous? Last Modified: Aug 22, 2013
- Barbeau DN, Grimsley LF, White LE, El-Dahr JM, Lichtveld M (2010). "Mold exposure and health effects following hurricanes Katrina and Rita". Annu Rev Public Health 31: 165–78. doi:10.1146/annurev.publhealth.012809.103643. PMID 20070193.
- Shoemaker RC, House DE (2006). "Sick building syndrome (SBS) and exposure to water-damaged buildings: time series study, clinical trial and mechanisms". Neurotoxicol Teratol 28 (5): 573–88. doi:10.1016/j.ntt.2006.07.003. PMID 17010568.
- Kumar, Manisha; Verma, Rajesh K (September 2010). "Fungi diversity, their effects on building materials, occupants and control– a brief review". Journal of Scientific and industrial Research 69 (9): 657–661. ISSN 0975-1084.
- Wilson SC, Holder WH, Easterwood KV, et al. (2004). "Identification, remediation, and monitoring processes used in a mold-contaminated high school". Adv. Appl. Microbiol. 55: 409–23. doi:10.1016/S0065-2164(04)55016-5. PMID 15350804.
- Krieger J, Jacobs DE, Ashley PJ, et al. (2010). "Housing interventions and control of asthma-related indoor biologic agents: a review of the evidence". J Public Health Manag Pract 16 (5 Suppl): S11–20. doi:10.1097/PHH.0b013e3181ddcbd9. PMID 20689369.
- Samson, Robert A., Ellen S. Hoekstra, Jens C. Frisvad (2000). Introduction to food- and airborne fungi (6., rev. ed. ed.). Utrecht, The Netherlands: Centraalbureau voor Schimmelcultures. ISBN 978-9070351427.
- Kankolongo M, Hell K, Nawa I (June 2009). "Assessment for fungal, mycotoxin and insect spoilage in maize stored for human consumption in Zambia". J. Sci. Food Agric. 89 (8): 1366–75. doi:10.1002/jsfa.3596.
- Upadhaya S, Park M, Ha J (September 2010). "Mycotoxins and their biotransformation in the rumen: a review" (PDF). Asian-Aust. J. Anim. Sci. 23 (9): 1250–9.
- Reddy K, Salleh B, Saad B, Abbas H, Abel C, Shier W (2010). "An overview of mycotoxin contamination in foods and its implications for human health". Toxin Reviews 29 (1): 3–26. doi:10.3109/15569541003598553.
- He J, Zhou T (June 2010). "Patented techniques for detoxification of mycotoxins in feeds and food matrices". Recent Pat Food Nutr Agric 2 (2): 96–104. PMID 20653554.
- Liu, Yan; Wu, Felicia (19 February 2010). "Global Burden of Aflatoxin-Induced Hepatocellular Carcinoma: A Risk Assessment". Environmental Health Perspectives 118 (6): 818–824. doi:10.1289/ehp.0901388.
- Tanuma H, Hiramatsu M, Mukai H, et al. (2000). "Case report. A case of chromoblastomycosis effectively treated with terbinafine. Characteristics of chromoblastomycosis in the Kitasato region, Japan". Mycoses 43 (1–2): 79–83. PMID 10838854.
- "Tainted Mengniu Milk Products Caused by Mildewed Feed, Regulator Says". Bloomberg. 26 December 2011.
- Barrett JR (January 2000). "Mycotoxins: of molds and maladies". Environ. Health Perspect. 108 (1): A20–3. PMC 1637848. PMID 10620533.
- MSI Mold and Spore Information: Toxic Mold Symptoms
- CDC: http://www.cdc.gov/mold/default.htm
- US EPA: Mold Information — U.S. Environmental Protection Agency
- US EPA: EPA Publication #402-K-02-003 "A Brief Guide to Mold, Moisture, and Your Home"
- NIBS: Whole Building Design Guide: Air Decontamination
- NPIC: Mold Pest Control Information — National Pesticide Information Center
- Mycotoxins in grains and the food supply: