mold health issues mold health issues mold health issues refer to the harmful health effects of moulds ("molds" in american english) and their mycotoxins. however, recent research has shown these adverse health effects are caused not exclusively by molds, but also other microbial agents and biotoxins associated with dampness, mold, and water-damaged buildings, such as gram-negative bacteria that produce endotoxins, as well as actinomycetes and their associated exotoxins. approximately 47% of houses in the united states have substantial levels of mold, with over 85% of commercial and office buildings found to have water damage predictive of mold. as many as 21% of asthma cases may result from exposure to mold. substantial and statistically significant increases in the risks of both respiratory infections and bronchitis have been associated with dampness in homes and the resulting mold. light micrograph of the hyphae and spores of the human pathogen aspergillus fumigatus molds and many related microbial agents are ubiquitous in the biosphere, and mold spores are a common component of household and workplace dust. while the most molds in the outdoor environment are not hazardous to humans, many found inside buildings are known to be. reaction to molds can vary between individuals, from relatively minor allergic reactions through to severe multi-system inflammatory effects, neurological problems, and death. the united states centers for disease control and prevention (cdc) 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." mold spores and associated toxins can cause harm primarily via inhalation, ingestion, and contact. in higher quantities such as those found in water-damaged buildings, they can present especially hazardous health risks to humans after sufficient exposure, with three generally accepted mechanisms of harm and a fourth probable mechanism: allergic reactions, including allergic bronchopulmonary aspergillosis invasive mold infections (mycosis) toxicity (poisoning by mycotoxins) innate immune dysfunction. health effects studies have shown that people who are atopic (sensitive), already have allergies, asthma, or compromised immune systems and occupy damp or moldy buildings are at an increased risk of health problems such as inflammatory responses to mold spores, metabolites such as mycotoxins, and other components. other problems are respiratory and/or immune system responses including respiratory symptoms, respiratory infections, exacerbation of asthma, and rarely hypersensitivity pneumonitis, allergic alveolitis, chronic rhinosinusitis and allergic fungal sinusitis. a person's reaction to mold depends on their sensitivity and other health conditions, the amount of mold present, length of exposure, and the type of mold or mold products. some molds also produce mycotoxins, which, in sufficient quantity, can pose serious health risks to humans and animals. the colloquial term "toxic mold" (or more accurately, toxigenic mold) refers to molds that produce mycotoxins known to harm humans, 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. the five most common genera of indoor molds are cladosporium, penicillium, aspergillus, alternaria, and trichoderma. damp environments that allow mold to grow can also allow the proliferation of bacteria and release volatile organic compounds. symptoms of mold exposure symptoms of mold exposure can include: nasal and sinus congestion, runny nose respiratory problems, such as wheezing and difficulty breathing, chest tightness cough throat irritation sneezing / sneezing fits health effects linking to asthma adverse respiratory health effects are associated with occupancy in buildings with moisture and mold damage. infants may develop respiratory symptoms due to 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 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 to penicillium. the levels are deemed 'no mold' to 'low level', from 'low' to 'intermediate', and '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 several 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 and weak immune systems, which can often 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. flood-specific mold health effects among children and adolescents, the most common health effect post-flooding was lower respiratory tract symptoms, though there was a lack of association with measurements of total fungi. another study found that these respiratory symptoms were positively associated with exposure to water damaged homes, exposure included being inside without participating in clean up. despite lower respiratory effects among all children, there was a significant difference in health outcomes between children with pre-existing conditions and children without. children with pre-existing conditions were at greater risk that can likely be attributed to the greater disruption of care in the face of flooding and natural disaster. although mold is the primary focus post flooding for residents, the effects of dampness alone must also be considered. according to the institute of medicine, there is a significant association between dampness in the home and wheeze, cough, and upper respiratory symptoms. a later analysis determined that 30% to 50% of asthma-related health outcomes are associated with not only mold, but also dampness in buildings. another health effect associated with dampness and mold is sick building syndrome (sbs), which is defined by manifestations of symptomatic illness as a result of poor indoor air quality and pollutant exposures. signs of potentially illness-causing buildings include condensation on the windows, high humidity in the bathrooms, a moldy odor, or water leakage. while there is a proven correlation between mold exposure and the development of upper and lower respiratory syndromes, there are still fewer incidences of negative health effects than one might expect. barbeau and colleagues suggested that studies do not show a greater impact from mold exposure for several reasons: 1) the types of health effects are not severe and are therefore not caught; 2) people whose homes have flooded find alternative housing to prevent exposure; 3) self-selection, the healthier people participated in mold clean-up and were less likely to get sick; 4) exposures were time-limited as result of remediation efforts and; 5) the lack of access to health care post-flooding may result in fewer illnesses being discovered and reported for their association with mold. there are also certain notable scientific limitations in studying the exposure effects of dampness and molds on individuals because there are currently no known biomarkers that can prove that a person was exclusively exposed to molds. thus, it is currently impossible to prove correlation between mold exposure and symptoms. mold-associated conditions health problems associated with high levels of airborne mold spores include allergic reactions, asthma episodes, irritations of the eye, nose and throat, sinus congestion, and other respiratory problems. several studies and reviews have suggested that childhood exposure to dampness and mold might contribute to the development of asthma. 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. fungal infection further information: mycosis 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 dermatophyte fungi take the form of mold, as opposed to a yeast, with an appearance (when cultured) that is similar to other molds. opportunistic infection by molds such as talaromyces marneffei and aspergillus fumigatus is a common cause of illness and death among immunocompromised people, including people with aids or asthma. mold-induced hypersensitivity 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. mycotoxin toxicity main article: mycotoxin 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. 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. aflatoxin is an example of a mycotoxin. it is a cancer-causing poison produced by certain fungi in or on foods and feeds, especially in field corn and peanuts. toxic effects from mold were thought to be the result of exposure to the mycotoxins of some mold species, such as stachybotrys chartarum. in 1927, ismailson, a soviet scientist, noted a form of mycotoxicosis in employees in a binder twine factory. in the 1940s, "stachybotryotoxicosis" was identified in ukraine as a new disease in humans in close contact with moldy hay, including inhalation of the associated dust, which caused, among other symptoms, a "haemorrhagic exúdate". following cases of pulmonary hemorrhage in infants in cleveland, ohio in 1993–94, several related studies suggested a causal relationship between exposure to s. chartarum and the disease. an anonymous panel from within the cdc revisited the cases and argued that the link was not proven. subsequent studies with mice and rats exposed to s. chartarum and associated mycotoxins showed that pulmonary hemorrhage could occur, suggesting the link is plausible. the american academy of pediatrics also found the link plausible, and subsequent analysis and case studies with humans have further noted the association. as well, a 1987 report by the united states army medical research institute of infectious diseases suggested that the effects of "trichothecene mycotoxins are more than 10 times greater via inhalation than via intravenous exposure." the presumed mechanism of action is that stachybotrys produces a compound, stachylysin, which is a hemolysin that disintegrates (lyses) red blood cells. innate immune activation the health hazards produced by mold have