been associated with sick building syndrome (sbs), but previously, controversy existed around whether studies had sufficiently demonstrated that indoor exposures to these common organisms posed a significant threat. in 1986, a study noted an airborne outbreak of toxicosis from trichothecenes associated with stachybotrys atra in a chicago house affecting a family including their maid; symptoms included diarrhea, headaches, fatigue, dermatitis, malaise, and severe leg pains, which resolved following remediation of the mold contamination. this study drew attention to how mycotoxins in indoor environments might impact health. in the early 2000s, several small studies concluded that individuals with significant dampness and mold exposure displayed cognitive and neurological deficits on par with mild-to-moderate traumatic brain injury along with immunological changes. these studies were criticised for their methodologies, such as by not showing a possible mechanism of action for the harm, and not controlling for the possibility of malingering by mold-exposed individuals involved in litigation, although the associated critiques were also problematic. researchers also contested whether the amount of spores that could be breathed in by humans would be sufficient to cause a toxic effect and that no association between spore counts and adverse health effects existed. however, when also considering spore fragments (that have more surface area to carry mycotoxins) as well as whole spores, the amount of exposure was estimated to be 1,000x to 1,000,000x higher than previously thought. moreover, inhalational exposure "provides a pathway to the central nervous system along the olfactory and trigeminal nerve axons in the nasal sensory epithelium that bypasses the blood–brain barrier." despite these early studies, a 2003 position paper by the american college of occupational and environmental medicine (acoem) claimed the link between mold and building-related symptoms was "weak and unproven". further to this, the center for legal policy at the manhattan institute paid $40,000 to globaltox (later, veritox), a company associated with two of the same authors of the acoem paper, to produce a "lay translation" of their study that would be "more assessable ... to judges". this lay paper claimed that the notion that human health could be adversely affected by inhaled molds or their toxins was "junk science" and was referenced in legal cases in the united states to deny related legal claims. the united states chamber of commerce, the largest lobbying group in the u.s., also promoted this paper (and is still doing so as of 2020). a 2006 position paper by the american academy of allergy, asthma, and immunology (aaaai) maintained a similarly sceptical position as the acoem paper in denying that mold in indoor environments could cause severe effects. in 2008, the united states government accountability office published a report on indoor mold, reviewing the literature to date and acknowledging the possibility of immune and toxic effects, while calling for further research. by 2009, the who noted a strong association between dampness and inflammatory responses, while also recognising that "synergistic interactions among microbial agents" might make it "difficult to detect and implicate specific exposures in the causation of damp building-associated adverse health effects." gram-negative bacteria, which create endotoxins known to produce inflammatory responses, might also be partly responsible, as might actinomycetes and their associated exotoxins. while it may be difficult to determine the relative contributions of the molds, bacteria, and dust particles to which people are exposed, studies clearly show that such combinations activate stronger, synergistic immune responses than predicted by adding the effects of the individual stimuli. later in 2009, a carefully controlled, seminal study published by kilburn demonstrated that mold exposure was associated with extensive adverse effects on multiple physiological systems. he compared the responses of 105 mold-exposed individuals to those of 202 unexposed controls, as well as those of 100 people exposed to a wide variety of chemicals. rather than asking people how they felt, kilburn measured physiological and mental function. he found highly significant abnormalities in the responses of mold-exposed individuals compared to controls on 12 of the 14 physiological functions quantified and 10 of the 13 psychological tests administered. these abnormalities included extreme problems with balance correlated with cerebellar abnormalities, decreased grip strength, impaired color vision, impaired visual fields, slowed reaction times, slowed performance on perceptual motor tasks, impaired memory, and decreased performance on problem-solving tasks as well as a variety of respiratory problems. chemical-exposed individuals had similar abnormalities. like many researchers, kilburn attributed the adverse effects of mold exposure primarily to the toxins some molds produce. currently available data suggest mold's effects are more the result of chronic activation of the immune system, leading to chronic inflammation. such immune activation does not necessarily require toxin exposure; rather, exposure to non-toxic mold stimuli or fungal skeletal elements is sufficient to activate immune responses and trigger inflammation. nineteen innate-immune pattern-recognition receptors have been identified that recognize common components of fungal cell walls or fungal rna/dna, activating inflammatory responses. studies exposing mice to controlled doses of s. chartarum spores show activation of the innate immune system, along with neural, cognitive, and emotional dysfunction, even when mycotoxins were removed and mice were exposed only to spore skeletal elements. in 2012, a ten-year longitudinal study found that dampness and mold seemed to be an underlying cause of sick building syndrome. a 2018 review of 16 associated studies, including kilburn's, concluded that people exposed to molds and mycotoxins had "symptoms affecting multiple organs, including the lungs, musculoskeletal system, as well as the central and peripheral nervous systems" and also noted that such exposure has now been implicated in the pathogenesis of autism-spectrum disorder. an in vitro study of human neurological system cells showed damage caused by inflammatory and immune processes (along with disruption of the blood-brain barrier) in response to mycotoxins at exposure levels that would be expected in water-damaged buildings. ex vivo studies of human peripheral blood mononuclear cells showed inflammatory and innate immune responses upon exposure to specific molds and mycotoxins, such as s. chartarum (and an associated mycotoxin, satratoxin g) and various strains of aspergillus. furthermore, children living in water-damaged homes show systemic inflammation, immune activation, and probably poorer cognitive function, too. tellingly, many of the affected biomarkers, hormones, and pathways in individuals affected by inhaled mycotoxins are consistent with studies of ingested mycotoxins, such as trichothecene exposure. the who estimates the prevalence of significant dampness and mold in buildings to be at least 20%, while other estimates of us homes suggest a prevalence as high as 47%. sleeping disorders are also associated with exposure to dampness and mold, consistent with the decrease in α-melanocyte stimulating hormone (α-msh) associated with this syndrome. patients may also present with psychological symptoms given the neuroinflammatory markers and growth factors involved. exposure sources and prevention the primary sources of mold exposure are from the indoor air in buildings with substantial mold growth and the ingestion of food with mold growths. air while mold and related microbial agents can be found both inside and outside, specific factors can lead to significantly higher levels of these microbes, creating a potential health hazard. several notable factors are water damage in buildings, the use of building materials which provide a suitable substrate and source of food to amplify mold growth, relative humidity, and energy-efficient building designs, which can prevent proper circulation of outside air and create a unique ecology in the built environment. a common issue with mold hazards in the household can be the placement of furniture, resulting in a lack of ventilation of the nearby wall. the simplest method of avoiding mold in a home so affected is to move the furniture in question. prevention of mold exposure and its ensuing health issues begins with the prevention of mold growth in the first place by avoiding a mold-supporting environment. extensive flooding and water damage can support extensive mold growth. following hurricanes, homes with greater flood damage, especially those with more than 3 feet (0.91 m) of indoor flooding, demonstrated far higher levels of mold growth compared with homes with little or no flooding. 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, as some materials cannot be remediated. thus, the concept of mold growth, assessment, and remediation is essential in preventing health issues arising due to the presence of dampness and mold. 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 noticeable but do not indicate toxicologically significant exposures. food moldy nectarines that were in a refrigerator. the nectarine with black mold is also affecting the nectarine underneath. 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 significant 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. also, 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. 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. bedding bacteria, fungi, allergens, and particle-bound semi-volatile organic compounds (svocs) can all be found in bedding and pillows with possible consequences for human health given the high amount of exposure each day. over 47 species of fungi have been identified in pillows, although the typical range of species found in a single pillow varied between four and sixteen. compared to feather pillows, synthetic pillows typically display a slightly greater variety of fungal species and significantly higher levels of β‐(1,3)‐glucan, which can cause inflammatory responses. the authors concluded that these and related results suggest feather bedding might be a more appropriate choice for asthmatics than synthetics. some newer bedding products incorporate silver nanoparticles due to their antibacterial, antifungal, and antiviral properties; however, the long-term safety of this additional exposure to these nanoparticles is relatively unknown, and a conservative approach to the use of these products is recommended. flooding flooding in houses causes a unique opportunity for mold growth, which may be attributed to adverse health effects in people exposed to the mold, especially children and adolescents. in a study on the health effects of mold exposure after hurricanes katrina and rita, the predominant types of mold were aspergillus, penicillium, and cladosporium with indoor spore counts ranging from 6,142 – 735,123 spores m−3. molds isolated following flooding were different from mold previously reported