Mold is a natural and sometimes even beneficial part of our environment. When the gases (mycotoxins) of these molds are trapped within a dwelling or workplace they can create Health problems for the inhabitants and structural damage to the property. There are over 200,000 species of molds known to man worldwide. Approximately only 220 are known to occupy indoor spaces. Out of those we have targeted 10 that we find most dangerous. If an individual is hypersensitive then any mold in any quantity can be dangerous. It is impossible to determine how mold effects you in particular as everyone has their specific situation. Alamo Fire & Water Restoration realizes this and it is our opinion that these molds listed below have the potential to cause problems with the healthiest of persons. This list is by no means complete but rather the top ten most dangerous. In this list you will find information related to the particular species of mold such as what types of building materials it grows on, what types of symptoms it is believed to produce in humans.
Top 10 Toxic Molds
Aspergillus sp. - There are more than 175 different species of Aspergillus, sixteen of which have been documented as etiological agents of human disease. These species are frequently isolated from forage products, grains, nuts, cotton, organic debris and water damaged organic building materials. The diseases caused by species of Aspergillus are relatively uncommon and are rarely occur in individuals with normally functioning immune systems. However, due to the substantial increase in populations of individuals with HIV, chemotherapy patients and those on corticosteroid treatment, contamination of building substrates with fungi, particularly Aspergillus are of concern. Aspergillosis is now the second most common fungal infection requiring hospitalization in the United States. In addition, this genus has been reported to be allergenic. Many species produce mycotoxins that may be associated with diseases in humans and other animals. Toxin production is dependent on the species or strain within the species and on the food source for the fungus. Some of these toxins are carcinogenic including aflatoxins and ochratoxin. Aspergillus is a common cause of extrinsic asthma with symptoms including edema and bronchiospasms, and chronic cases may develop pulmonary emphysema. These fungi are frequently secondary opportunistic pathogens in patients with bronchiectasis, carcinoma, other mycosis, sarcoid, and tuberculosis. Some species can also cause onychomycosis- infection of the nail. Isolation and Speciation of Aspergillus requires the culture of the fungus under different conditions of media, humidity, and temperature.
Aspergillus flavu - This fungus can be found in water damaged carpets and building materials. It has been reported to be allergenic and its presence is associated with asthma. This fungus is also associated with aspergillosis of the lungs and/or disseminated aspergillosis as well as ear and eye infections. Infections of lung, heart, and bladder have been reported on occasion. Some strains are capable of producing a group of mycotoxins – in the aflatoxin group. The production of the toxins is dependent on the substrate and growth conditions.
Aspergillus fumigatus - This fungus is a saprophyte with worldwide distribution and is commonly found in house dust. The fungus occurs in outdoor and indoor air, in different types of soil and on decaying plant material, compost, wood chips, feathers and bird droppings, self-heated hay and crops. This fungus is an important causal agent of systemic mycosis in domestic animals and in humans (immune compromised patients). Aspergillus fumigatus has also been reported to cause asthma and rhinitis (allergies). This fungus produces a large number of specific mycotoxic and tremorgenic metabolites.
Aspergillus versicolor - This fungus can be found in air and house dust. Its presence in indoor air often indicates signs of moisture problems in buildings and it is readily found in water damaged building materials. This species produces the mycotoxin, sterigmatocystin, which is reported to be carcinogenic. The fungus has a characteristic musty, earthy odor, often connected with moldy houses and is the cause of eye, nose, and throat irritation.
Cladosporium sp. - C. herbarum is the most frequently found species in outdoor air in temperate climates. It is often found indoors, usually in lesser numbers than outdoors. The dry conidia become easily airborne and are transported over long distances. This fungus is often encountered in dirty refrigerators, especially in reservoirs where condensation is collected. On moist window frames, it can easily be seen covering the whole painted area with a velvety olive-green layer. Cladosporium often discolors interior paint, paper, or textiles stored under humid conditions. Houses with poor ventilation, houses with thatched straw roofs and houses situated in low damp environments may have heavy concentrations of Cladosporium, which will be easily expressed when domestic mold is analyzed. It is commonly found on the surface of fiberglass duct liner in the interior of supply ducts. It is also found on dead plants, woody plants, food, straw, soil, paint, and textiles. The ability to sporulate heavily, ease of dispersal, and buoyant spores makes this fungus the most important fungal airway allergen; and together with Alternaria, it commonly causes asthma and hay fever in the Western Hemisphere. A few species of this genus cause disease, which range from phaeohyphomycosis, a group of mycotic infections characterized by the presence of demataceous septate hyphae. Infections of the eyes and skin by black fungi (also classified as phaeohyphomycosis), and chromoblastomycosis, chronic localized infection of the skin and subcutaneous tissue that follows the traumatic implantation of the etiologic agent are also caused by this fungus. Chromoblastomycosis lesions are verrucoid, ulcerated, and crusted. Skin abscesses, mycotic keratitis and pulmonary fungus ball have been recorded in immuno- compromised patients. It may also cause corneal infections and mycetoma, characterized by localized infections that involve cutaneous and subcutaneous tissue, fascia, and bone consisting of abscesses, granulomata, and draining sinuses, usually in immuno-compromised hosts. Fungal colonies are powdery or velvety olive-green to olive-brown. Other characteristics include dark conidia 1- or 2-celled, variable in shape and size, ovoid to cylindrical and irregular, typically lemon-shaped.
Fusarium sp. - Commonly found in soil, plants, grains, and often times it is found in humidifiers. This fungus is the most common cause of mycotic keratitis. This mold has been isolated from skin lesions on burn patients, nail infections, ear infections, varicose ulcer, mycetoma , osteomyelitis following trauma, and disseminated infection. This fungus produces very harmful toxins, especially in storage of infected. crops. These toxins, known as trichothecene (scierpene) toxins target the circulatory, alimentary, skin, and nervous systems. Fusarium can also produce 1). Vomotoxin on grains which has been associated with outbreaks of acute gastrointestinal illness in humans. 2). T-2 Toxin and related trichothecenes are some of the deadliest known toxins. If ingested in sufficient quantity, T-2 toxin can severally damage the entire digestive tract and cause rapid death due to internal hemorrhage. 3). Fumosin, commonly found in corn and corn based products, with recently outbreaks of veterinary mycotoxicosis causing "crazy horse disease". 4). Zearalenone toxin which is similar in chemical structure to the female sex hormone estrogen and targets the reproductive organs. Morphological characteristics of this fungus include extensive cotton-like mycelium in culture, often with some tinge of pink, purple or yellow.
Mucor sp. - Often found in soils, dead plant material (hay), horse dung, fruits and fruit juice. It is also found in leather, meat, dairy products, animal hair, and jute. It is almost always in house dust, frequently in air samples and old dirty carpets. Wood chips and sawdust are often attacked by M. plimbeus causing "wood chips disease" and "furrier’s lung". Accumulated dust in ventilation ducts may contain high concentrations of viable Mucor spores. Asthmatic reactions to Mucor have been described. It is a Zygomecete fungus that may be allergenic (skin and bronchial tests). It is an opportunistic pathogenic organism and it may cause mucorosis in immune compromised individuals. The sites of infections are the lung, nasal sinus, brain, eye, and skin. Infection may have multiple sites. This organism and other Zygomycetes will grow rapidly on most fungal media. Conidia (aplanospores) are globose to ellipsoidal,7-8 microns in diameter, yellowish brown and slightly rough-walled, and are produced in sporangia that are developed around a piriform columella with typical projections. Identification is based on the way sporangia are formed.
Penicillium sp. - A wide number of organisms belong to this genus. Identification to species is difficult. Often found in aerosol samples. Commonly found in soil, food, cellulose, paint, grains, and compost piles. It is commonly found in carpet, wallpaper, and in interior fiberglass duct insulation. Although this fungus is less allergy-provoking than the other molds, Penicillium is reported to be allergenic (skin) and it may cause hypersensitivity pneumonitis and allergic alveolitis in susceptible individuals. It can cause other infections such as keratitis, penicilliosis, and otomycosis. Some species can produce mycotoxins including 1). Ochratoxin which is damaging to the kidneys and liver and is also a suspected carcinogen; there is also evidence that impairs the immune system. 2). Citrinin that can cause renal damage, vasodilatation, and bronchial constriction. 3). Gliotoxin which is an immunosuppressive toxin, and 3). Patulin that is believed to cause hemorrhaging in the brain and lungs and is usually associated with apple and grape spoilage. It can also cause extrinsic asthma. P. camemberti has been responsible for inducing occupational allergies among those who work with soft white cheeses on which the fungus grows. P. chrysogenum has been found on building materials, including paints, chip boards, and wallpaper.
Rhizopus sp. - Fungus found throughout the environment. It has been reported to be allergenic and it is often linked to occupational allergy. It may cause mucorosis in immune compromised individuals. It may also cause zygomycosis (rhino-facial-cranial area, lungs, gastrointestinal tract, and skin). This disease is associated with the acidotic diabetes, malnourished children, severely burned patients, and other diseases such as leukemia and lymphoma, immunosuppressive therapy, or use of cytotoxins and corticosteroids. The fungi show a propensity for vessel invasion resulting in embolization and necrosis of surrounding tissue.
Stachybotrys sp. - Considerable recent media attention has been focused on the fungi Stachybotrys chartum due to infant deaths in Cleveland from pulmonary hemosiderosis which may be associated with contamination of residences with this fungi. Stachybotrys thrives on water damaged cellulose rich materials such as sheet rock, paper, ceiling tiles, cellulose containing insulation backing and wallpaper. The presence of this fungus in buildings is significant because of the mold’s ability to produce mycotoxins, which are extremely toxic, such as Satratoxin H. Exposure to these toxins can occur through inhalation, ingestion or dermal exposure. Symptoms include dermatitis, cough, rhinitis, nose bleeds, a burning sensation in the mouth and nasal passage, cold and flu symptoms, headache, general malaise, and fever. Inhalation of conidia may also induce pathological changes (pneumomycotoxicoses). Satratoxin H has been reported to be abortogenic in animals and in high doses or chronic low doses it can be lethal. S. chartarum produces other macrocyclic and trichoverroid trichothecenes and, like Memnoniella echinata, produces phenylspirodrimanes, which are immunosuppressive. Stachybotrys typically appears as a sooty black fungus occasionally accompanied by a thick mass of white mycelia. As a general rule, air sampling for Stachybotrys yields unpredictable results mainly due to the fact that this fungus is usually accompanied by other fungi such as Aspergillus and Penicillium that normally are better aerosolized than Stachybotrys. Bulk or surface sampling of suspect materials can be analyzed in a laboratory for identification by light microscopy.