Moldy Claims
Infection
Unlike “acquired immunity,” the misfiring of which underlies allergic responses, the second major functional division of our immune system, “innate immunity,” does not have to “learn” to recognize invading foreign organisms. Instead, it immediately recognizes certain repetitive patterns of foreign organisms as a first line of defense to ward off potential infection before it can be established. Repeated exposure to the same challenge does not produce an increasingly strong innate immune response to that challenge.See Burns, L.A. et al., supra note 1;Tramont, E.C., General or nonspecific host defense mechanismamechanisms, 33-41 in Principles and Practice of Infectious Disease(G.L. Mandell et al., eds.) (Churchill Livingstone, Inc., New York 1990).
Following after the innate response, the adaptive (learned) immune response then develops. Both are important in protecting us from infection with molds.
Fungi and Infection Generally
Fungal Infections in Immune-Compromised Individuals
Superficial fungal infections of the skin or mucosal surfaces are common among people with normal immune systems. These superficial infections include infections of the feet (athlete's foot), nails, groin (jock itch), dry body skin (ringworm) and the oral or vaginal mucosa. Another fungal infection of the superficial layers of the skin is a condition known as “Pityriasis (Tinea) versicolor,” in which there are patches of skin with variable pigmentation. Some of the organisms involved in superficial infections, for example Trychophyton rubrum, can be found growing as an indoor mold, while others, such as Microsporum canis and Trychophyton mentagrophytes, can be found on pets that live indoors. As previously mentioned, Candida albicans is commonly found on human mucosal surfaces, but it causes problems only if other normally resident microorganisms are eliminated or if the individual has a severely impaired immune system. Local factors such as moisture in shoes or boots and in body creases and the loss of skin integrity are important factors in development of superficial fungal infections.
Apart from the exceptions noted above, fungal infections involving deep tissue invasion nearly always occur in persons who have severely impaired immune systems. Individuals at risk include those with blood disorders such as acute leukemia, cancer patients who are receiving intense chemotherapy, persons who are taking immunosuppressive drugs to prevent rejection of organ transplants, people with uncontrolled diabetes and AIDS patients.
For all of these individuals, concern is greatest when they are hospitalized, at which time their immune systems may be the most severely compromised. In the hospital, intense measures are taken to avoid fungal, bacterial, and viral infections, but outside that restricted environment fungi are so ubiquitous that few protective actions can be taken beyond avoiding recognizable sources of intense fungal exposure.
In sum, apart from clearly immune-compromised individuals, there is no sound scientific basis for believing that mold or other fungi in indoor environments cause infection beyond the common varieties mentioned above. Immune-compromised individuals should take special care, especially in hospitalized settings, but most individuals have little to fear infection-wise from indoor molds that over-the-counter remedies cannot cure.
See Burns, L.A. et al.;Tramont, E.C., General or nonspecific host defense mechanisms, 33-41 in Principles and Practice of Infectious Disease(G.L. Mandell et al., eds.) (Churchill Livingstone, Inc., New York 1990).
Hay, R.J., Dermatophytosis and other superficial mycoses, 2017-28 in Principles and Practice of Infectious Disease(G.L. Mandell et al., eds.) (Churchill Livingstone, Inc., New York 1990); Walker, T.S., Fungi that cause superficial, cutaneous, and subcutaneous mycoses, 298-305 in Microbiology (T.S. Walker, ed.) (W.B. Saunders Company, Philadelphia 1998).
Lenhart, S.W., et al., Histoplasmosis – Protecting workers at risk, DHHS CDC National Institute for Occupational Safety and Health (NIOSH) and National Center for Infectious Diseases (NCID), NIOSH Publication No. 97-146.
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