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Health Effects

Health Effects
Global Indoor Health Network - Health effects of indoor air pollution
Mold, mycotoxins and other indoor contaminants can cause a wide variety of health effects. 

Contamination in water-damaged buildings is a very complex situation that can result in multi-symptom, multi-system health problems.

There are thousands of articles, studies, books and papers available on this topic.  We have numerous research papers, reports by government agencies and other reports posted on our website.

A few of the key statements and conclusions regarding the health effects are provided below. 


From the 2009 World Health Organization report:

WHO Guidelines for Indoor Air Quality: Dampness and Mould

Indoor air pollution--such as from dampness and mould, chemicals and other biological agents--is a major cause of morbidity and mortality worldwide.

Many of the health effects may result from recurrent activation of immune defence, leading to exaggerated immune responses and prolonged production of inflammatory mediators. Overproduction of these compounds damages the surrounding tissues and may manifest itself as chronic inflammation and inflammation-related diseases, such as asthma.

From the Executive Summary:

Exposure to microbial contaminants is clinically associated with respiratory symptoms, allergies, asthma and immunological reactions. 

Toxicological evidence obtained in vivo and in vitro supports these findings, showing the occurrence of diverse inflammatory and toxic responses after exposure to microorganisms isolated from damp buildings, including their spores, metabolites and components.

From the Introduction, page 1:

Exposure to microbial contaminants is clinically associated with respiratory symptoms, allergies, asthma and immunological reactions.

From the Introduction, page 5:

Mechanisms of injury include exposure to Beta-glucans, toxins, spores, cell fragments and chemicals followed by immune stimulation, suppression and autoimmunity as well as neurotoxic effects.

From Chapter 2:

Mycotoxins, or fungal toxins, are low-relative-molecular-mass biomolecules produced by fungi, some of which are toxic to animals and human beings. Mycotoxins are known to interfere with RNA synthesis and may cause DNA damage.

From Dr. Ruth Etzel:

What the Primary Care Pediatrician Should Know about Syndromes Associated with Exposures to Mycotoxins

Mycotoxins can have protean manifestations; the symptoms depend on the specific toxin or mixture of toxins, the age, sex, and diet of the child, the dose, and whether exposure is by ingestion, inhalation, skin and mucosal exposure, or a combination of two or more of these routes.  The most well-characterized presentations among infants and children are summarized in Table 2 under four headings: vomiting illness, bone marrow failure, acute pulmonary hemorrhage, and recurrent episodes of apnea and/or pneumonia.


From Jack Thrasher, Ph.D.:

The Biocontaminants and Complexity of Damp Indoor Spaces: More Than What Meets the Eyes

Exposure of occupants mainly results from inhalation and, to a lesser extent, skin absorption and ingestion.  Molds produce mycotoxins during rapid growth.  At low concentrations, they cause mycotoxicosis in humans and animals. The mycotoxins causing disease include aflatoxins, ochratoxin A, trichothecenes, citreviridins, fumonisins and gliotoxins.  Mycotoxins can regulate the immune system up or down as well as inhibit synthesis of protein, RNA and DNA.  Moreover, they can form DNA adducts, protein adducts and cause oxidative stress as well as mitochondrial directed apoptosis.

Toxic encephalopathy involves multiple symptoms, including loss of balance, recent memory decline, headaches, lightheadedness, spaciness/disorientation, insomnia, loss of coordination.

From the 1989  report by the Massachusetts Special Legislative Commission on Indoor Air Pollution:

The Commonwealth of Massachusetts, Special Legislative Commission on Indoor Air Pollution: Indoor Air Pollution in Massachusetts

The Commission's efforts confirm the seriousness of the indoor air pollution health threat, which worsened with the energy conservation efforts of the 1970s.  More insulation and tighter construction led to lower ventilation rates and build-up of contaminants.  Many 'sick' buildings have been identified where occupants suffer severe or recurring discomforts such as headaches, dizziness, fatigue, eye irritation, and respiratory problems.  Other conditions attributable to indoor air contaminants include: cancer; bronchitis; pneumonia; heart, circulatory and respiratory problems; impaired vision; skin rash; chemical sensitivity; birth defects; and mental, nervous and immunological disorders.
From Dr. Harriet Ammann:

Is Indoor Mold Contamination a Threat to Health? 

Health effects from exposures to molds in indoor environments can result from allergy, infection, mucous membrane and sensory irritation and toxicity alone, or in combination.

Mycotoxins are nearly all cytotoxic, disrupting various cellular structures such as membranes, and interfering with vital cellular processes such as protein, RNA and DNA synthesis.
  • Vascular system (increased vascular fragility, hemorrhage into body tissues, or from lung, e.g., aflatoxin, satratoxin, roridins).
  • Digestive system (diarrhea, vomiting, intestinal hemorrhage, liver effects, i.e., necrosis, fibrosis: aflatoxin; caustic effects on mucous membranes: T-2 toxin; anorexia: vomitoxin.
  • Respiratory system: respiratory distress, bleeding from lungs e.g., trichothecenes.
  • Nervous system, tremors, incoordination, depression, headache, e.g., tremorgens, trichothecenes.
  • Cutaneous system: rash, burning sensation sloughing of skin, photosensitization, e.g., trichothecenes.
  • Urinary system, nephrotoxicity, e.g. ochratoxin, citrinin.
  • Reproductive system; infertility, changes in reproductive cycles, e.g., T-2 toxin, zearalenone
  • Immune system: changes or suppression: many mycotoxins.

From a 1989 U.S. EPA Report for Congress on Indoor Air Pollution

U.S. EPA Report for Congress on Indoor Air Quality. Volume II: Assessment and Control of Indoor Air Pollution

Health effects from indoor air pollution cover the range of acute and chronic effects, and include eye, nose, and throat irritation, respiratory effects, neurotoxicity, kidney and liver effects, heart functions, allergic and infectious diseases, developmental effects, mutagenicity, and carcinogenicity.

From a report on the neurotoxic effects of toxigenic mold and mycotoxins:

Neurotoxic Effects of Toxigenic Molds and Mycotoxins 

Exposure to mycotoxins may occur via enteric, inhalation, or direct contact to skin and mucosa.  Acute and chronic disorders, irritation, systemic reactions and even cancer may develop after the exposure to these toxins.  

Symptoms include respiratory complaints that involve the nose and lungs; eye symptoms, and mucous membrane irritation. The major presentations are headache, general debilitating pains, nose bleeding, fevers with body temperatures up to 40 degrees C (104 degrees F), cough, memory loss, depression, mood swings, sleep disturbances, anxiety, chronic fatigue, vertigo/dizziness, and in some cases, seizures.

Mycotic demyelinating optic neuritis is a neurological disorder of the visual system caused by mycotoxins released by indoor toxic molds. 

Other neurobehavioral manifestations in the mold-exposed individuals are abnormal decrease in steady balance, reaction time, blink-reflex latency, color discrimination, visual fields, and grip, compared to control. Hence, most exposed patients have reduced cognitive functioning in multiple domains, with memory and executive functions the most commonly affected areas. 

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