Good explanation of Health Effects of Mold by Dr. Rylander

[Guest guest]

Mold – an indoor health risk

Department of Environmental Medicine, University of Gothenburg,

Box 414, 405 30 Gothenburg, Sweden, tel +46 31-773-36 01, fax +46 31-825004

e-mail: ragnar.rylander@...

Introduction

Of the different agents in the indoor environment that can cause symptoms or disease, much data indicate that mold is very most important. Widespread discomfort in the airways, increased risk of infections, serious lung diseases and disturbances to the immune system are effects that have been related to exposure to molds.

Knowlege that mold is a risk factor in the indoor environment goes far back in time. The Bible gives instructions as to how mold growth indoors should be handled and controlled (the book of Genesis).

In 1870, a physician in England – C H Blackley – who was curious about whether molds affect man, breathed in mold spores and described his reaction according to the following:

"I have all reason to believe that the microscopic molds, when they come into contact with the mucous membranes of the airways, will give rise to symptoms not unlike those observed in hay fever in certain respects but very different in other respects – similar to symptoms seen in influensa."

When he had breathed in the spores, Blackley became very hoarse and lost his voice for two days. These symptoms were followed by an airway catarrh.

The intention of this report is to provide an environmental medical basis for why mold growth in buildings must be addressed. The report gives a review of the different disease conditions that can occur after exposure to airborne molds in the indoor environment and identifies current risk groups. A number of large research projects are being carried out around the world to further identify the risks, and new information is continuously being presented. The information that exists today is however sufficient to motivate strong measures for a complete removal of molds in buildings.

Repeated exposure to airborne fungi can cause an inflammation in the airways (non-allergic asthma). The symptoms are irritation and a feeling of swelling in the nose and throat, hoarseness and irritation cough with or without mucous and sometimes chest wheezing. Other symptoms can also appear, such as eye irritation, headache, pronounced fatigue and skin problems such as redness, warmth or itchiness. Joint pain has also been described. If one has an airways inflammation, one is often also sensitive to airborne agents in the environment, such as tobacco smoke, dust and perfume, and to cold air.

Airways inflammation can be caused by fungi taken up by cells in the lung’s immune defense system. These react by excreting different agents that both attract other defense cells to the lung tissue and affect cells in other parts of the body. Airways inflammation is common among persons who have been exposed to molds and can affect up to half of those who are exposed.

Persons with airways inflammation caused by molds recover if they leave the environment for a period of time, but hypersensitivity in the airways can remain for several years after having left the moldy building.

Allergic alveolitis is a lung disease in which white blood cells collect in the lung tissue (granulomas) and, in serious cases, fibrosis of the same type seen in silicosis may develop. The disease gives rise to breathlessness, irritation in the airways, dry cough, fever and weight loss. It was previously thought that the disease occurred only in work environments, such as among farmers or workers in the lumber industry, but several recent reports show that there is also a risk in indoor environments where there is mold in the air. Children have also contracted the disease.

Some data indicate that the disease can occur in a so called subclinical phase, that is, that there is an inflammation in the lung tissue that cannot be demonstrated from x-ray changes or changes in lung function. Among children and adults living in houses with high levels of molds in the indoor air, changes have been found in the number of a certain type of white blood cell – T lymphocytes - which are also found in persons with allergic alveolitis. This indicates that the risk for development of the disease in persons living or working in moldy indoor environments may be underestimated.

The risk for infections, such as colds and ear infections, increases with exposure to large amounts of mold cells. An infection cause by molds themselves is very uncommon and occurs almost exclusively among persons with disturbances in the immune defense system, for example as a result of treatment with cytotoxins.

Among children staying in areas with high levels of molds, the risk for colds, bronchitis and ear infection increases. It is not always easy to demonstrate these effects since all children catch cold or suffer ear infections at some time. It is necessary to make comparisons between groups of children in daycare centers or schools with and without mold growth. It has been shown that the risk of infections decreases if the moldy environment is cleaned. Among adults, there is an increased risk of bronchitis and sinus infection.

The mechanism underlying the increased infection risk is not yet known, but it is likely that mold cells have the ability to affect the immune defense system.

A special form of pneumonia among neonatals has been shown in residences with extremely high levels of molds. It has been suggested that this is caused by a special mycotoxin excreted by the Stachybotrus chartarum mold, but this has not yet been confirmed. It may also have to do with a decrease in the body's defense against infections in general. In other investigations, inflammatory changes including nosebleeds have been described among school children in buildings with high levels of molds.

Molds contain several agents (allergens) that can give rise to dramatic reactions in the eyes, airways or skin after repeated exposure to small doses. Persons with mold allergy react quickly when they enter a moldy area, with eye irritation, stuffy nose or marked breathing discomfort.

Allergy to mold cells is unusual and is seen in only a few persons per 1000. When an allergy has developed, this specific hypersensitivity ordinarily remains for a number of years or is even life-long.

Several types of molds can produce strong toxins. As yet, the best known of the effects of such toxins derive from the ingestion of moldy grains, canned goods or products such as peanuts, on whose surface toxin-producing molds can grow.

Mycotoxins can act directly but most often have to be metabolized by the body before they exert their effect. This metabolism takes place in the liver or kidneys. An increased frequency of liver cancer has been proposed after consumption of moldy foods and changes in the function of the nervous system and kidney damage are described among persons who have eaten moldy grains.

As concerns the indoor environment, the role of mycotoxins is not yet clear. Some investigations have demonstrated mycotoxins either in specific areas or in cultivations of molds that have been found in these areas. There is a number of case descriptions concerning persons who have exhibited disturbances in the function of the nervous system in connection with staying in buildings with high levels of moulds. These effects have also been described among children.

In determinations of the amounts of fungi in indoor air, it is not sufficient to count the number of live moulds – the total amount of mold (the biomass of the mold) must be determined. The total number of cells may be tenths of thousand times higher than the number of viable cells.

The diseases described above are caused by agents on or produced by molds that retain their effect even when the mold cell is dead or broken into pieces. Several of these agents are very resistent and retain their effect in the environment for a long period of time. In a determination of mold exposure, the total number of mold cells must be determined, a suitable indicator of the mold mass.

When renovating a building, it is not sufficient to simply dry out building materials. Surfaces with colonies of mold (live or dead) must also be removed.

Mold spores are particles in the size of 3-10 um, which can be transported by air flows between different rooms or from the housing construction into a room. There may thus be higher levels of molds in a room without there being any mold colonies in the room itself.

The broad documentation of health risks resulting from exposure to mold makes it possible to identify two special risk groups.

There is a very intensive development of the immune system towards the surrounding environment during the first ten years of life. The immune system must be adapted to the stresses that exist in a normal environment, and the adaptation to different agents with allergic characteristics is especially important. A suitable mixture of infections and allergens during the developing years makes the risk for developing asthma and other allergies relatively small. Damage to the defense system results in imbalances and increased risks for infections and allergies. Mold cells and different agents in these cells have strong effects on the inflammation and immune system. This type of exposure must thus be kept as low as possible for children.

Another risk group is those in occupations where moldy materials are handled, such as those who work with cleaning moldy buildings. There are not yet any descriptions of systematic investigations among this occupational group, but reports on individuals show that the diseases and symptoms described above can occur.

This review shows that exposure to mold cells can lead to a number of different diseases, some of them of a serious nature. It is especially important that exposure to mold is kept low for children to ensure optimal health conditions and a decreased risk for infections and allergies. The medical effects are caused by agents in molds that are stable and independent of whether the mold is alive, which places particular demands on measures aimed at cleaning such environments.

The references below are those whose results have been mentioned in this report. Many other references are available on the subject and information on these can be given from the authors of this report.

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Auger PL. Mycotoxins and neurotoxicity in Johanning E and Ynga CS (eds) Fungi and bacteria in indoor environments. Easter New York Occupational Health Program Lathma NY 12110, 1994, pp. 161-168.

Dales RE, Zwanenburg H, Burnett R, lin CA. Respiratory health effects of home dampness and mold among Canadian chidlren. Am J Epidemiol 1991;134:196-203.

Etzel R, Montana E, Sorenson WG, Kullman GF Allan TM, Dearborn DG. Acute pulmonary hemorrhage in infants associated with exposure to Stachybotrus atra and other fungi. Arch Pediatr Med 1998;152:757-762.

Garrett MH, Rayment PR, Hooper MA, Abramson MJ, Hooper BM. Indoore air fungal spores, hosue dampness and associations with environmental factors and respiratory health in children. Clin Exp Allergy 1998;28:459-467.

Gravesen S. Fungi as a cause of allergic disease. Allergy 1979;34:135-154.

Hendry KM and Cole EC. A review of mycotoxins in indoor air. J Toxicol Environ Health 1993;38:183-198.

Husman TM. Health effects of indoor-air microorganisms. Scan J Work Environ Health 1996;22:5-13.

Johanning E. Health Problems related to fungal exposure – the example of toxicogenic Stachybotrus chartarm (atra) in Johanning E and Yang CS (eds) Fungi and bacteria in indoor environments. Eastern New York Occupational Health Program Latham NY 12110, 1994, pp. 169 –182.

Koskinen OM, Husman TM, Hyvärinen AM, Reponen TA, Nevalainen AI. Two moldy day-care centers: a follow-up study of respiratory symptoms and infection. Indoor Air 1997;7:262-268.

Park H-S, Jung K-S, Kim SO, Kim SJ. Hypersensitivity pneumonitis induced by Penicillium expansum in a home environment. Clin Exp Allergy 1994;24:383-385.

Salvaggio J, Aukrust L. Mold-induced asthma. J Allergy Clin Immunol 1981;84:242-246.

Samson RA. Mycotoxins: a mycologist’s perspective. J Med Vet Mycol 1992;30:9-18.

Suda T, Sato A, Ida M, Gemma H, Hayakawa H, Chida K. Hypersensitivity pneumonitis associated with home ultrasonic humidifiers. Chest 1995;107:711-717.

Thörn Å, Lewné M, Belin L. Allergic alveolitis in a school environment. Scan J Work Env Health 1996;22:311-314.