Possible sources of Sick Building Syndrome in a Tennessee Middle School

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Archives of Environmental Health

Sept-Oct, 2001

Possible sources of Sick Building Syndrome in a Tennessee Middle School.

Author/s: M. Scheel

SICK BUILDING SYNDROME (SBS), which is characterized by a high incidence of

anomalous health-related complaints by occupants of a particular building,

can be attributed to poor indoor air quality in tightly enclosed buildings

(e.g., buildings with inadequate or contaminated ventilation systems).

Often, the contamination is a biological source within the building or it

may be drawn inside via the ventilation system. Buildings with high humidity

and water infiltration problems are particularly prone to mold growth. In

recent investigations of SBS in schools and office buildings, researchers

have determined that there is a correlation between the presence of certain

fungal types and SBS symptoms. (1) Mold spores are known allergens, but

certain fungi pose a more serious health threat. Stachybotrys chartarum

(also known as S. atra) has been of particular concern in SBS cases in light

of the 1993 outbreak of pulmonary hemorrhage and hemosiderosis (i.e.,

bleeding in the lungs) in Cleveland, Ohio. Several infants died during this

outbreak; investigators thought the illness was caused by inhalation of

Stachybotrys spores, which contaminated the homes of the individuals. (2,3)

Growth of Stachybotrys requires high humidity, moisture, and cellulose

materials (i.e., straw, wood, or wallboard). Its spores produce toxic

chemical metabolites known as macrocyclic trichothecenes, which inhibit

protein synthesis. (4) The toxic effects of exposure to Stachybotrys were

discovered in Eastern Europe during the 1930s, during which time there was

an apparent outbreak of disease among horses and other livestock. The

symptoms of the disease in these animals included nervous disorders, dermal

necrosis, hemorrhage, shock, and even death. In 1938, Russian scientists

discovered that the disease was caused by ingestion of hay contaminated with

Stachybotrys chartarum, and they coined the term " stachybotryotoxicosis " for

the disease. A few cases of the disease appeared among humans who handled

straw, but the symptoms were generally less severe than those of the animals

that had ingested the fungus. (5)

In a recent clinical study, mice developed severe inflammation and

hemorrhage in alveolar and bronchial lumen upon intranasal exposure to

Stachybotrys spores (6)--a condition known as " lung mycotoxicosis. " Data

from epidemiological studies of Stachybotrys-related SBS suggest that human

symptoms are compatible with animal models. (7) Exposure to this fungus

causes a suppressed immune cell count (7) and reportedly causes

neurobehavioral and respiratory disorders. (8) The most common symptoms

reported upon prolonged exposure to this fungus are respiratory problems,

headache, dizziness, memory loss, chronic fatigue, rashes, diarrhea, and

conjunctivitis.

Students and staff at Central Middle School often experienced symptoms that

were consistent with Stachybotrys contamination. In 1998, the students of a

science class conducted research to determine the environmental health of

their school. During this project, they discovered black fungal growth on

cellulose ceiling tiles in several places throughout the building. The areas

of growth seemed to occur under areas where the roof, or pipes, had leaked

onto the ceiling tiles. In this study, we determined that there was a black

fungus in the school (i.e., Stachybotrys), and we have presented steps that

should be taken to remediate the fungal growth.

Materials and Method

This study was conducted at Central Middle School in Murfreesboro,

Tennessee, during January and February of 1999. Fungal contamination

assessment and specimen collection began on the second floor (i.e., in the

east wing), and specimens were collected from all hallways, restrooms, and

accessible classrooms. Bulk sampling of the mold-contaminated ceiling tiles

was conducted with forceps that were sterilized in 70% ethanol (Fisher

Scientific [Pittsburgh, Pennsylvania]) and air-dried. The surface of each

tile was gouged; therefore, the sample included substrate material and the

fungal contaminant. Samples were placed into clean resealable plastic bags,

which were then sealed. We used transparent tape to obtain surface mold

samples, which we then used to prepare contact slides for immediate

visualization with the light microscope.

Bulk samples were moist-chambered in glass petridishes lined with wet filter

paper and incubated at room temperature. These samples were inspected

periodically for visible fungal growth. The growing samples, which were

placed under a dissecting microscope, were mounted in lactophenol, during

which process we used sterile jewelers' forceps. The prepared slides were

then examined under a light microscope. Stachybotrys samples were cultured

in duplicate in a cornmeal/malt/yeast extract agar (4.25 gm cornmeal malt

agar (DIFCO Laboratories [Detroit, Michigan]); 1.25 gm agar (Sigma Chemical

Company [st. Louis, Missouri]); 0.25 gm malt extract (Carolina Biological

Supply Company [burlington, North Carolina]); and 0.25 gm yeast extract

(DIFCO), all of which were dissolved in 250 ml of distilled water growth

medium.

Results

Bulk samples were taken from 9 sites of mold-contaminated ceiling tiles and

from 1 ceiling dust sample. Of these samples, we confirmed that 3 of the

mold sites and the dust sample were positive for viable spores of the genus

Stachybotrys. The sites that were positive for this fungus (Fig. 1) were not

localized, but they were found on both the 1st and 2nd floors of the

building and in the east and west wings. The total area of confirmed

contamination exceeded 2 [ft.sup.2]; this area met the criterion for

professional remediation, as suggested by Case Western Reserve University in

association with the Cuyahoga County (Cleveland) Board of Health.

[FIGURE 1 OMITTED]

The positive samples contained intact, determinate conidiophores, which

varied in color between colorless and brown, and swollen phialides

(colorless to brown) with 1-celled dark olivaceous spores were present (Fig.

2). Conidiophores and a large number of spores were found in 2 other

samples, but we were unable to consider them viable, active colonies because

the spores were not intact.

[FIGURE 2 OMITTED]

The prepared contact slides indicated that many of the patches of mold

consisted of a mixture of fungal species. Stachybotrys spores were evident

on a majority of these slides. Other fungal contaminants identified included

the xerophilic genera Aspergillus and Penicillium, both of which are known

respiratory allergens that produce mycotoxins. Ulocladium, a hydrophile that

grows on cellulose material, was also identified.

Discussion

The symptoms of SBS reported by the students and staff at Central Middle

School correlate with those common to Stachybotrys contamination. The

presence of Stachybotrys, as well as other mycotoxin-producing fungi,

implicates these organisms as possible causes of illness at the school.

Stachybotrys contamination of the school was presumably more extensive than

could be demonstrated here, as evidenced by the large number of spores in

the negative samples and the growth of this fungus from a dust sample.

Remediation of this contamination should include careful removal and

replacement of water-damaged ceiling tiles, repair of all sources of water

infiltration, cleaning or removal of carpeting, and thorough cleaning of the

ventilation system. Given the prevalence of toxin-producing fungi throughout

the school, a professional service that specializes in the cleaning and

restoration of contaminated buildings should be consulted.

In this study, we sought to determine the possible fungal sources of SBS at

a local middle school. Three genera of mold found at the school contained

mycotoxins. Stachybotrys contamination was suspected, given the nature of

the health complaints at the school and the description of the fungus given

by the students. The Stachybotrys examined was most likely S. chartarum, as

the conidial morphology of this species is unique and is rarely confused

with other species in the genus. (5) We limited species identification to

visual inspection with a light microscope, and, therefore, we were unable to

make absolute confirmations. Visualization with the electron microscope

would enhance spore morphology and would determine conclusively the identity

of the species.

The negative health effects of inhalation of Stachybotrys spores in SBS

cases are difficult for investigators to measure. Exposure time, the

concentration and toxicity of spores, and the health status of the

individuals involved must all be considered. Individuals who are very young,

immunocompromised, hypersensitive, or allergic to mold, suffer more acute

symptoms upon exposure to this fungus than do other individuals. The

association of Stachybotrys with SBS has been established clearly, but this

evidence is based upon epidemiology studies. The difficulty in proving a

firm causal relationship between the presence of Stachybotrys and SBS in

humans lies in the minute amount of trichothecene mycotoxin required to

adversely affect health, as well as from the lack of success to date in

recovering and quantifying trichothecenes from affected human subjects. The

attempts of researchers to detect the products resulting from the hydrolysis

of macrocyclic trichothecenes in human body fluids have been unsuccessful.

Recently, however, Stachybotrys chartarum was recovered from the

bronchoalveolar lavage fluid of a child with pulmonary hemosiderosis. (9)

The fungus also contaminated the child's home.

Stachybotrys requires cellulose material and a chronically wet environment

for optimal growth. The ceiling tiles at Central Middle School contained

ample cellulose material, and these materials were often saturated with

water in places where the roof leaked through to their back surfaces. These

conditions provided a perfect growth medium for Stachybotrys. Stachybotrys

has been found in water-damaged buildings in which many other cases of SBS

have been reported. (1,7,8,10) Water-damaged buildings not only harbor toxic

fungi, such as Stachybotrys, Aspergillus, and Penicillium, but they may also

promote growth of endotoxin-producing gram-negative bacteria. (11)

Many of the leaks at Central Middle School (and the subsequent mold growth)

were near intake vents of the heating, ventilation, and cooling (HVAC)

system. This finding suggests that the fungal spores may have contaminated

the HVAC system, thus providing a means for their dissemination throughout

the school. Viable Stachybotrys found in a dust sample taken from the

ceiling near an HVAC outflow vent corroborated this assumption, as did the

variability of locations and distances between positive sites. More

importantly, investigators have found that airborne Stachybotrys spores are

highly respirable, and they contain trichothecene mycotoxins. (4) Further

testing of the filters and interior of the HVAC system for Stachybotrys will

be necessary if we wish to determine if contamination has occurred, and, if

so, what remedial action will be required. Indoor air samples should be

taken for the measurement of the concentration of fungal spores. Although

Stachybotrys often gives false-positive readings when measured in air

samples, a new method of measuring trichothecene toxicity in airborne

particulates has been developed. (12) Ideally, indoor fungal spore

concentration should approximate the outdoor concentration.

Relocation of occupants from contaminated buildings has resulted in a

significant decrease in symptoms that are related to SBS. (8,9) When

occupant relocation is not an option, as in the case of Central Middle

School, all contaminated materials must be either removed or cleaned

professionally. If further water infiltration is to be prevented, all

leaking pipes and roof leaks should be repaired. Ceiling tiles with visible

mold growth should be removed by an air-quality control professional, and

the tiles should be discarded in sealed plastic bags. The carpeting (found

throughout most of the school) is a " sink " for fungal spores and dust, and

it should be cleaned professionally or, preferably, removed. During the year

following the completion of this study, roof leaks at Central Middle School

were repaired, and the contaminated ceiling tiles and carpeting were

replaced.

Stachybotrys-related SBS is a condition found only in buildings with

chronically wet cellulose building materials. Although remediation of mold

infestation in water-damaged buildings can be quite costly, water

infiltration is preventable in most cases. Adherence to building codes and

frequent inspections of roof areas and plumbing for possible leaks may be a

cost-effective method of preventing mold growth in building materials and

the subsequent possibility of the occurrence of SBS symptoms. In areas of

high humidity, dehumidifiers may prevent the growth of the xerophilic molds

Aspergillus and Penicillium, which are frequently associated with SBS

symptoms.

References

(1.) Cooley JD, Wong WC, Jumper CA, et al. Correlation between the

prevalence of certain fungi and Sick Building Syndrome. Occup Environ Med

1998; 55(9):579-84.

(2.) Jarvis BB, Sorenson WG, Hintikka EL, et al. Study of toxin production

by isolates Stachybotrys chartarum and Memnoniella echinata isolated during

a study of pulmonary hemosiderosis in infants. Appl Environ Microbiol 1998;

64(10):3620-25.

(3.) Etzel RA, Montana E, Sorenson WG, et al. Acute pulmonary hemorrhage in

infants associated with exposure to Stachybotrys atra and other fungi. Arch

Pediatr Adolesc Med 1998; 152(8):757-62.

(4.) Sorenson WG, Frazer DG, Jarvis BB, et al. Trichothecene mycotoxins in

aerosolized conidia of Stachybotrys atra. Appl Environ Microbiol 1987;

53(6):1370-75.

(5.) B. Stachybotrys chartarum: the toxic indoor mold. American

Phytopathological Society [serial on-line] 1999 Feb 1. Available from:

URL:http://www.scisoc.org/feature/stachybotrys/Top. html

(6.) Nikulin M, Reijula K, Jarvis BB, et al. Effects of intranasal exposure

of Stachybotrys atra in mice. Fund Appl Toxicol 1997; 35 (2):182-88.

(7.) Johanning E, Biagini R, Hull D, et al. Health and immunology study

following exposure to toxigenic fungi (Stachybotrys chartarum) in a

water-damaged office environment. Arch Occup Environ Health 1996;

68(4):207-18.

(8.) Sudakin DL. Toxigenic fungi in a water-damaged building: an

intervention study. Am J Ind Med 1998; 34(2):183-90.

(9.) Elidemir O, Colasurdo GN, Rossmann SN, et al. Isolation of Stachybotrys

from the lung of a child with pulmonary hemosiderosis. Pediatrics 1999;

104:964-66.

(10.) Hodgeson MJ, Morey P, Leung WY, et al. Building-associated pulmonary

disease from exposure to Stachybotrys chartarum and Apergillus versicolor. J

Occup Med 1998; 40(3):241-49.

(11.) Andersson MA, Nikulin M, Koljalg U, et al. Bacteria, molds, and toxins

in water-damaged building materials. Appl Environ Microbiol 1997;

63(2):387-93.

(12.) Yike I, Allan T, Sorenson WG, et al. Highly sensitive protein

translation assay for trichothecene toxicity in airborne particulates:

comparison with cytotoxicity assays. Appl Environ Microbiol 1999;

65(1):88-94.

CHRISTINA M. SCHEEL

WAYNE C. ROSING

ANTHONY L. FARONE

Department of Biology

Middle Tennessee State University

Murfreesboro, Tennessee

The authors thank Glen Eubanks and his students at Central Middle School who

initiated this investigation and D. for his technical

expertise in the preparation of the figures used in this article.

Submitted for publication July 14, 2000; accepted for publication September

19, 2000.

Requests for reprints should be sent to L. Farone, Ph.D., Biology

Department, Middle Tennessee State University, P.O. Box 60, Murfreesboro, TN

37132.