CDC Mold Prevention Stategies and Possible Health Effects

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Mold Prevention Strategies and Possible Health Effects in the

Aftermath of Hurricanes and Major Floods Vol 55, No RR8;1

Mold is a greater hazard for persons with conditions such as

impaired host defenses or mold allergies. Many of the major

noninfectious health effects of mold exposure have an immunologic

(i.e., allergic) basis (6). Exposure to mol...

[PDF Version] Jun 9, 2006

http://www.cdc.gov/mmwr/preview/mmwrhtml/rr5508a1.htm

Hypersensitivity Pneumonitis

Hypersensitivity pneumonitis (HP), also known as extrinsic allergic

alveolitis, is a granulomatous interstitial lung disease. A wide

range of materials, including fungi, can be inhaled and thus

sensitize susceptible people by inducing both antibody and cell-

mediated immune responses. Re-exposure of sensitized individuals

leads to lung inflammation and disease. Building-related HP caused

by fungi and bacteria has been well demonstrated. Usually, only a

small fraction of those with a given exposure develop HP, so poorly

understood host factors play an important role in disease

pathogenesis.

The presentation of HP is complex and can be either acute or

chronic. The acute form is often associated with heavy exposures and

characterized by chills, fever, malaise, cough, and dyspnea

appearing 4 to 8 hours after exposure. It is often confused with

pneumonia. The chronic form is thought to be induced by continuous

low-level exposure. Onset generally occurs without chills, fever, or

malaise and is characterized by progressive shortness of breath with

weight loss. Chronic HP can be confused with idiopathic pulmonary

fibrosis or other forms of interstitial lung disease.

The diagnosis of HP, especially the chronic form and the mild form,

is often missed early in the course of the disease. If it does occur

in the aftermath of Hurricanes Katrina and Rita, it will take a high

degree of clinical suspicion to detect it. In general, when HP is

suspected, a careful clinical and exposure history should be

performed. Patients should be asked about their possible exposure to

damp and water-damaged areas, farms, birds, hot tubs, and other

environments that might cause HP. Environmental sampling for the

presence of microorganisms known to cause HP and serologic testing

for circulating precipitins can help to establish causative

exposures. Chest imaging using chest x-rays or high-resolution

computed tomography scanning of the thorax, lung-function tests,

broncholaveolar lavage, and lung biopsy all have roles in diagnosis.

A recent, large multicenter study found that under conditions of low

or high prevalence, six predictors could be used in combination for

noninvasive diagnosis of HP:

exposure to a known offending antigen,

positive precipitating antibodies to the offending antigen,

recurrent episodes of symptoms,

inspiratory crackles on physical examination,

symptoms occurring 4 to 8 hours after exposure, and

and weight loss.

Optimal treatment is elimination of causative exposures. The IOM

report provides information about management of building-related HP

that will be relevant to reoccupation of structures contaminated by

fungi after Hurricanes Katrina and Rita. Such management includes

giving standard medical therapy, such as systemic corticosteroids

and removing sources of fungal contamination from the environment.

The report notes that, in some cases, if efforts to remove mold from

a building are unsuccessful in relieving symptoms, then the patient

may need to move to another home or office.

Fungal Infections

Infection with fungal species that contaminated buildings, building

constituents, and the environment after Hurricanes Katrina and Rita

is an important concern. In general, individuals with impaired host

defenses (especially if impaired because of cell-mediated immunity

or neutropenia) suffer the most severe types of fungal infections

(Table 3). However, invasive fungal infections can also occur in

individuals with normal host defenses and, in certain situations,

can even be life threatening (Table 4).

Individuals at greatest risk for developing invasive fungal

infection from heavy fungal contamination after Hurricanes Katrina

and Rita are those with impaired host defenses (Table 3). Any

impairment in cell-mediated immunity or neutropenia (e.g., human

immunodeficiency virus [HIV] infection, leukemia, lymphoma, diabetes

mellitus) increases risk for many types of invasive fungal

infections. Severely immunosuppressed individuals, such as solid-

organ or stem-cell transplant recipients, or those receiving cancer

chemotherapy agents, corticosteroids, or other agents inhibiting

immune function are at much higher risk for these infections:

locally invasive infections of the lungs, sinuses, or skin; and

systemic infections. Aspergillus species, zygomycetes, and Fusarium

species are particularly important problems. These serious

infections are often fatal, even with aggressive antifungal therapy.

Aspergillus spp., zygomycetes, and Fusarium spp. are particularly

important problems (52,53,56). These serious infections are often

fatal, even with aggressive antifungal therapy (52,53,56).

Persons with normal host defenses also are subject to fungal

infections (52,53) (Table 5), and persons with impaired host

defenses can acquire any of these, often with greater severity

Colonization of lung cavities (e.g., tuberculosis cavities or

emphysematous blebs) by Aspergillus spp. can cause pulmonary

aspergillomas (fungus balls) (6,52), which are conglomerations of

Aspergillus spp. hyphae matted together with fibrin, mucus, and

cellular debris. These often do not cause symptoms, but they can be

associated with hemoptysis (52,53). An exposure-response relation

has never been established linking levels of exposure to Aspergillus

spp. with development of any of these conditions. Therefore, to what

degree exposure to fungal contamination after major hurricanes or

floods would increase any risk is unclear. However, despite unknown

benefit, persons with clinically significant obstructive pulmonary

diseases (e.g., asthma, cystic fibrosis, COPD), and persons with

cavitary lung disease from conditions such as tuberculosis should

avoid airborne exposure to materials that have become heavily

contaminated with fungal growth in the wake of major hurricanes or

floods.

Fungal brain abscesses are uncommon in healthy individuals, but they

can occur. The primary infection results from inhalation of

infectious conidia from the environment; the route of infection

appears to be hematogenous dissemination from the lungs.

Preventing Adverse Health Effects From Environmental Fungal

Contamination After Major Hurricanes or Floods

Persons should reduce their exposure to molds as much as possible

(with the realization that fungi are ubiquitous). Persons with

underlying or induced immunosuppressed conditions or diseases caused

by immune sensitization to fungal constituents present in mold

growth should be especially careful to reduce exposure. If exposure

to heavily mold-contaminated materials is unavoidable, persons

should use appropriate administrative, engineering, and personal

protection controls. Because a person's likelihood of developing

adverse health effects from mold exposure depends on the type of

exposure and on individual susceptibility, precautionary measures

need to be customized. Recommended measures are based on

professional judgment because of lack of available scientific

evidence. For example, no research studies have evaluated the

effectiveness of personal protective equipment in preventing illness

from mold exposure. Total avoidance of heavily contaminated

buildings or other high exposure situations is suggested for persons

with specific underlying conditions such as profound

immunosuppression. Respiratory protection, dermal protection, and

occlusive eye protection recommendations are customized to various

populations and exposure-associated activities. Repeated or

prolonged exposure probably poses a greater health risk than do

exposures of a similar intensity, but short duration. Preventive

precautions are especially important for persons who expect to be

highly exposed for a long time.

Public Health Strategies and Recommendations for State and Local

Officials

Recommendations from CDC are for protecting and monitoring the

health and safety of workers and residents who enter, repair, or

destroy flooded buildings. The recommendations are focused on

limiting human exposure to mold and other microbial agents and

preventing any adverse health effects related to such exposure.

Several factors are assumed:

In the aftermath of major hurricanes and floods, buildings or

materials soaked for >48 hours are contaminated with mold unless

proven otherwise by inspection or adequate environmental sampling or

cleaned according to the EPAs recommendations (13).

Workers and residents might be exposed to high levels of mold-

related contaminants.

Sufficient evidence exists of an association between adverse health

outcomes and exposure to damp indoor environments or materials

contaminated with fungal growth.

Insufficient evidence exists for establishing health-related

guidelines on the basis of concentrations of mold (quantitative

measure) or species of mold (qualitative measure) in either indoor

or outdoor environments.

Allergen testing to determine the presence of IgE to specific fungi

might be a useful component in the complete clinical evaluation and

diagnosis of mold-related allergies and in the decision to avoid

exposure to fungal allergens that might be causing allergic

symptoms. However, testing for IgE sensitization to molds has

important limitations. Allergens used in these tests are often

poorly standardized and the tests often have unclear sensitivity and

specificity. In addition, allergen testing is not relevant to

diseases that are not mediated by IgE.

Clear, concise, and practical recommendations and actions are

necessary to limit exposure to mold and to prevent mold-related

health outcomes where possible.

Assessing Exposure to Mold

Exposure assessment is usually a critical step in determining

whether persons are exposed to a hazard at a level that could have

an adverse health effect. The mere presence of a chemical or

biologic hazard in the environment is insufficient to create a

public health hazard. The contaminant must be present in an

environmental medium (e.g. air, water, food, and dust) that allows

it to come in contact with persons and move along a biologic pathway

(e.g., inhalation, ingestion, and absorption). In addition, the

concentration of the contaminant must be sufficient to create a

biologic response that leads to an adverse health outcome. Mold and

its spores exist in damp materials. Disturbing mold releases

potentially hazardous particulates into the air, which can then be

drawn into the sinuses and lungs. Although molds also might directly

attack the skin or openings in the skin, the most common route of

exposure is through the air and into the body by inhalation.

Environmental sampling for molds has limited value and, in most

instances, is not needed after major hurricanes or floods.

Exposure Assessment

Building interiors should be assumed to be substantially

contaminated with mold in the following circumstances:

The building was saturated with water for >48 hours.

Visible mold growth is extensive and in excess of that present

before a major hurricane or flood

Signs of water damage are visible or mildew odors are strong.

Exposure to materials and structures contaminated with mold should

be assumed to present a potential health risk regardless of the type

of mold. Risk for illness does not necessarily vary with the type of

mold or the extent of contamination.

Preventing Excessive Exposure to Mold

Preventing excessive exposure to mold is the best way to avoid

harmful health consequences. The preferred approach to preventing

mold exposure is to prevent water from infiltrating a building or

damaging household goods and structures. After major hurricanes or

floods, substantial water damage and mold growth might occur in many

buildings.

Avoidance

Persons

The following persons should avoid mold-contaminated environments

entirely:

transplant recipients, including those who received organ or

hematopoietic stem cell transplants during the preceding 6 months or

who are undergoing periods of substantial immunosuppression,

persons with neutropenia (neutrophil count <500/µL) attributed to

any cause, including neoplasm, cancer chemotherapy, or other

immunosuppressive therapy,

persons with CD4+ lymphocyte counts <200/µL attributed to any cause,

including HIV infection, and

other persons considered by their physicians to have profoundly

impaired antifungal host defenses caused by congenital or acquired

immunodeficiency.

The following persons might be able to tolerate limited exposure,

but they should consult with their physicians and should consider

avoiding areas where moldy materials are disturbed:

persons receiving chemotherapy for cancer, corticosteroid therapy,

or other immunosuppressive drug therapy, as long as neutropenia or

CD4+ lymphopenia are not present,

persons with immunosuppressive diseases such as leukemia, lymphoma

or HIV infection, as long as there is not marked impairment in

immune function,

pregnant women,

persons aged >65 years,

children aged <12 years, particularly infants, and

persons with chronic, obstructive, or allergic lung diseases

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Use of a differential activation protocol for the Limulus amebocyte

lysate (LAL) assay showed bacterial endotoxin and fungal (13)-ß-D-

glucans in cyst fluids from human kidneys with PKD. Fungal DNA was

detected in kidney tissue and... Dec 29, 2005

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