Fungal Contamination - CDC

This is a portion of an article published by the CDC through the Morbidity and Mortality Weekly Review. The entire article (36 pages) can be viewed at: http://www.cdc.gov/mmwr/PDF/rr/rr5508.pdf


Potential Health Effects of Fungal Contamination

In recent years, the health effects of exposure to mold in built environments have been a subject of intense public concern. These concerns and how they are approached will have important implications for the reconstruction and rehabilitation of cities in states affected by major hurricanes or floods.

Many clinical conditions could be caused by the fungal contamination associated with flooding after major hurricanes or floods. Predicting what might occur is speculative. However, many of these conditions are uncommon and will be recognized only if there is a high clinical index of suspicion (Table 2). Anticipating what medical problems could be associated with post-flood fungal contamination might help in preventing them by identifying susceptible populations and making recommendations for reducing potentially harmful exposures.

Although this report focuses on potential health effects of fungal contamination, other exposures are also of concern. For example, dampness favors proliferation of dust mites and microorganisms such as bacteria (44,45) and nontuberculous mycobacteria (46). Endotoxins (components of the cell walls of Gram-negative bacteria) have strong inflammatory properties (6,44,45,47--49). Moisture also can release chemical constituents from building materials (6). Standing water supports rodent and cockroach infestations (15,44,45) and proliferation of mosquitoes (30). Fecal contamination of the environment raises concerns about protozoal and helminthic parasites (50). Fungi are not the sole potential cause of many conditions discussed in this report, and these conditions are only a subset of the conditions of concern to clinicians and public health professionals dealing with the aftermath of major hurricanes or floods (51).

Overview of Fungal-Induced Diseases

Fungi can cause a variety of infectious (52--58) and noninfectious conditions (6,44,45,47,59,60). Several basic mechanisms can underlie these conditions, including immunologic (e.g., IgE-mediated allergic), infectious, and toxic (6). Several of these mechanisms contribute to pathogenesis of a fungal-induced disease. The types and severity of symptoms and diseases related to mold exposure depend in part on the extent of the mold present, the extent of the person's exposure, and the susceptibility of the person (e.g., persons who have allergic conditions or who are immunosuppressed are more susceptible than those without such conditions). Molds produce a variety of volatile organic compounds (6,7,60), the most common being ethanol (61), which are responsible for the musty odors associated with fungal growth. Exposure to moldy indoor environments is also associated with a variety of upper and lower respiratory tract symptoms (6).

One Syndrome associated with Fungal Contamination:

Organic dust toxic syndrome (ODTS) has been reported among workers in a variety of agricultural and industrial settings and is thought to involve inhalation exposure to materials with heavy microbial contamination (67--69). Etiologic exposures that cause ODTS are often a poorly defined mixture of substances, including fungi, bacteria, and microbial constituents such as endotoxin (67--69). ODTS is characterized by fever and influenza-like symptoms, including general weakness, headache, chills, body aches, and cough occurring 4--12 hours after heavy exposure to organic dust (67--69). Dyspnea also is sometimes present. Results of chest auscultation and chest radiographs are usually normal (67,68). The peripheral white blood count is often elevated during attacks. Accurate patient history is critical for making a correct diagnosis. Although the symptoms resemble those of acute HP, they are not caused by response of the immune system to a specific antigen in the environment (67,68).

ODTS poses a risk for workers performing renovation work on building materials and is a realistic concern for workers handling heavily contaminated materials in the aftermath of major hurricanes or floods. ODTS is best prevented by minimizing exposure through engineering controls, administrative controls, and respirators (69). For agricultural workers handling organic dusts, CDC recommends using the most practical respirator with the highest assigned protection factor.