Issue link: https://hi.iaq.net/i/191637
Climate Change, the Indoor Environment, and Health 162 CLIMATE CHANGE, THE INDOOR ENVIRONMENT, AND HEALTH (Boone and Gerba, 2007; Gubler et al., 2001). Increased dampness indoors, possibly exacerbated by building deterioration, may exacerbate or increase the risk of developing select respiratory diseases caused by mold and bacterial exposure (IOM, 2004; WHO, 2007). Fungi Fungi pose a special set of problems because they are ubiquitous, grow easily in the environment, and cause human diseases. However, the language surrounding fungal interactions with humans is fraught with imprecision, which leads to confusion. In addition, there are several distinct types of fungi, including yeasts, molds, and dimorphic yeasts (fungi that live as yeasts under one set of circumstances but can act like molds in other circumstances) (Holland and Vinh, 2009). The distinctions are important because the dimorphic yeasts are able to live both in the environment and in humans and cause some degree of invasive disease even in healthy humans. Examples include Histoplasma capsulatum, Coccidioides immitis, Blastomyces dermatitidis, Sporothrix schenkii, and Paracoccidioides brasiliensis. Those agents are relatively regional in their distribution and are therefore often referred to as endemic fungi. In healthy hosts, they can cause usually self-limited respiratory illnesses, such as valley fever due to C. immitis. They are organisms that live in the upper layer of soil outdoors and are rarely associated with indoor exposures and have rarely associated with indoor exposures to date. However, a white paper commissioned by EPA (Morey, 2010) suggests a mechanism by which this could change. It indicates that the upper layer of soil is prone to disturbance by dust storms, which may become more common in geographic areas that experience drought because of shifts in climatic conditions. This may in turn lead to greater indoor penetration of pathogenic fungi contained in soil and to higher indoor exposures in the absence of enhanced HVAC filtration or settled dust removal. Invasive fungal infections are quite rare in humans and occur almost exclusively in the setting of immunocompromise, either inborn, such as some primary immunodeficiencies, or acquired, such as that acquired through transplantation or chemotherapy. However, with the advent of more drugs that affect immunity, such as tumor-necrosis factor alpha– (TNF-α)-blocking agents used for rheumatoid arthritis and inflammatory bowel disease, the number of people at risk for the development of fungal infection is increasing (Tsiodras et al., 2008). In susceptible persons Aspergillus fumigatus, a thermotolerant filamentous mold, can cause invasive disease that is usually spread by inhalation. Pneumonias that occur in the setting of immunocompromise carry high morbidity and mortality. In the nonimmunocompromised host, the most important fungal disease in the respiratory tract is allergic bronchopulmonary aspergillosis Copyright © National Academy of Sciences. All rights reserved.