INDUCTION OF DEPRESSION BY EXPOSURE TO DAMP ...

albicans, A. fumigatus, or Gram-negative bacterium Pseudomonas aeruginosa (Allard et
al., 2009). When either fungal lysate was administered, a Th2 cytokine response with
airway eosinophilia and mucus cell metaplasia was observed. Administration of the P.
aeruginosa lysate resulted in neutrophil influx with Th1 cytokine secretion and no mucus
production. However, administration of the bacterial lysate with the fungal lysates
resulted in Th1-associated cytokine profiles with neutrophilia and diminished mucous
production. Additional studies using varied amounts and types of fungi and bacteria will
further elucidate the potential synergies and deviations of inflammatory reactions that
may occur in exposures to damp buildings. However, studies currently indicate that such
reactions do occur. These interactions due to co-exposure of bacteria and fungi are
important to consider in exposure studies since both organisms exist in damp buildings.
Mycotoxins and Health Effects
Exposures to mycotoxins in damp buildings and their potential effects on human
health are frequently explored in research. Mycotoxins are secondary metabolites created
by fungal organisms. It is widely believed that some of these mycotoxins are produced as
a defense mechanism to limit the growth of competing organisms. This is the case with
P. chrysogenum which produces penicillin. Mycotoxins are primarily maintained in or on
the cell wall of the spores and hyphae and are readily released into the surrounding
materials (Hinkley and Jarvis, 2000; Curtis et al., 2004; Islam et al., 2007). These
compounds are large enough to not be highly volatile and thus require active agitation or
air currents to become airborne (Kelman et al., 2004).
Mycotoxins have been frequently studied for their ability to induce adverse health
effects (Etzel, 1998; Bunger, 2004; Bondy and Pestka, 2000). The importance of fungal
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