clinical laboratory tests in patients or by identification of the source in the building (Samet, 1990). Hypersensitivity pneumonitis, humidifier fever (see above), and infection with Legionella species are included in this category of illness. Prevalence rates for specific syndromes are largely unknown and estimates vary tremendously among buildings.
Some researchers believe that there is a set of nonspecific symptoms that are distinguishable, that are different from the other conditions described above, and that are due to indoor allergens (Burge, 1990). Fungus-related