These spores are easily aerosolized and can cause a variety of symptoms including allergic reactions. Most symptoms occur if the individual is immune-compromised in some way (HIV, cancer, etc).
Both Penicillium and Aspergillus spores share similar morphology on non-viable analysis and therefore are lumped together into the same group. Only through the visualization of reproductive structures can the genera be distinguished. Also included in this group are the spores of the genera Trichoderma, Acremonium, Verticillium and Paecilomyces.
Small, round spores of this group lack the necessary distinguishing characteristics when seen on non-viable examination.