There is evidence that inhalation of mycotoxin producing fungi results in immunological disregulation, with potential neurological effects. The toxins are present in both the spores and the mycelium of moulds such as Fusarium, Aspergillus and Penicillium. The nature of inhaled mycotoxins and their effects on humans are current topics of research in several countries. Fungal Infections Lung infections resulting from inhaled fungi and yeasts have been recognised for a very long time, but are still not as common as allergies. It is common for such infections to be occupationally related, as a result of long term exposure to fungal spores or aerosolised yeast cells.
Immunosuppression is also a common predisposing factor to respiratory fungal infections.
Other host factors such as age, smoking and underlying illness may also play a part in depressing the normal defences of the lung to such an extent that fungal infections may establish. Some pathogenic fungi known to cause lung disease due to colonisation by the organism include Blastomyces dermatitidis, Histoplasma capsulatum, Coccidioides immitis and Paracoccidioides brasiliensis. These fungi exhibit a morphologic transition from the mycelial or saprophytic form to the parasitic form found in infected tissue, in most cases a conversion to a budding, yeast-like form. Opportunistic fungal infections have commonly been caused by Aspergillus species and the yeast Candida. These infections, usually insidious in onset, depend primarily on altered host resistance rather than inoculum size.