Fungi are a major group of living things, originally considered plants lacking chlorophyll, leaves, true stems, roots and reproducing by spores, but now treated as the separate kingdom fungi.
They occur in all environments on the planet and include important decomposers and parasites. Parasitic fungi infect animals including human, other animals, birds, and insects with consequences varying from mild itching to death, in general, humans have a high level of inmate immunity to fungi and most of the infections they cause are mild and self limiting (Adeleke, 2006).
Fungi are contacted during our everyday routines, some which are potentially pathogenic to human and other not human could be exposed simply by walking by a construction areas were the oil has been disturbed and scattered into the wind by the machinery, also can be exposed while jogging, hiking, hunting and fishing. The study of fungi as animal and human pathogen is called mycology (Emmons 1979)
Also, they are eukaryotic, unicellular, or multi-cellular organisms that, because they lack chlorophyll, are dependent upon external food sources. They are ubiquitous in all environments and play a vital role in the Earth’s ecology by decomposing organic matter. Familiar fungi includes yeasts, rusts, smuts, mushrooms, puffballs, and bracket fungi. Many species of fungi live as commensal organisms in or on the surfaces of the human body. “Mold” is the common term for multicellular fungi that growths as a material of intertwined microscopic filaments (hyphae). Exposure of molds and other fungi and their spores is unavoidable except when the most stringent of air filtration, isolation, and environmental sanitation measures are observed, e.g in organ transplant isolation units.
Molds and other fungi may adversely affect human health through three processes. (1) allergy (2) infection and (3) toxicity. One can estimate that about 10% of the population has allergic antibodies to fungal antigens. Only half of these, or 5%, would be expected to show clinical illness. Furthermore, outdoor molds are generally more abundant and important in airway allergic disease than indoor molds leaving the latter with an important, but minor over all role in allergic airway disease