A primary human pathogen is an agent (fungus, bacterium, virus) causing any kind of disease in humans, either superficially or within the body (invasive, systemic). All fungal propagules (all kind of cells, spores) existing in the natural environment can be transmitted to the human body. Fungal infections usually start in the lung by inhalation of contaminated air, or on the skin, nails, and mucosa (vagina, mouth, sinuses) by direct contact (e.g., through wounds), and rarely also in the gastrointestinal tract by intake of contaminated food or water. Fungal infections in humans are rarely serious (lifethreatening) unless the patient's immune system is weakened, for