Fungal infection. Coloured scanning electron micrograph (SEM) of a fungal infection of a cell culture. A single hyphae of an aspergillus species fungus grows across the surface of a cultured cancer cell. Fungus and mould spores are ubiquitous in the environment and generally infect cultures via an airborne route. Heating and air-conditioning systems are notorious for having high concentrations of spores. Aspergillus is a genus consisting of many mould species found in numerous habitats. Aspergillus is also common in the home, including bedding. Some species of aspergillus can cause illness in humans and animals. Magnification x 3200 when printed at 10cm wide.