In this chapter we study fungi as pathogens of animals, including humans. There are many pathogens of insects amongst the fungi and fungus-like organisms: Microsporidia, Trichomycetes, Laboulbeniales and entomogenous fungi. Inevitably, discussion of insect disease eventually turns to thoughts of the potential for biological control of arthropod pests. In other animals, cutaneous chytridiomycosis is an emerging disease of amphibians; so, too, is aspergillosis disease of coral, and both have potential lessons to teach about the emergence of new diseases from organisms that have long, but benign, associations with the host.
Our main concern, though, are the mycoses that are the fungus diseases of humans. We describe the clinical groupings set up for human fungal infections; fungi within the home, and their effects on health through production of allergens and toxins.
In the penultimate section we attempt a comparison of animal and plant pathogens and briefly discuss the essentials of epidemiology. We finish with a short discussion of mycoparasitic and fungicolous fungi; that is, fungi that are pathogenic on other fungi.
Pathogens of insects
Insects are the most diverse group of animals on Earth, occurring in most terrestrial environments, though only a few species are found in marine habitats, as these are dominated by the crustaceans. Over a million species of insects have been described, which is more than half of known living organisms, and taking into account estimates of the number of species that are yet to be described, the Class Insecta probably includes about 90% of all species on the planet.