Fungal Diseases

Fungi are eukaryotic organisms with chitin in their cell walls. They can be unicellular or multicellular and reproduce sexually and/or asexually. Fungi are saprophytes and absorb their nutrients from the environment. Their importance for veterinary and, more specifically, poultry medicine is twofold: (a) they can directly infect hosts, and (b) they can produce toxic metabolites, mycotoxins. While fungi are ubiquitous in the environment, and infections are common, they cause clinical disease infrequently and only under specific conditions. Favorable conditions include immunocompromised hosts or microbiota of the host that has been damaged by antibiotic treatment. The two most important fungal infections are aspergillosis and candidiasis. Damage to the host after fungal infections occurs due to physical destruction of tissue by the fungi and by the immune answer of the host. Molds growing on feedstuffs produce mycotoxins, which are then taken up with the feed. There are several hundred mycotoxins produced by different fungi, acting by various mechanisms and thus causing a variety of clinical symptoms and lesions.