With few exceptions, veterinary and human mycology deal with the same fungal pathogens. Veterinary medical mycology deals with fungal disease in both invertebrate and vertebrate animals. Invertebrate fungal infections are typically dealt with on an individual basis by mycologists working with other specialists. Because fungal infections involving invertebrate animals are unusual, classical mycologists are typically needed to assist with the identification of the pathogenic fungus. In fact, the first reported animal disease was the fungus Beauvera bassiana that nearly destroyed the silk industry in China by attacking silkworms (Bassi A. 1835. Del male del segno calcinacio o muscordino malattia che affligge:Bachi da seta. Teoria Orcesi. Lodi).
When fungi are suspected to cause animal disease, having criteria to distinguish infection, colonization and contamination is important in reaching a diagnosis. Unlike people, animals are typically covered over their entire body with large amounts of hair, or feathers in the case of birds. They are frequently contaminated with a variety of fungi that may or may not be causing the disease that is present. The same criteria used for human infections must be applied:
- Are the symptoms compatible with a fungal infection?
- Was a fungus seen in clinical specimens or tissue sections?
- Was the isolated fungus compatible with the fungus seen in clinical specimens or tissue sections?
- Was the fungus growing in viable host tissue or sterile body fluids?
These types of questions will assist in deciding if a particular fungus is really causing the disease in the animal. As an example, we have a discussion of ringworm in the cattery. This discussion has logical parallels with other animal species.
Some fungi are restricted to particular animals. The zoophilic (animal loving) dermatophyte Microsporum gallinae causes disease on chickens, but not humans. In contrast, the dermatophyte Microsporum canis may cause ringworm on both animals and humans. Ringworm in pets and livestock is not uncommon. In Europe, a vaccine to prevent ringworm infection in cattle, which can damage the animal’s skin that will be used to make leather products, is successfully used. By understanding the epidemiology of the disease and the disease-causing fungus, epidemics caused by dermatophytes can be predicted and prevented. This information is important in deciding how to treat the infected animals.
In domesticated animals, the same antifungal agents that are used to treat fungal disease in humans are used to treat their infections. There are exceptions; for example aquatic animals such as fish are treated differently. Some of the more common infections of the skin and tails are caused by organisms no longer considered to be fungi, e.g., Saprolegnia spp. To determine specific therapy, please refer to fungal infections in humans and how they are treated.