What causes mange in animals?

Mange in animals is caused by microscopic parasites known as mites. These tiny creatures infest the skin of the host animal, leading to various skin conditions characterized by itching, hair loss, and inflammation. There are different types of mites responsible for different forms of mange, such as Sarcoptes scabiei, which causes sarcoptic mange, and Demodex mites, which lead to demodectic mange. The underlying issue with mange is the reaction of the animal's immune system to the presence of these mites, resulting in the clinical signs associated with the condition.

Other options do not fit because bacteria, viruses, and fungi are associated with other types of infections and diseases, rather than the specific parasitic infestation that defines mange. Bacterial infections could lead to secondary skin issues, viral diseases usually affect other bodily functions or systems, and fungi are more often associated with different conditions such as ringworm. Thus, the role of mites is unique to the pathology of mange.