Mange in dog and causative agents

Mange means an infection of the skin with mites, which usually results in loss of hair and scaly skin.
There are different mites which affect pets, the most common of which are:
1. The sarcoptic mite or dog scabies mite, it is common in dogs.

2. Ear mites - These are very common in cats and also occur in dogs.
3. Demodex, which cause demodectic mange. There are two types which occur in dogs, namely localized and generalized.

4. Cheyletiellosis, or 'walking dandruff', which can occur in both dogs and cats.
Mites are much like smaller versions of ticks and are roughly oval to circular short-legged insects barely visible to the naked eye. These are permanent parasites; each of their life stages relies on a host, and only survive for a short while when separated from that host, usually less than a week. They can spend their whole life on the same host.
Transmission between hosts is by direct contact due to the mite's short lifespan off-host. Generally, mites of dogs and cats feed on skin debris. Some can also feed on tissue fluid or blood. Enzymes are secreted by the mite from its salivary glands when it bites into the skin, to digest its 'food'.
Mites cause problems due to their burrowing behavior, which can damage layers of the skin, causing irritation and inflammation. Allergies to mite saliva or the mites themselves can cause severe itching in hypersensitive animals. Non-burrowing mites can cause irritation as they walk along the skin surface.