Dog Mites And Canine Mange
Animals tend to be referred to as mangy when they look unkempt, dirty and scruffy. However many diseases can cause this appearance, so unless they actually have mites, they aren't mangy in the true sense of the word.
Mites are annoying little critters found worldwide. There are thousands of different species, but only a few hundred are associated with diseases in animals or humans. Many of the remainder live free in the environment and are not parasitic. Mites can affect many different animals, including most domestic and wild animals, as well as humans.
There are several different mites which affect our pets, the most common of which are:
- the sarcoptic mite, or dog scabies mite (Sarcoptes scabei var canis). Sarcoptic mange is common in dogs. Scabies in cats is caused by a different parasite, called Notoedres cati.
- ear mites (Otodectes cynotis). These are very common in cats and also occur in dogs.
- demodex sp. mites, which cause demodectic mange. There are two types which occur in dogs, namely localized and generalized. Different species of the parasite affect dogs and cats, though this type of mange occurs only rarely in cats.
- cheyletiellosis, or 'walking dandruff', which can occur in both dogs and cats.
"Those which parasitize dogs and cats 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."
Mites are much like smaller versions of ticks, with an average body length of 0.2 to 0.4mm. Most are roughly oval to circular short-legged insects barely visible to the naked eye. Like other arthropods, including insects, they have an external skeleton made of chitin covering their bodies to prevent them from being squashed.
Mites are similar to ticks, spiders and scorpions. All are arachnids and as adults all have four pairs of jointed, bendable legs and a body divided into two segments. Those which parasitize dogs and cats 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 entire life on the same host.
Generally, transmission between hosts is by direct contact, due to the mite's short lifespan off-host. Some mites can be transferred to humans and cause intense itching, but the infection of humans by dog or cat mites is usually only short-lived.
"Mites cause problems due to their burrowing behavior, which can damage layers of the skin, causing irritation and inflammation."
Unlike parasites such as worms, most mites live on your pet's exterior. Those targetting cats and dogs are external, living either in tunnels in the skin surface (burrowing mites), on the skin surface (non-burrowing mites), or in hair follicles (follicular mites).
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 pre-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.
Mange can refer to infection with any of these mites and while they are all similar creatures, the treatments used for different types of mites vary.
|Payne, P.A., Dryden, M.W., Carter,G.R. External Parasitic Diseases of Dogs and Cats. In: A Concise Guide to Infectious and Parasitic Diseases of Dogs and Cats International Veterinary Information Service, Ithaca NY. www.ivis.org
Tilley, L.P., Smith, F.W.K. The Five Minute Veterinary Consult Canine and Feline. Second Edition. Lippincott Williams & Wilkins, Baltimore, 2000.