Scabies in animals

Itch mites in dogs, cats, rabbits and guinea pigs are briefly mentioned in Appendix A. People, who own a dog or a cat, usually discover the problem at a fairly late point. Scabies in dogs and cats must be controlled because the animals suffer from itching and because the mites can cause pseudo-scabies with the people who come into contact with the pets.

Dogs
Dogs only have one kind of itch mites. British studies have shown that 1% of English dogs suffer from canine scabies (mange). In infected dogs, crusty rashes are found on the edges of ears as well as in the elbow region. You may get an early suspicion of scabies in dogs by if the dog make scratching movements in the air with a hind leg, is a sign of increased irritability where you touched it.

Fox scab
Foxes in the wild are sometimes infected by scabies to such an extent that mites fall off them wherever they go. Therefore, itch mites from infected foxes can infect, for example, dogs. If you use your dog for hunting and to hunt foxes from their burrows, you should treat your dog with a mite-repellent, for example, a pour-on product in the coat before hunting.

Cats
There are two kinds of itch mites, which infect cats. One which is similar to the human itch mite, and a smaller, slightly different itch mite. The smallest of the mites, Notoedres cati, is rare in our parts of the world. However, it is seen from time to time. It can infect dogs. Scabies in cats, Feline Scabies (Notoedric Mange) appear as a scaly, crusty rash on the outer parts of the ears, between the ears and in the face where the skin can be heavily thickened.
Each species of itch mites each have their favorite places on the cats. In cows, the tail heads are popular with the itch mites, and in pigs, mites are almost exclusively found on the inside of the ears.

Diagnosis
The veterinarian will help diagnose the animal. The mites are detected through a microscope. Samples of the suspicious crust are removed with a scalpel or sharp spoon.

Treatment
If you have doubts about the treatment, your veterinarian can help you. The pesticides are available at the pharmacy and you can choose to both diagnose and treat the pet yourself. Please be aware that some pesticides can cause illness in young cats, as well as weak cats. Therefore, be sure to read the instructions carefully before applying the pesticide. Pesticides against scabies in animals also work against lice on the same animals.

Scabies from animals

Physiological types of the human itch mite, Sarcoptes scabiei, are found on a wide variety of mammals, with which we often come into contact.

Pseudo-scabies
Itch mites from animals may, when they given the opportunity, taste the skin of the humans with which the infected animal is in contact. However, they cannot settle in the skin, and consequently pseudo-scabies disappear shortly after the actual host animal has been treated or when contact with the animal stops.

The diagnosis is difficult to make. You might see small crusty papules of the skin – not actual burrows. Itching is the most prominent symptom and is often what makes people seek medical advice. Generally, from the papules’ location on the body, you may suspect that they are caused by contact with an infected animal. The papules’ location is closely linked to the way in which you associate with the animal. Scabies from cows may appear in the back of the neck, shoulders and wrists. This makes sense when you see a farmer attach milking machine to cows. The itch mites easily penetrate fabrics. Dogs or cats in bed allows for papules and itching all over the body. Otherwise, pseudo-scabies from cats and dogs are usually found on the flexible parts of the arms, chest, abdomen, thighs and lower legs. Be aware that fur mites from dogs and cats can cause similar symptoms in humans.

Waiting period
In order to be infected with pseudo-scabies, you must have been in contact with the infected animal for a relatively long period of time – 3 weeks or more. Scabies and pseudo-scabies are of allergic reaction to the mites’ presence in the skin. The first mites that burrow, does not cause any symptoms. They merely activate the immune system. It is not until a few weeks after the infection that the skin will react to new mites with papules and itching. If you have had scabies before – either human scabies or pseudo-scabies – your immune system is already activated and your skin will react more quickly to the pseudo-scabies.

Appearance

Itch mite seen from the side

Fig. 72 An itch mite seen from the side, from above and from below (Mellanby)

The adult female itch mite is only 1/3 mm long. The other stages, which are most numerous, are smaller. The color is brown and white.

The body is round and the rear legs are relatively long. When the mites dig, it extends the hind legs in order to get mouthparts at an appropriate angle when biting. The mite’s body is grooved and covered with small spines, which possibly help it dig.

Itch mites

Itch mite

Itch mite

Small mites that burrow into the outermost layer of skin – the stratum corneum – are collectively called itch mites. There are many kinds of itch mites, but luckily for us, they each stick to one animal species. The species that are most important to us is called Sarcoptes scabiei. The word scabies is Latin and means rash or itching.

Physiological types. Humans have their own itch mite, Sarcoptes scabiei typicus. Other varieties of the same species infest other mammals. They look so much like the human itch that they are considered different physiological types of the same species. Examples of such a physiological difference can be that the cow’s itch mite is active in temperatures down to about 8 °C. The human itch mite cannot endure temperatures below 16 °C. In practice, it is not possible to distinguish between Sarcoptes scabiei from different host animals. The different types of Sarcoptes scabiei transmit between different kinds of host animals, but they can only breed on host animals of the same kind as the one they came from.

Scabies is characterized by intense itching and rash where the mites live. You cannot feel the mites digging in the skin. The disease scabies is the host’s reaction to the mites in the skin. Controlling the itch mites is carried out by applying a pesticide that kills both mites and eggs.

The following section deals with the itch mites in humans.