Mange

This is a contagious skin disease caused by one of several species of mites. The disease is transmitted when larvae, nymphs, or fertilized females are transferred to a susceptible host. Mange can be transmitted directly from horse to horse or indirectly through contaminated objects that harbor the mites or through contaminated stabling quarters.

Mange is characterized by loss of hair, itching, and intense irritation to the skin. In severe cases, this can lead to debilitation; in drastic instances, it can even lead to death.

The incubation period is two to six weeks and depends on the number of mites transferred, the site of transfer, and host susceptibility. A horse in poor physical condition, for example, would be more susceptible than a horse on a healthy diet and exercise program. Mange was prevalent some years ago, especially in large groups of horses, but is not nearly as common today.

There are four basic types of mange. They are as follows:

Sarcoptic Mange This is caused by the mite known as Sarcoptes equi, which burrows into the skin. The female mite is the first to attack as she creates tubular burrows in which to lay her eggs. The burrow is created as the female literally eats her way along. As she travels, she leaves behind in the burrow 10 to 40 eggs, along with her excrement. When the young hatch, they compound matters by starting burrows of their own. The burrows of both the female and the young, for the most part, lie very close to the skin surface. The irritation that results from this burrowing is intense, and afflicted horses will be seen to rub almost constantly.

Hair will fall out of the affected patches of skin and scabs will form. The rubbing and scratching of affected horses often cause raw spots on the skin that serve as open doors for the invasion of other harmful agents.

The female mite is a hardy creature that can live in moist situations in tack or in the woodwork of stables. Its greatest enemy is a dry condition.

Treatment of afflicted horses consists of applying mite-killing solutions by spraying, rubbing, or dipping. Toxaphene dip is reported to give control with one application.

Psoroptic Scapies--This form of mange is a notifiable and quarantinable disease in the countries in which it is found. These mites do not burrow into the skin as the sarcoptes do, but are scavengers on the skin surface. They have piercing mandibles which enable them to penetrate the skin and suck its juices. As a result, they produce a great deal of irritation to the horse, but are easily controlled by applying mite-killing solutions to the skin.

Unfortunately, they, too, have the ability to exist for long periods outside the body in tack, bedding, and woodwork under moist conditions.

These mites are found primarily in sheltered areas of the body, such as under the forelock and mane, at the root of the tail, under the chin, between the hind legs, and in the folds of skin where the forearm joins the chest.

Treatment is the same as that for sarcoptic mange.

Chorioptic MangeThis is also known as leg mange. This variety of mange pretty much confines itself to the cannon bone area, especially on the rear legs. In severe cases, skin lesions can spread to the flanks, shoulder, and neck. The disease is characterized by severe itching, scaling, crusting, and thickening of the skin. This type of mange is seen more often in the winter months than during the summer. Most apt to be afflicted are draft horses with "feathered" lower legs. Treatment is the same as for the two types of mange listed above.