_The treatment required for the sick animals_ is largely rest, a light diet and a comfortable, clean, well-ventilated stall, free from draughts.

Windows in the stall should be darkened. If the stable is cold, the body of the animal should be covered with a blanket and the limbs bandaged. Two ounces of alcohol and one drachm of quinine may be given three or four times daily. Small doses of raw linseed oil may be given if necessary.

Horses that are exposed to cold, wet weather or worked after becoming sick, frequently suffer from pneumonia, pericarditis, gastro-enteritis and other diseases. Such complications should be given prompt treatment.

It is very advisable to give a protective serum to horses that are shipped or transported long distances, and exposed to the disease in sale or transfer stables.

GLANDERS, FARCY.--This is a contagious and infectious disease of solipeds that is characterized by the formation of nodules and ulcers on the skin, nasal mucous membrane and lungs.

Although glanders is one of the oldest of animal diseases, it was not until 1868 that its contagious character was demonstrated. The disease is widely distributed. It became more prevalent in the United States after the Civil War. The vigorous control measures practised by the State and Federal health officers have greatly decreased the percentage of animals affected with glanders. At the present time the disease is more often met with in the large cities than in the agricultural sections of the country.

[Ill.u.s.tration: FIG. 114.--_Bacillus mallei_.]

_The specific cause of glanders is the Bacillus mallei_ (Fig. 114). This microorganism was discovered in 1882. It is present in the discharges from the nasal mucous membrane and the ulcers. These discharges may become deposited upon the feed troughs, mangers, stalls, harness, buckets, watering troughs, drinking fountains and attendants' hands and clothing.

Healthy horses living in the same stable with the glandered animals may escape infection for months. It is usually the diseased animal's mate, or the one standing in an adjoining stall, that is first affected. Catarrhal diseases predispose animals to glanders, as the normal resistance of the mucous membranes is thereby reduced. The most common routes by which the germ enters the body are by way of the digestive and respiratory tracts. It may enter the body through the uninjured mucous membranes of the respiratory tract and genital organs, or through wounds of the skin.

_The period of incubation_ may be from a few to many days.

_The symptoms_ may be _acute_ or _chronic_ in nature. The _acute form_ pursues a rapid course. It is frequently seen in mules and a.s.ses, and it may develop from the subacute or chronic form in horses. When the disease is acute, the animal has a fever, is stupid, does not eat, and may have a diarrhoea. In this form the lymphatic glands suppurate, the animal loses flesh rapidly and dies in from one to two weeks.

[Ill.u.s.tration: FIG. 115.--Nasal septum showing nodules and ulcers.]

The _chronic form_ is the most common. It develops slowly and lasts for years. The early symptoms of the disease (chilling and fever) usually escape notice. The first visible symptom is a nasal discharge of a dirty white color from one or both nostrils. This is usually scanty at first, and intermittent, but later becomes quite abundant. The discharge is very sticky, and adheres to the hair and skin. The most frequent seat of the disease is in the respiratory organs, lymph glands and skin. Nodules and ulcers appear on the nasal mucous membrane (Fig. 115), but they may be so high up as to escape notice. The ulcers are very characteristic of the disease. They are angry looking, with ragged, raised margins, and when they heal leave a puckered scar. The submaxillary glands may be enlarged, and at first more or less hard and painful, but later they become nodular and adhere to the jaw or skin. Nodules and ulcers may form on the skin over the inferior wall of the abdomen and the inside of the hind limbs and are known as "farcy buds." Lymphatic vessels near these buds become swollen and hard.

The animal loses flesh rapidly, does not withstand hard work, and the limbs usually swell.

It is sometimes difficult to diagnose the disease. The ulcers on the nasal mucous membranes and elsewhere are very characteristic, and when present enable the examiner to form a diagnosis. In cases of doubt, a bacteriological examination of the nasal discharge may be made, or we may resort to one or several of the various diagnostic tests. The Mallein test is quite commonly used. The sterilized products of a culture of the _B.

mallei_ are injected beneath the skin of the suspected animal. This causes a rise in body temperature and a hot, characteristic swelling at the point of injection in glandered animals.

[Ill.u.s.tration: FIG. 116.--_Streptococcus pyogenes equi_.]

_Treatment is not recommended_ at the present time. Nearly all of the States have laws which aim to stamp out the disease wherever found by killing all affected animals, and thoroughly disinfecting the stables, harness and everything which has been near the animal. Diseased animals should be carefully isolated until slaughtered, and all animals exposed to them should be subsequently tested for glanders.

CONTAGIOUS PLEUROPNEUMONIA (STABLE PNEUMONIA).--This is an infectious disease of solipeds that usually results in a fatal inflammation of the lungs and pleural membrane.

Many writers have described this disease as a.s.sociated with influenza, but it is frequently seen as a separate disease, usually involving only the lungs and pleurae. It is prevalent in several parts of the United States, more particularly the horse centers or large markets, where it appears in the form of epidemics. In several of these localities it is known as western or stable fever.

_The specific cause is not definitely known_. The _Streptococcus pyogenes equi_ (Fig. 116) is very commonly present. This germ grows in the diseased tissues. The disease is spread by direct or indirect contact, as when well or susceptible animals are placed in the same stable with an animal affected with the disease, or in stalls which have recently held diseased animals.

_The period of incubation_ is from four to ten days following exposure.

_The symptoms_ are those commonly seen at the beginning of an attack of simple pneumonia and pleurisy. They consist of chills, high fever, cough, depression, difficult and labored breathing and loss of appet.i.te. The disease usually runs a course of from one to three weeks. The death-rate is thirty per cent or more.

_The treatment_ is mainly preventive. Stables where horses having pleuropneumonia have been kept should be cleaned and disinfected by spraying the floors, stalls and walls with a four per cent water solution of a cresol disinfectant. It is advisable to subject all newly-purchased animals to a short quarantine period before allowing them to mix with the other animals in the stable. Exposed animals may be given a protective serum.

_The curative treatment_ is the same as recommended for the treatment of simple pneumonia and pleurisy.

QUESTIONS

1. What is the specific cause of distemper? Give the symptoms and treatment.

2. What are the different methods of spreading influenza? Give the symptoms and treatment.

3. Give the cause and methods of controlling glanders.

4. Give the cause and treatment of contagious pleuropneumonia.

CHAPTER x.x.x

INFECTIOUS DISEASES OF CATTLE

[Ill.u.s.tration: FIG. 117.--A case of "lumpy jaw."]

ACTINOMYCOSIS, "LUMPY JAW."--This is an infectious disease that is characterized by the formation of tumors and abscesses (Fig. 117), and the destruction of the infected tissues. The disease is common in cattle and usually affects the bones and soft parts of the head. In the United States, where the disease is known as "lumpy jaw" the jawbone is commonly affected.

In European countries the disease frequently involves the tongue, and the term "wooden tongue" is applied to it. The disease may affect regions of the body other than the head. Actinomycosis of the lungs sometimes occurs.

Swine and horses may be affected by this disease.

_The specific cause_ of actinomycosis is commonly known as the ray fungus (Fig. 118). This fungus grows on certain plants, and the animal usually contracts the disease by eating plants or roughage that have the fungus on them. Gra.s.ses having awns that are capable of wounding the mucous membrane of the mouth and penetrating the gums are most apt to produce the disease.

Young cattle that are replacing and erupting their teeth are most p.r.o.ne to "lumpy jaw." Conditions that favor bruising of the jaw and external wounds favor the development of actinomycosis.

The fungus grows in the tissues, causing an inflammatory reaction and destruction of the tissue. The ray fungus can be seen in the diseased tissue or the pus as yellowish, spherical bodies about the size of a grain of sand. Each of these bodies is formed by a large number of club-like bodies arranged about a central ma.s.s of filaments.

[Ill.u.s.tration: FIG. 118.--The ray fungus.]

_The local symptoms_ are characteristic (Fig. 117). The tumor may involve the soft tissues of the head. If the jawbone is affected the tumor feels hard and cannot be moved about. Sometimes it is soft and filled with pus.

Tumors of long standing may possess uneven, nodular surfaces and fistulous openings. When the tongue is affected, it is swollen and painful, and prehension and mastication of the food may be impossible. When the pharynx is the seat of disease, breathing and swallowing are difficult and painful.

Actinomycosis of the lungs may present the appearance of a chronic pulmonary affection. If the disease involves the head and lungs, the animal may become unthrifty and emaciated. In doubtful cases a microscopic examination of a piece of the tumor, or some of the pus, may be necessary.

_The treatment is surgical and medicinal_. Small, external tumors may be removed by an operation. Sometimes an incision is made into the diseased tissue and a caustic preparation introduced.

The most desirable method of treatment is the administration of large doses of iodide of pota.s.sium in a drench, or in the drinking water. The dose is from one to three drachms daily for a period of seven to fourteen days. The size of the dose depends on the size of the animal and its susceptibility to iodism. An animal weighing 1000 pounds may be given two drachms. The treatment is kept up until the symptoms of iodism develop. The condition is indicated by a loss of appet.i.te and a catarrhal discharge from the eyes and nostrils. When this occurs, the treatment should be stopped, and the animal drenched with one-half pound of Epsom salts, and the dose repeated after three or four days. After an interval of two weeks, the iodide of pota.s.sium treatment should be repeated if the growth of the tumor is not checked.

EMPHYSEMATOUS ANTHRAX, "BLACK LEG."--"Black leg" is an acute infectious disease of cattle that is characterized by lameness and superficial swellings in the region of the shoulder, quarter or neck. The swellings are hot and painful and usually contain gas.

_The specific cause_ of "black leg" is a rod-shaped, spore-producing germ, the bacillus of emphysematous anthrax (Fig. 119). This germ possesses great vitality, and may live indefinitely in the soil. It has been known to live for years in clay and undrained soils. Young animals that are in high condition are predisposed to the disease.

The germ enters the body through abrasions in the skin and mucous membrane of the mouth and intestines.

"Black leg" is a common disease of young cattle in all sections of the country where cattle-raising is engaged in extensively. Outbreaks of the disease are most prevalent in the early spring after the snow has melted, and in the late summer in localities where cattle graze over the dried-up ponds and swampy places in the pasture. The germs of black leg may be carried from a farm where the disease is prevalent to non-infected premises by surface water. The opening up of drainage ditches through stock-raising communities may be followed by outbreaks of the disease.

[Ill.u.s.tration: FIG. 119.--Bacillus of emphysematous anthrax.]

_The symptoms_ of black leg develop quickly and may terminate fatally in a few hours. These are general dulness, stiffness, prostration and loss of appet.i.te. Lameness is a prominent symptom. The animal may show a swelling in the regions of the shoulder and hindquarters or on other parts of the body. The swelling is very hot and painful at first, but if the animal lives for a time, it becomes less tender, crackles when pressed on and the skin may feel cold and leathery. Fever is a constant symptom. In the highly acute form of the disease nervous symptoms, such as convulsions and coma, occur.

_The tissue changes_ in the region of the swelling are characteristic. An incision into the swelling shows a b.l.o.o.d.y, dark exudate and the surface of the muscular tissue is dark. Frothy, b.l.o.o.d.y liquid escapes from the mouth, nose and a.n.u.s.