Special Report on Diseases of Cattle Part 60

It has likewise been a.s.serted that the disease may be transmitted by various kinds of insects which carry the bacilli from the sick and inoculate the healthy as they pierce the skin. When infection of the blood takes place from the intestines the carbuncles may be absent. It has already been stated that since anthrax spores live for several years, the disease may be contracted in winter from feed gathered on permanently infected fields.

The disease may appear sporadically, i. e., only one or several animals may be infected while the rest of the herd remain well, or it may appear as an epizootic attacking a large number at about the same time.

_Symptoms._--The symptoms in cattle vary considerably, according as the disease begins in the skin, in the lungs, or in the intestines. They depend also on the severity of the attack. Thus we may have what is called anthrax peracutus or apoplectiform, when the animal dies very suddenly as if from apoplexy. Such cases usually occur in the beginning of an outbreak. The animal, without having shown any signs of disease, suddenly drops in the pasture and dies in convulsions, or one apparently well at night is found dead in the morning.

The second type (anthrax acutis), without any external swellings, is the one most commonly observed in cattle. The disease begins with a high fever.

The temperature may reach 106 to 107 F. The pulse beats from 80 to 100 a minute. Feeding and rumination are suspended. Chills and muscular tremors may appear and the skin show uneven temperature. The ears and base of the horns are cold, the coat staring. The animals are dull and stupid and manifest great weakness.

To these symptoms others are added in the course of the disease. The dullness may give way to great uneasiness, champing of the jaws, spasms of the limbs, kicking and pawing the ground. The breathing may become labored.

The nostrils then dilate, the mouth is open, the head raised, and all muscles of the chest are strained during breathing, while the visible mucous membranes (nose, mouth, r.e.c.t.u.m, and v.a.g.i.n.a) become bluish. If the disease has started in the bowels, there is much pain, as shown by the moaning of the animal; the discharges, at first firm, become softer and covered with serum, mucus, and blood.

As the disease approaches the fatal termination the weakness of the animal increases. It leans against supports or lies down. Blood vessels may rupture and give rise to spots of blood on the various mucous membranes and b.l.o.o.d.y discharges from nose, mouth, r.e.c.t.u.m, and v.a.g.i.n.a. The urine not infrequently contains blood (red water), and death ensues within one or two days.

A third type of the disease (anthrax subacutus), which is rarely observed, includes those cases in which the disease is more prolonged. It may last from three to seven days and terminate fatally or end in recovery. In this type, the symptoms are practically as described in the acute form, only less marked.

In connection with these types of intestinal anthrax, swellings may appear in different parts of the body under the skin, or the disease may start from such a swelling, caused by the inoculation of anthrax spores in one of the several different ways already described. If the disease begins in the skin, it agrees in general with the subacute form in prolonged duration, and it may occasionally terminate in recovery if the swellings are thoroughly incised and treated.

_Lesions._--These swellings appear as edemas and carbuncles. The former are doughy tumors of a more or less flattish form pa.s.sing gradually into the surrounding healthy tissue. As a rule, they are situated beneath the skin in the fatty layer, and the skin itself is at first of healthy appearance, so that they are often overlooked, especially when covered with a good coat of hair. When they are cut open they are found to consist of a peculiar, jellylike ma.s.s of a yellowish color and more or less stained with blood.

The carbuncles are firm, hot, tender swellings, which later become cool and painless and undergo mortification. The edemas and carbuncles may also appear in the mouth, pharynx, larynx, in the tongue, and in the r.e.c.t.u.m.

The bodies of cattle which have died of anthrax soon lose their rigidity and become bloated, because decomposition sets in very rapidly. From the mouth, nose, and a.n.u.s bloodstained fluid flows in small quant.i.ties. When such carca.s.ses are opened and examined it is found that nearly all organs are sprinkled with spots of blood or extravasations of various sizes. The spleen is enlarged from two to five times, the pulp blackish and soft and occasionally disintegrated. The blood is of tarry consistency, not firmly coagulated, and blackish in color. In the abdomen, the thoracic cavity, and in the pericardium, or bag surrounding the heart, more or less blood-stained fluid is present. In addition to these characteristic signs, the carbuncles and swellings under the skin, already described, will aid in determining the true nature of the disease. The most reliable method of diagnosis is the examination of the blood and tissues for anthrax bacilli, which requires a trained bacteriologist. The cases of fatal anthrax number from 70 to 90 per cent, and are usually more numerous at the first outbreak of the disease.

_Differential diagnosis._--The diagnosis from blackleg may be made by noting the subcutaneous swellings which appear upon the patient. Those of blackleg are found to crackle under pressure with the finger, owing to the presence of gas within the tissues, while the tumors of anthrax, being caused by the pressure of serum, are entirely free from this quality and have a somewhat doughy consistence. The tumors of blackleg are usually on the shoulder or thigh and are not found so frequently about the neck and side of the body as are the swellings of anthrax. The blood of animals dead of blackleg is normal, and the spleen does not appear swollen or darkened, as in those affected with anthrax. The chief differences between anthrax and Texas fever are that the course of the former is more acute and the blood of the animal is dark and of a tarlike consistence, while in the latter it is thinner than normal. The presence of Texas-fever ticks on the cattle would also lead one to suspect that disease in regions where cattle are not immune from it.

_Treatment._--In cases which originate from external wounds, the swellings should be opened freely by long incisions with a sharp knife and washed several times daily with carbolic-acid solution (1 ounce to a quart of water). Care should be taken to disinfect thoroughly any fluid discharge that may follow the incision. When suppuration has set in the treatment recommended in the chapter on wounds should be carried out.

In the treatment of animals showing symptoms of anthrax, the serum recommended under the next heading of "Prevention" should be administered in large doses. Animals showing only a high temperature with no other symptoms of the disease should be given from 30 to 50 cubic centimeters of the serum, but if the gravity of the disease is p.r.o.nounced 100 cubic centimeters should be administered. In most instances a drop in temperature may be observed and a diminis.h.i.+ng of the severity of the symptoms. At times, however, a relapse occurs about the second or third day following the serum injection, when it becomes necessary to administer another dose of serum. It has been proved that animals affected with anthrax may recover after injections of potent serum.

_Prevention._--In this disease prevention is the most important subject demanding consideration. The various means to be suggested may be brought under two heads: (1) The surroundings of the animal, and (2) preventive inoculation.

(1) Surroundings.--What has already been stated of those conditions of the pastures which are favorable to anthrax, after a little thought, will suggest to most minds some of the preventive measures which may be of service in reducing losses in anthrax localities. All that conduces to a better state of the soil should be attempted. The State or Nation, by appropriate engineering, should do its share in preventing frequent inundations. If pools of stagnant water exist in the pastures, or if any particular portions are known by experience to give rise to anthrax, they should be fenced off. Efforts should likewise be made toward the proper draining of swamp lands frequented by cattle. Sometimes it has been found desirable to abandon for a season any infected or dangerous pastures. This remedy can not be carried out by most farmers, and it is liable to extend the infected territory. In some instances withdrawal of cattle from pastures entirely and feeding them in stables is said to have reduced the losses.

It is of the utmost importance that carca.s.ses of animals which have died of anthrax be properly disposed of, as every portion of such animal contains the bacilli, ready to form spores when exposed to the air. Perhaps the simplest means is to bury the carca.s.ses deep, where they can not be exposed by dogs or wild animals. It may be necessary to bury them on the pasture, but it is better to remove them to places not frequented by susceptible animals and to a point where drainage from the graves can not infect any water supply.

If they are moved some distance it must be borne in mind that the ground and all objects which have come in contact with the carca.s.s should be disinfected. This is best accomplished with chlorid of lime. For was.h.i.+ng utensils, etc., a 5 per cent solution may be prepared by adding 3 ounces to 2 quarts of water. This should be prepared fresh from the powder, and it is but little trouble to have a small tin measure of known capacity to dip out the powder, to be added to the water whenever necessary. The carca.s.s and the ground should be sprinkled with powdered chlorid, or, if this is not at hand, an abundance of ordinary, unslaked lime should be used in its place.

The removal of carca.s.ses to rendering establishments is always fraught with danger, unless those who handle them are thoroughly aware of the danger of scattering the virus by careless handling in wagons that are not tight. As a rule, the persons in charge of such transfer have no training for this important work, so that deep burial is to be preferred. Burning large carca.s.ses is not always feasible; it is, however, the most certain means of destroying infectious material of any kind, and should be resorted to whenever practicable and economical. All carca.s.ses, whether buried, rendered, or burned, should be disposed of unopened. When stables have become infected they should be thoroughly cleaned out, and the solution of chlorid of lime freely applied on floors and woodwork. The feed should be carefully protected from contamination with the manure or other discharges from the sick.

(2) Preventive inoculation.--One of the most important discoveries in connection with the disease was made by Louis Pasteur in 1881, and consisted in the new principle of producing immunity by the inoculation of weakened cultures of the bacillus causing the disease. This method has been quite extensively adopted in France, and to some extent in other European countries, and in the United States. The fluid used for inoculation consists of bouillon in which modified anthrax bacilli have multiplied and are present in large numbers. The bacilli have been modified by heat so that to a certain degree they have lost their original virulence. Two vaccines are prepared. The first or weaker, for the first inoculation, is obtained by subjecting the bacilli to the attenuating effects of heat for a longer period of time than in the case of the second, or stronger vaccine, for a second inoculation some 12 days later.

There are several difficulties inherent in the practical application of Pasteur's vaccine. Among them may be mentioned the variable degree of attenuation of different tubes of the vaccine and the varying susceptibility of the animals to be inoculated. The use of this vaccine is increasing, nevertheless, and has reduced the mortality in the affected districts from an average of 10 per cent in the case of sheep, to less than 1 per cent, and from 5 per cent with cattle, to less than one-half of 1 per cent.

It is very important to call attention to the possibility of distributing anthrax by this method of protective inoculation, as the bacilli themselves are present in the culture liquid. It is true that they have been modified and weakened by the process adopted by Pasteur, but it is not impossible for such modified virus to regain its original virulence after it has been scattered broadcast by the inoculation of large herds. It is obviously unsafe to have such vaccine injected by a layman; instead, it should be handled only by a competent veterinarian.

There are other disadvantages in this method of vaccination, and they all must be given due consideration. The unstable keeping quality of the Pasteur vaccine is a very important factor to be considered. Experience in this line has proved that Pasteur vaccine may deteriorate within a very short time after its preparation, and in repeated instances it has proved inert within three months of its preparation. When exposed to warm temperature and light, it deteriorates very rapidly; and when it is considered that the products of manufacturers may be stored under unfavorable conditions in branch houses and on the shelves of rural drug stores, the loss of potency can be readily explained. These deficiencies have been recognized by many investigators, and because of the superior keeping qualities particular attention has been directed toward the preparation of a spore vaccine by Zenkowsky of Russia, Detre of Hungary, and Nitta of j.a.pan. For the purpose of producing a spore vaccine it is desirable to use a peptone-free agar medium, and after inoculation with an attenuated culture of the anthrax bacillus, it is allowed to grow at a temperature of 37 C. for 4 to 7 days. By this time an abundance of spores will have formed. The growth is then collected in sterile flasks and heated to a temperature of 60 C. for one-half hour to destroy the vegetative forms of the organism. If it is desired to use for vaccination one million spores, it is advisable to dilute the vaccine to a quant.i.ty of which 1 cubic centimeter would contain this number. Of such a vaccine 1 cubic centimeter would const.i.tute the dose for cattle and horses. In all forms of vaccination against anthrax in sheep the greatest care must be exercised, as these animals are very susceptible to the disease, and at times vaccines which have no ill effects on cattle will prove fatal to sheep. Therefore the dose of the spore vaccine for sheep should not be more than one-fourth of that given to cattle.

Sclavo, Sobernheim, and others have established that injections of increasing quant.i.ties of virulent cultures into immune animals produced a serum which has great protective value against anthrax. Such protective serum may be produced in the various susceptible animals.

For immunization purposes it is advisable to use the simultaneous method; that is, both the spore vaccine and the anthrax serum should be injected.

It is desirable to divide the herd to be treated into groups of ten or twelve and inject, first, each animal of the group with the serum, following this with the injection of the spore vaccine. The serum should be injected on one side, either on the neck or back of the shoulder, and the spore vaccine on the other side, injections being made subcutaneously. In herds in which the disease has already made its appearance it is necessary to take the temperatures of all the animals and to subject to the simultaneous vaccination only those that show no rise in temperature. All others should be given the serum-alone treatment in doses varying in accordance with the severity of the symptoms manifested by the individual animals. If the examination reveals a considerable number of infections, it is advisable to use the serum alone for all the animals, and in three or four weeks to revaccinate by the simultaneous method. The dosage should depend on the potency of the serum, serum of a high potency naturally being most desirable. Thus serum in 10 cubic centimeter doses for large animals, and 3 to 5 cubic centimeter doses for smaller ones, has been found to be effective in producing a temporary immunity.

As anthrax is entirely different from blackleg, vaccine for the latter does not act as a preventive against the former.

ANTHRAX IN MAN (MALIGNANT PUSTULE, OR CARBUNCLE).

Anthrax may be transmitted to man in handling the carca.s.ses and hides of animals which have succ.u.mbed to the disease. The infection usually takes place through some abrasion or slight wound of the skin into which the anthrax spores, or bacilli, find their way. The point of inoculation appears at first as a dark point or patch, compared by some writers to the sting of a flea. After a few hours this is changed into a reddened pimple, which bears on its summit, usually around a hair, a yellowish blister, or vesicle, which later on becomes red or bluish in color. The burning sensation in this stage is very great. Later this pimple enlarges, its center becomes dry, gangrenous, and is surrounded by an elevated, discolored swelling. The center becomes drier and more leatherlike, and sinks in as the whole increases in size. The skin around this swelling or carbuncle is stained yellow or bluish, and is not infrequently swollen and doughy to the touch. The carbuncle itself rarely grows larger than a pea or a small nut, and is but slightly painful.

Anthrax swellings or edemas, already described as occurring in cattle, may also be found in man, and they are at times so extensive as to produce distortion in the appearance of the part of the body on which they are found. The color of the skin over these swellings varies according to the situation and thickness of the skin and the stage of the disease, and may be white, red, bluish, or blackish.

As sooner or later these carbuncles and swellings may lead to an infection of the entire body, and thus be fatal, surgical a.s.sistance should at once be called if there is well-grounded suspicion that any swellings resembling those described above have been caused by inoculation with anthrax virus.

Inasmuch as physicians differ as to medicinal treatment of such accidents in man, it would be out of place to make any suggestions in this connection.

Extensive data are available, however, on the effectiveness of anthrax serum for the treatment of the disease in man. It is recommended that from 30 to 40 cubic centimeters of serum be injected in three or four different places. Should no improvement follow in 24 hours additional injections of 20 to 30 cubic centimeters should be administered.

In most instances the results are favorable, and this treatment is acknowledged to be superior to any other mode of treatment known for the disease.

To show that the transmission of anthrax to man is not so very uncommon, we take the following figures from the 1890 report of the German Government: The attention of the authorities was brought to 111 cases, of which 11 terminated fatally. The largest number of inoculations were caused by the slaughtering, opening, and skinning of animals affected with anthrax; hence, the butchers suffered most extensively. Of the 111 thus affected, 36 belonged to this craft. Infected shaving brushes also are very dangerous.

In addition to anthrax of the skin (known as malignant pustule), human beings are subject, though very rarely, to the disease of the lungs and the digestive organs. In the former case the spores are inhaled by workmen in establishments in which wool, hides, and rags are worked over, and it is therefore known as woolsorter's disease. In the latter case the disease is contracted by eating the flesh of diseased animals which has not been thoroughly cooked. These forms of the disease are more fatal than those in which the disease starts from the skin.

BLACKLEG.

[Pl. XLII.]

Blackleg, black quarter, quarter ill, symptomatic anthrax, charbon symptomatique of the French, Rauschbrand of the Germans, is a rapidly fatal, infectious disease of young cattle, a.s.sociated with external swellings which emit a crackling sound when handled. This disease was formerly regarded identical with anthrax, but investigations by various scientists in recent times have definitely proved the entire dissimilarity of the two affections, both from a clinical and a causal standpoint. The disease is produced by a specific bacillus, readily distinguishable from that causing anthrax. (Pl. XXVIII, fig. 4.) Cattle between 6 months and 2 years of age are the most susceptible. Sucking calves under 6 months are rarely attacked, nor are they so susceptible to inoculation as older animals. Cattle more than 2 years of age may become affected, but such cases are infrequent. Sheep and goats may also contract the disease, but man, horses, hogs, dogs, cats, and fowls appear to be immune.

Like anthrax, blackleg is more or less restricted to definite localities.

There are certain pastures upon which the disease regularly appears in the summer and fall of the year. As to any peculiarities of the soil nothing is definitely known. Some authors are inclined to regard moist, undrained, and swampy pastures favorable to this disease, but these theories will hardly hold, as it is found in all kinds of soil, in all alt.i.tudes, at all seasons of the year, and under various climatic conditions. It occurs in this country from the Atlantic to the Pacific and from Mexico to Canada, but it is more prevalent in the Western and Southwestern States. In Europe it exists in France, various parts of Germany, in Belgium, Norway, Denmark, Italy, and in the Alps of Switzerland. In Africa it occurs in Algeria and to some extent in Natal and bordering countries. In South America it prevails quite extensively throughout Argentina. Cattle in Cuba and Australia also suffer.

_Cause._--The cause of the disease is a bacillus resembling in some minor respects the anthrax bacillus and differing but little from it in size. It also possesses the power of forming within itself a spore. In Plate XXVIII, figure 4, this is represented as an uncolored spot located in one end of the rod, which is enlarged so that the rod itself appears more or less club-shaped. What has already been stated concerning the significance of the spore of the anthrax bacillus applies equally well to these bodies.

They resist destructive agents for a considerable time, and may still produce disease when inoculated after several years of drying. This fact may account for the occasional appearance of blackleg in stables. In order to meet the requirements for the development of the spores, which takes place only in the absence of the atmosphere, it is necessary that the wound be very small and deep enough to penetrate the subcutaneous tissue.

Several observers have found this organism in the mud of swamps. By placing a little of the mud under the skin, the disease has been produced.

Since the disease may be produced by placing under the skin material containing the specific bacilli and spores, it has been a.s.sumed that cattle contract the disease through wounds, princ.i.p.ally of the skin, or very rarely of the mouth, tongue, and throat. Slight wounds into which the virus may find access may be caused by barbed wire, stubbles, thorns, briers, gra.s.s burs, and sharp or pointed parts of feed. Infection by way of digestive tract is also probable.

_Symptoms and lesions._--The symptoms of blackleg may be either of a general or of a local nature, though more frequently of the latter. The general symptoms are very much like those belonging to other acute infectious or bacterial diseases. They begin, from one to three days after the infection has taken place, with loss of appet.i.te and of rumination, with dullness and debility, and a high fever. The temperature may rise to 107 F. To these may be added lameness or stiffness of one or more limbs, due to the tumor or swelling quite invariably accompanying the disease.

After a period of disease lasting from one to three days the affected animal almost always succ.u.mbs. Death is preceded by increasing weakness, difficult breathing, and occasional attacks of violent convulsions.

The most important characteristic of this disease is the appearance of a tumor or swelling under the skin a few hours after the setting in of the const.i.tutional symptoms described above. In some cases it may appear first.

This tumor may be on the thighs (hence "blackleg," "black quarter"), the neck, the shoulder, the breast, the flanks, or the rump; never below the carpal (or knee) and the hock joint. It more rarely appears in the throat and at the base of the tongue. The tumor, at first small and painful, spreads very rapidly both in depth and extent. When it is stroked or handled a peculiar crackling sound is heard under the skin; this is due to a collection of gas formed by the bacilli as they multiply. At this stage the skin becomes dry, parchment-like, and cool to the touch in the center of the tumor. If the swelling is cut into, a frothy, dark-red, rather disagreeable-smelling fluid is discharged. The animal manifests little or no pain during the operation.

As it is frequently desirable to know whether the disease is anthrax or blackleg, a few of the most obvious post-mortem changes may here be cited.

The characteristic tumor with its crackling sound when stroked has already been described. If after the death of the animal it is more thoroughly examined, it will be noted that the tissues under the skin are infiltrated with blood and yellowish, jellylike material and gas bubbles. The muscular tissue beneath the swelling may be brownish or black, shading into dark red. (Pl. XLII.) It is soft, easily torn and broken up. The muscle tissue is distended with numerous smaller or larger gas-filled cavities, often to such extent as to produce a resemblance to lung tissue. Upon incision it does not collapse perceptibly, as the gas cavities are not connected with one another.

In the abdomen and the thorax bloodstained fluid is not infrequently found, together with bloodstaining of the lining membrane of these cavities. Blood spots (or ecchymoses) are also found on the heart and lungs. The liver is congested, but the spleen is always normal in appearance.