Actinomycosis may also involve the udder, the spermatic cord of castrated animals, the v.a.g.i.n.a, and, when it becomes generalized, the brain, liver, spleen, and muscular tissue.
Actinomycosis may in some cases be confounded with tuberculosis. The diagnosis does not offer any difficulties, since the presence of the actinomyces fungus at once removes any existing doubts. As has already been intimated, these grains, simulating sulphur b.a.l.l.s, are visible to the naked eye, and their nature is readily determined with the aid of a microscope.
The course of the disease is quite slow. As the tumors grow they may interfere with the natural functions of the body. According to their situation, mastication, rumination, or breathing may be interfered with, and in this way the animal may become emaciated. Actinomycosis of the jawbones leads to destruction of the teeth and impedes the movements necessary to chewing the feed. Similarly, when the disease attacks the soft parts of the head obstructions may arise in the mouth by an inward growth of the tumor. If tumors exist in the pharynx they may partially obstruct the movements necessary to breathing, or close the air pa.s.sages and cause partial suffocation. Actinomycosis of the tongue, in interfering with the many and varied movements of this important organ, is also a serious matter. There is no reason to suppose that the localized disease interferes with the general health in any other way than indirectly until internal organs, such as the lungs, become involved.
A very small proportion of the cases may recover spontaneously, the tumors being encysted or undergoing calcification. In most cases the disease yields readily to proper treatment, and about 75 per cent of the affected animals may be cured.
_Prevention._--The question as to how and where animals take this disease is one concerning which we are still in the stage of conjecture, because so far we possess very little information concerning the life history of the actinomyces itself. The quite unanimous view of all observers is that animals become infected from the feed. The fungus is lodged upon the plants and in some way enters the tissues of the head, the lungs, and the digestive tract, where it sets up its peculiar activity. It is likewise generally believed that the fungus is, as it were, inoculated into the affected part. This inoculation is performed by the sharp and pointed parts of plants which penetrate the mucous membrane and carry the fungus with them. The disease is therefore inoculable rather than contagious. The mere presence of the diseased animal will not give rise to disease in healthy animals unless the actinomyces grains pa.s.s directly from the diseased into some wound or abrasion of the healthy or else drop upon the feed which is consumed by the healthy. Not only are these views deducible from clinical observation, but they have been proved by the positive inoculation of calves and smaller animals with actinomyces. The danger therefore of the presence of actinomyces for healthy animals is a limited one. Nevertheless an animal affected with this disease should not be allowed to go at large or run with other animals. If the fungus is being scattered by discharging growths we certainly can not state at this stage of our knowledge that other animals may not be infected by such distribution, and we must a.s.sume, until more positive information is at hand, that this actually occurs.
It is, however, the opinion of the majority of authorities that when actinomycosis appears among a large number of animals they all contract it in the same way from the feed. Much speculation has therefore arisen whether any particular plant or group of plants is the source of the infection and whether any special condition of the soil favors it. Very little positive information is at hand on these questions. It would be very desirable for those who live in localities where this disease is prevalent to make statistical and other observations on the occurrence of the disease with reference to the season of the year, the kind of feed, the nature of the soil (whether swampy or dry, recently reclaimed, or cultivated for a long time) upon which the animals are pastured or upon which the feed is grown.
It is highly probable that such investigations will lead to an understanding of the source of the fungus and the means for checking the spread of the disease itself. Veterinarian Jensen, of Denmark, made some observations upon an extensive outbreak of actinomycosis a number of years ago which led him to infer that the animals were inoculated by eating barley straw harvested from pieces of ground just reclaimed from the sea.
While the animals remained unaffected so long as they pastured on this ground or ate the hay obtained from it, they became diseased after eating the straw of cereals from the same territory. Others have found that cattle grazing upon low pastures along the banks of streams and subject to inundations are more p.r.o.ne to the disease. It has also been observed that feed gathered from such grounds, even after prolonged drying, may give rise to the disease. Actinomycosis is not infrequent in cattle in the Southwest and is generally supposed to be the result of eating the p.r.i.c.kly fruit of the cactus plant, causing wounds of the mucous membrane and subsequent infection with the parasite. Much additional information of a similar kind must be forthcoming before the source and manner of infection in this disease and its dependence upon external conditions will be known. It is not at all improbable that they may vary considerably from place to place.
_Treatment._--Until recently this has been almost entirely surgical. When the tumors are external and attached to soft parts only, an early removal may lead to recovery. This, of course, can be undertaken only by a trained veterinarian, especially as the various parts of the head and neck contain important vessels, nerves, and ducts which should be injured as little as possible in any operation. Unless the tumor is completely removed it will reappear. Disease of the jawbones is at best a very serious matter and treatment is liable to be of no avail.
In March, 1892, an important contribution to our knowledge of this subject was made by Nocard, of the Alfort Veterinary School, in a communication to the French Central Society of Veterinary Medicine. He showed clearly that the actinomycosis of the tongue, a disease which appears to be quite common in Germany, and is there known as "wooden tongue," could be quickly and permanently cured by the administration of iodid of pota.s.sium. Nocard calls attention to the success of Thoma.s.sen, of Utrecht, who recommended this treatment so long ago as 1885, and who has since treated more than 80 cases, all of which have been cured. A French veterinarian, G.o.dbille, has used the same remedy in a number of cases of actinomycosis in the tongue, all of which have been cured. Nocard also gives details of a case which was cured by himself.
All the cases referred to were of actinomycosis of the tongue, and no one appears to have attempted the cure of actinomycosis of the jaw until it was undertaken by Norgaard, of the Bureau of Animal Industry. In April, 1892, he selected a young steer in fair condition which had a tumor on the jaw measuring 15-1/2 inches in circ.u.mference and from which a discharge had already been established. This animal was treated with iodid of pota.s.sium, and the result was a complete cure.
The iodid of pota.s.sium is given in doses of 1-1/2 and 2-1/2 drams once a day, dissolved in water, and administered as a drench. The dose should vary somewhat with the size of the animal and with the effects that are produced. If the dose is sufficiently large signs of iodism appear in the course of a week or 10 days. The skin becomes scurfy, there is weeping from the eyes, catarrh of the nose, and loss of appet.i.te. When these symptoms appear the medicine may be suspended for a few days and afterward resumed in the same dose. The cure requires from three to six weeks" treatment.
Some animals, generally the ones which show no signs of iodism, do not improve under treatment with iodid of pota.s.sium.
If there is no sign of improvement after the animals have been treated four or five weeks, and the medicine has been given in as large doses as appear desirable, it is an indication that the particular animal is not susceptible to the curative effects of the drug, and the treatment may therefore be abandoned.
It is not, however, advisable to administer iodid of pota.s.sium to milch cows, as it will considerably reduce the milk secretion or stop it altogether. Furthermore, a great part of the drug is excreted through the milk, making the milk unfit for use. It should not be given to animals in advanced pregnancy, as there is danger of producing abortion.
The best results are obtained by pushing the drug until its effect is seen.
The many tests to which this treatment has been subjected have proved, with few exceptions, its specific curative value. In addition to this the tumor should be painted externally with either the tincture of iodin or Lugol"s solution, or the drug should be injected subcutaneously into the tumor.
G.o.dbille has given as much as 4 drams of pota.s.sium iodid in one day to a steer, decreasing the dose one-fourth dram each day until the dose was 1-1/4 drams, which was maintained until the twelfth day of treatment, when the animal appeared to be entirely cured.
Nocard gave the first day 1-1/2 drams in one dose to a cow; the second and succeeding days a dose of 1 dram in the morning and evening, in each case before feeding. This treatment was continued for 10 days, when the animal was cured.
_Actinomycosis and the public health._--The interest which is shown concerning this cattle disease is largely due to the fact that the same disease attacks human beings. Its slow progress, its tendency to remain restricted to certain localities, and the absence of any directly contagious properties have thus far not aroused any anxiety in other countries as to its influence on the cattle industry, not even to the point of placing it among the infectious diseases of which statistics are annually published. Its possible bearing on public health has, however, given the disease a place in the public mind which it hardly deserves.
It has already been stated that the actinomyces fungus found in human disease is considered by authorities the same as that occurring in bovine affections. It is therefore of interest to conclude this article with a brief discussion of the disease in man and its relation to actinomycosis in cattle.
In man the location of the disease process corresponds fairly well to that in cattle. The majority of cases which have been reported in different parts of the world--and they are now rather numerous--indicate disease of the face. The skin, tongue, or the jawbones may become affected, and by a very slow process it may extend downward upon the neck and even into the cavity of the chest. In many cases the teeth have been found in a state of more or less advanced decay and ulceration. In a few cases disease of the lungs was observed without coexisting disease of the bones or soft parts of the head. In such cases the fungus must have been inhaled. The disease of the lungs after a time extends upon the chest wall, where it may corrode the ribs and work its way through the muscles and the skin. An abscess is thus formed discharging pus containing actinomyces grains. Disease of the digestive organs caused by this fungus has also been observed in a few instances.
Granting the ident.i.ty of the disease in man and cattle, the question has been raised whether cattle are responsible for its occurrence in man. Any transmission of the infectious agent may be conceived of as taking place during the life of the animal and from the meat after slaughter. That human beings have contracted actinomycosis by coming in contact with diseased cattle is not shown by the cases that have been reported, for the occupations of most of the patients did not bring them into any relation whatever with cattle. While the possibility of such direct transmission is not denied, nevertheless it must be considered as extremely remote.
Practically the same position is maintained at present by most authorities as regards the transmission of the disease to man by eating meat. Israel, who has studied this question carefully, found the disease in Jews who never ate pork,[5] and who likewise were protected from bovine actinomycosis by the rigorous meat inspection practiced by that race.
Furthermore, it must be borne in mind that actinomycosis is a local disease, causing great destruction of tissue where the fungus multiplies, but which very rarely becomes generally disseminated over the body from the original disease focus. The fungus is found only in places where the disease process is manifest to the eye or becomes so in a very short time after the lodgment of the fungus. Only the greatest negligence would allow the actually diseased parts to be sold and consumed. Finally, this parasite, like all others, would be destroyed in the process of cooking.
Most authorities thus do not believe that actinomycosis in man is directly traceable to the disease in animals, but are of the opinion that both man and animals are infected from a third source, which has already been discussed above. How far these views may be modified by further and more telling investigations of the parasite fungus itself no one can predict.
There are still wide gaps in our knowledge, and the presentation above simply summarizes the prevailing views, from which there are dissenters, of course. An attempt to give the views of both sides on this question would necessitate the summarizing and impartial discussion of all the experiments thus far made--a task entirely beyond the scope of the present work.
Whether an animal affected with actinomycosis should be used for human food after all diseased organs and tissues have been thoroughly removed is a question the answer to which depends on a variety of circ.u.mstances. Among these may be mentioned the thoroughness of the meat inspection itself, the extent of the disease, and the general condition of the animal affected.
The Federal meat-inspection regulations require that carca.s.ses of animals showing generalized actinomycosis shall be condemned. If carca.s.ses are in a well-nourished condition, showing uncomplicated localized lesions of actinomycosis, they may be pa.s.sed after the infected organs or parts have been removed and condemned. When the disease of the jaw is slight, strictly localized, and without pus formation, fistulous tracts, or lymph-gland involvement, the tongue, if free from disease, may be pa.s.sed. The heads affected with actinomycosis (lumpy jaw), including the tongue, shall be condemned, except that when the lesions in the jaw are strictly localized and slight in extent, the tongue may be pa.s.sed, if free from disease.
ANTHRAX.
Anthrax or charbon may be defined as an infectious disease which is caused by specific bacteria, known as anthrax bacilli, and which is more or less restricted by conditions of soil and moisture to definite geographical localities. While it is chiefly limited to cattle and sheep, it may be transmitted to goats, horses, cats, and certain kinds of game. Smaller animals, such as mice, rabbits, and guinea pigs, speedily succ.u.mb to inoculation. Dogs and hogs are slightly susceptible, while fowls are practically immune. The variety of domesticated animals which it may attack renders it one of the most dreaded scourges of animal life. It may even attack man. Of this more will be stated further on.
ACTINOMYCOSIS (LUMPY JAW).
DESCRIPTION OF PLATES.
PLATE x.x.xIX. Actinomycosis. (From Johne"s Encyklopadie d. gesammt.
Thierheilkunde.)
Fig. 1. Actinomycosis of the jaw. The lower jawbone has been extensively eaten away by the disease.
Fig. 2. Actinomyces fungus from a tumor of the jawbone in cattle, magnified 550 times.
PLATE XL. Actinomycosis of the jaw. (Reduced one-half. From Johne"s Encyklopadie d. gesammt. Thierheilkunde.) The lower jaw is sawed through transversely, i.e., from right to left, and shows the disease within the jawbone itself; _a_, within the mouth, showing the papillae on the mucous membrane of the cheek; _b_, front view of a molar tooth; _c_, the skin covering the lower surface of the jawbone; _d_, the jawbone hollowed out and enlarged by the formation of cavities within it, which are filled with the soft growth of the actinomycotic tumor. The section makes it appear as if the bone were broken into fragments and these forced apart; _e_, a portion of the tumor which has broken through the bone and the skin and appears as a tumor on the cheek. The little roundish ma.s.ses represent the granulomata (minute tumors) in which the fungus vegetates.
PLATE XLI. Actinomycosis of the lungs.
Fig. 1. Transverse section of the ventral lobe of the right lung, from a case studied in the laboratory. The yellowish dots represent the places where the actinomyces fungus is lodged. The larger yellowish patches are produced by the confluence of a number of isolated centers. The entire lobe is of a dark flesh-red color, due to collapse and bronchopneumonia.
Fig. 2. The cut surface of a portion of the princ.i.p.al lobe of the same lung, showing the recent invasion of antinomycosis from the other lobe: _a_, large air tube; _b_, artery; _c_, a pneumatic lobule; _d_, lobule containing minute yellowish dots. In these the actinomyces fungus is lodged.
Fig. 3. Cut surface of a small portion of another lung, showing a few lobules, _a._ The fungus is sprinkled throughout the lung tissue in the form of yellowish grains, as shown in the ill.u.s.tration. The pleural covering of the lung tissue is shown in profile above.
[Ill.u.s.tration: PLATE x.x.xIX.
Fig. 1 Fig. 2 ACTINOMYCOSIS.]
[Ill.u.s.tration: PLATE XL. ACTINOMYCOSIS OF THE JAW.]
[Ill.u.s.tration: PLATE XLI.
Fig. 1 Fig. 2 Fig. 3 ACTINOMYCOSIS OF THE LUNGS.]
_Cause._--The cause of anthrax is a microscopic organism known as the anthrax bacillus. (See Pl. XXVIII, fig. 7.) In form it is cylindrical or rodlike, measuring 1/5000 to 1/2500 inch in length and 1/25000 inch in diameter. Like all bacteria, these rodlike bodies have the power of indefinite multiplication, and in the bodies of infected animals they produce death by rapidly increasing in numbers and producing substances which poison the body. In the blood they multiply in number by becoming elongated and then dividing into two, each new organism continuing the same process indefinitely. Outside the body, however, they multiply in a different way when under conditions unfavorable to growth. Oval bodies, which are called spores, appear within the rods, and remain alive and capable of germination after years of drying. They also resist heat to a remarkable degree, so that boiling water is necessary to destroy them. The bacilli themselves, on the other hand, show only very little resistance to heat and drying. It has long been known that the anthrax virus thrives best under certain conditions of the soil and on territories subject to floods and inundations. The particular kinds of soil upon which the disease is observed are black, loose, warm, humous soils; also those containing lime, marl, and clay, finally peaty, swampy soils resting upon strata which hold the water, or, in other words, are impervious. Hence fields containing stagnant pools may be the source of infection. The infection may be limited to certain farms, or even to restricted areas on such farms. Even in the Alps, more than 3,000 feet above sea level, where such conditions prevail in secluded valleys, anthrax persists among herds.
Aside from these limitations to specific conditions of the soil, anthrax is a disease of world-wide distribution. It exists in most countries of Europe, in Asia, Africa, Australia, and in our own country in the lower Mississippi Valley, the Gulf States, and in some of the Eastern and Western States. It seems to be gradually spreading in this country and every year occurs in new districts.
Meteorological conditions also have an important share in determining the severity of the disease. On those tracts subject to inundations in spring a very hot, dry summer is liable to cause a severe outbreak. The relation which the bacillus bears to these conditions is not positively known. It may be that during and immediately after inundations or in stagnant water the bacilli find nourishment enough in the water here and there to multiply and produce an abundant crop of spores, which are subsequently carried, in a dry condition, by the winds during the period of drought and disseminated over the vegetation. Animals feeding upon this vegetation may contract the disease if the spores germinate in the body.
Another source of the virus, and one regarded by many authorities as perhaps the most important, is the body of an animal which has died of anthrax. It will be remembered that in such bodies the anthrax bacilli are present in great numbers, and wherever blood or other body fluids are exposed to the air on the surface of the carca.s.s there the formation of spores will go on with great rapidity in the warm season of the year. It will thus be readily understood how this disease may become stationary in a given locality and appear year after year and even grow in severity if the carca.s.ses of animals which have succ.u.mbed to it are not properly disposed of. These carca.s.ses should be buried deeply, so that spore formation may be prevented and no animal have access to them. By exercising this precaution the disease will not be disseminated by flies and other insect pests.
We have thus two agents at work in maintaining the disease in any locality--the soil and meteorological conditions, and the carca.s.ses of animals that have died of the disease. Besides these dangers, which are of immediate consequence to cattle on pastures, the virus may be carried from place to place in hides, hair, wool, hoofs, and horns, and it may be stored in the hay or other fodder from the infected fields and cause an outbreak among stabled animals feeding upon it in winter. In this manner the affection has been introduced into far-distant localities.
_How cattle are infected._--We have seen above that the spores of the anthrax bacilli, which in their functions correspond to the seeds of higher plants and which are the elements that longest resist the unfavorable conditions in the soil, air, and water, are the chief agents of infection.
They may be taken into the body with the feed and produce disease which begins in the intestinal tract, or they may come in contact with scratches, bites, or other wounds of the skin, mouth, and tongue, and produce in these situations swellings or carbuncles. From such swellings the bacilli penetrate into the blood and produce a general disease.