CHAPTER VIII.. Parasites of the Digestive Apparatus.

PARASITES OF THE DIGESTIVE APPARATUS.

Parasites of the digestive apparatus are extremely common in ruminants, some, like the infusoria of the rumen, being of no importance, others, on the contrary, appearing to play a predominating part in the development of certain forms of anæmia and serious wasting diseases, such as the various forms of gastro-intestinal strongylosis, coccidial enteritis, etc.

GASTRO-INTESTINAL STRONGYLOSIS IN SHEEP.

PARASITIC GASTRO-ENTERITIS. OVINE PASTEURELLOSIS.

Verminous diseases of the abomasum are common in the sheep and goat, but (in France at least) appear rare in the ox.

=Causation.= Gastro-intestinal strongylosis is produced by various parasites of the genus Strongylus, such as Strongylus contortus, Strongylus convolutus, Strongylus instabilis, Strongylus circumcinctus, Strongylus filicolis, which occur not only in the abomasum, but also in the small portions of the first intestine, sometimes in very large numbers.

The first is a threadlike worm, pointed at both extremities, and from ½ to 1 inch in length. It exhibits a red tint, which zoologists refer to the presence of blood in its digestive apparatus, derived from the host’s intestinal mucous membrane. Some doubt has been thrown on the nature of this coloration, however; and certain Italian authors, in common with Lignières, have declared it due to a certain red pigment developed in the tissues of the parasite, the spectroscopic reaction of which differs from that of hæmoglobin.

The strongyles are said not to penetrate the mucous membrane, but simply live on the intestinal contents. This may be true of certain varieties, but it is none the less certain that others penetrate the mucous membrane deeply, even to the extent of becoming half-embedded in it. Particularly is this the case with Strongylus circumcinctus, found in the epizooty which occurred at Grignon, and also found by Moussu in grave epizooties which he has from time to time investigated.

According to Lignières this gastro-intestinal strongylosis only plays a trifling part in the development of the above-mentioned disease, which he declares to be due to infection with a cocco-bacillus of the Pasteurella group, the development of which alone, he states, explains all the symptoms.

In France the disease now under consideration has never extended beyond limited regions, but in Argentina, where Lignières carried out his investigations, it is said to be very fatal. Lignières bases his opinion on the following facts:—

Firstly, that experimental verminous infection of young animals does not produce either anæmia or cachexia.

Secondly, that animals in excellent condition may prove to be infested with large numbers of parasites.

Thirdly, that animals which have succumbed to this disease, hitherto regarded as verminous, sometimes prove to harbour few or no parasites.

Fourthly, that this grave and fatal disease, and the symptoms by which it is clinically recognised, can be produced with cultures of the cocco-bacillus, which he has isolated.

These statements are very precise, but Moussu declares that he has never yet been convinced of the reliability of the last statement referring to experimental transmission, any more than of the data regarding alleged protective vaccination.

=The symptoms= of gastro-intestinal strongylosis or ovine pasteurellosis point to a progressive pernicious anæmia of chronic or subacute form. Rapidly progressive cases are exceptional.

In France the form seen is almost invariably chronic. The animals appear dull, sluggish, and feeble; they lose appetite, waste, become anæmic, then cachectic, and, after several months, die of exhaustion and wasting, after having shown diarrhœa during the later stages.

The fæces are pasty, and exhale a very marked putrefactive odour. There is little room to doubt that auto-intoxication from resorption of intestinal products is continually going on.

The animal’s general appearance is bad, the ears are pendant, the wool is dry and dull, and can be removed in handfuls by the slightest pull. There are no other external symptoms, and the diagnosis can only be arrived at by discovering the eggs of the parasite in the fæces.

=Lesions.= Post-mortem examination reveals all the general lesions of advanced cachexia and of gastro-enteritis of varying intensity. The abomasum and first portions of the small intestine usually contain a considerable number of strongyles; tæniae are often present in the intestine, and Moussu declares that he has always found a certain number of hooked worms and œsophagostomes.

The peritoneal, pleuritic, and pericardial exudates common in most wasting conditions are always present, but the quantity of exudate in each cavity varies within wide limits. The liquid may even resemble that due to inflammation or infection; sometimes it is light pink or red in colour.

Pulmonary lesions usually exist. Moussu has almost always found gastric strongylosis associated with pulmonary or tracheo-bronchic strongylosis, but Lignières asserts that the Argentine cases showed nodules of hepatisation which had nothing to do with the pulmonary strongylosis, and which appeared to result from areas of pneumonia produced by the specific cocco-bacillus and other organisms. He has even found abscesses and cavernous spaces in the lung.

=Pathogeny.= According to Lignières the specific agent of pernicious anæmia is a cocco-bacillus which stains well with fuchsin, violet, blue, safranin, etc., but does not take Gram, and which in cultures assumes either the strepto-bacillary form or occurs in barrel-shaped masses. It grows in simple bouillon at 38° C., but better still in peptonised bouillon, which turns turbid for five or six days, afterwards becoming limpid in consequence of the organisms falling to the bottom of the vessel. It does not coagulate milk. On agar the culture is thin, bluish, shows an iridescent reflection, and when old appears whitish. Grown on gelatine, the appearances are similar—the gelatine is not liquefied; on serum the pellicle is scarcely visible.

The organism is said to be pathogenic for guinea-pigs, rabbits, dogs, and, of course, for sheep. Moussu, however, does not consider that the reported cases of transmission through the blood stream or by subcutaneous injection are really convincing or characteristic. He does not question the fact that Lignières discovered a special pathogenic agent in all cases and in all his patients; but what appears to him debatable is the exclusive part which Lignières attributes to that agent.

The fact that in Argentina, just as in France, strongyles have always been discovered in epizootics of this nature of itself constitutes something; and causes the second fact, that it has never yet been proved that any heavy mortality occurred in the absence of parasitic infestation, to assume considerable importance. Moussu regards these two facts as the greatest obstacles to Lignières’ theory. He states that in his view the verminous affection is the essential, primordial and primitive affection, and that microbic infection is only secondary, and an almost inevitable result of grave verminous infestation.

It is quite certainly wrong to think that verminous affections may continue with scarcely any injury to the animal, especially when such a belief is based on observation of a few parasites which are not of a predatory character. In most cases of the kind now under consideration, the various parasites found (Strongylus circumcinctus and filicolis, Anchylostomes, etc.) cause more or less grave lesions.

These intestinal wounds facilitate the infection to which the fatal course of the disease is due. The disease, then, is not a special unvarying infection, but consists of multiple superposed infections.

It is wrong to believe and to teach that the parasitic disease is of no importance, and Moussu declares his belief that the proposed vaccinations will prove unavailing. He is of opinion, on the other hand, that when the parasitic invasion can be overcome the mortality will be checked, and only those animals which are already suffering from severe infections will succumb. Is not this precisely what has been observed in human pathology regarding miners’ anæmia or miners’ worm disease (anchylostomiasis)?

=The diagnosis= presents no difficulty for those who have had a little practice with the microscope, since the presence of eggs of the parasite can always be detected in the fæces in cases where external signs have given rise to suspicion of gastro-entestinal strongylosis.

The macroscopic diagnosis on post-mortem examination is not so easy as might be supposed, and when very small varieties are in question it is sometimes necessary to examine the mucous membrane of the abomasum or intestine very carefully in order to discover the parasite.

=The prognosis= is grave, because before attention has been drawn to many patients, the entire herd may be more or less infested. It is also grave because the pastures are infested with eggs or embryos, and the power of increase of these parasites is enormous.

=Treatment.= The earliest and most energetic means should be adopted in all cases. Treatment comprises:—

Drainage of swampy pastures.

Dressing of the pastures with chemical manures, preferably with iron sulphate, at the rate of 40 to 80 lbs. per acre.

Disinfection of manure to destroy the contained eggs or embryos.

The use of chalk, iron sulphate, various acids, etc.

As regards curative treatment, the diseased animals should be grouped and isolated as far as possible, and should receive doses of the following vermifuge:—

Powdered areca nut 2 ounces. Arsenic 30 grains.

The above is sufficient for ten animals, and a dose should be given daily for a period of six days in a small quantity of bran. Treatment is completed by abundant nourishment, and by distributing about the pastures pieces of rock-salt suitably protected.

Many other vermicides or vermifuges have been suggested, but are less easy to use. They comprise essence of turpentine, mixtures of oil with essence of turpentine and benzine, picrate of potash in doses of 7 to 20 grains per day, ethereal extract of male fern, etc.

LUMBRICOSIS OF CALVES.

Following the example of human medicine, we apply the term “lumbricosis” to a disease caused by ascarides in calves, although Neumann separates the ascarides of calves from the lumbricoid ascarides with which they are usually confused in current practice.

=Causation.= The disease is exclusively due to infestation with embryos of the parasite, which in young calves afterwards develop in the first portions of the intestine and in the abomasum, interfering with secretion, and producing mechanical disturbance, colic, and digestive irregularity, eventually followed by marked loss of condition. Death may even follow, either from rupture of the pylorus or duodenum, or from secondary septicæmia of intestinal origin, due to the parasites burrowing into the mucous membrane and facilitating infection. In adults of all species lumbricosis is rare. It occurs principally in young animals from the time of weaning up to the age of eighteen months or two years.

=The diagnosis= cannot usually be formed until the parasites are found in the fæces, but microscopic examination sometimes reveals the presence of the eggs, and thus excites suspicion.

Provided the condition is diagnosed early, the =prognosis= is not grave; but when patients have become exhausted and anæmic they require a long time to recover, even when freed from parasites.

=Treatment.= Guittard recommends empyreumatic oil as very efficacious, and gives it in doses of 2½ to 3 drachms diluted with ordinary oil, or emulsified with any kind of mucilage.

Calomel gives good results, and maybe administered in doses of 15 to 60 grains, according to the animal’s age and size.

Powdered areca nut would probably be easier to administer with the food. Oil of turpentine is given mixed with ordinary oil, but its action is less certain.

STRONGYLOSIS OF THE ABOMASUM IN THE OX.

Although well studied by Stadelmann and Ostertag in Germany, and by Stiles in America, this disease has not yet been regarded in France as giving rise to accidents.

It is produced by the Strongylus convolutus rel Ostertagi, which becomes embedded under the epithelium of the mucous membrane and causes the formation of small nodules, the size of a pin’s head or lentil, which can be detected on palpation. The cavity thus formed beneath the epithelium communicates with the gastric cavity by a little orifice, through which the cephalic end of the parasite passes.

PARASITIC GASTRO-ENTERITIS, DIARRHŒA, AND ANÆMIA IN CATTLE, SHEEP AND LAMBS.

A disease characterised by anæmia with wasting and diarrhœa is sometimes produced in cattle by the presence in the fourth stomach of small strongyles varying in size between 3 and 9 millimètres in length, according to the variety encountered. One variety of the smaller size has been named by McFadyean Strongylus gracilis. Penberthy, who described the disease in the Jour. of Comp. Path. and Therap. for 1894, p. 249, states that in certain cases he also found the Strongylus ventricosus, the Tricocephalus affiinis, and minute straight worms about ²⁄₂₅ of an inch long, which he regarded as anguillulæ. Neumann declares that pernicious anæmia with catarrh of the abomasum in young animals is due to Strongylus convolutus.

=The symptoms= comprise anæmia, wasting, and diarrhœa of varying severity. In acute cases, which are common between the ages of six months and two years, husk is sometimes (accidentally) present. The disease is rarest in summer. Certain animals lose flesh rapidly, though appetite is retained. Acute fœtid watery diarrhœa follows. The animal shows tenesmus, appears dejected, and has a temperature of 103° to 105° Fahr. The mucous membranes become pale, the pulse small and weak, the appetite capricious, the eyes sunken, belly tucked up, coat harsh and dry and hide tight. Wasting is rapid. The animals are listless, and often lie down for long periods. Death occurs from exhaustion.

=The parasite.= Scrapings from the abomasum and intestine when diluted with water and viewed under a lens show minute bodies resembling short, fine hairs. When isolated these are easily visible with the naked eye. In situ they appear to be lying on the mucous membrane, sometimes with the head fixed in the latter. They vary in length from ³⁄₂₅ to ⁶⁄₂₅ of an inch, and are brownish in colour. For a detailed description see Penberthy loc. cit. McFadyean (Jour. of Comp. Path. and Therap. for 1896, p. 314) also gives a very full description, illustrated by plates, of the two species of strongyles which he regards as the cause of gastritis in cattle in England.

=The lesions= are those of wasting diseases. The first three gastric compartments may be thin, but usually show no abnormality. The mucous membrane of the abomasum shows evidences of catarrh, is sometimes covered with a loose croupous material, or is denuded of its epithelium and even extensively destroyed. In acute cases it is more or less deeply reddened over spots or extensive patches. Occasionally it appears jelly-like, owing to effusion into its substance. Except for the catarrhal condition the small intestines may be healthy, but the large, especially the colon and cæcum, show lesions similar to, but more pronounced than, those of the abomasum.

=The treatment= comprises administration of the usual vermifuges, of which Penberthy prefers turpentine. The diet should be nutritious and easily digestible. Among drugs, non-irritant iron salts, cod liver oil, bitter vegetable tonics and common salt are recommended. The animals should be housed and kept warm; the litter, containing parasites, should be destroyed. The pastures may be dressed with salt and lime; those worst infected should be ploughed. An uninfected water supply is essential.

=Parasitic Gastro-enteritis in Sheep and Lambs.= A disease in seven to eight months old lambs, closely resembling the above, was described by McFadyean in the Jour. of Comp. Path. and Therap. for 1897, p. 48. Sheep over one year old were not affected.

=The symptoms= comprised diarrhœa, rapid wasting, impaired appetite, thirst, a tendency to lick and swallow sand or earth, dulness, and continued fever (105° to 108° Fahr.). There was no evidence of acute pain or of marked cough.

=Duration.= The disease sometimes proved fatal in one or two days, but sometimes extended over several days or weeks. The mortality varied from 10 to 20 per cent., but in many cases almost all the members of a flock exhibited diarrhœa and loss of condition.

=The cause= appeared to be the presence of small nematode worms in the fourth stomach, which generally exhibited gastritis with inflammatory congestion of the mucous membrane, though in a considerable number of cases the lining membrane of the stomach was markedly anæmic. In a large number of cases the irritation of the mucous membrane was continued into the duodenum, but as a rule the remainder of the small intestine was not inflamed.

The worms named by McFadyean Strongylus cervicornis are from 10 to 12 mm. in length, so that although not of microscopic dimensions they cannot be seen when suspended in the stomach contents. They are readily detected in microscopical preparations under a low power.

=The treatment= is similar to that of gastro-enteritis in cattle, but chief attention should be directed to prophylaxis.

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A verminous disease, closely simulating the above, and affecting cattle, sheep, and goats in Texas, is described by Ch. Wardell Stiles in the Annual Report of the United States Department of Agriculture for 1900, p. 356. The disease was of mixed character, and consisted in various degrees of verminous gastritis, verminous enteritis, and verminous bronchitis. In the stomach were found the common twisted wireworm (Strongylus contortus) and Ostertag’s encysted wireworm (Strongylus Ostertagi). It appeared to be present in every calf, steer and cow examined (post-mortem), and was undoubtedly the chief agent in causing death. The sheep and goats were very similarly affected. In the bowel of cattle were found the hookworm (Uncinaria radiata), nodular disease worm (Œsophagostoma columbianum): in that of sheep the hookworm (Uncinaria cernua) and nodular disease worm (Œsophagostoma columbianum), and the fringed tapeworm (Thysanosoma actinioides). In the lungs of the cattle Strongylus micrurus (the small-tailed lungworm), and of sheep the threadworm strongyle (Strongylus filaria) were detected.

=Treatment.= Sulphate of copper, gasoline and coal-tar creosote were tried, but the best results were obtained from doses of 30 grains (for a lamb) up to 100 grains (for a two-year-old sheep) of thymol in 1 per cent. coal-tar creosote solution.

INTESTINAL COCCIDIOSIS OF CALVES AND LAMBS (PSOROSPERMOSIS, HÆMORRHAGIC ENTERITIS, BLOODY FLUX, DYSENTERY, ETC.).

=History.= This disease is very common in the Avalon and surrounding districts, sometimes assumes the characteristics of a true epizootic, and affects young bovine animals between the ages of six months and two years, but is commonest and most contagious in animals of from ten to eighteen months old.

It attacks animals in good or bad condition, without distinction of breed or species. It begins towards the end of July, attains its maximum development towards the end of August and September, and disappears in October, though occasionally it continues until November. In exceptional cases Degoix has seen it during January and February in animals which had returned from the fields to the byres about the end of November. It develops earlier than verminous bronchitis, in conjunction with which, however, it often occurs. It is commonest in warm, moist, rainy years, and amongst animals pastured on swampy ground containing numerous springs and streams. Year after year it attacks animals occupying particular pastures in summer. The soil of these pastures is undoubtedly infested with the germs of the disease, just as in places the soil is infested with anthrax bacilli. The appearance of symptoms is preceded by an incubation period of one or two months. The length of this incubation period is fixed by the observations which Degoix has made during the past twenty years, and depends on the time which elapses between the animals being turned into infected pastures and the appearance of the preliminary symptoms.

=Symptoms.= The disease commences with liquid, serous, fœtid, greenish-black diarrhœa, the material being voided without special straining and the animals losing neither their spirits nor appetite. Fever can scarcely be detected, the temperature ranging between 38° and 39° C. On the second or third day the diarrhœa changes in character. Though it always remains fœtid, it now becomes mucous, reddish-black, or sanguinolent, and contains more or less frequent blood clots of varying size.

The passage of this material causes violent straining, which becomes more and more common, and is accompanied by very pronounced rectal tenesmus. The animals stand with their backs arched for one or two minutes, sometimes longer, and the liquid escapes in large quantities, soiling the quarters and hocks. The animals are dull, show a certain degree of colic, and frequently grind the teeth. Appetite is lost, thirst is severe, and rumination ceases. Wasting makes rapid strides, the coat stares, the animals have difficulty in standing on account of their weakness, fever sets in, and the temperature rises to 40° C. This condition may last from five to ten days and terminate either in recovery or death. Recovery is frequently rapid in animals which have continued to eat, and in which the acute period has been of short duration—five to seven days at most. On the other hand, it is slow if the appetite has disappeared and the acute period has been prolonged beyond ten days.

The diarrhœa, which has lost its sanguinolent character towards the sixth or eighth day, may continue for somewhat longer. The attacks of straining become rare, and cease between the tenth and fifteenth days. The appetite remains capricious for a long time.

Convalescence is marked by alternate improvement and retrogression. The animals are weak, and only recover quickly under energetic treatment and forced feeding with concentrated digestible foods like milk, soup, cooked grain, etc., administered for three weeks or more.

Death may occur towards the tenth or fifteenth day from exhaustion. The patients become very anæmic and thin, the eyes are withdrawn into the orbits, and the animals appear indifferent to what goes on about them. They still groan feebly, occasionally grind the teeth, and lie continually on the chest with the head extended. The body temperature falls and death follows.

In well-bred animals in good condition the disease sometimes assumes a much graver and more rapidly progressive form, with peracute symptoms, and makes as many, if not more, victims than that previously described.

The process is as follows: After suffering for a day from serous diarrhœa, to which the owners pay little attention, the animals show sanguinolent diarrhœa and pass blood clots. This is almost immediately followed by very violent convulsive attacks—true eclampsia. The animals are then unable to stand, lie on the side with the head outstretched and resting on the ground, the eyes withdrawn into the sockets and often showing pirouetting movements (nystagmus), the neck drawn upwards and backwards (opisthotonos), and the limbs rigidly extended. From time to time the whole body is shaken by extremely violent convulsive movements.

This condition, which is sometimes preceded by weakness of the hind quarters and symptoms of locomotor ataxia and inco-ordination, may continue from six to thirty-six hours; in nine cases out of ten it terminates in death.

=Causation.= On microscopic examination of the serous dejections one finds distributed throughout the liquid mass very small numbers of ovoid corpuscles having a double outline, and contents of varied appearance; these are the coccidia.

When the diarrhœa has become sanguinolent and muco-fibrinous, the fluid contains these coccidia in considerable quantities, and large numbers of them may be found in the mucus, where they are mixed with epithelial débris, blood corpuscles, and lymphatic cells, etc. They are rarer in the clots. Coccidia cannot be found in the fæces of healthy animals, even in those occupying the same pastures with the diseased. Should the clinical symptoms be thought insufficient of themselves clearly to identify the disease, a simple microscopic examination of the fæces will remove any doubt.

=Lesions.= Post-mortem examination immediately after death enables one exactly to identify the habitat of the parasite and the lesions it produces. These lesions are to be found throughout the large intestine, from the cæcum to the anus.

The large intestine is almost or entirely empty, the mucous membrane is reddish-brown in colour, lies in folds, is œdematous, and everywhere covered with a coating of mucus. This coating varies in character at different points; in places it forms more or less thickened patches of greyish or yellowish colour, and of a resistant character, as though mixed with coagulated fibrin. These patches are fairly well defined, they are irregular in form, and vary in width from some millimètres up to several centimètres. They are more or less adherent to the mucous membrane, from which they can easily be stripped away. The mucous membrane thus exposed is slightly depressed, and of a whitish colour, thus markedly contrasting with the surrounding red coloration. This depression represents a slight ulceration, which, though superficial, is clearly visible to the naked eye.

Microscopic examination of the mucus patches reveals the existence, both superficially and in the depths, of epithelial cells derived from the mucous membrane, of vesicular cells derived from the Lieberkuhnian follicles, of numerous blood and lymphatic corpuscles, and, distributed irregularly throughout this mass of cells, of coccidia, resembling those found in the dejections.

In thin sections of the intestine, made through the ulcerated mucus-covered patches, and in a direction perpendicular to the mucous membrane, one finds that the epithelial covering of the intestine has disappeared.

The Lieberkuhn’s follicles are shortened, their orifices are irregular and partly blocked with epithelial débris. In a large number of these follicles the blind extremity is dilated, and more or less filled with coccidia, varying in appearance according to their stage of development. The epithelial cells normally lining these blind ends seem to have disappeared, and to have been replaced by the parasites. This, however, is not really the case. It is easy to prove by suitable dissection (after maceration of the sections in 30 per cent. alcohol) that the coccidia are lodged in epithelial cells which have become modified in shape and undergone hypertrophy as the parasite has grown, whilst the nucleus has been pushed to one end and undergone atrophy.

Alongside the deceased glands may be found others which are quite healthy. In the parts which are most markedly affected the interglandular connective tissue is infiltrated and slightly thickened. Degoix has never discovered coccidia in the cells of the intestinal mucous membrane itself. The lesions may be met with throughout the large intestine, but are more numerous and grave as the rectum is approached.

This disease is characterised by extensive inflammation, affecting the entire mucous membrane of the large intestine, by more or less extensive ulceration of this bowel, the ulcers being covered with muco-fibrinous patches rich in coccidia, by localisation of the parasites in the epithelial cells of the glandular cul-de-sac, by the appearance of the disease at a special time of year and in special districts, where it assumes the form of an enzooty, and by the fact that it always appears in the same pastures. The mortality varies between 12 and 25 per cent. from year to year.

=Microscopic appearances.= The protozoa which produce this disease assume the form of ovoid cysts, varying in length from 18 to 25 µ, and measuring at the widest part about 13 µ. They possess a hyaline envelope whose existence is proved by its double contour line, and yellowish, granular, highly refractile contents. This granular material does not always occupy the whole of the cavity. At a certain stage of development it collects towards the centre, forming a nucleus and leaving clear spaces at the poles of the cell. At a later stage this nucleus divides into four portions which afterwards separate.

=Treatment.= The protozoa, in their cystic condition, are very resistant to destructive influences. The most common natural cause of their destruction is drying in the open air. Unfortunately, in the localities where the patients usually live, that is, filthy byres, wet pasturages, etc., this destruction only takes place to a very limited extent.

The disease can be attacked by prophylactic and therapeutic measures.

Prophylaxis consists—firstly, in destroying the parasites contained in the dejections by the free use of 3 per cent. sulphuric acid solution; and, secondly, in removing the young animals from infected fields during the months between June and September.

Therapeutic treatment comprises—firstly, stimulant applications to the abdomen; secondly, disinfection of the intestine by the administration of salol, benzo-naphthol, very diluted solutions of creolin, etc.; thirdly, intestinal irrigation by the administration of mucilaginous drinks containing bicarbonate of soda, supplemented by general tonic treatment and the supply of concentrated, very nourishing, and easily digested food (Degoix, Revue générale de Médecine Vétérinaire, No. 28, February 15th, 1904, p. 177).

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McFadyean describes a similar disease to the above in two to three months old lambs (Jour. of Comp. Path. and Therap., March, 1896, p. 31). The mortality reached 10 per cent. The lambs at the time the disease broke out in the flock were closely folded together with the ewes on growing roots, which, needless to say, were much soiled with earth and fæces before they were completely consumed.

INTESTINAL HELMINTHIASIS IN RUMINANTS (Ox, Sheep, Goat).

Verminous disease of the intestine is often accompanied by similar disease of the stomach (gastro-intestinal strongylosis of the sheep, lumbricosis of the calf), but it also occurs apart from the presence of gastric parasites. Parasites are more frequent in the intestine than in the abomasum, because the alkaline intestinal juices prove a much more favourable medium for their development than do the acid juices of the stomach.

The actual parasites may include ascarides, strongyles, hooked worms, œsophagostomes, tricocephales, sclerostomes, and various tæniæ (Tænia expansa et alba). Many of these have already been, or will hereafter be, referred to.

Helminthiasis due to round worms like strongyles, and the various forms of hooked worm, is graver than that due to flat worms, but most extraordinarily varied collections are sometimes met with. Speaking generally, however, helminthiasis more particularly affects young animals like calves, lambs, and yearling sheep, is rarer in adults, and in all cases the complications it produces are of trifling importance in adults as compared with those caused in the young.

The persistence of verminous diseases in certain infested countries, districts, farms, or pastures is explained by the enormous number of eggs or embryos passed with the fæces and disseminated with manure, as well as by the high degree of resistance of the eggs and embryos to destructive influences.

=Causation.= The various forms of intestinal helminthiasis are all due to embryos or eggs of worms obtaining entrance to the stomach or bowels of susceptible animals. Nevertheless, external conditions largely favour infestation. The existence of marshes, ponds, and stagnant water on certain pastures, heavy annual rainfall, the occurrence of wet seasons, etc., favour the existence and growth of embryos, and, as a consequence, the infestation of animals.

=The symptoms= of intestinal helminthiasis are always very vague, whether the victims be oxen, sheep, or goats. They point to the slow and progressive development of a pernicious anæmia, characterised primarily by interference with appetite and digestion, then by anæmia, and finally by cachexia. The patients are dull, lose condition, suffer from depraved appetite, and, during the cachectic period, from diarrhœa, and die in a condition of exhaustion. These forms of helminthiasis are much more frequent in sheep than in oxen.

=The diagnosis= is only arrived at by discovering parasites in the fæces, or, in those doubtful cases where one has been led to make a microscopic examination of the excrement, by the detection of large numbers of eggs.

From an economic standpoint the =prognosis= is grave, because severely infected animals recover their condition very slowly, whatever treatment be adopted.

=Treatment= includes the measures previously indicated regarding the destruction of germs, eggs, or embryos distributed over the pastures, and the drainage of wet grounds and stagnant pools. Where such diseases are common, the pastures should be dressed with iron sulphate, and the stable manure disinfected or burned.

Curative treatment comprises the administration of such anthelmintics as can be given with the food. They should not require to be administered by force, as this proceeding would not only necessitate a great loss of time, but might result in accidents.

Arsenious acid, in doses of 15 grains per day, and tartar emetic, in doses of 75 to 150 grains, according to the animal’s size, are among the best drugs for oxen, and may be given for four or five days running. Benzine, oil of turpentine, and empyreumatic oil are more difficult to administer.

In the case of sheep, preference should be given to areca nut, in doses of 75 to 120 grains, according to the animal’s size, and to tansy, which are convenient to give, and can be added to bran, oats, or beetroot.

Adult tapeworms of oxen are of relatively minor importance, but one tapeworm of sheep, viz., the fringed tapeworm (Thysanosoma actinioides), also known as Tænia fimbriata; Moniezia fimbriata deserves notice, as at times it forms a veritable scourge to the sheep industry of North America and South America.

=Disease.= The disease in sheep caused by the fringed tapeworm has been studied in detail by Curtice, who considers that next to scab it is the most important sheep disease of the western plains of North America. The financial loss it causes is extensive, and results from the failure of the lambs to fatten, the small crop of wool, and the weakening of the animals, so that they cannot withstand cold winter weather. The parasites develop slowly, and are present in considerable numbers before their presence is suspected. Toward September the lambs fail to grow as they should; in November the symptoms are marked. First, the worms produce local irritation of the intestine, which finally develops into a chronic catarrhal inflammation; their presence in the gall-ducts produces similar results, and obstructs the flow of bile; infected lambs are large-headed, under-sized, and hidebound; their gait is rheumatic, and they appear more erratic than the other sheep, standing oftener to stamp at the sheep dogs or herds, and lagging behind the flock when driven; the general symptoms are those of malnutrition, and Curtice considers them nearly identical with the symptoms of the “loco” disease; in fact, he states that it is extremely difficult to distinguish between the two diseases, and believes that the fact that the worms “may tend to produce depraved appetites and a morbid craze for a particular food is also reason for suspecting that the loco disease may depend on the tapeworm disease.” General systemic disturbances result from malnutrition; the usual fat is absent; serous effusions are noticed in the body cavities, serous infiltration in the connective tissue.

=Treatment= is similar to that of parasitic gastro-enteritis of sheep and lambs (which see).