Part 91

Inoculation. The disease has been produced experimentally by inoculation only. Feeding experiments on rabbits, cats and Guinea pigs, the sucking by puppies of an infected dam for 14 days, coitus, and even the careful dropping of infected blood under the eyelid failed to convey it. Lousy rats with sores on face, one cat doubtless scratched by a bone, and one rabbit supposed to be infected by sexual congress (Rouget) offer exceptions, which in the light of the general results must be looked on as probable inoculations through wounds.

Successful inoculations were made with blood, lymph gland, spleen, bone marrow, aqueous humor, serum, œdema fluid, and testicular juice. The effectiveness of inoculation did not vary materially with the different fluids used, with the amount, nor with the point selected for its insertion, subcutaneous, intravenous, intraperitoneal, or on a mere scratch.

Virulence is lost in the dead body in 24 hours or less; when the infected blood is kept aseptically in vitro, in 3 or 4 days at most; or when completely dried. Heating to 122° F. for 30 minutes sterilized, while at 114.8° F. for half an hour the trypanosoma became nonmotile, but not quite non-virulent.

Symptoms. Hyperthermia is marked about the time of the appearance of the infusoria in the blood. (Horse 106.7°; dog 104°; rabbit 105.8°), and in the horse there was a paroxysm with each new swarm of the parasite. In one ass intermissions were not observed. In rabbits there was no constant ratio between the temperature and hæmatozoa, hyperthermia was constant or nearly so. The horse had marked hyperthermia up to death, dogs and cats showed a marked descent even to subnormal, before death.

Anæmia is a marked feature the red globules being greatly reduced, and they show a tendency to clump in masses instead of forming rouleaux. The serum added to healthy blood has the same effect on that. Leucocytosis is not constant nor excessive (15,000 to 34,000 per c.m. at the highest). In clotting the blood may form a buffy coat.

Œdema is common in horse, rabbit, cat and dog especially about the head, legs, belly and genital organs. Rabbits often show swellings, excoriations and sores of the labia, prepuce and penis favoring inoculation by this channel.

Conjunctivitis is common in cats, dogs, rats, rabbits, often in connection with facial œdema, and corneal opacities and ulcers, and turbidity of the aqueous humor may follow.

Nasal catarrh often interferes materially with breathing.

Muscular wasting and debility are prominent phenomena, especially in horse, dog, cat and rabbit, the loss of weight reaching 20 or 30 per cent.

Lesions. These are like those of surra. Enlargement of the lymph glands, spleen and liver, firmness, friability and dark color of the spleen; effusions, petechiæ, and even hæmorrhages of the serosæ, lungs and stomach, and great atrophy of the muscles and adipose tissue are prominent features. The liver is always fatty in rabbits. In the shafts of the long bones, the fat is replaced by red marrow. The bone marrow is sometimes red, at others pale.

The trypanosomata in the blood vary greatly. In infected rats and mice they appear 3 or 4 days after inoculation, are almost constantly present thereafter, and as a rule, encrease steadily up to 2,000,000 or 3,000,000 per c.m. In dogs they appear in 4 to 6 days, in cats in 5, in Guinea pigs in 5 to 7, and in horses in 7 days. In rabbits there were found 60,000 per c.m., in dogs 100,000 to 300,000, and in Guinea pigs 200,000 to 500,000. In one Guinea pig they did not appear until 6 weeks after inoculation and then rapidly encreased to a fatal termination. More commonly a few can be found about a week after inoculation, and then they disappear for a variable period. They have been found in the bone marrow when they could not be recognized in the blood. Again, after subcutaneous flank inoculation in the rat, they were found in the corresponding inguinal glands 1 to 3 days before they could be detected in the blood. After death they are found most abundantly in the bone marrow and spleen, but they have not been found in the intestinal contents nor urine except in the case of hæmorrhages or local sores.

No soluble toxin appears to be formed, and no immunization is effected by the serum. Blood serum kept several days until the infusoria had died and then passed through a Berkefeld filter had no apparent effect on the animal economy even in large doses. Blood heated to 122° F. was equally harmless. The same is true of extracts of organs and of bile from infected animals.

Attempts to secure immunity by injecting the blood serum of affected animals, after it had been sterilized by heat, filtration, or standing one week in vitro proved of absolutely no effect. The blood of the fœtus almost at full term proved valueless, and the young born of infected mothers proved fully susceptible when inoculated. The serum of the Guinea-pig, which is naturally somewhat resistant, proved no protection to other animals. Bile mixed with infecting blood in vitro, kills the trypanosoma, but such blood has no protective effect on animals. Sewer rats and white rats inoculated and re-inoculated with the common rat trypanosoma (T. Lewisi) until immune from that organism, show a full susceptibility to the trypanosoma of nagana.

Flesh feeding and vegetable feeding have made no difference in the susceptibility in the case of rats. Feeding with the hæmatozoa has produced no immunity.

It is evident that prevention must follow the same lines as in Surra, due consideration being had of the greater number of genera susceptible.

LUNG PLAGUE OF CATTLE.

Synonyms. Definition: infectious, cattle fever, with long incubation, insidious onset, excessive pulmonary exudation, infarctions and sequestra. History: ancient, modern; England, Norway, Sweden, Denmark, United States,—its extinction in 1887 to 1892—Massachusetts, New Jersey, S. Africa, Australia, Tasmania, New Zealand. Causes: contagion only. Bacteriology: Nocard’s organism cultivated in collodion capsules in vivo, as actively motile refrangent points, morphology uncertain. Modes of transmission, exhalations from sick inhaled by susceptible, ingestion of infected food, pastures, watering troughs, ponds, commingling of herds, attendants, dealers, stables, manure, unrestricted commerce, convalescent cattle, breed, hot seasons. Lesions: profuse exudation in lymph networks of lungs, marbling, parenchymatous cell proliferation, compression and gangrene of lobulets, thrombi, sequestra, infarction, fibroid sac, or stalactite-like fibroid peribronchial formations, hepatization, pleural effusions and false membranes, pericardial, bronchial, lymph glands congested. Incubation: 6 to 30 days, protracted cases, bearing on quarantine. Symptoms: conditions affecting gravity, breed, excitement, heat, chill, susceptibility, usually insidious, infrequent cough, roused by cold water, dusty food, exertion, etc., hurried breathing when driven, slight auscultation râles, hyperthermia (103° to 108° F.), dulness, anorexia, suppression of milk, stiffness, no pandiculation, troubled breathing, auscultation, and percussion signs of extensive consolidation, tenderness of chest walls, in bad cases stands obstinately, head extended, mouth open, tongue protruded, grunts with expiration, heavy breath, nostrils dilated, nasal and buccal discharge, rapid emaciation, fœtid diarrhœa, erect hair, pale, scurfy, adherent skin, varied chest râles, abortion. Mild in winter, severe in summer. Loss of one-third or one-half weight in one week. Chronic cases, fibroid and necrotic changes, sequestra. Diagnosis: Anamnesis, inoculation: from tuberculosis by high fever, rapid, extensive infiltration, early succession of new cases, failure to react under tuberculin, absence of tubercles; from bronchitis and pulmonary strongylosis, by the succession of cases in place of many at once, the extensive exudation, the evident cause (exposure or infected place), and by the lesions; from fibrinous pneumonia, by absence of climatic cause, the more extensive consolidation, more troubled breathing, and coexistence of old and recent lesions; from infectious pneumonia by the greater area consolidated, more exalted hyperthermia, more marked dyspnœa, the absence of white points of alveolar cell proliferation, and by the old and recent lesions; from septicæmia hæmorrhagica, by its occurrence at all seasons, on all soils, by the absence of sanguineous swellings at other parts, by the absence of cocco-bacillus from the exudate, and by its non-inoculability on sheep, horses, pigs and rodents; from needle in pericardium, by its epizoötic prevalence, fever, and the absence of preliminary gastric and later cardiac, morbid phenomena; from emphysema by the fever, absence of drumlike tympany, and presence of consolidation; from aspergillosis of the lung by the fever, more rapid progress and extended consolidation, by the harmlessness to birds, by the absence of aspergillus from expectoration and lung; from insolation by the absence of the causes of heat stroke, of the implication at once of a number of exposed animals, of the excessive hyperthermia, the brain symptoms and sudden deaths. Treatment: a poor economy, to be punished when extinction is attempted. Prevention: importation under three months quarantine, surveillance of three months more in case of single animals; applied to lung plague countries and those adjoining; disinfect cars and boats that have been used in lung plague country; exclude hay and fodder from lung plague country; also litter, bags, head ropes, horns, hoofs, hides, hair. To extirpate: stop all ingress of possibly infected cattle, stop movement of cattle, prohibit common or unfenced pasturage, kill without indemnity in case of violation, record all cattle, make necropsy of all dead, kill and pay for all infected herds, disinfect all infected premises and things, use horses in removing and plowing under manure. Unaided owner may: breed all his stock, in buying bull quarantine him, allow no intercourse between his herd and others, get new cattle from herds only that have had no illness nor losses for a year, and no exposure, and bring by thoroughly safe route, in disinfected cars or boats, then quarantine, under special attendants. Immunization; by a first attack, inoculation in tail, intravenous, of sterilized exudate. Conditions permitting and forbidding immunization.

Synonyms. Bovine Pleuro-Pneumonia, Contagious Pleuro-Pneumonia, Peripneumonie (Fr.), Lungenseuche Vieseuche (Ger.), Pneumosarcia, Peripneumonia Exudativa, Epizoötic Pleuro-Pneumonia, Pulmonary Murrain, Slijmlongziekte (Dutch), Pulmonea dei Bovina (Ital.), Phush phush pirdaho, Pheepree (Bengalee).

Definition. An infectious febrile disease, occurring casually in cattle only, so far as known, and characterized by a prolonged incubation (10 to 90 days), a tardy insidious onset, inflammation of the bronchia, lungs and pleuræ, a profuse exudation into the interlobular connective tissue and chest, a very extensive area of consolidation, pulmonary infarction, and sequestra.

History. It is difficult or impossible to identify this disease among the various animal plagues in ancient times. Yet when lesions are given it may be admitted in different cases. Aristotle, writing 350 years before Christ says “the cattle that live in herds are subject to a malady which causes the breathing to become hot and frequent. The ears droop and they cannot eat. They die rapidly and the lungs are found spoiled.” Here the facts that cattle alone suffered, that large herds suffered most, that the lungs were the seat of very marked lesions, and that fever and mortality were both marked, point forcibly toward lung plague. Valentini’s description of a fatal lung disease in cattle also stands out prominently in the obscure records. The first full and definite report is that given by Bourgelat of its prevalence in Franche-Compté in 1769. Later the records are frequent and from all over Europe, indicating its general prevalence before as well as after Bourgelat.

Much more important are its definite extensions into new countries after a long interval of immunity as showing that with trustworthy records such invasions can always be satisfactorily accounted for by the introduction of cattle or their fresh products from a previously infected area. Into Holland it was imported from Germany in 1835 by Vanderbosch a Guelderland distiller and spread over the whole country. Attempts were made in Friesland, and at first successfully, to stamp it out by slaughter and disinfection, but the demands of the trade toward England grew so enormously that it was being constantly introduced anew and the measure was abandoned. The British Consul at the Hague, in 1839 sent some Dutch cows to a friend in County Cork, Ireland, which led to the general infection of that island and indirectly of Great Britain. In 1842, under the Free Trade Act, England became at once deluged with lung plague cattle from Holland, Belgium and France on the one side, and Ireland on the other. Soon the whole island had been infected except exclusively breeding districts (Welsh and Scottish Highlands, etc.) into which no cattle were ever introduced from outside.

In 1847 an importation of English cattle into Sweden conveyed the disease, where it prevailed for some time and even infected Denmark through shipments of cattle, but was finally extirpated by the pole axe and disinfectants.

In 1860, Norway imported infected Ayrshire cattle for the Royal Agricultural College at Aas, but the imported and exposed stock were promptly destroyed and the previous immunity of the country has been maintained up to the present.

Denmark was infected in 1848 by importation from Sweden, and on different other occasions from Germany and England, but by prompt and rigid suppressive measures, stamped out the disease on each occasion. This was true also of Schleswig so long as it remained a part of Denmark, but the infection entered in the commisariat parks of the German army in 1864, and the principality remaining in German hands, the lung plague became permanently established.

Mecklenburg-Schwerin and Oldenburg also maintained vigorous suppressive measures and for long kept clear of the infection.

Into Brooklyn, lung plague was introduced in 1843 through the purchase of an English ship cow by a dairyman (Peter Dunn). From this centre the infection spread until it prevailed in Connecticut, New York, New Jersey, Rhode Island, Pennsylvania, Maryland, Virginia, District of Columbia, Ohio, Indiana and Illinois.

In 1879, measures were taken in New York and New Jersey to extirpate the disease but failed to receive the requisite continued support and were practically abandoned. It was only in 1887 when the infection had reached Chicago, the largest cattle market in the world, that the National and State Governments were aroused to the gravity of the danger, and, the Federal Government supplying the funds and the Illinois Government the authority, the beginning of a real attempt at extinction was seriously undertaken. The author acted as chief of the national veterinary force in Illinois in 1887, and takes great pleasure in recording that at the end of three months from the date of his arrival, the last acute case of the disease had been disposed of and the frightful danger that had threatened the nation through the Chicago stock yards had been removed. The supervision was maintained for a year later, and some old sequestra were later found in the lungs of cattle slaughtered, but no acute nor dangerous cases of the disease. This was followed by vigorous suppressive work in other infected states and by September, 1892, the quarantine was raised and the nation pronounced free from lung plague. The last cases were met with in New Jersey, early in 1892. In this last anti-lung-plague crusade the National Government inspected 1,605,721 cattle in 166,951 herds, made 356,404 necropsies, purchased 21,961 head of cattle, and disinfected 4,128 premises. 7,438 cattle were found affected at the necropsy.

Another line of infection was started by 4 Dutch cows, landed at Boston in 1859, and before the end of the year the infection had extended into 20 different townships in Mass. In 1860, a State Commission was created, with Dr. E. F. Thayer as veterinary commissioner, and in the next few years they destroyed 1,164 cattle, and stamped out the plague at a total cost of $77,511.07.